Metabolic Processes: Photosynthesis

Modified True/FalseIndicate whether the sentence or statement is true or false. If false, change the identified word or phrase to make the sentence or statement true.____ 1. The organelle that is unique to eukaryotic photoautotrophs is the chromoplast. _____________________________ 2. Light energy is principally transferred by chlorophyll b. _____________________________ 3. When exposed to bright white light chlorophyll fluoresces green. _____________________________ 4. In general, photosynthesis rates are lower at lower oxygen concentrations. ____________________________________________ 5. The location of the H+ reservoir in the chloroplast is the intermembrane space. ___________________________________Multiple ChoiceIdentify the letter of the choice that best completes the statement or answers the question.____ 1. Of the following biological compounds, which one contains the element, nitrogen?a.fatty acidsd.starchb.sugare.proteinc.glycerol____ 2. An oxidation/reduction is best shown by which of the following? amino and carboxyl group form a peptide bondb.two small molecules chemically combine to form a large onec.a base reacts with an acid to form water and a saltd.electrons are transferred from one substance to anothere.a large molecule is broken into two smaller molecules____ 3. The activity of an enzyme can be altered by changing the pH of its surroundings slightly. This change in pH works bya.causing the enzyme to precipitateb.masking its active sitec.increasing the activation energy of the reactiond.breaking its peptide bondse.altering its three dimensional shape____ 4. Which of the following is not a cofactor or coenzyme?a.Zn2+d.Fe2+b.Mn2+e.NADP+c.NAD+____ 5. Which of the following statements concerning allosteric regulation is not true?a.Allosteric sites are usually located next to, but separate from, the active site.b.Alosterically controlled enzymes usually have quaternary structure.c.’Activators’ tend to keep all the active sites available to the normal substrate.d.’Allosteric inhibitors’ stabilize the inactive form of the enzyme.e.Allosteric regulators attach to their sites using weak bonds.____ 6. Which of the following processes most likely does not involve anaerobic conditions?a.yeast causing bread dough to riseb.bacteria working in an aeration tank at a sewage plantc.bacteria in the soil help in compostingd.alcohol is produced in fermentatione.sewage breaks down in a septic tank____ 7. In an investigation of the pigments in the leaves of a particular plant, one spot moved 8.0 cm from the origin, while the solvent front moved 10.0 cm. What would the Rf value of the pigment be?a.80.0d.1.25b.8.0e.0.8c.2.0____ 8. Photophosphorylation specifically refers to thea.synthesis of glucose via carbon fixationb.splitting water as a result of lightc.synthesis of ATP by photolysisd.reduction of NADPH by electron transporte.synthesis of ATP using light____ 9. During carbon fixation, which of the following is a product?a.ATPd.carbon dioxideb.3-phosphoglyceratee.oxygenc.NADPH____ 10. The name of the process whereby a plant uses oxygen in light.a.transpirationd.photorespirationb.translocatione.photosynthesisc.photophosphorylationImagine you have five small glass jars that are sealed to the atmosphere. All the jars are filled with a bicarbonate solution (as a source of carbon dioxide) and an indicator. The differences between each jar are described below:Jar #1: Has a small fish.Jar #2: Has one small fish in addition to some aquatic plants.Jar #3: Has three small fish in addition to some aquatic plants.Jar #4: Has some aquatic plants.Jar #5: Has some aquatic plants, but the jar is completely surrounded by aluminum foil.The indicator shows you how much carbon dioxide is in each jar. The following table shows the relative amounts:Colour of pH indicator solutionRelative amount of carbon dioxideredhighgreenmedium (equivalent to atmosphere)bluelowThe following table shows the results of an experiment where the tubes were allowed to stand under natural light for several hours.ObservationJar #1Jar #2Jar #3Jar #4Jar #5Starting colour of indicatorgreengreengreengreengreenFinal colour of indicatorredgreenredbluegreen____ 11. The following are statements regarding the above results:I. respiration is taking place in all five test tubesII. respiration is exceeding photosynthesis in Jar#3III. photosynthesis is occurring in Jar#5IV. the lowest concentration of carbon dioxide is found in Jar#2Which of the above statements are correct?a.II and IIId.II and IVb.I and IIe.III and IVc.I and IVOptional Multiple Choice – The correct answer is indicated by a (*)1. Photoexcitation occurs whena. 