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BIOLOGY

BIOLOGY. DNA/RNA. What is DNA?. Every new cell that develops in your body needs an exact copy of the DNA from the parent cell . All organisms must be able to pass copies of their DNA on to their offspring in order to continue the species.

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BIOLOGY

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  1. BIOLOGY DNA/RNA

  2. What is DNA? Every new cell that develops in your body needs an exact copy of the DNA from the parent cell. All organisms must be able to pass copies of their DNA on to their offspring in order to continue the species.

  3. The structure of DNA is related to 2 primary functions: To store & use information, to direct activities of the cell To copy itself exactly for new cells that are created.

  4. DNA and RNA are polymers (repeating subunits) of nucleotides. DNA is made of two long strands, in the shape of a double helix or twisted ladder, of a chain of nucleotides.

  5. Each nucleotide is made of three parts: Deoxyribose (a five carbon sugar) (s) A phosphate group (p) A nitrogen base (G, C, A, T)

  6. The nitrogen base can be any one of the following 4 bases: Adenine Guanine Thymine Cytosine

  7. “A” Always goes with “T” (held together by 2 hydrogen bonds) “G” always goes with “C” (held together by 3 hydrogen bonds)

  8. Adenine and Guanine are Purines (double rings of carbon) Thymine and Cytosine are Pyrimidines (single ring of carbon)

  9. In 1953 two scientists figured the shape of the DNA molecule was a double helix: James Watson (currently participating in the Human Genome Project in CA) & Francis Crick. Rosalind Franklin also helped.

  10. Replication Original Strand New Strand DNA makes DNA, this happens in interphase This is the process of DNA duplication. The strand unzips along the hydrogen bonds, then the complimentary nucleotide attaches to the missing part.

  11. *Adenine can only bond w/ Thymine, while Cytosine can only bond w/ Guanine. What would the complimentary strand look like? C G A T T A C G T __________________________

  12. What is RNA? RNA or Ribonucleic acid has the primary function of synthesizing proteins & is made from DNA.

  13. RNA is different from DNA in 3 ways!!!! 1) RNA has only one strand of nucleotides instead of two 2) RNA has ribose as its sugar base instead of deoxyribose 3) RNA has the nitrogen base URACIL instead of Thymine

  14. There are 3 types of RNA Messenger RNA or mRNA it serves as a template for the assembly of amino acids when proteins are made

  15. 2. Transfer RNA or tRNA it is a folded back strand & can exist in 20 or more varieties, each bonding to only one specific amino acid

  16. Ribosomal RNA or rRNA is the glob-shaped form found on the ribosome. It assembles the amino acids in the correct order.

  17. TRANSCRIPTION DNA makes mRNA RNA is produced from DNA through this process. Transcription means “to write across” A group of 3 sequential bases of mRNA is called a codon. A list of all 64 possible amino acids codons can be found in your textbook.

  18. TRANSLATION protein synthesis Translation takes place in the cytoplasm! It is the process in which mRNA attaches to a ribosome; tRNA which carries a specific amino acid attaches its anticodon to the correct mRNA codon building a chain of amino acids which codes for a specific protein.

  19. A protein may consist of hundreds or thousands of amino acids which codes for a specific protein, & all these amino acids must be arranged in a particular sequence for the protein to function properly

  20. Sample codon questions Met-Ala-Pro-Gly Possibly Aspartic acid A codon sequence of AUG GCU UCC GGU would code for what amino acid? If Glumatic acid is GAG, a mutation of its third base would result in a codon for which amino acid?

  21. Sample Questions for Codons Tryptophan GCU-CAU-CGG An amino acid sequence of Alanine-Histine-Arginine would have which codon sequence? Given the codon sequence UGG what amino acid will be produced?

  22. Sample protein synthesis DNA: TAC-AGT-GTG-TTA-ATC **mRNA: *tRNA: amino acids:

  23. 12.4 DNA part 2 Notes Genetic changes

  24. Mutation in reproductive cells are changes on the sequence of nucleotides with a gene in a sperm or egg cell; when these cells take part in fertilization the changed gene would be a part of the genetic makeup of the offspring

  25. Mutations in body cells. EX: Skin, muscle; may cause problems for the individual but would not be passed on to offspring.

  26. Mutagens any agent that can cause a change in DNA; some examples are high energy radiation, chemicals, and even high temperatures

  27. Types of Mutations Point mutations – any change in a single base in DNA; might affect the structure of a protein (Ex: sickle cell)

  28. Frame shift mutation - where a single base is added or deleted

  29. Chromosomal Mutations occurs in all living organisms, more common in plants formed when parts of chromosomes are broken off and lost during meiosis or mitosis; caused by nondisjuntion

  30. Types of Chromosomal mutations

  31. Deletion – part of a chromosome is left out Insertions – part of chromatid breaks off and attaches to its sister chromatid duplication of genes Inversion – a part of a chromosome breaks off and is reinserted backwards Translocation – part of one chromosome breaks off and is added to a different chromosome

  32. Repairing DNA Enzyme proofread the DNA and replace incorrect nucleotides with correct nucleotide; not perfect the greater the exposure to a mutagen the more likely a mistake will not be corrected

  33. GENETIC TECHNOLOGY DNA notes part 3

  34. Applied Genetics For thousands of years people have tried to produce plants and animals with desirable traits

  35. Three methods that people use to develop organisms with desirable traits: • Selective Breeding – a process of selecting a few organisms with desired traits to serve as parents of the next generation • EX: Cows that produce more milk, vegetables that resist disease

  36. 2 Types of Selective Breeding: • Inbreeding – crossing 2 individuals with similar sets of genes to produce specific traits (may lead to genetic disorders) • Hybridization – crossing 2 genetically different individuals to have the best of both parents

  37. Three methods that people use to develop organisms with desirable traits: 2) Cloning – producing organisms that are genetically identical to the organism form which it was produced

  38. Three methods that people use to develop organisms with desirable traits: 3) Genetic Engineering (Recombinant DNA) – genes from one organism are transferred into the DNA of another organism, used to produce medicine, improve food crops and help cure human genetic disorders (such as insulin, Human Growth Hormone, Factor VIII (protein in hemophiliacs)

  39. Three Steps Involved: 1) Isolate- using restrictive enzymes to cleave (cut) the foreign DNA fragment to be inserted. Use the Restrictive Enzymes Hae III and EcoRI to cut the DNA below: Hae III=CCGG EcoRI=GAATTC (palindrome) GGCC CTTAAG

  40. 2)Attach the DNA fragment to a “vehicle” or vector 3)Transfer the vehicle into the host (recipient) organism

  41. Additional Terms: Plasmids- small rings of DNA found only in bacterial cells Genesplicing- rejoining of DNA fragments TransgenicOrganism- organism that contains the foreign DNA

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