Biology 3

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Biology 3
2010-06-15 21:40:40

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  1. What is a nucleotide and what 3 things is it made of?
    it is the basic functional unit of dna made of a sugar a phosphate and a nitrogenous base
  2. What kind of bonds connect the bases of dna together on the RUNGS of the ladder?
    Hydrogen bonds
  3. ____ combinations of bases code for _____ amino acids
    64 combos and 20 aas
  4. What is transcription and where does it take place?
    DNA is converted to RNA in the nucleus
  5. DNA =________ sugar and RNA=_________ sugar
    • DNA is deoxyribose and is double stranded
    • RNA is ribose and is single stranded
  6. DNA has _______ instead of ______, found in RNA.
    • DNA has thymine
    • RNA has uracil
  7. What carries the RNA out of the nucleus?
    The mRNA brings the RNA out of the nucleus to the ribosome
  8. What allows the RNA to code for protein?
    The tRNA has an anticodon that matches with each 3 set of bases on the DNA and has an attached amino acid. The amino acids all together form a protein.
  9. What is rRNA and what makes it?
    The rRNA is used to make the large and small subunit of the ribosome and it is made in the nucleolus.
  10. What is added to the rRNA strand after transcription?
    A 5' cap and a poly-a tail for signaling in the cell
  11. Where does DNA translation take place?
    In the cytoplasm at the RIBOSOME
  12. What occurs in the three stages of translation?
    1.Initiation: mRNA attaches itself to the ribosome; the first codon in the mRNA is always AUG (initiation codon-start sequence), which codes for methionine; tRNA brings in the first amino acid (methionine) and places it in its proper place.

    • 2.Elongation: Subsequent amino acids are brought to the ribosome and bonded
    • together with a peptide bond.

    3.Termination: There are three codons which are known as stop codons (UAA, UAG, UGA). These serve as the signal to stop protein synthesis and release the protein from the ribosome.
  13. primary shape of protein is........
    unique sequence of amino acids“Beads on a string”
  14. secondary shape of protein.........
    Twisting or folding of the polypeptide backbone; hydrogen bonds between the peptide bonds of the backbone stabilize the secondary structure; there are two types of secondary structure: α helix and β pleated sheet.
  15. tertiary structure of protein
    • interactions between the various kinds of side chains of amino acids
    • Interactions between the various kinds of side chains of amino acids; hydrogen bonds, ionic bonds, and hydrophobic interactions are weak bonds between side chains that collectively hold the protein in a specific conformation; stronger bonds are the disulfide bridges, covalent bonds between the side chains of cysteine pairs.
  16. quaternary structure of a protein
    • interaction of two or more polypeptides
    • Examples: collagen and hemoglobin
  17. missense vs. nonsense mutation
    • if the substitution changes the amino acid (a mis- sense mutation), the protein may or may not be functional depending on the location of the mutation;
    • if the substitution produces a premature termination codon (a non- sense mutation), the protein will be prematurely terminated, and will be nonfunctional.
  18. point mutation
    Point Mutations: When a single nucleotide base is substituted by another nucleotide base
  19. 5 conditions for the Hardy Weinberg to make sure that Hardy Weinberg equation can be used o predict the frequency of alleles
    • 1) Random Mating
    • 2) No natural selection
    • 3) No migration or immigration
    • 4) Large populations
    • 5) No mutations
  20. hardy weinberg equation (just read)
    • p2+ 2pq + q2= 1 p+q=1
    • p = frequency of dominant allele
    • q = frequency of recessive allele
    • p2 = frequency of homozygous dominant individuals
    • 2pq = frequency of heterozygous individuals
    • q2 = frequency of homozygous recessive individuals.
  21. Endocrine Vs. Exocrine System
    Endocrine secretes hormones directly into the blood, exocrine secretes into a tube or duct (i.e. enzymes)
  22. What are the 3 types of hormones?
    steroids, peptides, and amino acid derivatives
  23. What does the hypothalamus secrete
    • connects the nervous system to the endocrine system
    • also controls hunger, thirst body temp, etc.
    • i.e.
    • it secretes TRH (thyrotrypin releasing hormone) which makes the thyroid release thyrotropin
    • it secretes Gn RH which controls the release of gonotropin hormones
  24. What does the anterior pituitary secrete?
    • Growth Hormone (somatotropin) Stimulates protein synthesis and promotes growth of bone. ProlactinStimulates secretion of milk and developement of the breasts. TSH (thyroid stimulating hormone) Stimulates the thyroid to secrete thyroxine. ACTH(adrenocorticotropichormone) Stimulatestheadrenalcortextoreleasecortisol.
    • FSH (follicle stimulating hormone) Stimulates growth of ovarian follicle; promotes formation of sperm in testes.
    • LH (luteinizing hormone) Stimulates ovulation and formation of corpus luteum; causes secretion of female sex hormones by the ovaries and testos-
    • terone by the testes.