Review Projects – 2013 Big Idea 3 Mr. Bennett

Review Projects – 2013 Big Idea 3 Mr. Bennett

LO 3.1: The student is able to construct scientific explanations that use the structures and mechanisms of DNA and RNA to support the claim that DNA and, in some cases, that RNA are the primary sources of heritable information. SP 6.5: The student can evaluate alternative scientific explanations. Explanation:Genes, which are units of heritable information are found on chromosomes at specific loci that Gregor Mendel had through his laws of segregation and independent assortment, with the experiment with pea plants. The order of the nucleotide chains create the specific genes that will code for certain proteins that will be expressed as a phenotype. Historical experiences have also supported the claim that DNA is the genetic material for inheritance. T.H. Morgan showed that genes are located on chromosomes, with DNA and proteins as components of the chromosomes, by studying bacteria and viruses. Hershey and Chase physically experimented with radioactive dyes and successfully concluded that DNA was the genetic material. The DNA strand is a double helix that is made up of four nucleotides adenine, guanine, thymine, and cytosine, deoxyribose sugar, and a phosphate group. The viruses store their entire genomes in the form of RNA, instead of DNA, which can conclude that RNA can be a primary source of heritable information. Therefore, genes will be passed on from generation to generation. M.C. Question:Which dyed-chemical would help recognize that DNA is the primary sources of heritable information, basing your prediction on the Hershey and Chase Experiment? A) Nitrogen B) Sulfur C) Phosphorus D) A and C E) A, B, and C Learning Log Question/Free Response: 1) Compare and contrast the structures of DNA and RNA. 2) How are genes expressed? If there was a point mutation on the DNA, how would it be affected?

LO 3.2: The student is able to justify the selection of data from historical investigations that support the claim that DNA is the source of heritable information.SP 4.1: The student can justify the selection of the kind of data needed to answer a particular scientific question. Explanation: While it was known that some molecule existed that transferred genetic information, scientists even sixty years ago were not sure what molecule caused this. In the 1950’s scientists Alfred Hershey and Martha Chase were able to prove which molecule was that of inheritance. Using bacteriophages, a virus made up of just DNA and proteins, yet still known to be able to transform other cells, they made an experiment, for which they grew two batches of phages. One in a mixture with radioactive sulfur, and the other in a mixture with radioactive phosphorus. Sulfur is only used in proteins and phosphorus in DNA. In two tests they transformed bacteria with each of the different radioactively tagged batches. After transformation each mixture was centrifuged which brings the heavy cells down to the pellet and leaves everything else in the supernatant. In the radioactive protein batch the supernatant was radioactive but the transformed cells were not, meaning the proteins did not enter the cells. However in the radioactive DNA batch the supernatant was not radioactive but the transformed cells were, meaning DNA entered the transformed cells. When the results of these two tests are combined, it supports the claim that DNA is the molecule of inheritance. Multiple Choice Question:Assume the setup of the experiment is the same, with the proteins tagged with radioactive sulfur and DNA tagged with radioactive phosphorus, and the bacteriophages only have time to inject into cells, not lyse them. If bacteriophages infected cells by inserting their entire construction (proteins and DNA) into the target bacteria rather than just the molecule of inheritance, but only the molecule of inheritance transforms it, the Hershey Chase experiment: I: Would always produce a radioactive pellet II: Show radioactive molecules in all areas of the mixture after it is centrifuged III: Still would support that DNA is the molecule of inheritance IV: Have inconclusive results as to the molecule of inheritance A) I B) I & III C) II & III D) I & IV E) II & IV Free Response Question:In a repeat of their experiment, to save money, Hershey and Chase chose to mark the DNA and protein with radioactive carbon, rather than purchasing radioactive sulfur for the proteins and radioactive phosphorous for the DNA, and grew the bacteriophages for both batches in the same environment. What results concerning the supernatant and pellet would this trial yield and why? What would this suggest about which substance is the molecule of inheritance?

LO 3.3 The student is able to describe representations and models that illustrate how genetic information is copied for transmission between generations. SP 1.2 The student can describe representations and models of natural or man-made phenomena and systems in the domain. Explanation: Meiosis is the cell process responsible for creating haploid gametes used for organisms to reproduce and pass their genetic information onto their offspring. While normal cell divisions create two identical daughter cells with a 2n number of chromosomes, Meiosis generates four unique haploid (n chromosomes) gametes which are used solely for reproduction. In order to do this, Meiosis goes through two phases and undergoes two series of cell divisions. Also, other phenomena unique to Meiosis such as crossing over and random assortment help to create genetic variation of gametes and in turn offspring, which is one of the driving forces of evolution within populations. M.C. Question: Which of the following stages of Meiosis is NOT responsible for a source of genetic variation? A) Prophase I B) Metaphase I C) Anaphase I D) Fertilization E) None of the Above Learning Log/FRQ-style Question: Identify TWO of the processes in sexual reproduction that result in genetic variation and explain how each contributes to this.

LO 3.4: The student is able to describe representations and models illustrating how genetic information is translated into polypeptides. SP 1.2: The student can describe representations and models of natural or man-made phenomena and systems in the domain. Explanation: Translating DNA into polypeptides is a 2 step process. The DNA is transcribed to RNA, and the RNA is translated into polypeptides. RNA polymerase moves from the 5’ to 3’ direction, unzipping the double helix, while adding complimentary bases (except for uracil, which replaces thymine). The RNA is then refined, introns are cut away as exons are spliced by the spliceosome and a 5’ cap and poly-A tail are added to reduce the chance of degradation. Once ejected from the nucleus to the cytoplasm, the mRNA enters the ribosome, where tRNA brings over individual amino acids, whose anticodons from complimentary pairs with the mRNA. As the mRNA moves through the ribosome, polypeptides are added to the previous to extend the chain. • M.C. Question: Why is the third anticodon usually irrelevant in the process of translation? • All anti codons have the same third anticodon • B) The proofreading mechanism of eukaryotic cells uses the third • anticodon as an reference point for checking the rest of the • polypeptide • C) The anticodon sits on a kink in the tRNA, therefore the third • anticodon doesn’t usually make complete contact • D) Because tRNA carries 2 anticodons, not one. Learning Log/FRQ-style Question: 3’- …ATGTCTCGTGTTCTCTGA…-5’ is a strand of DNA whose complimentary strand has been transcribed into mRNA and then translated into a polypeptide chain. A) What is the complimentary strand? B) What is the mRNA transcription? C) What is the polypeptide chain? Use the table provided (on the next page.) What would happen to the polypeptide if there were a point mutation that changed the given DNA strand to 3’-… ATGTCTCGTGTTCTCTTA…-5’?

Humans have developed various genetic engineering methods that give us the ability to manipulate heritable information. The most basic form of DNA manipulation can be seen through the use of restriction enzymes and plasmids. Restriction enzymes are utilized for their ability to cut DNA at specific places, leaving a “sticky end.” When “sticky ends” of different DNA join together, recombinant DNA is formed. Plasmids, small rings of bacterial DNA, are used as vessels for recombinant DNA to reach a cell in which it can be replicated. Another example of technology that gives humans the ability to observe and manipulate genetic information is PCR. Polymerase chain reaction technology is used to amplify sections of DNA in order to determine the nucleotide sequences. Explanation Learning Objective 3.5 Science Practice 6.4 The student can make claims and predictions about natural phenomena based on scientific theories and models. • The student can justify the claim that humans can manipulate heritable information by identifying at least two commonly used technologies. M.C. Question Which of the following statements concerning PCR is false? A) Copies can be synthesized from even a microgram of DNA. B) PCR can produce about 1,000 DNA copies, after that, enzymes necessary to carry out the process denature. C) A stable DNA polymerase is required. D) Ligase does not splice the “sticky ends” of DNA cut by restriction enzymes. Learning Log/ FRQ- style Question Scientists have observed that a certain a certain worm swells in size in response to heat. A) How could they determine which gene codes for the change in size? B) Explain how bacteria can be altered to make genetically engineered products.

Explanation: Gene expression is regulated by the transcription and translation of an organism’s genetic material. The sequence of DNA or RNA nucleotides determined what amino acids will be produced, and ultimately what proteins will be formed. These proteins are what determine how a certain gene will be expressed. Change in the genetic material will lead to a change in amino acid sequence, then a change in protein, and ultimately a change in expression. There are several ways that the nucleotide sequence of the genetic material can be affected. Frameshift mutations result when the number of nucleotides is changed, and the entire sequence is “shifted”. Both deletions and insertions of specific bases can lead to these types of changes. The sequence of the nucleotides can also be changed without shifting the nucleotides, for example in the case of a base-pair substitution. The number of bases remains the same, but the “correct” base is replaced by a different nucleotide. This can code for the wrong amino acid, change the shape of the protein, and change gene expression. http://evolution.berkeley.edu/evosite/evo101/images/dna-mutation.gif LO 3.6 The student can predict how a change in a specific DNA or RNA sequence can result in change in gene expression. SP 6.4 The student can make claims and predictions about natural phenomena based on scientific theories and models. • FR Question: • The process of transcription utilizes a specific enzyme. • Identify the enzyme and compare it to a similar enzyme used in DNA replication. • Describe why the use of this enzyme might lead to mutations in DNA. • Identify and explain two mutations in genetic material that might arise due to specific qualities of this enzyme, and describe their possible effects on gene expression. • MC Question: • AUGUCAUAG AUGUGAUAG • What is the effect of the previous change in DNA sequence? • No effect • One amino acid will be duplicated, but the overall protein will not be affected • Because one base pair was deleted, a frameshift mutation will occur causing a nonsense mutation, and the protein will not be synthesized • The base-pair substitution will cause the transcription to be terminated early, altering the number of amino acids in the protein and changing overall protein structure

