Week 4 practice questions and answers PDF

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Practice questions with answers in bold for week 4 of bio 102...

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Chapter 10 1) In autotrophic bacteria, where are the enzymes located that can carry on carbon fixation (reduction of carbon dioxide to carbohydrate)? A) in chloroplast membranes B) in chloroplast stroma C) in the cytosol D) in the nucleoid E) in the infolded plasma membrane 2) When oxygen is released as a result of photosynthesis, it is a direct by-product of A) reducing NADP+. B) splitting water molecules. C) chemiosmosis. D) the electron transfer system of photosystem I. E) the electron transfer system of photosystem II. 3) A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment? A) red and yellow B) blue and violet C) green and yellow D) blue, green, and red E) green, blue, and yellow 4) Halobacterium has a photosynthetic membrane that is coloured purple. Its photosynthetic action spectrum is exactly complementary (opposite to) the action spectrum for green plants. What wavelengths of light do the Halobacterium photosynthetic pigments absorb? A) red and yellow B) blue, green, and red C) green and yellow D) red and green E) blue and red 5) What are the products of linear photophosphorylation? A) heat and fluorescence B) ATP and P700 C) ATP and NADPH D) ADP and NADP E) P700 and P680 6) Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes? A) the splitting of water B) the absorption of light energy by chlorophyll C) the flow of electrons from photosystem II to photosystem I D) the synthesis of ATP E) the reduction of NADP+ 1 Copyright © 2018 Pearson Canada Inc.

Chapter 10 7) Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH 8 solution. What would be likely to happen? A) The isolated chloroplasts will make ATP. B) The Calvin cycle will be activated. C) Cyclic photophosphorylation will occur. D) The isolated chloroplasts will generate oxygen gas. E) The isolated chloroplasts will reduce NADP+ to NADPH. 8) Which of the following statements best describes the relationship between photosynthesis and respiration? A) Respiration runs the biochemical pathways of photosynthesis in reverse. B) Photosynthesis stores energy in complex organic molecules, whereas respiration releases it. C) Photosynthesis occurs only in plants and respiration occurs only in animals. D) ATP molecules are produced in photosynthesis and used up in respiration. E) Respiration is anabolic and photosynthesis is catabolic. 9) The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during A) photosynthesis. B) respiration. C) both photosynthesis and respiration. D) neither photosynthesis nor respiration. E) photorespiration. 10) Generation of proton gradients across membranes occurs during A) photosynthesis. B) respiration. C) both photosynthesis and respiration. D) neither photosynthesis nor respiration. E) photorespiration. 11) Some photosynthetic bacteria (e.g., purple sulphur bacteria) have only photosystem I, whereas others (e.g., cyanobacteria) have both photosystem I and photosystem II. Which of the following might this observation imply? A) Photosystem II was selected against in some species. B) Photosynthesis with only photosystem I is more ancestral. C) Photosystem II may have evolved to be more photoprotective. D) Linear electron flow is more primitive than cyclic flow of electrons. E) Cyclic flow is more necessary than linear electron flow. 12) In thylakoids, protons travel through ATP synthase from the thylakoid space to the stroma. Therefore, the catalytic "knobs" of ATP synthase would be located A) on the side facing the thylakoid space. B) on the ATP molecules themselves. C) on the pigment molecules of photosystem I and photosystem II. D) on the stromal side of the membrane. E) built into the centre of the thylakoid stack (granum). 2 Copyright © 2018 Pearson Canada Inc.

