47. Which of the following statements about action potentials is correct?
(A) Action potentials for a given neuron vary in magnitude.
(B) Action potentials for a given neuron vary in duration.
(C)Action potentials are propagated down the length of the axon.
(D) Movement of ions during the action potential occurs mostly through the sodium pump.
(E)None of the above.

43. Sensory transduction of light/dark information in the vertebrate retina is accomplished by (A) rods and cones (B) horizontal cells (C)amacrine cells (D) ganglion cells (E)bipolar cells

44. The amnion cells of human embryos are derived from___________. (A) hypoblasts (B) epiblasts (C)trophoblasts (D) allantois (E)None of the above.

45. Signals from _______ induce cells above to become cells of neural plate. (A) archenteron (B) vegetal pole (C)yolk sac (D) notochord (E)None of the above.

46. What happens when a resting neuron's membrane depolarizes? (A) There is a net diffusion of Na+ out of the cell. (B) The equilibrium potential for K+ (EK) becomes more positive. (C)The neuron's membrane voltage becomes more positive. (D) The cell's inside is more negative than the outside. (E)None of the above.

48. Which of the following is a potential problem associated with genetically engineered plants? (A) Disease resistance genes may escape into the wild. (B) It will be difficult to breed engineered plants with natural types. (C)Engineered plants will be less nutritious. (D) Genetically engineered plants will not be able to reproduce on their own. (E)All of the above.

49. Scientists believe that the direction birds go when migrating is guided in part by ________. I) the stars in the night sky  II) the sun during the day  III) the magnetic field of the Earth (A) only I (B) only II (C)only III (D) I, II, and III (E)None.

50. The correct sequence of sensory processing is (A) sensory perception → stimulus reception → sensory transduction → sensory adaptation. (B) sensory perception → sensory transduction → stimulus reception → sensory adaptation. (C)stimulus reception → sensory perception → sensory adaptation → sensory transduction. (D) sensory adaptation → stimulus reception → sensory transduction → sensory perception. (E)stimulus reception → sensory transduction → sensory perception → sensory adaptation.

1. Which cellular structure generates adenosine triphosphate in prokaryotic? (A) Ribosomes (B) Mitochondria (C) Golgi apparatus (D) Plasma membrane

2. Which of the following is a ketone body? (A) Oxaloacetate (B) Acetone (C) α–hydroxybutyrate (D) All of the above

3. Which organelle is critical in initiating programmed cell death when triggered by ER stress? (A) Golgi apparatus (B) Mitochondria (C) Nucleus (D) Vacuole