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Biology Grade 12 Unit 3: ENERGY TRANSFORMATION

130 national exam questions have come from this unit. It runs 44 pages; one careful study pass takes about 3.7 hours, and its difficulty is moderate among Biology units. Each section below lists the questions set from it, with the year, and opens the page that teaches it.

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3.2 Photosynthesis · read p. 117

2018 E.C., Q23 – Which of the following structures in a leaf is primarily responsible for controlling gas exchange and water loss?
2017 E.C., Q24 – Which tissues of plant leaves are involved in waterproofing, major photosynthetic and major gas exchange activities, respectively?
2015 E.C., Q52 – Which one of the following leaf structures is correctly matched with its function?
2014 E.C., Q34 – Which one of the following is an adaptation to reduce water loss in plants?

3.2.1 Photosynthetic pigments · read p. 120

2018 E.C., Q82 – Which pigment is most responsible for the absorption of light energy in photosynthesis?
2017 E.C., Q63 – Which one of the following comparisons between cyclic and non-cyclic photophosphorylation is correct? Non- cyclic photophosphorylation
2016 E.C., Q42 – As compared to non-cyclic photophosphorylation, the cyclic photophosphorylation uses the
2016 E.C., Q41 – Which one among the following processes occurs during the light independent phase of photosynthesis?
2014 E.C., Q98 – The suitability of the structural arrangement of a chloroplast in relation to its function can be indicated by the fact that
2014 E.C., Q70 – In the below diagram of the chloroplast, what are the sites of the light-dependent and light-independent reactions of photosynthesis respectively?
2013 E.C., Q74 – The scan is low contrast with faint text bleeding through from the reverse of the page and a small 'Scanned with CamScanner' watermark at the bottom left.]
2013 E.C., Q72 – What structural arrangements make chlorophyll suit for its function?
2011 E.C., Q90 – Which of the following results in the production of oxygen during photosynthesis?
2011 E.C., Q25 – What is the ultimate source of the electrons that replace those lost from the photosystem II during photosynthesis?
2008 E.C., Q76 – What is the advantage that a photosystem containing molecules of different types of light sensitive pigments have?
2008 E.C., Q3 – What is the molecule in plant cells that first captures the radiant energy from the sun light?
2007 E.C., Q76 – which of the following happens in both cyclic and non-cyclic photophosphorylation?
2006 E.C., Q31 – The molecule of which pigment is located at the reaction center of a photosystem?
2005 E.C., Q74 – Which of the following is NOT true about photo system-II?
2005 E.C., Q85 – One of the following would be harder to see under the ordinary light microscope that is more likely to be available in school laboratories .

