CONCEPT QUESTION 1992 (DNA*):		L. PETERSON/AP BIOLOGY
 	Biological recognition is important in many processes at the molecular, 
	cellular, and organismal levels. Select three of the following, and for each 
	of the three that you have chosen, explain how the process of recognition 
	occurs and give an example.
		a.    Organisms recognize others as members of their own species.
		b.    Neurotransmitters are recognized in the synapse.
		c.    Antigens trigger antibody responses.
	        d.   *Nucleic acids are complementary.
		e.    Target cells respond to specific hormones.
 
  
  d)   Nucleic acids are complementary
     Definitions (1 point)
  
  ___     DNA and RNA are nucleic acids
     Nucleic acids are polymers of nucleotides
     Nucleotide = sugar (deoxyribose and ribose), phosphate, nitrogenous base
     Mechanisms (1 point for each)
  
  ___     A with T or U, C with G or Chargaff's Rules
     Pyrimidine with Purine or Single ring with Double ring
     2 Hydrogen Bonds with A+T/U and 3 Hydrogen Bonds with G+C or H bonds
     Antiparallel orientation 5'---3'/3'---5'
     Template requirement or semiconservative replication mechanism
     Primers
     DNA/RNA polymerase requirements
     Elongation/Initiation Factors
     Divalent Cations
     Examples (1 point)
  
  ___     Replication of DNA (2 strands of dsDNA are complementary)
     Transcription of DNA into mRNA, tRNA, rRNA
     Translation - mRNA-tRNA (codon/anticodon complementarity)
     Hybridization - DNA-DNA/DNA-RNA/Probes