LO 3.7: The student can make predictions about natural phenomena occurring during the cell cycle. SP 6.4: The student can make claims and predictions about natural phenomena based on scientific theories and models. Explanation: The cell cycle is a series of stages that are regulated by checkpoints. Checkpoints are also called internal controls. Checkpoints are internal and external stop-and-go signals such as maturation promoting factors. The cell cycle is controlled by cyclins and cyclin-dependent kinases. During the first stage of the cell cycle, interphase, cell growth, DNA synthesis, and preparation for mitosis occurs. Mitosis, which alternates with interphase, occurs after DNA replication. Mitosis consists of four stages: prophase, metaphase, anaphase, and telophase. During prophase, chromosomes turn into two-strand chromatids, the nuclear membrane disappears, and spindle fibers begin to form. During metaphase, the chromosomes align at the equatorial plate (center) of the cell and each of the chromosomes attaches to a spindle fiber. The chromosomes split in half into sister chromatids, which then separate and ascend to opposite poles of the cell during anaphase. During telophase, cleavage of the cellular membrane occurs and the nuclear membrane reappears. Cytokinesis ultimately produces two genetically identical daughter cells at the end of mitosis that are both diploid (2n), like the parent cell. Another type of cell division, meiosis is followed by fertilization, which ensures genetic variation. Meiosis follows the same stages as mitosis, except all of the phases occur twice, resulting in four haploid (n) daughter cells. The genetic variation in meiosis comes from a process called crossing-over in which homologous chromosomes exchange genetic material. Fertilization fuses two gametes, which increases genetic variation as well as restores the diploid amount of chromosomes so meiosis can occur again. • M.C. Question: Embryonic cells in humans cycle rapidly. This rapid occurrence of cell cycling is controlled by cyclin concentration and maturation promoting factor (MPF) activity. What is the effect of cyclin concentration on MPF activity? • As cyclin concentration increases, MPF switches itself off and destroys its own cyclin. • As cyclin concentration increases, cyclins associate with Cdk molecules and the MPF complex initiates mitosis. • As cyclin concentration decreases, the MPF will cause phosphorylation of various proteins of the nuclear lamina. • As cyclin concentration decreases, enough molecules of MPF are produced to pass the G2 phase checkpoint. • Cyclin concentration has no effect on MPF activity. Learning Log/FRQ-Styled Question: A fern and a bird seem to be showing signs of similar types of disease. In order to get a better idea of how quickly the disease is multiplying, biologists observe the cell cycle of both the fern and the bird. They do this by observing how often cytokinesis, the final division of a cell into two daughter cells, occurs. The figure to the right shows two types of cells undergoing cytokinesis. Identify which cell is an animal cell and which cell is a plant cell. How do you know this? Compare and contrast cytokinesis in animal cells and plant cells. http://images.tutorvista.com/content/cell-reproduction/meiosis-and-mitosis-comparison.gif

LO 3.8: The student can describe the events that occur in the cell cycle. SP 1.2: The student can describe representations and models of natural or man-made phenomena and systems in the domain. Explanation: The time a cell spends dividing (mitosis followed by cytokinesis) takes up only a small fraction of the cell cycle. The about 90% of a cell’s existence is spent in interphase in which a cell grows and copies its chromosomes in preparation for the mitotic phase. Interphase is made of G1 phase (“first gap”), S phase (“synthesis”), and G2 phase (“second gap”). During all three sub phases of interphase the cell grows and produces proteins and cytoplasmic organelles; however, DNA is only synthesized in the S phase. A cyclically operating set of cyclin-dependent kinase molecules in the cell strictly regulates checkpoints in the cell cycle between sub phases and prevent the cell from growing and dividing out of control. If, for example, at the G2 checkpoint there is not enough cyclin present, MPF will not be activated and the cell will not enter the mitotic phase. The cell cycle is both culminated and began in the mitotic phase which consists of prophase, metaphase, anaphase, telophase, and cytokinesis. The mitotic spindle is a key part of the cell cycle, especially cell division. The mitotic spindle assembles proteins into spindle fibers, beginning at the centrosome, that connect to the kinetochore of chromosomes and pull them apart in anaphase. Cell division is completed after either a cleavage furrow forms in an animal cell or a cell plate forms in a plant cell. M.C. Question: A culture of mammalian cells normally grows in one even layer on a substratum. The cells receive DNA from a virus that prevents density-dependent inhibition, but the cells do not grow and divide out of control. This is because the cells began apoptosis in response to the virus exhibit anchorage dependence produce MPF in response to the new DNA have undergone metastasis have too much cyclin Learning Log/FRQ-style Question: Suppose give a tissue sample a drug that prevents degradation of cyclin. Explain why the cell grows and divides out of control. What would cause this in a natural environment? Explain the roll of metastasis in determining how much of a threat a tumor poses to the life of an organism. Why?

LO 3.9: The student is able to construct an explanation, using visual representations or narratives, as to how DNA in chromosomes is transmitted to the next generation via mitosis, or meiosis followed by fertilization. SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices. Explanation: Most single celled organisms reproduce asexually through mitosis. The cell replicates its DNA in the s phase of interphase, which produces two copies of the parent cell’s DNA. During the M phase, the cell goes through the phases of mitosis, transforming a single cell with two sets of DNA into two daughter cells that are genetically identical to the parent cell. Most multicellular organisms reproduce sexually through meiosis. The cell replicates its DNA in the S phase of interphase, which, like mitosis, produces two identical copies of the parent cell’s DNA. The chromosomes condense and line up at the metaphase plate with homologous chromosomes next to each other. The chromosomes then perform crossing over, which switches a piece of one chromosome with a homologous piece of the other to produce recombinant chromosomes. The homologous chromosomes then separate into two daughter cells, with a haploid set of replicated chromosomes. The chromosomes of the two separate cells line up at the metaphase plate, and the sister chromatids separate and form four haploid gametes, all genetically different from each other. When fertilization occurs, the two gametes from the two parent organisms fuse to produce a new diploid cell that is genetically different from each parent, and contains half of each parents’ DNA. Multiple Choice Question: In what order do these steps occur ? • Sister chromatids separate • Homologous chromosomes separate • DNA replicates • Crossing over occurs • Tetrads are positioned at the metaphase plate • 3, 5, 4, 2, 1 • 3, 5, 4, 1, 2 • 3, 1, 4, 2, 5 • 3, 4, 5, 2, 1 • 3, 4, 5, 1, 2 FRQ Question: Explain three ways in which meiosis contributes to genetic diversity within a species.

LO 3.10 The student is able to represent the connection between meiosis and increased genetic diversity necessary for evolution. SP 7.1 The student can connect phenomena and models across spatial and temporal scales. Explanation: In meiosis, independent assortment, crossing over, and random fertilization ensure the genetic variation. Independent assortment is when each homologous pair of chromosomes independently paired with other chromosomes and this process take place throughout both meiosis I and II. Another factor is crossing over, segments of non-sister chromatids from the break point joint with other chromatid allowing new combinations of maternal and paternal genes that occurs in meiosis I. Lastly, random combination of chromosomes pair up with 1 of the 8.4 million chromosomes. The random combination and independent assortment also meant that some traits link together as transmitted from parents to the offspring, such as diseases. One single male and female are able to produce a zygote with about sixty four million of diploid combinations. Combining crossing over, meiosis contributes diversity of unique individuals that are most suited to their environment can reproduce offspring and transmitting the favored genes. • M.C. Question: What is the importance of crossing over? • It provide extra genetic materials for daughter cells. • It increases the likelihood that daughter cells contain different genetic material. • It produces the protein that associated with DNA in chromosomes. • It separate homologous chromosomes. Learning Log/FRQ-style Question: Explain how meiosis contribute to reproduction of the fittest. If meiosis takes place in eukaryotic cells and crossing over was not present, how would genetic diversity be affected?

LO 3.12 The student is able to construct a representation that connects the process of meiosis to the passage of traits from parent to offspring. SP 1.1 The student can create representations and models of natural or man-made phenomena and systems in the domain SP 7.2 The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring understandings and/or big ideas. Explanation: Sexual reproduction is the union of male and female gametes to form a fertilized egg, or zygote. The resulting offspring inherit one half of their traits from each parent. Adults are diploid, signified as 2N, having two alleles available to code for one trait. The gametes must be haploid, signified by N, containing only one allele; so that when two haploid gametes combine, they produce a normal diploid individual. The process where haploid sex cells are created from diploid parents is called meiosis. In meiosis, the cell goes through 2 phases, where in both, the chromosomes align in the center of the cell, spindle fibers attach, the chromosomes separate and then the two separate sides divide. However, not all offspring from one reproducing pair are identical, so there must be reasons for the genetic diversity experienced during the passage of traits from parents to offspring. Sometimes, neighboring non-sister chromatid absorbs the new piece of chromatid into the chromosome and releases the corresponding piece to be absorbed by the first chromosome in a process called crossing over. Nondisjunction may also occur when the spindle fibers may not attach to a chromosome, overloading one cell while leaving the other with less chromosomes. This could result in Kleinfelters and Turners syndrome in the offspring. Though the changes may sometimes come down to a mutation which causes some genes to either be translocated, inserted, inverted or deleted, which may result in a unique passage of traits to offspring. M.C. Question: Which of the following is not true about the process of Meiosis? A)Spindle fibers are made of microtubules, which extend from the chromosomes and attach to the outside of the cell. B)In Metaphase, the chromosomes align in the center of the cell. C)There are two phases to Meiosis. D) Adults only have 2 possible alleles able to be coded for any one trait. Learning Log: Explain why “inheritable variation” drives Darwin’s Theory of Evolution.

