34. The development of Alzheimer disease is associated with deposits of
(A) beta-amyloid proteins.
(B)protein kinase A.
(C)myosin.
(D)hemoglobin.
(E) cAMP-response-element-binding protein (CREB).

30. Mycorrhizal association with plant roots is best described as: (A) detrimental to the roots. (B)only a temporary association dependent on water uptake. (C)a symbiotic relationship between the plant and certain bacteria (D)a fungus root interrelationship. (E) a kind of fungal parasite on plant roots.

31. The correct arrangement of flower parts from the outside to the inside is: (A) carpels, stamens, sepals, petals. (B)petals, stamens, carpels, sepals. (C)stamens, sepals, petals, carpels. (D)sepals, petals, stamens, carpels. (E) stamens, carpels, sepals, petals.

32. The release of factors by cells that influence the activity of nearby cells is referred to as: (A) autocrine signaling. (B)paracrine signaling. (C)pheromonal signaling. (D)synaptic signaling. (E) endocrine signaling.

33. The critical function of the sodium-potassium pump of neurons is to move (A) Na+ and K+ into the cell and H+ out of the cell through an antiport mechanism. (B)Na+ and K+ out of the cell. (C)Na+ and K+ into the cell. (D)Na+ out of the cell and K+ into the cell. (E) Na+ into the cell and K+ out of the cell.

35. Within the vestibular system of vertebrates, hair cells help detect movement when their cilia are bent by (A) gravity. (B)statoliths. (C)the tectorial membrane. (D)otoliths. (E) the basilar membrane.

36. What is the role of calcium in muscle contractions? (A) to break the cross-bridges as a cofactor in the hydrolysis of ATP (B)to spread the action potential through the T-tubules (C)to transmit the action potential across the neuromuscular junction (D)to bind with troponin, changing its shape so that binding sites on the actin filament are exposed (E) to re-establish the polarization of the plasma's membrane following an action potential

37. The glandular secretions involved in digestion that would most likely be released as inactive precursors are (A) protein-digesting enzymes (B)fat-solubilizing bile salts (C)acid-neutralizing bicarbonate (D)carbohydrate-digesting enzymes (E) nucleases

38. Newborn humans face thermoregulatory challenges as do small mammals. One mechanism they use to generate heat is (A) shivering thermogenesis in "brown fat." (B)nonshivering thermogenesis in "brown fat." (C)convection in "brown fat." (D)evaporation in "brown fat." (E) radiation in "brown fat."

39. The "hematocrit" is a measure of which blood constituent or index? (A) blood clotting time (B)leukocytes number (C)erythrocytes volume (D)blood oxygen saturation rate (E) plasma volume

40. Most of the carbon dioxide in the blood of humans is transported (A) as dissolved CO2 in plasma. (B)as bicarbonate ion in plasma. (C)attached to hemoglobin in red blood cells. (D)attached to hemoglobin in plasma. (E) as carbonic acid.