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.

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.

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.

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.

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

4. How many cycles of β-oxidation are required to completely process a saturated arachidic acid (C20)? (A) 7 (B) 8 (C) 9 (D) 18

5. The phosphate buffer system is maximally effective at a pH close to its pKa of 6.86. What is the pH of a mixture of 0.5 M NaH2PO4 and 0.05 M Na2HPO4?(A) 5.86 (B) 6.86 (C) 7.19 (D) 7.86