Chapter 10 13) In metabolic processes of cell respiration and photosynthesis, what do the prosthetic groups such as heme and iron-sulphur complexes in components of the electron transport chain do? A) donate electrons B) act as reducing agents C) act as oxidizing agents D) transport protons within the mitochondria and chloroplasts E) both oxidize and reduce during electron transport 14) A flask containing photosynthetic green algae and a control flask containing water with no algae are both placed under a bank of lights, which are set to cycle between 12 hours of light and 12 hours of dark. The dissolved oxygen concentrations in both flasks are monitored. Predict what the relative dissolved oxygen concentrations will be in the flask with algae compared to the control flask. A) The dissolved oxygen in the flask with algae will always be higher. B) The dissolved oxygen in the flask with algae will always be lower. C) The dissolved oxygen in the flask with algae will be higher in the light, but the same in the dark. D) The dissolved oxygen in the flask with algae will be higher in the light, but lower in the dark. E) The dissolved oxygen in the flask with algae will not be different from the control flask at any time. 15) Three "turns" of the Calvin cycle generate a "surplus" molecule of glyceraldehyde 3phosphate (G3P). Which of the following is a consequence of this? A) Formation of a molecule of glucose would require nine "turns." B) G3P more readily forms sucrose and other disaccharides than it does monosaccharides. C) Some plants would not taste sweet to us. D) The formation of sucrose and starch in plants involves assembling G3P molecules, with or without further rearrangements. E) Plants accumulate and store G3P. 16) When do plants respire? A) in the dark only. B) in the light only. C) both in light and dark. D) never—they get their ATP from photophosphorylation. E) only when excessive light energy induces photorespiration. 17) According to the endosymbiotic theory, the original chloroplast was a A) chemisynthetic archaea. B) green algae. C) purple sulphur bacteria. D) mitochondria. E) photosynthetic prokaryote.

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Chapter 10 18) CO2 + H2O → [CH2O] + O2 represents the simplified equation for A) chemiosmosis. B) chemisynthesis. C) photosynthesis. D) photophosphorylation. E) respiration. 19) When pigments in an excited state relax back to ground state, they A) release energy as fluorescence and heat. B) lose an electron. C) release energy as fluorescence. D) release energy as heat. E) absorb photons. 20) Chemiosmosis in chloroplasts and mitochondria share all but one of the following conditions. A) Iron-rich cytochrome is used for electron transport. B) Electrons are passed through carriers that are progressively more electronegative. C) Protons are pumped across a membrane into a reservoir. D) An ATP synthase complex is embedded within the membrane. E) Electrons are donated from organic compounds. 21) If the process of photosynthesis had never evolved on Earth, this planet would A) only contain anaerobic organisms. B) have no land and be primarily ocean. C) have no water and be dry land. D) be very similar to the way it is today. E) have no oxygen and thus no life.

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Chapter 10 Use the following figure to answer questions 22-23.

22) The figure above shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different? A) Green and yellow wavelengths inhibit the absorption of red and blue wavelengths. B) Bright sunlight destroys photosynthetic pigments. C) Oxygen given off during photosynthesis interferes with the absorption of light. D) Other pigments absorb light in addition to chlorophyll a. E) Aerobic bacteria take up oxygen, which changes the measurement of the rate of photosynthesis. 23) What wavelength of light in the figure is most effective in driving photosynthesis? A) 420 mm B) 475 mm C) 575 mm D) 625 mm E) 730 mm 24) To identify the molecule that accepts CO2, Calvin and Benson manipulated the carbonfixation cycle by either cutting off CO2 or cutting off light from cultures of photosynthetic algae. They then measured the concentrations of various metabolites immediately following the manipulation. How would these experiments help identify the CO2 acceptor? Study the figure above to help you in determining the correct answer. A) The CO2 acceptor concentration would decrease when either the CO2 or light are cut off. B) The CO2 acceptor concentration would increase when either the CO2 or light are cut off. C) The CO2 acceptor concentration would increase when the CO2 is cut off, but decrease when the light is cut off. D) The CO2 acceptor concentration would decrease when the CO2 is cut off, but increase when the light is cut off. E) The CO2 acceptor concentration would stay the same regardless of the CO2 or light.