2ADP + 2Pi —> 2 ATP on 2 cytochromesb. light releases electrons from double covalent bonds on chlorophyll ac. 2 H2O —> 4H+ + O2 + 4 electronsd. pallisade mesophylle. ultra-violet (UV)2. In a C3 plant most of the photosynthesis activity occurs in thea. bundle sheath cellsb. spongy mesophyllc. RUDP; 2PGAd. pallisade mesophylle. pyruvic acid3. C4 plants “fix” CO2 onto ________; to form ______________.a. RUDP; 2PGAb. pyruvic acid; 2PGAc. PEP; oxaloacetic acidd. chlorophyll a (bulk); chlorophyll be. glucose, water4. C3 plants “fix” CO2 onto __________; to form ____________.a. PEP; oxaloacetic acidb. pyruvic acid; 2PGAc. RUDP; 2PGAd. Glycogen, pyruvatee. Alcohol, aspartame5. The antenna pigments includea. chlorophyll a (bulk); chlorophyll b (all)b. chlorophyll b (all); carotenoids (all)c. Xanthophylls, cyaninsd. chlorophyll a (bulk); chlorophyll b (all); carotenoidse. Glycine, methylglycol6. The light reaction PRIMARILY absorbs light from the visible spectrum that isa. ultra-violet (UV)b. violetc. redd. The matrixe. green7. The light reaction occursa. the thyakoid membraneb. in the matrixc. in the stromad. Granae. Vacuole8. The dark reaction occurs in thea. matrixb. thyakoid membranec. stromad. lammmellaee. pancreas9. In the following equation, the 6 O2 originated from the6 CO2 + 12 H2O —-1 —2—> 6O2 + C6H12O6 + 6 H2Oa. 6 CO2b. 12 H2Oc. 6 H2Od. sulphure. antimony10. In the following equation, the C6 on glucose originated from the6 CO2 + 12 H2O —-1 —2—> 6O2 + C6H12O6 + 6 H2Oa. 12 H2Ob. 6 CO2c. C6H12O6d. Sulfur gase. air11. 1 and 2 on the ——-> are6 CO2 + 12 H2O —-1 —2—> 6O2 + C6H12O6 + 6 H2Oa. CO2, H2Ob. chlorophyll a and chlorophyll bc. light and chlorophylld. aspartame and proteine. DNA and chlorine12. The major end products of the LIGHT REACTION is (are)a. 4 e- + 4H+ + O2b. ATP, NADPH2c. 6O2, 6 H2Od. NADPHe. FAD+13. Carotenoids absorb light PRIMARILY from the _________ portion(s) of the visible spectrum.a. red, violetb. bluec. greend. blacke. yellow-orange14. Both the end products of the LIGHT REACTION are used in the:a. reduction of 2 PGA’s to 2 PGAL’sb. oxidation of 2 PGA’s to 2 PGAL’sc. fixation of CO2 on RUPd. Calvin cycle15. Both the end products of the light reaction are used in thea. conversion of PGAL to DHAP through a series of reactionsb. oxidation of NADPHc. conversion of RUDP to PGAL through a series of reactionsd. Cellular respiration16. Which condition below favours the highest rate of PHOTOSYNTHESIS? (select only one)(a) CO2 0.2% light 7000 1x temperature 20oC(b) CO2 0.2% light 7000 1x temperature 15oC(c) CO2 10 % light 7000 1x temperature 25oC17. Regardless of light intensity and temperature, the rate of photosynthesis will not increase when the CO2 concentration isa. below 0.2%b. above 0.03%c. above 0.2%d. up to 100%e. below 0.011%18. The rate of photosynthesis is observed by :a. counting the O2 bubbles given offb. collecting O2 gas from the reactionc. looking at the water producedd. both <a> and <b> are feasiblee. counting the number of sugars19. Photosystem II receives electrons froma. photolysis of waterb. 2 cytochromesc. NADPH2d. Mitochondriae. rubisco20. Photosystem II produces _______ for the dark reactiona. ATP onlyb. both ATP and NADPH2c. PGALd. Electronse. protons21. In Photosystem I, chloroplasts use light to producea. histamineb. CO2c. Carbond. Carbonic acide. NADPH22. Light is one factor involved with the rate of photosynthesis. Two others area. temperature and CO2b. temperature and O2c. water and ozoned. sulphur concentration and aluminium ion concentratione. chlorine concentration and H ion concentration23. The oxygen released through photosynthesis is derived froma. CO2b. waterc. ATP24. Rank the events <a> to <c> from which occurs first to which occurs last. Select the event that comes last.a. P700 is oxidizedb. photophosphorylationc. P680 is oxidized25. Rank the events <a> to <c> from which occurs first to which occurs last. Select the event that comes first.a. photophosphorylationb. P680 is oxidizedc. P700 is oxidized26. During