LO 3.13: The student is able to pose questions about ethical, social or medical issues surrounding human genetic disorders. SP 3.1: The student is able to explain the causes of genetic disorders and identify ways that genetic disorders can lead to controversy. Explanation: Genetic disorders are caused by chromosomal changes in sexual reproduction that lead to the development of a human being who is hindered by the disorder. For example, Trisomy 21—a.k.a Down Syndrome– is a genetic disorder caused by an extra 21st chromosome; these individuals are more susceptive to medical issues. Women who are older are more susceptible to having children with Down Syndrome. Reproduction issues such as these lead families to seek help in prevention methods such as genetic testing, gene alteration, or even abortion. Ideas such as these create ethical and social issues about what is right and wrong, and how people are viewed in the eyes of others. M.C. Question: Nondisjunction in sexual reproduction is caused by all of the following EXCEPT: A. When a pair of homologous chromosomes fail to move apart properly B. When an error in meiosis II occurs C. When an inactive Bar Body in a zygote becomes active, taking the place of the Y chromosome D. When one gamete receives two of the same type of chromosome and another receives no copy E. Both A and C Learning Log/FRQ-style Question: Genetic disorders bring up many controversial topics. Explain why Sickle Cell Anemia is a genetic disorder and what are the symptoms of the disorder. What reproductive issues does this genetic disorder cause? What social, ethical, and medical issues does Sickle Cell Anemia pose?

LO 3.14: The student is able to apply mathematical routines to determine Mendelian patterns of inheritance provided by data sets.SP 2.2: The student can apply mathematical routines to quantities that describe natural phenomena. Explanation: Meiosis creates haploid (n) gametes that unite to produce a diploid (2n) zygote. Meiosis creates genetic variation through the independent assortment of chromosomes (metaphase 1), crossing over (prophase 1), and random fertilization. There are 8 million unique sperm and 8 million unique egg; therefore, there are 64 trillion possible combinations that could be produced through meiosis, each combination forming a unique children with different genotypes, and therefore, different phenotypes. Using the rule of multiplication and the rule of addition, we can calculate the probability that 2 parents will create an offspring with a specified genotype. For example, the rule of multiplication says that in a Mendelian cross between pea plants that are heterozygous for flower color (PpxPp), the probability of the offspring being homozygous recessive is 1/4 because the probability that an egg from the F1 generation will receive a p allele is 1/2, and the probability that a sperm from the F1 generation will receive a p allele is 1/2, and 1/2 x 1/2 = 1/4. Using the rule of addition, we can calculate the probability of the offspring being heterozygous from a Mendelian cross between pea plants that are heterozygous for flower color (PpxPp) is 1/2. The dominant allele could be in the sperm and the recessive allele in the egg, or vice versa; therefore, the probability that the offspring will be heterozygous is the sum of these two possibilities. The probability that the dominant allele will be in the egg with the recessive allele in the sperm is 1/2 x 1/2 = 1/4. The probability that the dominant allele will be in the sperm with the recessive allele in the egg is 1/2 x1/2 = 1/4. The sum of these two probabilities is 1/2.M.C. Question: Huntington’s disease is caused by a dominantallele. If one of your parents is heterozygous (Dd) and has the disease and the other is homozygous recessive (dd), what is the probability that you will not have the disease?a) 1b) 3/4c) 1/2 d) 1/4e) 0Learning Log/FRQ-Style Question: Two characteristics that Mendel studied were stem length (tall=T, short=t) and seed shape (R=round, r=wrinkled). If two plants that are heterozygousfor both traits (TtRr x TtRr), what proportion of the offspring would be expected in the following situations:a) homozygous dominant for both traits (TTRR)b) homozygous recessive for both traits (ttrr)c) heterozygous (TtRr)d) homozygous dominant for stem length and heterozygous for seed shape

LO 3.15: The student is able to explain deviations from Mendel’s model of the inheritance of traits SP 6.5: The student can use representations and models to communicate scientific phenomena and solve scientific problems Explanation: Through his study of pea plants at the monastery he called home, Mendell became the father of genetics by breeding his pea plants and tracking patterns to find how an organisms genotype effects its phenotype. Through his findings we have the Punnett Square, the concepts of Dominate Genes, Recessive Genes, Sex Linked Genes Homozygous Dominant Genotypes, Homozygous Recessive Genotypes, Heterozygous Genotypes, Incomplete Dominance, and Co-dominance. M.C. Question: If two heterozygous pink flowers (Red x White) produce offspring, what are the odds of them creating two red flowers? A) 1/4 B) 1/16 C) 1/2 D) 1/8 Learning Log/FRQ-style Question: Explain how a cows pelt expresses incomplete dominance. Also draw and label a Punnett Square that shows a cross between a heterozygous cow and a homozygous black cow.(Assume W = white and B= black).

LO 3.16 The Student is able to explain how the inheritance patterns of many traits cannot be accounted for by Mendelian genetics.SP 6.3 The student can articulate the reasons that scientific explanations and theories are refined or replaced. Explanation: While Mendel’s laws provide a simple model by which to study and observe genetics, they are often times too simple to predict more complex patterns. Mendel’s laws assume that each trait is determined by one pair of alleles, which is usually not the case. In many instances, there genotypes and phenotypes have complicated relationships and the basic principles of independent assortment and segregation do not apply. Since Mendel’s discoveries, further experiments have revealed that phenotype and genotype are influenced by a variety of factors other than one gene, including multiple alleles, autosomal linkage, sex-linked inheritance, polygenic inheritance, and environmental factors. M.C. Question: In which of the following situations would Mendel’s laws accurately predict offspring genotypes and phenotypes? A) The determining of blood type by multiple alleles B) Flower color based on dominance between two alleles at one locus C) A plant whose flower color is influenced by soil acidity D) A rat’s fur color derived from two genes Learning Log/ FRQ Style Question: Mendel’s ideas are correct in theory, but not universal. Upon discovering a new species of plant in which flower color varied, how could it be determined if the trait could be accounted for by Mendelian genetics or if different patterns applied?

LO 3.17 The student is able to describe representations of an appropriate example of inheritance patterns that cannot be explained by Mendel’s model of the inheritance of traits. SP 1.2 The student can describe representations and models of natural or man-made phenomena and systems in the domain. Explanation: In genetics Mendel’s Laws of inheritance do not always explain why the phenotypic ratios are statistically different from what is predicted. Sometimes there are genes that are not completely dominant or recessive; there is codominance and incomplete dominance. In codominance the alleles for a gene both have an equal affect on the phenotype expressed in different ways . In incomplete dominance the alleles for a gene matched together form a phenotype that falls between the extremes of the two for example, consider the snapdragon that has pink and white flowers, when a red and white flower reproduce they may create pink flowers. Also some traits are determined by genes found on the sex chromosomes. The sex-liked genes reside on X chromosomes because the Y chromosome is too small to carries very few genes. Most of ten the sex linked traits are recessive which is why they are most commonly expressed in males sine they have only on X chromosome. Some traits that are also acquired result from nonnuclear inheritance such as for the mitochondria and chloroplast. Both of these organelles are randomly assorted into gametes and daughter cells during meiosis and fertilization there fore the do not adhere to Mendelian rules. Also in animals for example the mitochondrial DNA is transmitted via egg instead of sperm, therefore traits determined by the mitochondria are maternally inherited. Punnett square diagrams are useful to better visualize and understand how genetic alleles are transferred. Multiple Choice Question: Using the figure to the right, which of the following are being expressed phenotypically by the set of alleles in the punnett square with the letters BW? Incomplete dominance Codominance Complete dominance Recessive trait • FRQ-Style Question: • Many phenotypes cannot be explained by Mendel’s Laws of inheritance. There are several phenotypic traits that are established based on other rules • Explain the pattern of inheritance that allows for there to be people born with blood type AB and list four parent blood type combinations that could result in an offspring with the AB blood type. • Colorblindness is a genetic disorder commonly found among men. It is rare to find a color blind woman. • Explain the genetic basis of how the gene causing colorblindness is transmitted . • Explain why mostly men are colorblind and why it is rare to find colorblind women.

LO 3.18: The student is able to describe the connection between the regulation of gene expression and observed differences between different kinds of organisms. SP 7.1 :The student can connect phenomena and models across spatial and temporal scales. Explanation: Cells in a multicellular organism come from the differences in gene expression. These differences happen during development as regulatory mechanisms turn specific genes on and off. It is supported that almost all cells of an organism have genetic equivalence. Whether or not these genes are expressed is determined by activation. Gene activation is based on cell signaling path involving cell molecules used in cell-cell communication and the membrane receptors that recognize them. A cell’s structure and function is given by observable cell-differentiation is the appearance of mRna’s on the tissue specific proteins that give the cell its characteristic. The patter of gene expression in a differentiated cell is controlled at the level of transcription. At this point transcription factors control the flow of genetic info from DNA to mRNA. Transcription factors do this function by allowing (activator) or blocking (repressor) the gathering of RNA polymerase to specific genes. Homeotic genes ( Hox Genes) are genes showed in most eukaryotic organisms, plants, and prokaryotes. The homeobox-encoded domain is the part of a protein that binds to DNA when the protein functions as a transcriptional regulator. Domains in these proteins determine which genes are regulated. Interactions of these latter domains with other transcriptional factors helps a homeo-domain containing protein recognize the transcription of developmental genes switching them on and off. M.C Question: Both unicellular and multicellular organisms must turn genes on and off continually in response to the signals given off from their internal and external environments, during the development of a multicellular organism which process must the organism go through so that each cell receives its proper characteristic and function? Transcriptional Regulation Differentiation Cell Communication Variation FRQ: The outcome of determination is marked by the expression of genes for tissue-specific proteins. These proteins are only found is certain cell types and give the cell its characteristic and function. The first evidence of differentiation is the appearance of mRNAs for these proteins. This usually happens at the level of transcription. Why do you suppose transcription is an important part in gene expression?