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Chapter 10 25) A gardener is concerned that her greenhouse is getting too hot from too much light, and seeks to shade her plants with coloured translucent plastic sheets. What colour should she use to reduce overall light energy, but still maximize plant growth? A) green B) blue C) yellow D) orange E) Any colour will work equally well. Use the following information to answer questions 26-27. A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. 26) Since the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed. What wavelengths of light should be used to maximize plant growth with a minimum of energy expenditure? A) full-spectrum white light B) green light C) a mixture of blue and red light D) yellow light E) UV light 27) If the power fails and the lights go dark, what will happen to CO2 levels? A) CO2 will rise as a result of both animal and plant respiration. B) CO2 will rise as a result of animal respiration only. C) CO2 will remain balanced because plants will continue to fix CO2 in the dark. D) CO2 will fall because plants will increase CO2 fixation. E) CO2 will fall because plants will cease to respire in the dark. 28) You have isolated pigments from an unknown plant and are studying their spectral absorption. You irradiate them with a specific wavelength, yet you see no fluorescence. What is the likely explanation? A) You didn't use the correct wavelength to excite the pigment. B) They have lost their electron. C) They are being photoprotected by other pigments. D) They are experiencing photorespiration. E) They have passed the photons absorbed to another pigment.

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Chapter 10 29) In mechanism, photophosphorylation is most similar to which of the following? A) substrate-level phosphorylation in glycolysis B) oxidative phosphorylation in cellular respiration C) the Calvin cycle D) carbon fixation E) reduction of NADP+ 30) Which process is most directly driven by light energy? A) creation of a pH gradient by pumping protons across the thylakoid membrane B) carbon fixation in the stroma C) reduction of NADP+ molecules D) removal of electrons from chlorophyll molecules E) ATP synthesis 31) Why are there several structurally different pigments in the reaction centers of photosystems? A) Excited electrons must pass through several pigments before they can be transferred to electron acceptors of the electron transport chain. B) This arrangement enables the plant to absorb light energy of a variety of wavelengths. C) They enable the plant to absorb more photons from light energy, all of which are at the same wavelength. D) They enable the reaction center to excite electrons to a higher energy level. E) This helps the plant function if some of the pigments become structurally damaged. 32) As electrons are passed through the system of electron carriers associated with photosystem II, they lose energy. What happens to this energy? A) It excites electrons of the reaction center of photosystem I. B) It is lost as heat. C) It is used to establish and maintain a proton gradient. D) It is used to phosphorylate NAD+ to NADP+, the molecule that accepts electrons from photosystem I. E) It is used to reduce NADP+ to NADPH. 33) The electrons of photosystem II are excited and transferred to electron carriers. From which molecule or structure do the photosystem II replacement electrons come? A) the electron carrier, plastocyanin B) photosystem I C) water D) oxygen E) carbon dioxide

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Chapter 11 1) What is most likely to happen to an animal's target cells that lack receptors for local regulators? A) They might compensate by receiving nutrients via a factor. B) They could develop normally in response to neurotransmitters instead. C) They could divide but never reach full size. D) They might not be able to grow and multiply in response to growth factors from nearby cells. E) Cells do not need local regulators. 2) In which of the following ways do plant hormones differ from hormones in animals? A) Plant hormones interact primarily with intracellular receptors. B) Plant hormones may travel in air or through vascular systems. C) Animal hormones are found in much greater concentration. D) Plant hormones are synthesized from two or more distinct molecules. E) Animal hormones are primarily for mating and embryonic development. 3) When a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway? A) receptor B) relay molecule C) transducer D) signal molecule E) endocrine molecule 4) Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to A) the active site of an allosteric enzyme that binds to a specific substrate. B) tRNA specifying which amino acids are in a polypeptide. C) a metabolic pathway operating within a specific organelle. D) an enzyme having an optimum pH and temperature for activity. E) an antibody in the immune system. 5) Which of the following is true for the signalling system in an animal cell that lacks the ability to produce GTP? A) It would not be able to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. B) It could activate only the epinephrine system. C) It would be able to carry out reception and transduction but would not be able to respond to a signal. D) It would use ATP instead of GTP to activate and inactivate the G protein on the cytoplasmic side of the plasma membrane. E) It would employ a transduction pathway directly from an external messenger.

