BIO test 3 - It is the study guide practice question that are identical to the questions PDF

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It is the study guide practice question that are identical to the questions that appear on the test....

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Bio 111 Exam 3 Study Guide Chapter 6 1. The process of cellular respiration, which converts simple sugars such as glucose into CO2 and water, is an example of __________.  a catabolic pathway 2. The cellular process of breaking down large molecules into smaller ones is defined as  Catabolism 3. Which of the following is a statement of the first law of thermodynamics?  Energy cannot be created or destroyed 4. Energy transformations are always associated with an increase in the  entropy of the universe. 5. Which of the following is an example of potential rather than kinetic energy?  a molecule of glucose 6. Which of the following is true for all exergonic reactions?  The reaction proceeds with a net release of free energy. 7. For the hydrolysis of ATP to ADP + i, the free-energy change is -7.3 kcal/mol under standard conditions (1 M concentration of both reactants and products). In the cellular environment, however, the freeenergy change is about -13 kcal/mol. What can we conclude about the free-energy change for the formation of ATP from ADP and i under cellular conditions?  It is about +13 kcal/mol. 8. Which of the following describes the critical role that ATP plays in cellular metabolism?  ATP serves as an energy shuttle in the cell, coupling exergonic and endergonic reactions. 9. Which of the following statements concerning catabolic pathways is true?  They provide energy that can be used to drive cellular work. 10. What is the difference (if any) between the structure of ATP and the structure of the precursor of the A nucleotide in RNA?  There is no difference.

the figure Activity of various enzymes (a) at various temperatures and (b) at various pH.

11. Which curves on the graphs in the figure may represent the temperature and pH profiles of an enzyme taken from a bacterium that lives in a mildly alkaline hot spring at temperatures of 70° Corhi gher ?  curves 3 and 5 12. Which temperature and pH profile curves on the graphs in the figure were most likely generated from analysis of an enzyme from a human stomach, where conditions are strongly acid?  curves 1 and 4

The following question are based on the reaction A + B ↔ C + D shown in the figure

13. Which of the following represents the ΔG oft her eac t i oni nt he figure?  D 14. Which of the following represents the activation energy required for the enzyme-catalyzed reaction in the figure?  B 15. Which of the following represents the activation energy required for a noncatalyzed reaction in the figure?  C 16. Enzymes are described as catalysts, which means that they __________.  increase the rate of a reaction without being consumed by the reaction 17. Which of the following statements about enzyme-catalyzed reactions is true?  The rate of the reaction is greater than when the same reaction occurs in the absence of an enzyme. 18. A solution of starch at room temperature does not readily decompose to form a solution of simple sugars because  the activation energy barrier for this reaction cannot easily be surmounted at room temperature. 19. The active site of an enzyme is the region that  binds substrates for the enzyme 20. Which of the following is true of enzymes?  Enzymes increase the rate of chemical reaction by lowering activation energy barriers 21. The mechanism by which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as  feedback inhibition

22. Please use the following information to answer the question(s) below. A series of enzymes catalyze the reactions illustrated in the following metabolic pathway: X → Y→ Z → A.Pr oduct A binds to the enzyme that converts X to Y at a position remote from its active site. This binding decreases the activity of the enzyme. What is substance X?  a substrate 23. Which of the following is an example of cooperativity?  binding of a molecule to one subunit of a tetramer, which promotes faster binding to each of the other three subunits 24. Which of the following reactions tend to require an input of energy?  dehydration 25. ATP hydrolysis in a test tube releases only about half as much energy as ATP hydrolysis in the cell. Which of the following is the best explanation for this observation?  ATP hydrolysis in a test tube occurs under standard conditions; in the cell, reactant and product concentrations differ from standard conditions.

Chapter 7 1. When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the glucose molecule becomes  oxidized. 2. Metabolic pathways that release stored energy by breaking down complex molecules are known as  catabolic pathways. 3. When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the NAD+ molecule becomes  Reduced 4. Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?  Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O). 5. The ATP produced in glycolysis is generated by  substrate-level phosphorylation. 6. The complete oxidation of glucose (C6H12O6) to carbon dioxide and water in aerobic respiration consumes how many molecules of oxygen (O2)?  6 7. Which of the following indicates a primary path by which electrons travel downhill energetically during aerobic respiration?  glucose → NADH→ el ec t r ont r ans por tc hai n→ ox y gen 8. The oxygen consumed during cellular respiration is involved directly in which process or event?  accepting electrons at the end of the electron transport chain 9. The ATP produced in the citric acid cycle is generated by  substrate-level phosphorylation. 10. Which kind of metabolic poison would most directly interfere with glycolysis?  an agent that closely mimics the structure of glucose but is not metabolized 11. Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?  Glycolysis

12. Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?  100% 13. During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is  retained in the two pyruvates. 14. Glycolysis results in a net production of which of the following from each molecule of glucose?  2 NADH, 2 pyruvate, and 2 ATP 15. Starting with one molecule of isocitrate and ending with fumarate, how many ATP molecules can be made through substrate-level phosphorylation (see the figure)?  1 16. Which statement about the citric acid cycle is correct?  The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle. 17. A young dog has never had much energy. He is brought to a veterinarian for help, and she decides to conduct several diagnostic tests. She discovers that the dog's mitochondria can use only fatty acids and amino acids for cellular respiration, and his cells produce more lactate than normal. Of the following, which is the best explanation of the dog's condition?  His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane. 18. For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle (see the figure), what is the total number of NADH + FADH2 molecules produced?

 12 19. The primary role of oxygen in cellular respiration is to  serve as an acceptor for electrons and hydrogen, forming water. 20. Inside an active mitochondrion, most electrons follow which pathway?  citric acid cycle → NADH→ el ec t r ont r ans por tc hai n→ oxy gen

21. Brown fat cells produce a protein called thermogenin in their mitochondrial inner membrane. Thermogenin is a channel for facilitated transport of protons across the membrane. What will occur in the brown fat cells when they produce thermogenin?  ATP synthesis will decrease, and heat generation will increase 22. Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C6H12O6) in aerobic cellular respiration?  60-64 23. Which statement best supports the hypothesis that glycolysis is an ancient metabolic pathway that originated before the last universal common ancestor of life on Earth?  Glycolysis is widespread and is found in the domains Bacteria, Archaea, and Eukarya. 24. The ATP made during fermentation is generated by which of the following?  substrate-level phosphorylation 25. In alcohol fermentation, NAD+ is regenerated from NADH by  reduction of acetaldehyde to ethanol

Chapter 8 1. Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?  ATP and NADPH 2. Where does the Calvin cycle take place?  stroma of the chloroplast 3. When oxygen is released as a result of photosynthesis, it is a direct by-product of  splitting water molecules. 4. In autotrophic bacteria, where are chlorophyll-like pigments located?  in infolded regions of the plasma membrane 5. Generation of proton gradients across membranes occurs during  both photosynthesis and cellular respiration.

6. Can you answer the following questions about photosynthetic pigments and the wavelengths of light they absorb? Use the absorption spectra to answer the following questions.

Approximately what wavelength of light is best absorbed by chlorophyll a, the pigment that participates directly in the light reactions?  435 nm Which wavelength of light is best absorbed by chlorophyll b?  455 nm You obtain the pigments called carotenoids in your diet when you eat carrots. Why do carotenoids appear yellow and orange?  They absorb blue/green light and reflect yellow and red wavelengths of light. 7. Which of the following events occurs in the light reactions of photosynthesis?  Light is absorbed and funneled to reaction-center chlorophyll a. 8. What are the products of linear electron flow?  ATP and NADPH 9. What is the relationship between wavelength of light and the quantity of energy per photon?  They are inversely related. 10. In photosynthetic cells, synthesis of ATP by chemiosmosis occurs during  both photosynthesis and cellular respiration. 11. Please use the following information to answer the question(s) below. Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He found that the largest groups were found in the areas illuminated by the red and blue light. What did Engelmann conclude about the congregation of bacteria in the red and blue areas?  Bacteria congregated in these areas because they were the areas where the most oxygen was released by the algae. 12. Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be  to test for liberation of O2 in the light. 13. Reduction of oxygen to form water occurs during  cellular respiration only

14. Photorespiration occurs when rubisco combines RuBP with  O2. 15. Photorespiration lowers the efficiency of photosynthesis by  reducing the amount of sugar produced. 16. In the process of carbon fixation, three molecules of RuBP combine with three molecules of CO2 to produce three six-carbon molecules, which are then split to produce 12 molecules of 3phosphoglycerate. After phosphorylation and reduction produce 12 glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle?  release of one G3P to make sugars and regeneration of RuBP 17. In which types of plants is the enzyme rubisco found?  C3 plants only 18. Reactions that consume CO2 take place in  the Calvin cycle only 19. In C3 photosynthesis, the reactions that require ATP take place in  the Calvin cycle alone. 20. Compared to C3 plants, C4 plants  can continue to fix CO2 even at relatively low CO2 concentrations and high oxygen concentrations. 21. The NADPH required for the Calvin cycle comes from  reactions initiated in photosystem I 22. Why are C4 plants able to photosynthesize with no apparent photorespiration?  They do not use rubisco to fix CO2. 23. CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they  fix CO2 into organic acids during the night when temperatures are cooler 24. As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. What is the source of the extra ATP?  cyclic electron flow 25. the figure shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. What wavelength of light is most effective in driving photosynthesis?  420 nm

Chapter 9 1. Humans produce skin cells by mitosis and gametes by meiosis. The nuclei of skin cells produced by mitosis will have  twice as much DNA as the nuclei of gametes produced by meiosis. 2. Compared to most prokaryotic cells, eukaryotic cells typically have  more DNA molecules and larger genomes. 3. Why is it difficult to observe individual chromosomes with a light microscope during interphase?  They have uncoiled to form long, thin strands. 4. Which of the following is true of kinetochores?  They are sites at which microtubules attach to chromosomes 5. In the figure, G1 is represented by which numbered parts of the cycle?