LO 3.19: The student is able to describe the connection between the regulation of gene expression and observed differences between individuals in a population. Growth factor One strand of each short double- stranded RNA is degraded; the other strand (miRNA) then associates with a complex of proteins. The miRNA-protein complex prevents gene expression either by degrading the target mRNA or by blocking its translation. The bound miRNA can base-pair with any target mRNA that contains the complementary sequence. 1 3 2 3 1 2 4 5 MUTATION Hyperactive Ras protein (product of oncogene) issues signals on its own Ras G protein 1 GTP 2 3 4 5 1 2 An enzyme called Dicer moves along the double- stranded RNA, cutting it into shorter segments. The micro- RNA (miRNA) precursor folds back on itself, held together by hydrogen bonds. 3 Ras p p p GTP p p p 4 Protein kinases (phosphorylation cascade) Chromatin changes 5 Receptor Transcription NUCLEUS Transcription factor (activator) RNA processing DNA Gene expression mRNA degradation Translation Protein that stimulates the cell cycle Protein complex Protein processing and degradation Protein kinases Defective or missing transcription factor, such as p53, cannot activate transcription MUTATION 1 Dicer 2 Degradation of mRNA OR 3 UV light Active form of p53 . DNA damage in genome miRNA DNA Target mRNA Protein that inhibits the cell cycle Hydrogen bond Blockage of translation EFFECTS OF MUTATIONS , Protein overexpressed Protein absent Cell cycle not inhibited Cell cycle overstimulated Increased cell division SP 7.1: The student can connect phenomena and models across spatial and temporal scales. Explanation: Gene expression controls cell products which determine the metabolism, nature and specialization of a cell. Most gene expression is regulated, which leads to more efficient energy usage. This involves promoters, terminators and enhancers to regulate gene expression. An example of a gene regulatory system is inducible and repressible regulatory systems, like operons in bacteria. In eukaryotes, gene regulation and expression uses more complex regulatory molecules, like cell-to-cell interactions and signaling to control gene expression. An example of this is hormones influencing cell metabolism. This gene regulation causes phenotypic differences between organisms with similar genes, which plays out in population genetics. • M.C. Question: In eukaryotes, many genes may have to interact with each • other, requiring more interacting elements than can fit around a single • promoter. This physical limitation is overcome by: • alternating promoters and operators • placing promoters on both sides of each gene • the use of very long promoters • distant sites in a chromosome controlling transcription • of a gene • E) having factors on one chromosome control genes on • another gene Learning Log/FRQ-style Question: What are the differences between gene expression that can be regulated in eukaryotic cells and in prokaryotic cells? Why? What is a control point in gene expression? How can gene expression be applied to a population? Draw and label this hypothetical situation in a eukaryotic cell.

LO 3.20 The student is able to explain how the regulation of gene expression is essential for the processes and structures that support efficient cell function. • SP 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices. • Explanation: Gene expression is process by which DNA directs protein synthesis. DNA changes to RNA to protein. There are two stages: transcription and translation. Each stage has three steps: Initiation, Elongation, and Termination. In transcription during Initiation the RNA polymerase binds to the promoter. DNA strands unwind and the polymerase initiates RNA synthesis. Then in Elongation the polymerase unwinds the DNA and adds a 3' to the ends. In Termination the RNA transcript is released and the polymerase detaches from the DNA. Translation is the change in language in the cell because the cell must translate the base sequence of an mRNA molecule to the amino acid sequence. This occurs in the ribosomes. • M.C. Question: Which of the following is false of gene expression? • A. The poly-A tail helps ribosomes attach to the 5' end of the mRNA • B. The TATA box is a promoter DNA sequence crucial in forming the transcription initiation complex • C. tRNA molecules transfer rRNA codon into a particular amino acid • D. The enzyme aminoacyl-tRNAsynthetase joins each amino acid to the tRNA • E. Template strand provides the template for ordering the sequence of nucleotides in an RNA transcript • Learning Log/FRQ-style Question: Explain the elongation cycle of translation. What is the role of the hydrolysis of GTP in this process?

LO 3.21: The student can use representation to describe how gene regulation influences cell products and function. SP 1.4: The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively. Explanation: Genes are not able to control an organism by themselves and so they must work with environmental elements of the organism. Certain genes are constantly “on” regardless of the environment and are responsible for DNA to replicate, express, and repair. They also contribute to protein synthesis & central metabolism function. Gene expression is the process that a gene uses to produce the gene product which is an RNA molecule or a protein. Gene regulation is the alteration of stages in gene expression resulting in the control of which genes are switched on or off and to what extent the genes are expressed. This regulation can occur in the following stages: Transcription, RNA transport, Translation, mRNA degradation. For example, a regulator gene codes for a repressor protein that will then bind to an operator gene; this causes the prevention of enzyme production because the gene is turned off. However, when the enzyme is needed again the repressor can be inhibited and so the gene will be turned on to produce that specific enzyme. M.C. Question: Which of the following is incorrect focusing on eukaryotic gene regulation? A)Enhancers are common B) Rely on small-protein molecule binding C)There is no operon used D)Primarily uses positive control (+) E)Uses methylation, acetylation, & barr bodies Learning Log/FRQ-style Question: Focusing on gene regulation, how do cells differentiate to synthesize different molecules? What do these synthesized molecules control? How does this affect expression?

LO 3.22 The student is able to explain how signal pathways mediate gene expression including how this process can affect protein production. SP 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices. Explanation : Cell signaling can occur through paracrine signaling (local communication), or endocrine signaling (communication through the blood stream). There are three steps to cell communication: reception, transduction, and the response. First, a signal molecule binds to a receptor protein: G-Protein-Linked receptor, Tyrosine Kinases, or ion channels. The signal transduction pathway occurs during the transduction step of cell communication. The pathway works as a domino effect where the activated receptor activates another protein, which releases another molecule that activates another protein and so on. Protein kinase is the enzyme that phosphorylates and activates the other proteins. The addition of a phosphate group from ATP to an inactive protein will activate that protein. Protein kinase is very important in regulating cell reproduction, and any abnormalities can lead to abnormal growth and cancer. Non-protein water-soluble molecules, called second messengers, play a role in carrying signal messages to parts of the body. These include cAMP, IP3, calcium ions and DAG. The response of cell communication is what activates a gene expression. After transduction, the last kinase enters the nucleus and activates a gene-regulating protein, a transcription factor. This protein stimulates a specific gene so that an mRNA is synthesized, which then directs the synthesis of a particular protein in the cytoplasm. M.C. Question: All of the following correctly describe the role of protein kinases, except? • Protein kinases regulate cell reproduction and growth. • Protein kinases transfer a phosphate group from ATP to a protein. • Protein kinase plays the largest role in the transduction step of cell communication D. Protein kinasesdephosphorylate another protein. FRQ Second messengers also play an important role in the signal transduction pathway. Describe the physical structure of second messengers and name two examples. Describe the role second messengers play in the signal pathway.

LO 3.23: The student can use representations to describe mechanisms of the regulation of gene expression. SP 1.4: The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively. Explanation: Gene expression regulation is the control of regulated genes being turned on and off by specific molecules. This process differs between prokaryotes and eukaryotes. Representations of these processes require knowledge of their functions. Among prokaryotic cells, regulatory proteins usually turn genes off. The cells rely on a protein ligand binding system. The regulatory proteins include repressors and activators. Repressor proteins occupy the operator region and block the action of RNA polymerase while activator proteins assist the attachment of RNA polymerase to the promoter region where RNA polymerase attaches to begin transcription. The promoter region, operator region, and the structural gene--genes that contain DNA sequences that code for enzymes directing production, all make up an operon. Two examples of these operons are the lac operon- which controls the breakdown of lactose. This operon is said to produce inducible enzymes since a substance (lactose) is required to turn it on. The trp operon (figure below) produces enzymes for the synthesis of tryptophan. These genes stop producing enzymes in the presence of the repressor therefore they are repressible enzymes. In Eukaryotic cells, these regulatory proteins are also used and operate similarily by influencing how readily RNA polymerase will attach to a promoter region. Nucleosome packing also influences whether a section of DNA will be transcribed. DNA segments are tightly packed by methylation (addition of methyl groups) of histones, making transcription more difficult. In contrast, acetylation of histones allows uncoiling and transcription of specific regions. All of this is regulating gene expression through the transcription of only selected genes. Fig 19.3 (campbell reece 7) Learning Log/FRQ-style Question: Describe how gene regulation occurs in bacteria cells through the operon theory. MC: Transcription of the structural genes in an inducible operon A) Always happens. B) begins when the pathway's substrate is present. C) starts when the pathway's product is present. D) stops when the pathway's product is present. E) doesn’t happen at all. Figure 18.21 (campbell reece 7)

Learning Objective 3.24: The student is able to predict how a change in genotype, when expressed as a phenotype, provides variation that can be subject to natural selection. Science Practice 6.2: The student can make claims and predictions about natural phenomena based on scientific theories and models. Science Practice 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring understandings and/or big ideas. Explanation: Genetic information is necessary for reproduction, survival and growth of all living organisms. The genetic information is processed by the cell which then results in a physical expression (phenotype). The processes are imperfect and random errors can occur which can alter the phenotype. Correct errors can be heritable and evolve. Genetic variations at the genome level, when expressed as phenotypes, are subject to natural selection. Which eventually leads to the evolution of species. Multiple choice Question: During the evolutionary process, which of the following is the correct sequence of events? A.)Change in phenotype—change in genotype—speciation—selection B.)Speciation—change in genotype—selection—change in phenotype C.) Speciation—selection—change in phenotype—change in genotype D.) Change in genotype—change in phenotype—selection—speciation E.)Selection—speciation—change in phenotype—change in genotype Explain how a mutation in genotype expressed in the phenotype can lead to a trait favored by natural selection. Give three example of organisms or mechanisms that are favored by natural selection.