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Chapter 11

6) Which of the following is usually true for receptors? A) They lead to changes in intracellular ion concentration. B) They open and close in response to protein signals. C) They are only attached to one membrane surface: exterior or interior. D) They preferentially bind with lipid signal molecules. E) They change their conformation after binding with signal molecules. 7) Which of the following is the best explanation for the inability of a specific animal cell to reduce the Ca2+ concentration in its cytosol compared with the extracellular fluid? A) blockage of the synaptic signal B) loss of transcription factors C) insufficient ATP levels in the cytoplasm D) low oxygen concentration around the cell E) low levels of protein kinase in the cell 8) Which of the following would be inhibited by a drug that specifically blocks the addition of phosphate groups to proteins? A) G protein-coupled receptor signalling B) ligand-gated ion channel signalling C) adenylyl cyclase activity D) phosphatase activity E) receptor tyrosine kinase activity 9) Adenylyl cyclase has the opposite effect of which of the following? A) protein kinase B) protein phosphatase C) phosphodiesterase D) phosphorylase E) GTPase 10) Caffeine is an inhibitor of phosphodiesterase. Therefore, the cells of a person who has recently consumed coffee would have increased levels of A) phosphorylated proteins. B) GTP. C) cAMP. D) adenylyl cyclase. E) activated G proteins.

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Chapter 11 11) An inhibitor of which of the following could be used to block the release of calcium from the endoplasmic reticulum? A) tyrosine kinases B) serine/threonine kinases C) phosphodiesterase D) phospholipase C E) adenylyl cyclase 12) Which of the following statements is true of signal molecules? A) When signal molecules first bind to receptor tyrosine kinases, the receptors phosphorylate a number of nearby molecules. B) In response to some G protein-mediated signals, a special type of lipid molecule associated with the plasma membrane is cleaved to form IP3 and calcium. C) In most cases, signal molecules interact with the cell at the plasma membrane and then enter the cell and eventually the nucleus. D) Toxins such as those that cause botulism and cholera interfere with the ability of activated G proteins to hydrolyze GTP to GDP, resulting in phosphodiesterase activity in the absence of an appropriate signal molecule. E) Protein kinase A activation is one possible result of signal molecules binding to G protein-coupled receptors. 13) Which of the following is a correct association? A) kinase activity and the addition of a tyrosine B) phosphodiesterase activity and the removal of phosphate groups C) GTPase activity and hydrolysis of GTP to GDP D) phosphorylase activity and the catabolism of glucose E) adenylyl cyclase activity and the conversion of cAMP to AMP 14) Which of the following is the best explanation for the fact that most transduction pathways have multiple steps? A) Most of the steps were already in place because they are steps in other pathways. B) Multiple steps in a pathway require the least amount of ATP. C) Multiple steps provide for greater possible amplification of a signal. D) Each individual step can remove excess phosphate groups from the cytoplasm. E) Each step can be activated by several G proteins simultaneously. 15) The best description of the function of phosphatases in signal transduction is that it A) moves the phosphate group of the transduction pathway to the next molecule of a series. B) prevents a protein kinase from being reused when there is another extracellular signal. C) amplifies the transduction signal so it affects multiple transducers. D) amplifies the second messengers such as cAMP. E) inactivates protein kinases and turns off the signal transduction.

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Chapter 11 16) What explains the increased concentration of Ca2+ in the ER? A) Calcium ions are actively imported from the cytoplasm into the ER. B) Calcium concentration is kept low in the cytoplasm because of its high usage level. C) Calcium cannot enter the plasma membrane through ion channels. D) Calcium levels in the blood or other body fluids are extremely low. E) The Ca ions are recycled from other molecules in the ER. 17) In which of the following ways could signal transduction most probably be explored in research to treat cancer? A) removal of serine/threonine phosphate acceptors from transduction pathways in colon precancerous growths B) alteration of protein kinases in cell cycle regulation in order to slow cancer growth C) increase in calcium ion uptake into the cytoplasm in order to modulate the effects of environmental carcinogens D) expansion of the role of transduction inhibitors in the cells before they give rise to cancer E) increase in the concentration of phosphodiesterases in order to produce more AMP 18) At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogens and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects? A) Estrogen is produced in very large concentration and therefore diffuses widely. B) Estrogen has specific receptors inside several cell types, but each cell responds...