the operation of photosystem Ia. NADPH is reduced and P700 is reducedb. P680 is reduced along with ATPc. P700 is oxidized and NADP+ is reducedd. ATP is reducede. The chloroplast is excited27. The general accomplishment of the DARK REACTION is thea. synthesis of ATPb. synthesis of PGALc. reduction of CO2 by hydrogend. Production of sulphuric acid gase. The production a alanine28. When light is absorbed by photosystem IIa. P700 is oxidized and CO2 is liberatedb. P680 is oxidized and O2 is liberatedc. P680 is converted to P700d. When the sun stops shininge. When the asparate shuttle stopsOther multiple choice questions can be found at: and, questions1. Temperature and pH affect enzyme activity. As with all other reactions, enzyme-catalyzed reactions _________________________ in speed with an increase in temperature. However, as the temperature increases beyond a critical point, the protein structure begins to get disrupted , resulting in _________________________ and loss of enzyme function. Every enzyme has a(n) _________________________ temperature at which it works best and activity tends to decrease on either side of this temperature. Most human enzymes work best at around _________________________. Some enzymes require nonprotein _________________________, such as zinc and manganese ions. Other enzymes may require organic _________________________ such as NAD+ and NADP+. A variety of substances inhibit enzyme activity. ___________________________________ are so similar to the enzyme’s substrate that they are able to enter he enzyme’s active site and block the normal substrate from binding. This process is reversible and can be overcome be increasing the concentration of the enzyme’s substrate. Another class of inhibitors does not affect an enzyme at its’ active site, they are called ___________________________________ and their effect cannot be overcome by adding more substrate.2. In a general, overall comparison of the reactions that occur during cellular respiration and photosynthesis, it can be said that the main reactant in respiration is ____________________, while in photosynthesis it is ______________________________ and _________________________. In contrast to this, the main products of cellular respiration are _________________________ and _________________________, while in photosynthesis the main product is ____________________ with an interesting waste product ____________________ that is very useful to many creatures on Earth. Cellular respiration is a process that ____________________ energy , while photosynthesis ____________________ energy.MatchingMatch each item with the correct statement below.a.ground stateg.photosystem Ib.excitationh.photosystem IIc.fluorescencei.noncyclic electron flowd.primary electron acceptorj.Z proteine.antenna complexk.photophosphorylationf.reaction centrel.cyclic electron flow____ 1. The release of energy as light as an electron returns to ground state.____ 2. The absorption of energy by an electron.____ 3. The lowest possible potential energy level of an electron.____ 4. Contains chlorophyll P680.____ 5. Transmembrane protein of chlorophyll a that absorbs light energy.____ 6. Contains chlorophyll P700.____ 7. Web of chlorophyll molecules that transfers energy to a reaction centre.____ 8. Light-dependent formation of ATP.____ 9. Photon-energized electrons move to produce only ATP.____ 10. Protein that helps split water into hydrogen ions, oxygen and electrons.Short Answer1. “Plants are the only important photosynthetic organisms.” Comment on this statement.2. What are the roles of water and light in photosynthesis?3. Photosystem I usually converts most of the light energy it receives to ATP and NADPH by noncyclic electron flow. There are times when some of the energy is used by cyclic electron flow.a. What is cyclic electron flow?b. Why is it called ‘cyclic’?c. At what times does cyclic electron flow occur?4. Complete the following table to compare the various ‘types’ of photosynthesis.C3C4CAMUsual areas were these plants are found.First enzyme to fix carbon dioxideName of molecule formed immediately following carbon dioxide fixation.Is there an ‘energy cost’ associated with carbon dioxide fixation? (Y/N)5. Design an experiment to show whether sulphur dioxide, a gas produced during many industrial processes, has an effect on