LO 3.25: The Student can create a visual representation to illustrate how changes in a DNA nucleotide sequence can result in a change in the polypeptide produced. SP 1.1: The student can create representations and models of natural or man-made phenomena and systems in the domain. Explanation: Alterations in a DNA sequence can lead to changes in the type or amount of the protein produced and the consequent phenotype. DNA mutations can be positive, negative or neutral based on the effect or the lack of effect they have on the resulting nucleic acid or protein and the phenotypes that are conferred by the protein. The three types of DNA mutations are frameshift, substitution, deletion, and insertion. By changing the nucleotide sequence, it therefore changes the anticodon and possibly the protein that is coded for. Changes in these genotypes, may result in changes in phenotypes. Genetic changes that enhance survival and reproduction can be selected by environmental conditions. DNA mutations is one of the primary sources for genetic diversity. • M.C. Question: If the sequence CAGGAGUUAAAG were mutated by the deletion of the first “A” in the sequence, what would be the new amino acid sequence? • ArgSer Stop • Arg Lys Ser • Tyr ArgAsn • Tyr Pro Stop Learning Log/ FRQ: Explain how a mutation to the marked base in the DNA sequence AAGUCACAG would effect the amino acid sequence and the polypeptide created. Draw a diagram to help you answer the question. a. Frameshift Mutation b. Point Mutation

Explanation: Living systems store, retrieve, transmit, and respond to information essential to life processes. This essential information is usually stored in the form of the genetic material known as DNA. When genetic information changes, either through natural processes (such as errors in replication, decoding and transfer of the information or genetic engineering, the results may be observable changes in the organism. Genetic variations at the genome level, when expressed as phenotypes, are subject to natural selection. Since all organisms, as well as viruses, exist in a dynamic environment, mechanisms that increase genetic variation are vital for a species’ ability to adapt to a changing environment. For example, although bacteria divide by binary fission and do not have the random assortment processes that occur in eukaryotic organisms, bacterial genetic information can be transmitted through conjugation, transduction and transformation. LO 3.26: The student is able to explain the connection between genetic variations in organisms and phenotypic variations in populations. M.C. Question: Errors in which of the following processes can lead to an altered phenotype? Transcription mRNA processing Translation All of the above SP 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring understandings and/or big ideas. Learning Log/ FRQ question: Name and describe 3 mechanisms that can introduce genetic variation in a population of bacteria.

LO 3.27: The student is able to compare and contrast processes by which genetic variation is produced and maintained in organisms from multiple domains.SP 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring understandings and/or big ideas.Explanation: Through DNA replication and repair different mutations occur, which increases genetic variation. Processes in prokaryotes such as transformation, transduction, transposition, and conjugation increase genetic variation. Transformation is the uptake of external DNA by a cell, transduction is when a phage transfers bacterial DNA, and conjugation incorporates genes from other bacteria through direct transfer of genetic material trough a pili. Transposition increases genetic variation because DNA segments known as transposons move around the genome and can sometimes leave behind mutations or cause mutations by inserting a gene. However, in eukaryotes, independent assortment , random fertilization, and crossing over increase genetic variation. Independent assortment allows allele pairs to separate independently during the formation of gametes and gives two equally probable arrangements of chromosomes in metaphase I. Random fertilization increases genetic variation because it states that the probability that any one sperm will fertilize any particular egg is about 64 trillion. Lastly crossing over is the exchange of segments between homologous chromosomes and it increases genetic variation because only “pieces” of the chromosome are exchanged between the homologous chromosomes.M.C. Question: What is a similarity between genetic variation in bacteria and in eukaryotes?A) Both contain only one copy of the genome (haploid)B) Both have plasmidsC) Both do crossing overD) Both do asexual recombinationE) None of these are correctFRQ-style Question: Describe the following thee types of genetic variation.Crossing OverIndependent AssortmentRandom fertilizationFor each of the two types of genetic variation that you choose,a. describe the process and how it increases genetic variationb. Explain why no two people can look exactly alike.

LO 3.28: The student is able to construct an explanation of the multiple processes that increase variation within ad population. SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices. Explanation:Meiosis can create genetic variation three ways: independent assortment, crossing over, and random fertilization. At metaphase I, the homologous pairs(1 maternal and 1 paternal chromosome), are situated on the metaphase plate. The homologous pairs can orient with its maternal or paternal. This orientations is random as flipping a coin; therefore there is a 50% chance that the daughter cell will get the maternal chromosome and 50% change for the paternal. Due to how the homologous pair of chromosomes is positioned independently of the other pairs at metaphase I, the first division will cause in each pair sorting the maternal/paternal homologues into daughter cells independently of every other pair. This is independent assortment. Crossing over on the other hand, begins in prophase I. The DNA molecules of two non-sister chromatids are broken at the exact same place and consequently are rejoined to each other’s DNA. In result, the two homologous segment will cross over producing chromosomes with new combinations of maternal and paternal genes. Furthermore, random fertilization adds to the genetic variation. The union of a male gamete with a female gamete during fertilization will produce a zygote with an estimation of 70 trillion diploid combinations. Genetic variation contributes to evolution due to natural selection. M.C. Question: Which of the following statements concerning about independent assortment is true? • It happens during prophase I. • It happens during metaphase I. • The homologous pairs, consist of one maternal and one paternal chromosome. • A and C are correct. • B and C are correct. Learning Log/FRQ-style Question: Order independent assortment, crossing over and random fertilization in sequential order. Explain each one thoroughly by telling how it contributes to genetic variation within a population. http://www.bristol.k12.ct.us/page.cfm?p=7096

LO 3.29 The student is able to construct an explanation of how viruses introduce genetic variation in host organisms. [See SP 6.2] • SP 6.2 The student can construct explanations of phenomena based on evidence produced through scientific practices. • Explanation: Viruses employ their hosts for reproduction purposes, injecting viral DNA or RNA into the host (e.g. a bacterium) and subsequently causing the machinery of the cell to produce more viruses. The lysogenic cycle includes a dormancy, in which the viral genetic information is incorporated into the bacterium’s DNA. The lysogenic cycle’s counterpart is the lytic cycle, in which RNA is transcribed and many viruses are then produced, resulting in the destruction of the cell. General transduction is another way that genetic information can be exchanged and variation increased due to the accidental uptake of bacterial DNA into the self-assembling phages. Proviruses from the retrovirus called HIV will use reverse transcriptase to produce DNA from RNA and then incorporate that genetic material (a provirus) into the cell’s genome. The provirus never leaves, leading to permanent changes in the cell (or organism)’s genome. The rapid reproduction and lack of proofreading in bacteria can lead to the spreading of viral mutations and further changes to such genes. • Learning Log Question: Why are viruses the primary agent for gene therapy, and how is this possible? Use an example of an important experiment to support your answer. Additionally, explain why the location of this practice in reference to the body is important. • Multiple Choice Question: Viruses may alter the genetics of host organisms through all of the following EXCEPT: • A) the lysogenic cycle of viral reproduction • B) the lytic cycle of viral production • C) Transduction of DNA from bacterium to bacterium • D) Provirus incorporation of viral DNA (synthesized from RNA) into the host cell’s DNA • E) None of the above

LO 3.30: The student is able to use representations and appropriate models to describe how viral replication introduces genetic variation in the viral population. SP 1.4: The students can use representations and models to analyze situations or solve problems qualitatively and quantitatively. Explanation: Viruses use genetic variation mainly through mutations and recombination. For mutations, RNA have unusually high rates, because of errors replicating their RNA genomes, that are not corrected by proofreading. Recombination also occurs in viruses and it enables a virus to pick up genetic information from viruses of the same type and sometimes from unrelated viruses or even the host genome. Viruses replicate via a component assembly model allowing one virus to produce many progeny simultaneously via the lytic cycle. Viruses have high efficient reproductive rates. Mutations occur through usual host pathways. There is also rapid evolution of virus with in the post. All of this allows the viral population to constantly be adapting. Multiple Choice: The flu is wide spread and you had it and gave it to your best friend. You have the memory cells for when you recover. So why did you get the flu again in a year? A) The memory cells have died and so the flu can attack the immune system again. B) A new strain has been formed through mutation because of no proof reading with reverse transcriptase. C) A new strain has been formed through mutation because of DNA polymerase with no proof reading. D) When your body came in contact with the flu again, the flu cells produced faster than the memory cells could replicate. Free Response: a) Describe two types of mutations that can take place in a viruses genetic code. b) If a scientist discovers a substance that affects the HIV infected cell shown to the right and gives it the ability to proofread, how would that affect the genetic variation of the HIV infected cells? Why?

