Which of the following does not occur during telophase?
A. Reassembly of the nuclear envelope
B. Reappearance of the nucleoli
C. Uncoiling of the
... [Show More] chromosomes
D. Centromere division
E. Dismantling of the spindles
D. Centromere Division
Explanation: Centromere division occurs during anaphase of mitosis and during anaphase II of meiosis
Enzymes which catalyze the phosphorylation of organic molecules are called
A. Lipases
B. Kinases
C. Mutases
D. Amylases
E. Esterases
B. Kinases
Explanation: Lipases digest fats; Mutases remove erroneous nucleotides from DNA; Amylases break down starches into disaccharides; Esterases cleave ester bonds
The primary transmitter of the parasympathetic nervous system is
A. Norepinephrine
B. Epinephrine
C. Acetylcholine
D. Cholinesterase
E. Amylase
C. Acetylcholine
According to the first law of thermodynamics,
A. Energy transfer leads to less organization
B. A system that is isolated from any energy source increases in entropy
C. Evolution is possible through the absorption of energy
D. Energy is balanced by living things
E. Total energy in an isolated system remains constant
E. Total energy in an isolated system remains constant
Explanation: The first law of thermodynamics states "in any process, the total energy of the universe remains constant," or in other words, energy can neither be created nor destroyed. This also applies to any isolated system, i.e., any system that does not exchange mass or energy with its surroundings
The myeline sheath is NOT
A. Produced by Schwann cells in the peripheral nervous system
B. Found surrounding all vertebral axons
C. Produced by the fusion of many lamellae of plasma membrane
D. Mostly lipid in composition
E. Used to increase the speed of an action potential
B. Found surrounding all vertebral axons
Explanation: The myeline sheath only surrounds certain axons, but not all of them
In the circulatory system, blood pressure gradually drops as blood flows from artery to capillary due to
I. Friction between blood and blood vessel walls
II. The increase in total cross-sectional area
III. Arteriosclerosis (artery plaque accumulation)
A. I only
B. II only
C. I and II
D. II and III
E. I, II, and III
C. I and II
Explanation: The process of slowing down blood flow results in a decrease in blood pressure. The reduction in speed is caused in two ways. First, the small diameter of each of the capillaries is not much larger than the diameter of the red bloods cells that pass through them. This results in the friction described in statement I. Secondly, because arterioles branch into so many capillaries, the total cross sectional area of the capillaries is much greater than that of the arterioles.
The exchange of oxygen for carbon dioxide and water vapor at the alveolus occurs by
A. Active transport
B. Passive diffusion
C. Pinocytosis
D. Phagocytosis
E. Facilitated diffusion
B. Passive diffusion
Explanation: Each of the compounds listed, oxygen, carbon dioxide, and water, are permeable to the cell membrane and do not require transport proteins. This eliminates A and E. Each compound travels down its respective concentration gradients, and does so by passive diffusion
Which of the following decreases during cellular cleavage?
A. Nuclear-to-cytoplasmic-material ratio
B. Surface-to-volume ratio of each cell
C. Nutrient and gas exchange
D. Cell size
E. Number of cells
D. Cell Size
Explanation: Since the amount of cytoplasm in the group of cells does not change with these rapid divisions, the volume of the cells decreases, increasing the surface-to-volume ratio and therefore the amount of nutrient and has exchange that each cell can participate in. It also increases the nuclear-to-cytoplasmic ratio, not because the amount of nuclear material is changing, but because the amount of cytoplasmic material present in each cell continues to decrease while the amount of nuclear material remains relatively consistent between cells [Show Less]