DAT Biology Practice Exam Questions With Correct Answers

DAT Biology Practice Exam Which of the following does not occur during telophase? A. Reassembly of the nuclear envelope B. Reappearance of the nucleoli C. Uncoiling of the chromosomes D. Centromere division E. Dismantling of the spindles - ANS 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 - ANS 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 - ANS 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 - ANS 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 - ANS 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 - ANS 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 - ANS 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 - ANS 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 In the process of glycolysis A. NAD+ is reduced to NADH B. The final product is acetyl coenzyme A C. Oxygen is required for maximal ATP production D. There is a net production of 4 ATP per glucose molecule E. Fructose-1,6-bisphosphate is converted into acetyl coenzyme A - ANS A. NAD+ is reduced to NADH Explanation: The final product of glycolysis is pyruvate, not Acetyl-CoA. Glycolysis does not require oxygen, it is anaerobic. There is a net production of 2 ATP per glucose molecule. Glycolysis is an anaerobic series of reactions that occurs in the cytoplasm that oxidizes glucose to pyruvate The raw materials of the earth's primitive environment (the "primordial soup" did not include A. Phosphorus B. Salts C. Methanol D. Water E. Ammonia - ANS A. Phosphorus Explanation: Organic molecules such as sugars and amino acids were synthesize in a primordial environment that contained simple inorganic and organic compounds including salts, methane, ammonia, hydrogen, and water Muscle movement on the cellular level is initiated by the release of Ca2+ from the terminal cistern. Terminal cistern are associated with A. Sarcoplasmic reticulum B. Myosin cross-bridges C. Myoglobin D. Canaliculi E. Thin filaments - ANS A. Sarcoplasmic reticulum Explanation: Muscle fibers store Ca2+ in the sarcoplasmic reticulum during contraction. The SR, analogous to the endoplasmic reticulum, runs extensively throughout the fiber so that released Ca2+ will come into immediate contact with each sarcomere and cause a uniform contraction. The Ca2+ is released from the terminal cisternae of the SR Non-cyclic photophosphorylation during the light reaction produces A. ATP only B. ATP and NADPH C. ATP and glucose D. NADPH and glucose E. Glucose and water - ANS B. ATP and NADPH Explanation: In the non-cyclic pathway electrons in photosystem II are excited, passed down an electron transport chain to make ATP, but instead of being returned to chlorophyll, the electrons are transferred to photosystem I, where they are excited again and then transferred t NADP+ in the high-energy state for form NADPH. Red is dominant over white in a certain flower. To test whether a red offspring is homozygous or heterozygous in this flower, A. Cross it with a red plant that had a white parent B. Cross it with a red plant that had two red parents C. Cross it with a white plant D. Two of the above will work E. None of the above will work - ANS D. Two of the above will work Explanation: C would be a cross between R_ and rr (white). This would determine the unknown genotype. If red resulted, then the genotype must be RR. If there are any white offspring, the unknown genotype must be Rr. A would be a cross between R_ and Rr. If two individuals with the genotype AaBbCc mate, what is the probability that they will produce offspring with the genotype AABBCC? A. 1/64 B. 1/32 C. 1/16 D. 1/4 E. 1/2 - ANS A. 1/64 Explanation: The probability of two heterozygotes producing offspring that are homozygous dominant for one trait is 1/4. The probability of two heterozygotes producing offspring that are homozygous dominant for two traits: 1/4 x 1/4= 1/16. By the same logic, the probability of two heterozygotes producing offspring that are homozygous dominant for three traits is: 1/4 x 1/4 x 1/4 Which of Mendel's laws describe the behavior of genes on non homologous chromosomes? A. Law of Dominance B. Law of Segregation C. Law of Definite Position D. Law of Recessiveness E. Law of Independent Assortment - ANS E. Law of Independent Assortment Explanation: Mendel's Law of Independent Assortment states that if traits are on different chromosomes, then the alleles of these different