LO 3.31: The student is able to describe basic chemical processes for cell communication shared across evolutionary lines of descent SP 7.2: The student can connect concepts in and across domain(s) to generalize or extrapolate in and/or across enduring understandings and/or big ideas.. Explanation: Cell communication allows for cells to carry out necessary processes, and allow for the organism to survive and function properly. Cell communication allows for chemical signals to be sent without physical contact. When one step of cell communication goes wrong, the consequence is normally detrimental. Cell communication has three steps reception, transduction, and the response. During reception a chemical signal is sent and binds to a protein either inside the cell or on the outer surface. This then causes a change in the receptor and transduction begins. Since the receptor changes shape it causes relay molecules to be sent and produce a series of changes in different molecules along the signal transduction pathway. This triggers the response which causes the cell to carry out a specific cellular activity. Cell communication is a product of evolution and is shared across evolutionary lines of descent. Evolution has favored certain traits, such as second messengers. They allow for a quicker response and can activate more than one target cell causing the response to be amplified. This evolutionary benefit explains why second messengers are present in both plant and animal cell communication. • M.C. Question: A scientist is conducting a field study on the effects of a new kind of soil on Alternantheraphiloxeroides, commonly known as Alligator weed. The soil is supposed to amplify the effects of auxin, in a beneficial way, to the Alligator weed. Which of the following are not related to auxin? • Polar Transport • Apical Meristem • Proton Pumps • Promotes germination of seeds • Promotes double fertilization Learning Log/FRQ-style Question: i) Plants and animals both evolved from single cell organisms, such as archaebacteria and eubacteria. Describe the difference between archaebacteria and eubacteria. ii) With evolution came cell communication, but even as time has passed the molecular processes of cell communication has remained the same in both plants and animals. Describe how plants and animals carry out cell communication. iii) The figure to the right, Figure 39.4, shows the process of de-etiolation in plants. The plant has been sprayed, therefore exposed, to a harmful pesticide that binds to the second messenger. What effect would this pesticide cause in the de-etiolation process? Figure 39.4

LO 3.33: The student is able to use representations and appropriate models to describe features of a cell signaling pathway. SP 1.4: The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively. Explanation: An example of cell signaling is the hormone signaling pathway of adrenaline, or epinephrine, in muscle cells. Epinephrine is excreted from specialized cells into the bloodstream, which it travels down until it arrives at a muscle cell. At the specific receptor cell, the hormone binds to a specific receptor protein, the G protein receptor. The activated epinephrine receptor exchanges an inactive GDP molecule with an active GTP. This activated G protein will in turn activate adenylyl cyclase (enzyme), which will activate the formation of cyclic AMP from ATP. This cAMP carries the signal through the plasma membrane of a muscle cell. The activation of the cAMP causes the activation of a protein kinase. This enzyme begins the transduction pathway, a phosphorylation cascade—one protein kinase phosphorylates another, until one activates a protein that produces a cellular response—that ultimately causes a cellular response. Adrenaline can cause an increase in blood glucose levels in the muscles, can increase mental awareness, among various other things. • Multiple Choice Question: The cAMP in cell signaling pathways acts as a(n) ________, which activates the _______________. • Enzyme, Cellular Response • 2nd Messenger, Protein Kinase A • Receptor, G-Protein • 1st Messenger, Receptor Protein Discussion Question: Why is a phosphorylation cascade necessary to activate the response in a cell signaling pathway? Why can protein kinase A not activate the response protein? What is a real world example of this?

LO 3.34: The student is able to construct explanations of cell communication through cell-to-cell direct contact or through chemical signaling. SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices. • M.C Question: Which of the following is not a way that immune cells interact? • Killer T-cells • Antigen-presenting cells • Helper T-cells • Neurotransmitters • Cell-to-cell contact Explanation: Cell communication can be done a few different ways including communicating over short distances and long distances. Cells that communicate short distances use local regulators which target certain cells in the area of the cell of the cell giving off the signal. When signals travel long distances, like in blood, the signal is released to target cells of another cell. Local, short distance signaling includes paracrine signaling (secreting cell) and synaptic signaling (nerve cell). Long distance communication includes hormonal signaling. Reception, Transduction, and Response are the three stages of cell signaling. It begins with the detection of a signal and ends with a cellular response. Learning Log/ FRQ-style Question: a. Explain the three stages of cell signaling. b. Chose two of the following and explain what cell is involved, and where the signaling takes place. i. paracrine signaling ii. synaptic signaling iii. hormonal signaling http://beauchemin.wikispaces.com/cell_communication

LO 3.35: The student is able to create representation(s) that depict how cell-to-cell communication occurs by direct contact or from a distance through chemical signaling. SP 1.1: The student can create representations and models of natural or man-made phenomena and systems in the domain. Explanation: Ways in which cells can communicate by direct contact are seen in the immune system with antigen presenting cells and t-cells, as well as the plasmodesmata that connects plant cells through holes in the cell wall (as well as tight junctions, gap junctions, and desmosomes). Cells can also communicate over short distances through regulator cells that go directly to neighboring cells. Examples include neurotransmitters and plant immune response. Cells can also be involved with long distance communication through pathways such as hormones in the endocrine system like insulin and testosterone. This communication typically triggers secondary responses inside a cell after initial binding of a chemical signal (ligand) to the surface of a cell’s membrane and cause communication within the cell with secondary messengers such as: cAMP, calcium ions, and IP3. Multiple Choice: Select the correct pathways of a hormone: I. Adenlylycyclase is activated II. Hormone binds to receptor III. Signal is transmitted IV. Extreme sudden stress V. G-Protein activated VI . cAMP activated VII. Epinephrine released by adrenal glands VIII. Protein binds to a second messenger that travels to the nucleus A) IV, VII, II, VI, I, V, VIII, III B) II, IV, VII, V, VI, III, I C) IV, VII, II, V, I, VI, VIII, III D) IV, VII, II, V, I, VI, III E) VI, IV, II, III, VII, V, I FRQ- Question: For each type of cell listed describe the pathway of communication and provide an illustration of the pathway for one of the examples. a) Neuron-Neuron b) Hormone- target cell c) Plant Cell- Plant Cell

LO 3.36~ The student is able to describe a model that expresses the key elements of signal transduction pathways by which a signal is converted to a cellular response. SP 1.5~ The student can reexpress key elements of natural phenomena across multiple representations in the domain. Explanation~ The three parts of cell communication are reception, transduction, and response. Reception begins with a ligand (signal molecule) binding to a receptor. Depending on the different type of signal molecule, it may bind to a G-Protein Linked Receptor, Tyrosine Kinase Receptor, Ligand Gated-Ion Channel, or an Intracellular Receptor (Steroid Hormone Receptor). Signal transduction is the process by which a signal is converted to a cellular response. Transduction is often done by protein phosphorylation which is when protein kinases phosphorylate (add a protein) to other relay molecules. This phosphorylation cascade is aided by second messengers. These include cyclic GMP, cyclic AMP, calcium ions (Ca2+), and inositol triphosphate (IP3). Usually a phosphorylation cascade is many steps long and involves multiple active protein kinases to reach the active protein that brings about the cell’s response to the signal. It’s important to remember that the more steps in the pathway the larger and more specific the response Transduction can also be done by protein modification such as methylation. MC Question~ After viewing the figure to the left and your knowledge of the subject, which of the following is FALSE in regards to the signal transduction pathways of insulin? The pathway promotes the usage or storage of glucose There are negative and positive feedback mechanisms to regulate the signal transduction pathways The process of insulin production is an example of a trigger mechanism in a signal transduction pathway The activation of the IP3 (seen in figure as PI-3 K) causes an automatic halt of the production of lipids to prevent disruption of the signal transduction pathway. Free Response/LL Question~ Your Aunt Enid goes to see a doctor for her yearly check-up and is told that several of her protein kinases are not functioning properly and he is seeing abnormal cell growth in her thyroid. Explain what the doctor believes to be causing this abnormal cell growth and what this could lead to for Enid. Enid goes to a specialist who tells her that her protein kinases are working fine but something else is causing this same problem the doctor saw. What other factor related directly to the functioning of protein kinases might cause Enid’s demise?

LO 3.37 The student is able to justify claims based on scientific evidence that changes in signal transduction pathways can alter cellular response. SP 6.1 The student can justify claims with evidence. Explanation: Signal transduction pathways are specific, and depend on various molecules involved, including signal molecules, receptor, and relay molecules. Whether a response is cytoplasmic or nuclear, small changes can effect signal amplification and efficiency. Evidence of this is shown through cell proteins, because depending on which proteins are present in a cell, relay molecules can cause a single response, branching responses, or inhibition of responses. Multiple choice question: Which of the following does NOT provide evidence that signal transduction pathways can alter cellular response? • Second messengers allow for signal amplification for the hormone epinephrine B) A relay molecule fails to activate a protein kinase C) A signal molecule binds specifically to G protein-linked receptors D) A phosphorylation cascade is carried out to activate a specific protein Free response question: • Use evidence to explain how a 3-step signal transduction pathway can be inhibited. Explain how this alters cellular response using an example. b) Offer a specific example for another way signaling may be inhibited.

LO 3.38: The student is able to describe a model that expresses key elements to show how change in signal transduction can alter cellular response. SP 1.5: The student can reexpress key elements of natural phenomena across multiple representations in the domain. Explanation: In transduction a signal molecule binds to a receptor embedded in the cell surface. A relay molecule then activates protein kinase 1 which then allows for the phosphorylation cascade to occur, and eventually the cellular response. A particular hormone may cause diverse responses in target cells with different receptors for the hormone, different signal transduction pathways, and different proteins for carrying out the response. An example of this is the different responses of epinephrine in mediating the body’s short term response to stress. Liver cells and the smooth muscle of blood vessels supplying skeletal muscle contain β-type epinephrine receptors, whereas the smooth muscle of intestinal blood vessels have α-type epinephrine receptors. These tissues respond differently to epinephrine, resulting in decreased blood flow to the digestive tract and increased delivery of glucose to major skeletal muscles, helping the body react quickly. • M.C. Question: A rare disease leads to an absence of DAG and IP3 in somatic cells. Which of the following effects would it induce in intracellular signaling? • A) Membrane-bound receptors would not be able to receive signal molecules • B) Calcium levels would decrease as the second messenger system between the membrane receptor and the cellular response would be deactivated. • C) The nucleus would receive the signal, but would not be able to transcribe the correct gene. • D) All of these results would occur if DAG was absent. Learning Log/FRQ-style Question: Describe the basic elements that differentiate a gut’s response to epinephrine and a bicep’s response to epinephrine and why are these differences important?

