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Biology Domain 3

Biology Domain 3. Genetics. Biology Standard 2:. Students will analyze how biological traits are passed on to successive generations. A. Basic Stuff. 1. DNA a. contains all genetic material b. instructions for LIFE

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Biology Domain 3

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  1. Biology Domain 3 Genetics

  2. Biology Standard 2: • Students will analyze how biological traits are passed on to successive generations.

  3. A. Basic Stuff • 1. DNA • a. contains all genetic material • b. instructions for LIFE • c. found in nucleus of eukaryotic cells and nuclear region of prokaryotic cells

  4. 2. Traits • a. all characteristics of an organism • b. located on genes found on DNA • c. passed from parent to offspring

  5. B. Nucleic Acids • 1. DNA • a. deoxyribonucleic acid • b. found in the nucleus • c. double helix • d. stores genetic information

  6. Don’t forget… • Base-pairing rules for DNA • Adenine (A) – Thymine (T) • Cytosine (C) – Guanine (G)

  7. Now think about this: • In a sample of yeast DNA, 31.5% of the bases are adenine (A). Predict the approximate percentages of C, G, and T. Explain.

  8. 2. RNA • a. ribonucleic acid • b. made in the nucleus, moves to ribosomes to make proteins • c. single stranded • d. transmits genetic information • e. 3 types (messenger, transfer, ribosomal) • mRNA, tRNA, rRNA

  9. Don’t forget… • Base-pairing rules for RNA • Adenine (A) – Uracil (U) • Cytosine (C) – Guanine (G)

  10. 3. How are nucleic acids made? • a. DNA Replication • 1. occurs in nucleus • 2. DNA uncoils and new DNA is added • 3. occurs before cell reproduces so that both cells have a full set of instructions

  11. b. RNA transcription • 1. occurs in nucleus • 2. single strands of RNA are made from information in DNA • 3. RNA leaves nucleus to direct the making of proteins on the ribosomes (protein synthesis)

  12. Now think about this… • If a DNA segment has the nucleotides AGCTAA, what would be the nucleotide sequence of the complementary RNA strand?

  13. One more! • If an mRNA strand reads GUC UAG CAU UUC, what was the DNA template that was used to produce this mRNA strand?

  14. c. Protein Synthesis • 1. also called translation • 2. information originally found in DNA is translated into proteins for body functions • 3. occurs on ribosomes • 4. Genetic Code is translation guide

  15. Don’t forget… • When using the genetic code, the DNA, mRNA, and tRNA are read in triplets (3 bases at a time! • mRNA triplets are called codons, tRNA triplets are called anticodons • The GENETIC CODE on your handout and in MOST textbooks works using mRNA codons!

  16. Now, think about this… • Use the genetic code to translate the following DNA strand into the correct amino acid sequence. • DNA: CAG TGC CTT TTG ACT • mRNA: • Amino acids:

  17. Now, try this one… • Use the genetic code to translate the following DNA strand into the correct amino acid sequence. • DNA: ATG AGA AGT AGG TAG • mRNA: • Amino acids:

  18. Last one… • Use the genetic code to translate the following DNA strand into the correct amino acid sequence. • DNA: TAC TTA ATC CCC GCC • mRNA: • Amino acids:

  19. C. Cell Reproduction • 1. Cells must reproduce for growth and development and to produce offspring • 2. 2 Types of Cell Reproduction • a. Mitosis • b. Meiosis

  20. 3. Mitosis • a. occurs for growth and development in multicellular organisms • b. simple ASEXUAL reproduction in unicellular organisms • c. cells are reproduced EXACTLY • d. DNA (chromosomes) are always copied completely before mitosis occurs so both new cells have an exact copy

  21. 4. Meiosis • a. traits are passed to offspring on chromosomes that are inherited from parents • b. Mom donates half in an egg, Dad donates half in sperm • c. Egg and sperm are produced through meiosis and are NOT identical to original cells

  22. Try this! • Which occurs during meiosis, but not during mitosis? • A. the nuclear membrane disappears • B. two divisions of the cell • C. cytokinesis of the parent cell • D. production of 2 daughter cells

  23. Try this! • The process in the diagram does NOT result in the formation of a • A. diploid cell • B. haploid cell • C. sex cell • D. gamete

  24. Try this! • Chromosomes determine all inherited traits because they are made up of • A. DNA • B.ATP • C. Centromeres • D. Chloroplast

  25. d. Genetic Variation • 1. when eggs and sperm are made, DNA CROSSES OVER (genetic information is switched) • 2. the cell splits twice, so only half of the original information is found in sperm and egg (REDUCTION DIVISION) • 3. genetic information is crossed and halved RANDOMLY

  26. e. Chromosomes • 1. DIPLOID--most cells have 2 copies of all genetic information (one copy from mom and one from dad) • 2. HAPLOID--Cells produced through meiosis only have one copy of genetic information • 3. Sexual reproduction—haploid egg + haploid sperm = diploid zygote

  27. Try this! • Genetic variation can arise in a number of different ways. The picture shows an example that occurs during meiosis. What example does the drawing show? • A. fertilization • B. segregation • C. crossing-over • D. independent assortment

  28. Try this! • Which term describes the rearrangement of genes in offspring that differ from those of their parents? • A. recombination • B. mutation • C. mitosis • D. asexual reproduction

  29. Warm-up • What are different versions of a gene for the same trait called? • A. phenotypes • B. alleles • C. hybrids • D. homozygous

  30. D. Heredity • 1. Traits are passed from parent to offspring through sexual (sometimes asexual) reproduction) • 2. Gregor Mendel • a. father of Genetics • b. conducted research on peas • c. proposed several laws concerning heredity

  31. 3. Mendel’s Laws • a. Law of Segregation • 1. gene pairs separate during meiosis • 2. you only get half of mom’s DNA and half of dad’s DNA • b. Law of Independent Assortment • 1. gene pair separation for one trait does not affect others • 2. genes for height separate independently of genes for hair color

  32. c. Law of Dominance • 1. you have two copies of a gene for any given trait (alleles) • 2. some copies are DOMINANT and some are RECESSIVE • 3. DOMINANT masks RECESSIVE • 4. Dominant Alleles—Capital Letter • 5. Recessive Alleles—Lowercase Letter

  33. Try this! • A human zygote, like most other human cells, contains 46 chromosomes. How many chromosomes does a human zygote receive from its mother? • A. 0 • B. 23 • C. 46 • D. 92

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