 I or V 6. Which of the following correctly matches a phase of the cell cycle with its description?  G1: follows cell division 7. The protein complex that activates progress through the M phase checkpoint will allow which of the following to occur?  cleavage of cohesin proteins by separase 8. Which of the following is true concerning cancer cells?  They evade the normal controls that trigger programmed cell death 9. The cell cycle is regulated at the molecular level by a set of proteins known as  Cyclins 10. Besides the ability of some cancer cells to divide uncontrollably, what else could logically result in a tumor?  lack of appropriate cell death 11. For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable?  It targets only rapidly dividing cells. 12. A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle. Which of the following would result if colchicine is added to a sample of cells in G2?  The chromosomes would segregate but in a disorderly pattern. 13. If the cell whose nuclear material is shown in the figure continues toward completion of mitosis, which of the following events would occur next?

 segregation of daughter chromosomes toward the poles 14. Where are the motor proteins that move chromosomes toward the poles of the mitotic spindle located?  on the kinetochores 15. What is a cleavage furrow?  a groove in the plasma membrane between daughter nuclei 16. Diatoms and some yeasts are unicellular eukaryotes that have mechanisms of nuclear division that may resemble intermediate steps in the evolution of mitosis. Which of the following is a characteristic feature of nuclear division in these organisms?  The nuclear envelope remains intact during division 17. A group of cells is assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. How many picograms would be found at the end of S and the end of G2?

 16; 16 18. Where do the microtubules of the spindle originate during mitosis in animal cells?  Centrosome In the figure, Question 19 and21

19. In the figure, DNA synthesis is represented by which numbered parts of the cycle? 

II

20. At which phase of mitosis do the sister chromatids become daughter chromosomes?  Anaphase 21. In the figure, which of the numbered regions would contain cells at metaphase?  III only 22. Please use the following information to answer the question(s) below. The unlettered circle at the top of the figure shows a diploid nucleus with four chromosomes that have not yet replicated. There are two pairs of homologous chromosomes, one long and the other short. One haploid set is black, and the other is gray. The circles labeled A-E show various combinations of these chromosomes.

What is the correct chromosomal condition for a nucleus at prophase of mitosis?  B 23. Cells from advanced malignant tumors frequently have very abnormal chromosomes as well as an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities?

 Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities. 24. You have a series of cells, all of which were derived from tumors. How might you determine which ones are malignant?  Prepare karyotypes to identify the ones with aberrant chromosome number or structure 25. Which of the following is true of benign tumors but not malignant tumors?  They remain confined to their original site.

Chapter 10 1. If an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following?  at most, 2 alleles for that gene 2. Which of these is a way that the sexual life cycle increases genetic variation in a species?  by allowing crossing over 3. A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following?  Its gametes must have 23 chromosomes 4. A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following?  63 chromosomes in 21 sets of 3 5. Refer to the life cycles illustrated in the figure. Which of the life cycles is (are) typical for animals?

 I only 6. What number and types of chromosomes are found in a human somatic cell?  44 autosomes and 2 sex chromosomes 7. Which of the following is true of a species that has a chromosome number of 2n = 16?  Each cell has eight homologous pairs. 8. Which of the following statements best describes a karyotype?  a display of all of the chromosomes of a single cell 9. Which of the following types of cells would be produced by meiosis?  a haploid animal cell 10. The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division malfunctions, and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following?  either anaphase I or II 11. Which of the following events occurs in meiosis but not in mitosis?

 synapsis of chromosomes 12. Chromatids are separated from each other during which of the following processes?  during both mitosis and meiosis II 13. When we see chiasmata under a microscope, that lets us know that which of the following processes has occurred?  prophase I 14. How do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis?  They have half the number of chromosomes and one-fourth the amount of DNA 15. For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes?  approximately 8.4 million 16. When homologous chromosomes cross over, what is the result?  Specific proteins break the two strands of nonsister chromatids and re-join them 17. Which of the following describes a karyotype?  organized images of a cell's chromosomes 18. To visualize and identify meiotic cells at metaphase I with a microscope, what would you look for?  pairs of homologous chromosomes all aligned at the cell's center 19. For the following question(s), match the key event of meiosis with the stages listed below. I. prophase I V. prophase II II. metaphase I VI. m...