photosynthesis. Be sure to include a clear hypothesis.Essay1. You may have come into this course with the impression that plants photosynthesize during the day and respire at night. Based on what you have learned in this course comment on this impression.2. Compare and contrast C4 and CAM photosynthesis in terms of their abilities to counter the process known as photorespiration.Unit 1 Test – Metabolic ProcessesAnswer Section according to government expectationsMODIFIED TRUE/FALSE1. ANS: F, chloroplast REF: C OBJ: 3.1LOC: MP1.052. ANS: F, chlorophyll a REF: K/U OBJ: 3.2LOC: MP1.013. ANS: F, red REF: K/U OBJ: 3.3LOC: MP1.014. ANS: F, higher oxygen concentrations REF: C OBJ: 3.5LOC: MP1.055. ANS: F, interior of the thylakoid REF: C OBJ: 3.6LOC: MP2.05MULTIPLE CHOICE1. ANS: E REF: K/U OBJ: 1.2 LOC: MP1.022. ANS: D REF: K/U OBJ: 1.3 LOC: MP1.043. ANS: E REF: K/U OBJ: 1.4 LOC: MP1.034. ANS: D REF: K/U OBJ: 1.4 LOC: MP1.035. ANS: A REF: K/U OBJ: 1.4 LOC: MP1.036. ANS: B REF: K/U OBJ: 2.1 LOC: MP1.067. ANS: E REF: I OBJ: 3.2 LOC: MP2.068. ANS: E REF: K/U OBJ: 3.3 LOC: MP1.059. ANS: B REF: K/U OBJ: 3.3 LOC: MP1.0510. ANS: D REF: K/U OBJ: 3.4 LOC: MP1.0611. ANS: B REF: I OBJ: 3.6 LOC: MP2.06OPTIONAL M.C. QUESTIONS:1b, 2d, 3c, 4c, 5d, 6c, 7a, 8c, 9b, 10b, 11c, 12b, 13b, 14a, 15c, 16a, 17c, 18d, 19a, 20a, 21e, 22a, 23b, 24a, 25b, 26c, 27b, 28bCOMPLETION1. ANS:increasedenaturationoptimal37?CcofactorscoenzymesCompetitive inhibitorsnon-competitive inhibitorsREF: K/U OBJ: 1.4 LOC: MP1.032. ANS:glucosecarbon dioxide/waterwater/carbon dioxidecarbon dioxide/waterwater/carbon dioxideglucoseoxygenreleasesstoresREF: K/U, C OBJ: 3.6 LOC: MP1.06, MP2.05MATCHING1. ANS: C REF: C OBJ: 3.3 LOC: MP1.062. ANS: B REF: C OBJ: 3.3 LOC: MP1.063. ANS: A REF: C OBJ: 3.3 LOC: MP1.064. ANS: H REF: C OBJ: 3.3 LOC: MP1.065. ANS: F REF: C OBJ: 3.3 LOC: MP1.066. ANS: G REF: C OBJ: 3.3 LOC: MP1.067. ANS: E REF: C OBJ: 3.3 LOC: MP1.068. ANS: K REF: C OBJ: 3.3 LOC: MP1.069. ANS: L REF: C OBJ: 3.3 LOC: MP1.0610. ANS: J REF: C OBJ: 3.3 LOC: MP1.06SHORT ANSWER1. ANS:While plants may be the most visible photosynthetic organisms, they are not the only ones and probably not the most important ones. In addition to the higher plants, which are usually the most familiar with people, organisms such as algae, photosynthetic protists and cyanobacteria also carry out photosynthesis. Given the size of the oceans, the photosynthetic organisms that live in this environment probably have a huge effect on global oxygen and carbon dioxide levels.REF: MC OBJ: 3.1, 3.5 LOC: MP3.032. ANS:- Water is needed as a source of hydrogen ions and electrons which are used in reduction reactions.- Light is needed as a source of energy to excite electrons of chlorophyll, which results in the splitting of water to form oxygen and release the hydrogen ions and electrons mentioned previously.REF: K/U OBJ: 3.3 LOC: MP1.053. ANS:a. In cyclic electron flow when photosystem I is struck by a photon with the correct energy, it will release electrons to the same carrier molecules as non-cyclic electron flow. These electrons move through a cytochrome system and cause hydrogen ions to move from the stroma across the thylakoid membrane to the inside of the thylakoid. The higher concentration of hydrogen ions inside the thylakoids can be used to make ATP. The chlorophyll molecule of PS I oxidizes the final electron carrier, gaining electrons to return to its reduced form.b. The term ‘cyclic’ is used because the chlorophyll of PS I serves as both the electron donor and electron acceptor.c. Cyclic electron flow would appear to occur when reserves of NADP+ are low, which would imply that levels of NADPH are high. These means there will be a shortage of electron acceptors, which results in electrons being accepted by the cytochrome electron carrier system.4. ANS:C3C4CAMUsual areas were these plants are found.temperatetemperate to tropicalaridFirst enzyme to fix carbon dioxiderubiscoPEP carboxylasePEP carboxylaseName of molecule formed immediately following carbon dioxide fixation.3-phosphoglycerateoxaloacetateoxaloacetateIs there an ‘energy cost’ associated with carbon dioxide fixation? (Y/N)NoYes, ATPYes, ATPREF: K/U, MC OBJ: 3.3, 3.4 LOC: MP1.05, MP3.035. ANS:Hypothesis: any clear statement indicating they understand the role of a hypothesis in framing the investigation.Controls: there should be some plants that will receive no treatment with sulphur dioxide, but otherwise are exposed to all the same conditions as the other plants.Replicates: there should be mention of repeating the experiment on several plants for both the treated and untreated group.Method: there should be some indication of how sulphur dioxide will be generated, how its application will be controlled and what will be measured to determine whether or not sulphur dioxide has an effect on photosynthesis or not.REF: I OBJ: 3.5 LOC: MP2.04ESSAY1. ANS:While it is true that plants photosynthesize during the day and respire at night it would be a mistake to assume that plants are this simple. Respiration is a process that continues on throughout the entire life of a plant, in other words it will occur both during the day and at night. Photosynthesis, on the other hand, having a requirement for light obviously can occur only when light is available. Many people choose to look at photosynthesis and respiration as ‘opposite’ processes. In terms of the gases they consume and produce, this is true, but from a biochemical point of view the reactions are extremely different. While respiration consumes oxygen and produces carbon dioxide, photosynthesis does the opposite.At night, only respiration is occurring and so there is a net production of carbon dioxide gas. As the sun rises and the light intensity increases, photosynthesis increase to a point where carbon dioxide consumption by photosynthesis equals carbon dioxide production by respiration. As light intensity increases further, the consumption of carbon dioxide in photosynthesis exceeds the production in respiration and there is a net consumption of carbon dioxide. In addition, photosynthesis will now produce more oxygen than respiration requires leading to net production of oxygen.REF: K/U OBJ: 3.6 LOC: MP1.062. ANS:Photorespiration is the oxidation of ribulose bisphosphate by rubisco and oxygen in light to form glycolate, which upon subsequent metabolism releases carbon dioxide. It is seen as a wasteful process both in terms of the carbon dioxide lost that could have become photosynthetic product, and the energy used along the way in releasing the carbon dioxide. This is a process that typically occurs in C3 plants such as many deciduous trees. Two mechanisms have evolved in higher plants to counteract the process of respiration, they are C4 and CAM photosynthesis.C4 photosynthesis is one response some plants have evolved to the problem of photorespiration. Plants such a corn and sugar cane are examples of such plants. The enzyme that fixes carbon dioxide in these plants is PEP carboxylase in the mesophyll cells of the vascular bundles, and the first product formed is oxaloacetate, a four carbon compound. PEP carboxylase has no oxygenase function as rubisco has so there is no initial problem with photorespiration. The oxaloacetate is converted to malate and shuttled into the bundle sheath cells where it is decarboxylated to pyruvate with the release of carbon dioxide which can now be fixed by rubisco which is present in these cells. However, the oxygen concentration in these cells is very low so photorespiration has been effectively eliminated but at the expense of some ATP. C4 represents a spatial separation of photosynthesis.CAM stands for crassulacean acid metabolism and is so named because it was first discovered in members of the plant family known as a the Crassulacea (e.g., cacti, pineapples, aloe). CAM is a way that some plants have evolved to avoid the problem of photorespiration. In this process the stomata of the plants are open during the night when it is cooler and less water can be lost. Carbon dioxide can enter, but the usual method of fixing the carbon, by using the energy produced in the light-dependent reactions obviously is not available. PEP carboxylase is used to fix carbon dioxide into organic acids which are stored in the vacuoles of the mesophyll cells. During the day, when the stomata are closed, the organic acids are decarboxylated and the carbon dioxide that is released is fixed by rubisco in the Calvin cycle which is located in the bundle sheath cells. There is a cost of some ATP in the process. CAM represents a temporal separation of photosynthesis.

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