CONCEPT 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])
	Change membrane potential (towards or away from threshold)
	Opening ion channels
	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)











































   CONCEPT QUESTION 1992:					L. PETERSON/AP BIOLOGY
	Survival depends on the ability of an organism to respond to changes in its 
	environment. Some plants flower in response to changes in day length. Some
	mammals may run or fight when frightened. For both of these examples,
	describe the physiological mechanisms involved in the response.


	FIGHT OR FLIGHT RESPONSE

ADAPTIVE

__	Turn on needed systems - turn off those not needed; 
	Understanding of Acute vs Chronic response - above and beyond statements in 
	question.

MECHANISM

__	Description of nerve pathway - (sensory-associative-motor)
__	Sympathetic nervous system (autonomic) - activation
__	Sympathetic system innervates adrenal medulla
__	Inhibition of parasympathetic by sympathetic
__	Parasympathetic - counters sympathetic, return to normal homeostasis;
	  acetylcholine = neurotransmitter
__	Epinephrine - adrenalin (cause and effect)
__	Norepinephrine - noradrenalin (cause and effect)
__	Source - Adrenalin from adrenal medulla (gland)
__	Source - Noradrenalin from adrenal medulla and/or sympathetic nerve endings
__	Receptor molecules on cell membranes
__	Use of cAMP (second messenger) to elicit intracellular response
__	Brief vs. sustained - contrasted (initial = sympathetic vs long = adrenal)
__	Chemical structure of adrenalin/noradrenalin

EFFECT

2 MAX - target tissues and effects
__	a.  pupillary muscles of eye - dilates pupils
__	b.  inhibits salivation
__	c.  bronchi of lungs - relaxes
__	d.  increases respiratory rate
__	e.  heart muscle - accelerates pulse, strengthens contraction
__	f.  piloerection - muscles attached to hair follicles
__	g.  liver - breaks down glycogen - stimulates release of glucose
__	h.  digestive tract - decreases digestive activities - peristalsis
__	i.  stomach, small intestine, pancreas - inhibits secretion of digestive enzymes
__	j.  stimulates release of fatty acids from fat cells
__	k.  peripheral circulation - vessels constrict
__	l.  inhibit sex structures
__       m. relax bladder - bowels
__       n.  decreased sensation of pain
__	o. "superhuman"

MAXIMUM - 7 points for this section

   CONCEPT QUESTION 1993:					L. PETERSON/AP BIOLOGY
		Membranes are important structural features of cells.

	   (a) Describe how membrane structure is related to the transport 
	          of materials across a membrane.
	   (b) Describe the role of membranes in the synthesis of ATP in either
	          respiration or photosynthesis.

	Membranes serve diverse functions in eukaryotic and prokaryotic cells. One
	important role is to regulate the movement of materials into and out of cells.
	The phospholipid bilayer structure (fluid mosaic model) with specific membrane
	proteins accounts for the selective permeability of the membrane and passive
	and active transport mechanisms. In addition, membranes in prokaryotes and in
	the mitochondria and chloroplasts of eukaryotes facilitate the synthesis of ATP
	through chemiosmosis.

	PART A. (6 Maximum)
	Membrane Structure (3 Internal Maximum)
	__ Phospholipid structure - hydrophilic, hydrophobic, amphipathic
	__ Phospholipid bilayer / fluid mosaic description
	__ Proteins embedded in the membrane
	__ Sterols embedded in the membrane
	__ Well-labeled diagram may replace one of the above

	Membrane Transport (3 Internal Maximum)
	__ Use of the term "selectively permeable" or a good definition of
	      selective permeability or an explanation of the role of phospholipids 
	      or proteins including nuclear pore proteins in determining selective 
	      permeability
	__ Description of the effect of size, charge, polarity, lipid solubility  on
	      membrane permeability

	Mechanisms + description related to structure:
	__ Passive transport: diffusion / osmosis + reference to membrane gradient
	__ Ion channel: transport as a mechanism for a change in permeability
	__ Facilitated diffusion: description (symport, antiport, uniport)
	__ Active transport: description
	__ Exocytosis, endocytosis, phagocytosis, pinocytosis: description

