DNA QUESTION 1979:				L. PETERSON/AP BIOLOGY

	In relation to the chemical nature of the gene, describe:
		a.  the chemical structure of the gene
		b.  the replication (self-copying) of the gene
		c.  gene mutations, including chromosomal aberrations
 
  
  STANDARDS:
  
  A.  CHEMICAL STRUCTURE:     max. = 6 points  (one point for any of the following)
  __  genes are composed of units of DNA
  __  name 3 out of 4 nitrogen bases
  __  N bases are paired (proper pairs: A-T, G-C)
  __  components of nucleotide/DNA
  __  N bases are purines (AG) and pyrimidines (TC)
  __  DNA is a double stranded helix
  __  H bonds between N bases in base-pairing
  __  the two DNA strands are antiparallel (mirror/ complements)
  __  DNA codes for amino acid sequence in proteins
  __  each gene has a start and stop nucleotide sequence
  __  operon concept (Discuss)
  __  RNA genes (recognize)
  __  DNA dimensions 
  
  B.  REPLICATION:       max. = 6 points (one point for any of the following)
  __  double stranded DNA "unzips"
  __  exposed N bases serve as a template for sequential base-pairing in forming new DNA
  __  new DNA formed in the 5'->3' direction
  __  both old DNA strands are complementarily copied at the same time
  __  only short sections are copied at one time
  __  DNA polymerase (I or III) enzymically controls DNA polymerization
  __  ligase is the enzyme for tying the new short sections (Okazaki sections) together
  __  pyrophosphatase catalyzes hydrolysis of pyrophosphate (from the polymerization)
  __  deoxynucleotide triphosphates are the precursor molecules 
        (substrates of DNA polymerase)
  __  energy for the bonds holding the DNA polymer together comes from nucleoside 
         triphosphates
          [NTP -> NMP + PPi -> 2 Pi]
  __  Replication occurs in interphase before mitosis/meiosis
  __  Additional replication information 
        (e.g., endonuclease, nicking enzyme, swivelase, RNA polymerase initiation of DNA 
         replication, etc.)
  
  C.  MUTATIONS:              max. = 6 points (one point for any of the following)
  __  POINT MUTATIONS (Describing each change in a N-base or base pair with the 
         subsequent genetic effect; describing the effect of each mutagenic agent: radiation, 
         chemicals, heat)
  __  CHROMOSOMAL ABERRATIONS (Description of: deletion, duplication, inversion, 
         translocation, trisomy, monosomy, polyploidy)