HUMAN SYSTEMS QUESTION 1992:               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.

  
  STANDARDS:   4 POINTS MAXIMUM FOR EACH PART (A - E)
  a)   Organisms recognize others as members of their own species.
  ___     Definition (1 point)
  ___     Importance of Species Recognition/Definition of Species/Reproductive Isolation 
      prezygotic (3 points)
  ___     Mechanisms (2 points)
  ___     Visual/Auditory/Chemical/Tactile/[Multiple/Ritual/Behavioral] 
     Recognition is Innate or Learned (Imprinting) (1 point)
  ___     Example (1 point)
     Visual - birds, fruit flies
     Auditory - birds, whales, frogs, insects
     Chemical - moths, voles
     Tactile - fruit flies, octopods
     Multiple - albatross, butterflies, fruit flies, people, dove
     Imprinting - ducks, goats
  b)  Neurotransmitters are recognized in the synapse
  ___     Definition (1 point)
  ___     Neurotransmitter is a chemical messenger
     Synapse definition
  ___     Mechanisms (1 point each)
     Neurotransmitter binds to receptor on postsynaptic membrane
     Receptor is a protein
  ___     "Lock and Key" Concept  (3 points)
     Enzymatic recognition and degradation of Neurotransmitter
     Reabsorption of Neurotransmitter by presynaptic membrane 
     Presynaptic/Postsynaptic Events (1 point for any one)
  ___     Stimulus (impulse, depolarization, signal, action potential) 
        travels from presynaptic membrane (axon terminus, synaptic knob),
     Membrane channels opened (calcium channels, ion channels, calcium goes in),
     Neurotransmitter released from presynaptic neuron (synaptic vesicle)
     Neurotransmitter diffuses across synapse/synaptic cleft
     Neurotransmitter binding alters permeability
     Depolarizes and/or hyperpolarizes postsynaptic membrane
       (creates EPSP-[excitatory postsynaptic potential]/creates IPSP-[inhibitory
         postsynaptic potential]) /  Opening ion channels
     Change membrane potential (towards or away from threshold)
     Alter metabolism inside postsynaptic cell (2nd messenger, cAMP)
     Reversible binding of Neurotransmitter
  
  
     Examples (1 point)
  ___     Acetylcholine (ACh)      Synapse Types
     GABA                Acetylcholinesterase (AChE)
     Norepinephrine      Catecholamines, L-dopa
     Dopamine and Serotonin - Biogenic Amines
     Endorphins/Enkephalins - Neuropeptides
  c)   Antigens trigger antigody response
  ___     Definitions (1 point for either)
     Antigen (Ag)   - foreign substance/non-self
     Antibody (Ab) - defensive protein produced in response to Ag
                     - structure (2 heavy and 2 light polypeptide chains)
     Processes (1 point for each)
  ___     Selection of B cell highly specific
     B cell surface Ab binds Ag to activate B cell -- plasma cell and memory cell
          clones
     Secondary response description
     Ag-Ab complex - amino acid sequence of light and heavy chains of hypervariable 
        regions at N-terminus
        Specific site of Ag binding with Ab (Ab binding with Ag)
     Receptors on B cells and capping
     Free Ag with Ab
     T-cell dependent activation of B cells - Macrophage (Ag Presenting Cell)
        activates Interleukins to activate Helper T cells and B cells
     Generation of Ab diversity
     Examples of Antigens or Resultant Antibodies (1 point)
  ___     IgG, IgM, IgA, IgD, IgE
     Bacterial cells, viruses, fungi, protozoa, allergens (pollen, dust, dander), grafts
     (HLA), Heterologous Ag (RBCs), Self Antigens 
  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
  
  e)   Target cells respond to specific hormones
     Definition (1 point for each)
     Hormone - chemical messenger released to travel to cause specific biological
        response within organism, effective at low concentration
     Protein hormone/receptor at cell surface (doesn't get in)
     Steroid hormone /receptor inside cell (does get in)
     Recognition of hormone is to specific  receptor (specific proteins)
     Protein hormone involves 2nd messenger (cAMP, etc.)
     Steroid hormone affects transcription
     Examples (1 point each)
     Any hormone/target or effect (no pheromones, allomones, attractants)