LO 3.39: The student is able to construct an explanation of how certain drugs affect signal reception and, consequently, signal transduction pathways. SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific processes. Explanation: Cell signaling begins when a signal molecule that is complementary in shape to a specific site on the receptor (intracellular or membrane) attaches there and behaves like a ligand. This ligand binding generally causes a receptor protein to undergo a change in shape, which can either directly activate the receptor, or to cause the aggregation of two or more receptor molecules which leads to further molecular events within the cell. The signal transduction pathway is activated which leads to a particular response within the cell. In a phosphorylation cascade, a series of different molecules in a pathway are phosphorylated in turn, each molecule adding a phosphate group to the next one in line. This cascade model continues until the final protein is activated and causes the cell's response. Some drugs that are competitive blockers can inhibit signal transduction by mimicking the shape of a signal molecule and binding to a receptor. This does not allow the actual signal molecule to bind to the receptor, which does not allow for the activation of signal transduction pathways. M.C. Question: Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins? A. G protein-coupled receptor binding B. ligand-gated ion channel signaling C. receptor tyrosine kinase activity D. adenylyl cyclase activity E phosphatase activity Learning Log/FRQ-Style Question: Suppose you are a scientist, researching ways to treat cancer. Signaling pathways play crucial roles in developmental processes as well as cancer by controlling gene expression and cell behavior. Cell division in mammalian cells is driven by protein kinases that regulate progression through the various phases of the cell cycle. In what ways could signal transduction most probably be explored to treat cancer?

LO 3.40 The student is able to analyze data that indicate how organisms exchange information in response to internal changes and external cues, and which can change behavior. SP 5.1 The student can analyze data to identify patterns or relationships. Explanation: The flight or fight response in animals is controlled by the sympathetic and parasympathetic nervous systems in the body. When an external cue, for example a predator or a bright light is introduced to the organism, the hypothalamus in the brain will stop activity of the parasympathetic nervous system. The energy that would be used for it is transferred to the sympathetic nervous system and adrenaline is released. The heart rate blood pressure increases, pupils become dilated, and the blood glucose level increases. In some organisms, the body will release hormones or pheromones that will alarm other organisms of the species so that they will be prepared for attack if necessary. An example is with minnows; when one fish is harmed, it will release a substance that alarms the neighboring minnows so that they will prepare for attack or hide. The parasympathetic nervous system, sometimes known as the “rest and digest” system, is responsible for reversing what the sympathetic nervous system has done. The heart rate, blood glucose level, and blood pressure will decrease, while digestion will start back to occur. MC Question: Which of the following is not is not directly involved when the "fight-or-flight" response to danger occurs? adrenal medulla posterior pituitary sympathetic nervous system an increased heart rate hypothalamus Learning Log/FRQ-style Question: Explain the process that occurs in the body of a mother eagle before she attacks someone that has approached her nest. Be sure to include the systems, organs, and glands involved. What happens in the mother’s body when she has finished her attack?

LO 3.41: The student is able to create a representation that describes how organisms exchange information in response to internal changes and external cues, and which can result in changes in behavior. • SP 1.1: The student can create representations and models of natural or man-made phenomena and systems in the domain. • Explanation: In both animals and plants, external cues trigger an internal response that results in a change in behavior. Short-term stress causes a fight or flight response in humans. External stimuli cause the hypothalamus to activate the adrenal medulla, which releases the hormones epinephrine and norepinephrine. These hormones cause increased blood pressure, breathing rate, metabolic rate, blood glucose and alertness as well as decreased digestive and kidney activity. Predators often cause behavioral defenses like fleeing, hiding, and self-defense. Because plants cannot perform such tasks, they can interact with each other to develop defenses. Due to herbivory, the eating of plants, plants can produce chemical toxins that are not toxic to humans but can taste bad to herbivores. This behavioral change is based on external stimuli that causes internal responses. • M.C. Question: Which of the following statements about epinephrine and norepinephrine is false? • They are members of the class compounds, the catecholamines • They are released by the adrenal medulla via nerve impulses • They respond to endocrine signals which may cause suppression of the nervous system • They cause a decrease in blood supply from the digestive system • and skin • E. They cause an increase in blood supply to the brain, heart and • skeletal muscles. • Learning Log/FRQ-style question: • Suppose a male fish’s territory is invaded. by the same species of fish • What may be his physiological and behavioral responses be? If the • invader had a yellow underside, how might this affect the male’s future • responses to threats? Design an experiment to test this.

LO 3.42: The student is able to describe how organisms exchange information in response to internal changes or environment. SP 7.1: The student can connect phenomena and models across spatial and temporal scales. Explanation: Animals exchange information in a similar way externally. In behavioral ecology, signals are what cause changes in other animals’ behaviors. The steps, reception, transmission, and response have a similar idea to them that cell communication does, and these steps constitute animal communication. The five main ways of animal communication include chemical, auditory, visual, tactical, and electric signals. Depending on the animal and its life style, different types of signals can be more advantageous than others. Pheromones , commonly found in mammals and insects, are major chemical substances whose production and responses are controlled genetically and they are usually involved in reproductive behavior. For example, moths emit pheromones that can attract males from an extended distance. Chemical signals can also produce a fight-or-flight response in communities. For example, when a minnow is injured, a substance stored in the glands is released and this substance initiates a fright response among fish in order to alert them of the possibility of predators and causing them to congregate in tightly-packed schools. The exchange of information between organisms is crucial to protecting populations from predators, helping them acquire prey, reproducing, recognizing offspring, and transmitting learned responses. Multiple Choice Question: Which of the following statements is incorrect regarding how organisms communicate and the resulting responses? • Most terrestrial mammals, as they are nocturnal, do not use visual displays as their main form of communication. • The act of communication between organisms increases the population’s likelihood of survival. • Many of the forms of signaling are controlled by an organism’s genetics. • Most signals are very inefficient when it comes to energy usage. • Chemical signaling involves animals emitting odors. Learning Log/FRQ-style Question: The figure on the right provides examples of animals exchanging information. Using the figure on the right, hypothesize what behavior the blue-footed booby is exemplifying as the male shows off his feet, as seen In the picture on the left. Be sure to include the type of signal with a justification, the reason for the behavior, the animal on the receiving end of the behavior, and the result of the behavior. http://animals.about.com/od/habitatprofiles/ig/Animals-of-the-Galapagos/Blue-Footed-Boobie.htm http://animal.discovery.com/animal-facts/animals-communicate.htm

Explanation: The central nervous systems detect external signals by using sensors to detect signals. These sensory neurons bring communicate the information to the spinal cord. The sensory neurons then communicate with the motor neurons causing a response from the muscles the motor neurons are connected to. The communication is done through neurons which use action potentials to send signals of electric charge. The neurons work by sodium channels on the neurons opening, allowing sodium to enter increasing the potential in the membrane until it reaches a certain point, at which all of the gates open allowing sodium to flood in making the potential shoot up, then the potassium channels open causing the potential to drop quickly and then the potential balances out again ready to be fired again. This action potential travels from neuron to neuron sending signals throughout the body. LO 3.43 The student is able to construct an explanation, based on scientific theories and models, about how nervous systems detect external and internal signals, transmit and integrate information, and produce responses. [See SP 6.2, 7.1] M.C. Question: Cocaine is a drug that floods the synapse with dopamine and blocks the reuptake of neurotransmitters how is this different from when dopamine is released normally? A) Normally the neurotransmitters are sent back through the synapse for reuse, which is why with cocaine, the synapse is flooded. B) This is the same as what normally occurs. C) Normally the neurotransmitters are used in the next neurotransmitter they get sent to, but cocaine blocks the sending of them, making them become flooded in the neurons. D) The cocaine blocks the ligand-gated ion channels sending the neurotransmitters into the space outside the neurons. SP 7.1: The student can connect phenomena and models across spatial and temporal scales. SP 6.2: The student can construct explanations of phenomena based on evidence produced through scientific practices. Learning Log/FRQ-style Question: Discuss the steps that the nervous system goes through to react to an outside stimulus like the hitting of knee by the doctor. What would be the effect on the kicking reflex if there was a toxin injected in the human that flooded the ligand gated ion channels with other neurotransmitters? http://www.edoctoronline.com/media/19/photos_6D35D6F0-4EAD-46BB-A161-E961A93AB28B.jpg

LO 3.44: The student is able to describe how nervous systems detect external and internal signals. [See SP 1.2] SP 1.2: The student can describe representations and models of natural or man-made phenomena and systems in the domain. Explanation: As organisms interact with their environment and are thrown into certain situations signals/stimuli are sent through the nervous system and are detected by receptors that are located on the dendrites (branched extensions) on a neuron which once detected are transported to the cell body. Those signals once in the cell body are transmitted down to the axon hillock (the part of the neuron where signals that travel down the nucleus are generated) which determines the overall charge of the neuron. The axon hillock then launches a transmission of neurotransmitters down the axon (this only happens if the neuron reaches a threshold of a -55mV charge), portion of the neuron (the long extension that transmits signals to other cells) which is sped up by the insulation and spacing of the myelin sheath (the fatty covering over the axon which is made up of Schwann cells). The neurotransmitters are then transported down the axon to the synapses (site of communication between a synaptic terminal and another cell). Once the synapse has received the neurotransmitters they are then transported to the synaptic terminal (bulb at the end of an axon in which neurotransmitters molecules are stored and released). At this point voltage-gated calcium ion channels open, elevating the calcium concentration with the synapses of the neuron , the calcium that is now present in the synapses allows neurotransmitters (surrounded by vesicles) to diffuse across the synaptic cleft. Which then allows neurotransmitters to bind to ligand-gated ion channels that are located on the postsynaptic membrane on the dendrites, or cell body of another. Those neurotransmitters are then interpreted as signals by the other neuron who undergoes the same processes, this all happens at a very rapid rate with all the neurons in the nervous system, thus producing a response from an external stimulus such as a gazelle undergoing the “fight or flight” response when confronted by a predator such as a lion. M.C. Question: MS (multiple sclerosis) is a disease that scars the nervous system (by degrading the myelin sheath covering of the axon). Given what you know about the function of the myelin sheath, which of following would be true in regarding the axon and how signals will travel down the axon? A) The axon would not be as insulated so signals will travel down the axon faster. B) The neurotransmitters would not travel down the axon at full speed. C) Signals will not travel down the axon at all. D) The axon will function normally. Learning Log/FRQ-style Question: Calcium is used to help signals get from one neuron to the next which helps form a response from an external stimulus. Describe a mechanism that would alter calcium concentration in the synapses of a neuron so that neurotransmitters would not be able to diffuse across the synaptic cleft and bind to the ligand channels on the postsynaptic membrane of a neighboring neuron.