traits should separate independently of each other into different gametes. The likelihood of two genes on the same chromosome separating independently of each other increase with the distant between two genes. Law of Dominance states that one factor (gene) of a pair may mask or inhibit the expression of the opposite member (recessive) of the pair. The Law of Segregation states that the members of a pair of genes are separate, or segregate, at the time of segregation Cellular respiration produces A. 2 ATP/mol of glucose B. 4 ATP/mol of glucose C. 12 ATP/mol of glucose D. 32 ATP/mol of glucose E. 36 ATP/mol of glucose - ANS E. 36 ATP/mol of glucose Explanation: Cellular respiration, consisting of glycolysis, Krebs cycle, and oxidative phosphorylation, yields approximately 36 ATP per mole of glucose Prokaryotes are fond in the kingdom A. Protista B. Plantae C. Fungi D. Monera E. Animalia - ANS D. Monera Explanation: Prokaryotes are found only in the kingdom Fonera. The members include bacteria and cyanobacteria (blue-green algae) During development, the solid ball of dividing embryonic cells develops a fluid-filled cavity in the middle. What is this cavity called? A. Morula B. Blastula C. Blastocoel D. Protoplasm E. Blastopore - ANS C. Blastocoel Explanation: The solid ball of embryonic cells is referred to as the morula. With the development of the fluid-filled cavity inside the morula, the ball of cells is referred to as a blastula. The blastula contains a fluid-filled cavity referred to as the blastocoel. Protoplasm is the cytoplasm within the cell. The blastopore is not formed until gastrulation and refers to the invagination of the embryo that occurs as the germ layers are formed Which of the following is characteristic of humans and fungi, but not bacteria? I. Eukaryotic II. Ribosomes III. Cell wall IV. Asexual reproduction A. I only B. II only C. I and II D. II, III, and IV E. I, III, and IV - ANS A. I only Explanation: All cells contain ribosomes During the course of DNA replication I. Only one parents strand is conservatively replicated II. Both parent strands act as templates for the synthesis of new complementary strands III. The newly synthesized DNA consists of one parent strand and one new strand A. I only B. II only C. I and III D. II and III E. I, II, and III - ANS D. II and III Explanation: As first demonstrated in the experiments of Messelsohn and Stahl, DNA replication is semi-conservative. This means the each newly synthesized duplex consists of one parental strand and one newly synthesized strand. In semi-conservative replication each parental strand is used as a template in the synthesis of a new, complementary strand. Each new duplex consists of one parental strand and one newly synthesized stand Transport of a substrate across a cell membrane with the aid of carrier molecules along the substrate's concentration gradient is defined as A. Phagocytosis B. Facilitated diffusion C. Active transport D. Osmosis E. Simple diffusion - ANS B. Facilitated diffusion Explanation: Facilitated diffusion provides the means for substances that are impermeable to the lipid bilayer to diffuse across through a protein channel along its concentration gradient. Simple diffusion is the movement of a substance across a permeable membrane along the substrate's concentration gradient. No protein carrier molecule is necessary. For example, CO2 can diffuse across the cell membrane, while Na+ would require a carrier molecule In a Hardy-Weinberg population where the frequency of the dominant allele B equals the frequency of the recessive allele b, what is the frequency of the heterozygotes in the population? A. 0 B. 0.25 C. 0.50 D. 0.75 E. 1.00 - ANS C. 0.50 Explanation: The HWE states p2 +2pq + q2 and p+q=1. If the frequency of the dominant allele is equal to the frequency of the recessive allele b then p=q=0.5 During recovery from oxygen debt, which of the following does not occur? A. Glucose is converted to pyruvate B. Pyruvate is converted to lactate C. Lactate is transported to the liver D. Lactate is converted to pyruvate - ANS B. Pyruvate is converted to lactate Explanation: During oxygen debt, the need for ATP exceeds the capacity of the mitochondria for oxidative phosphorylation. As a result, cells resort to anaerobic respiration in order to increase ATP yields. It is during this process that pyruvate is converted to lactate, not during recovery from oxygen debt