	(1 pt additional) A good example of one of the above mechanisms

	PART B. Role of the Membrane in the Production of ATP in 	Photosynthesis or Respiration (6 Maximum)
	Chemiosmosis:
	__ Involved molecules are embedded in the membrane
	__ Electron carriers are sequentially organized
	__ The energy comes from the flow of electrons
	__ H+ / Proton / pH gradient established
	__ Movement through the membrane generates ATP
	__ A specific protein makes ATP




	RESPIRATION		or		PHOTOSYNTHESIS
  __ Site is the mitochondrion			__ Site is the chloroplast
  __ Inner mitochondrial membrane			__ Thylakoid / grana membranes
       (cristae) are involved in eukaryotes		      are involved in ejkaryotes
  __ Folded membrane present			__ Folded membrane present
  __ Cell membrane is involved in			__ Thylakoid / grana membranes
        prokaryotes					      involved in prokaryotes
  __ Correct direction of H+ flow			__ Correct direction of H+ flow











































  CONCEPT QUESTION 1994:					L. PETERSON/AP BIOLOGY

Discuss how cellular structures, including the plasma membrane, specialized endoplasmic reticulum, cytoskeletal elements, and mitochondria, function together in the contraction of skeletal muscle cells.


To earn credit a student needed to demonstrate an understanding of basic cell anatomy and physiology as they relate specifically to the structure and function to muscle contraction. Standards were established to follow the cellular activities pertinent to muscle contraction from the neuromuscular junction, through contraction, and returning to the non-contractive state. Points were also awarded if the student included information from the neuromuscular junction, demonstrated an exceptional understanding of chronological information from the neuromuscular junction, demonstrated an exceptional understanding of chronological or spatial relationships, or included an elaboration of special features specific to the process of muscle contraction.

(2 pts) Neuromuscular junction
		Action potential of neuron -> neurotransmitter
		Concept of neurotransmitter
(1 pt)   Idea of a sarcomere as a functional unit
(1 pt)   Actin and Myosin in a sarcomere - (well labeled diagram w/text)
(2 pts) Plasma membrane / sarcolemma (no point for name alone)
		Receptor sites for neurotransmitters
		Change in permeability / Na+  K+
		Action potential distributed / depolarization
		T-tubules (continuous with specialized E.R.)
(2 pts)  Specialized E.R. - Sarcoplasmic reticulum (no point for name alone)
		T-tubule (only if not given above)
		Ca++ release / Calcium is involved with muscle contraction
		Change in permeability - release of Ca++
		 Ca++ recaptured into S.R. - contraction ends / active transport
(5 pts)  Cytoskeletal Elements
		Actin and myosin (linked to muscle function) 
			 microfilaments / myofibrils / myofibrils
		Actin - thin fiber (protein structure)
			Troponin (Ca++ interaction exposes active sites)
			Tropomyosin (is therefore unblocked)
		Myosin - thick fiber (protein structure)
		'clubs' - bridges - paddles for interaction with actin / ATP binding site
			ATPase site / hydrolysis of ATP
		Sliding Filament Concept
		Z line as a protein which separates sarcomeres (needs strong linkage)
		ATP functions to release mysoin heads from actin sites
(2 pts)  Mitochondria
		ATP production - cellular respiration
		Number of mitochondria is higher in muscle cells due to...
		Proximity within muscle fiber
		Chemiosmosis - elegant elaboration of ATP production



(2 pts) Other - Rarely Mentioned:
		Fast twitch / slow twitch (1 pt)
		Elaboration (1 pt)	
			(FT) - glycogen and anaerobic
			(ST) - oxidation of glycogen via TCA and thus aerobic
		All or nothing response
		Switches to anaerobic respiration after oxygen consumed / Myoglobin
		Muscles can only contract
		Rigor mortis 
		  (showing that ATP functions in release rather than contractive phase)
		Muscle cell is a muscle fiber or muscle cell is multinucleate
		Glycogen storage (mitochondria functions)
		Creatine phosphate - PO4 replacement
(1 pt)  Synoptic synchronization - exceptional chronology or spatial relationships