LO 3.45: The student is able to describe how nervous systems transmit information.SP 1.2: The student can describe representations and models of natural or man-made phenomena and systems in the domain.Explanation: Neurons can communicate with other cells at the synapse. In an electrical synapse, electrical current flows from one cell to another via a gap junction. In a chemical synapse, the synaptic terminal depolarizes causing the fusion of synaptic vesicles with the terminal membrane releasing neurotransmitters into the synaptic cleft. Neurotransmitters are chemical messengers, and some examples are acetylcholine, epinephrine, norepinephrine, dopamine, serotonin, and GABA. Transmission of information along neurons and synapses results in a response. The response can be stimulatory or inhibitory. MC Question: Which of the following is true regarding nerve impulses? • They are transmitted rapidly • They are electrochemical in nature • They are self-propagating • A and B are true • All of the above are true Learning Log/FRQ-style Question: Describe, in detail, the process of direct synaptic transmission as well as the result of this process.

LO 3.46The student is able to describe how the vertebrate brain integrates information to produce a response. SP 1.2 The student can describe representations and models of natural or man-made phenomena and systems in the domain. Explanation: In vertebrates, the nervous system is divided into the central nervous system, which contains the brain and spinal cord, and the peripheral nervous system, which is made up of nerves that carry information to and from the central nervous system. The nerves of the body are composed of cells called neurons. The structure of the neuron allows for the detection, generation, transmission and integration of signal information. Sensory neurons relay sensory information gathered from parts of the body and relay it back to the brain so the information can be processed and a response can be made. Motor neurons, through chemical signals called neurotransmitters, send messages back to a specific muscle or cell that needs to be stimulated. • M.C. Question: A spinal reflex differs from a normal sensory and motor reaction in that • Spinal reflexes are part of the central nervous system response, while normal reactions are part of the peripheral nervous system. • In a normal reaction, the spine transmits information through afferent nerve fibers, while reflex reactions are transmitted along efferent nerves. • Spinal reflexes can never be consciously controlled, while normal reactions can be controlled. • In a spinal reflex, the spine moves the muscles in response as soon as the sensory information reaches the spine while usually the impulse must reach the brain before a response. • Learning Log/FRQ-style Question: You were cooking dinner one night and cut your finger while slicing tomatoes. Describe how the nervous system detects this external signal, transmits and integrates the information, and then produces a response. Be as specific as possible. Then draw a neuron, label and describe the parts. http://intranet.tdmu.edu.ua/data/kafedra/internal/normal_phiz/classes_stud/en/nurse/1%20course/Introduction%20to%20psychology/02%20Role%20of%20the%20Nerve%20and%20Endocrine%20Regulation%20for%20Human%20Behavior.files/image012.gif

LO 3.47: The student is able to create a visual representation of complex nervous systems to describe/explain how these systems detect external and internal signals, transmit and integrate information, and produce responses. SP 1.1: The student can create representation and models of natural man-made phenomena and systems in the domain. Explanation: The nervous system coordinates internal organ function and responds to changes in the external environment.In the nervous system the basic structure that reflects function is the neuron, which is a nerve cell that has properties that allow it to conduct signals by taking advantage of the electrical charge across its cell membrane. A structure of a neuron consists of the axon, which transmits signals to other cells, the dendrites, which receive signals from other cells, and the synapse, where information is passed from the transmitting neuron.There are three stages in processing information by the nervous system that use specialized neurons: Sensory neurons, interneurons, and motor neurons. When you hear someone call your name that acts as an external stimuli and sensory neurons transmit information from the sensors that detected the stimuli and sends this information to the central nervous system(CNS), where interneurons integrate, or analyze the sensory input. Motor output leaves the CNS via motor neurons, which then communicate with effector cells, which are the cells that perform the body’s response to a stimuli. M.C. Question: What occurs sequentially when the nerve impulse is transmitted from the synapse of one neuron to the postsynaptic neuron? A) The nerve impulse is transmitted next to the axon of the presynaptic neuron. B) The synaptic vesicles release neurotransmitters into the synaptic cleft by exocytosis. C) The nerve impulse is transmitted to the postsynaptic neuron by a direct connection between the two. D) The nerve impulse is transmitted to the axon of the postsynaptic neuron. Learning Log/ FRQ-Style Question: Would severing a neuron’s axon stop the neuron from receiving or from transmitting information? Explain. Draw a diagram of a neuron and label it.

LO 3.48: The student is able to create a visual representation to describe how nervous systems detect external and internal signals.SP 1.1: The student can create representations and models of natural or man-made phenomena and systems in the domain. Explanation: Animals have nervous systems in order to detect external and internal changes, obtain this information and produce a response to it. The structure of the neuron allows the detection and transition of information. Neurons are the main structure of this system. Neurons contain a cell body, axon and dendrites; within the axon there are myelin sheaths that act as a conductor for the electric responses. Schwann cells, which form the myelin sheath help in travelling the impulse along the neuron. Responding to a stimulus opens channels allowing Na+ ions and K+ ions to cross the membrane depolarizing the cell, this allows threshold to be reached maintaining action potential. For transition across synapse to occur chemical messengers called neurotransmitters must inhibit and carry along information. M.C. Question: Which of the following is true about depolarization? A) A stimulus suddenly closes the ion channels in a cell B) Na+ influx makes the inside of the membrane less negative C)While the Na+ channels are open the K+ channels open too D)If the depolarization reaches threshold it stays in resting potential Learning Log/FRQ- style Question: Doctors check your reflexes and nervous system by tapping you on the knee. Explain how this test checks the functioning of our nervous system.

LO 3.49 The student is able to create a visual representation to describe how nervous systems transmit information. SP 1.1 The student can create representations and models of natural or man-made phenomena and systems in the domain. Explanation: The nervous system is a vast array of mechanisms and functions that allow the body to receive stimuli, interpret them, and respond in a way that is beneficial and effective. Essentially the body has an input of stimulus. Then transduction occurs to transform that stimulus into something the brain understands (i.e. neurons firing). As a result of transduction, sensory neurons transmit the information to the central nervous system (the brain and spinal cord). Depending on the stimulus, motor neurons may send a message to muscles to perform a response. The main mechanism behind this information transmittance is action potential, the firing of neurons. The influx of sodium and the efflux of potassium causes the neuron to depolarize and reach the action potential threshold. An electrical impulse is then sent down the axon to the dendrites. The signal changes to a chemical one and is transmitted across the synapse via neurotransmitters. The message continues to be sent until a response is induced. Questions are on the next slide The signal-transduction process involved with the neuron, the nervous system’s primary mechanism

LO 3.49 Multiple Choice Question • Suppose you are studying neurons and know there is some sort of mutation or inhibitory molecule present on one neuron. Knowing that the presynaptic neuron has already achieved action potential, which of the following possible defects on this presynaptic neuron would most likely inhibit a postsynaptic neuron from achieving an action potential? • A mutation in the Schwann cells on the axon causes the secretion of myelin for the myelin sheath to stop. • An inhibitory molecule renders the sodium and potassium channels of the neuron unusable after it fires a first time. • The dendrites are mutated in such a way that they are unable to experience inhibitory postsynaptic potentials. • The voltage-gated calcium ion channels on neuron are mutated in such a way that they stay open longer. FRQ Question The nervous system is the body’s primary mechanism to receive stimuli input and elicit an appropriate response. a. Describe a sample pathway in the nervous system involved when you pull your hand away after touching a hot stove. Explain an evolutionary adaption involved with this response and explain why it is beneficial. b. Describe the process of an action potential and how a neuron may influence other neurons or other cells using its action potential. c. Choose a neurotransmitter and explain what kind of response it may elicit in the body.

LO 3.50:The student is able to create a visual representation to describe how the vertebrate brain integrates information to produce a response. SP 1.1:The student can create representations and models of natural or man-made phenomena and systems in the domain. Explanation:The vertebrate brain is made up of mainly the cerebral cortex which houses millions of neurons. Neurons make up the nervous system. Astrocytes, radial glia, oligodendrocytes, and Schwann cells are all supporting cells of the neurons that provide a neurons nutrition and support. Within a neuron, dendrites bring the signal towards the body by allowing the signal travel down an axon. The axon hillock is the region of the cell body where the impulse is generated. The axons in the neuron are insulated by the myelin sheath which is made up of supporting cells. The Node of Ranvier is the space between Schwann cells on an axon. When the brain receives a signal, be it through an auditory signal or another signal, the axon hillock inside of the neuron will determine the overall charge of the signal and if the threshold is met then an action potential will be created to respond to the signal within the body. Multiple Choice Which of the following concerning a signal response is not true? A.) Sodium-gated channels are opened to allow NA+ into the neuron to produce an action potential. B.) Once integrated, motor neurons communicate with effector cells to create a response to an input. C.) Voltage gated Ca2+ channels are opened to allow Ca2+ ions into the presynaptic membrane. D.) Motor neurons travel through the autonomic nervous system to create a voluntary response to a signal. E.) Approximately -70 mV are required to reach an action potential. FRQ Question: A.)Motor neurons are fired to muscle cells or the endocrine system to produce a physiological response to a stimuli. Mention and describe two examples of a physiological response that would occur If you were to be awoken in the middle of the night due to a startling noise. B.) During integration, the Central Nervous System processes the sensory input to create a response. Describe the process of the reception and transduction of an signal in a neuron.

Review Projects – 2013 Big Idea 3 Mr. Bennett