3.2.5 Light-Independent Reactions (Calvin cycle) · read p. 125

2018 E.C., Q88 – What does photorespiration involve in C3 plants?
2018 E.C., Q25 – What is the main purpose of boiling a leaf in water during the starch test for photosynthesis?
2018 E.C., Q27 – What is the role of guard cells in the process of transpiration?
2018 E.C., Q84 – What is the role of NADPH in the light-dependent reactions of photosynthesis?
2018 E.C., Q86 – Which of the following plants uses the C4 pathway for carbon fixation?
2018 E.C., Q85 – Which of the following occurs during the light-independent reactions (Calvin cycle)?
2017 E.C., Q66 – What happens in the mitochondrion during the reactions of photorespiration?
2017 E.C., Q65 – All of the following events happen in the reduction stages of the Calvin cycle EXCEPT
2015 E.C., Q42 – In the CAM photosynthetic pathway,
2015 E.C., Q24 – Which one of the following factors of photosynthesis is correctly matched with its effect?
2015 E.C., Q23 – During light-independent reactions of photosynthesis, glucose is synthesized through
2014 E.C., Q99 – Which one of the following events occurs during the day time in the CAM photosynthetic pathway?
2014 E.C., Q97 – During the light-independent reactions of photosynthesis
2013 E.C., Q76 – Which of the following is a correct description of the CAM pathway of photosynthesis?
2013 E.C., Q73 – Why does photorespiration take place in a hot environment? Because plants close their stomata and face H O 2 CO 2 O
2013 E.C., Q75 – Which of the following is correct about the process of glucose production in the light-independent reactions of photosynthesis?
2011 E.C., Q78 – In an experiment to study photosynthesis, a plant was provided with radioactive carbon dioxide as a metabolic tracer and the radioactive carbon was incorporated first into oxaloacetate. Which one of the following would b
2010 E.C., Q76 – During photosynthesis, which of the following is first step in the transduction of light energy to chemical Energy?
2010 E.C., Q59 – Among the following crops, which one uses a non- photosynthetic pathways?
2009 E.C., Q10 – Which of the following plants use CAM photosynthesis?
2008 E.C., Q12 – From which of the following does the $O_2$ released during the process of photosynthesis originate?
2008 E.C., Q67 – Which of the following is the adaptation by $C_4$ plants that helps them to avoid photorespiration?
2007 E.C., Q79 – Which of the following is NOT true abut plants such as tef (Eragrostistef)
2005 E.C., Q90 – Where dose the light dependent reaction of photosynthesis occur in the chloroplast?

3.3 Contributions of photosynthesis for the continuity of life, for O₂ and CO₂ balance and global warming · read p. 134

Not asked in a national paper yet.

3.4 Cellular Respiration · read p. 136

Not asked in a national paper yet.

3.4.3 The site of cellular respiration · read p. 139

2018 E.C., Q91 – What is the main role of ATP in cellular metabolism?
2018 E.C., Q95 – Which part of the mitochondria is involved in oxidative phosphorylation?
2018 E.C., Q96 – What is the main purpose of a respirometer?
2018 E.C., Q98 – Which type of fermentation occurs in muscle cells when oxygen is scarce?
2018 E.C., Q92 – Which of the following is a product of the Krebs cycle?
2018 E.C., Q7 – Which of the following best describes the process of fermentation in yeast cells?
2018 E.C., Q87 – What is the primary reason that C4 and CAM plants are more efficient in hot, dry climates?
2018 E.C., Q97 – What happens during fermentation in the absence of oxygen?
2018 E.C., Q90 – Where does glycolysis occur in a eukaryotic cell?
2018 E.C., Q83 – Where does the light-dependent reaction of photosynthesis take place?
2018 E.C., Q6 – What is the main product of anaerobic respiration in muscle cells during vigorous exercise?
2018 E.C., Q81 – What is the primary function of the Calvin cycle in photosynthesis?
2018 E.C., Q94 – What is the final electron acceptor in the electron transport chain (ETC)?
2018 E.C., Q93 – What occurs during the pyruvate oxidation (link reaction)?
2018 E.C., Q35 – What is the primary function of oxidoreductase enzymes?
2017 E.C., Q83 – In a complete oxidation of glucose molecule, how many net ATP molecules are produced by substrate level phosphorylation?
2017 E.C., Q78 – Which one of the following statements describes an event of the process of electron transport system correctly?
2017 E.C., Q86 – What is the difference between aerobic and anaerobic respirations?
2017 E.C., Q70 – Which one of the following is correct about the energy liberation phase of glycolysis pathway? It
2017 E.C., Q69 – Which of the following is the difference between substrate level phosphorylation and oxidative phosphorylation? Substrate level phosphorylation
2017 E.C., Q62 – What are the roles of grana and stroma in the process of photosynthesis? Grana is a site for
2016 E.C., Q45 – Which one of the following descriptions about glycolysis is correct? It is a process
2016 E.C., Q21 – During oxidative phosphorylation, ATP is produced by combining ADP and inorganic phosphate using energy released from
2016 E.C., Q22 – Which one of the following comparisons between substrate-level and oxidative phosphorylation is correct? During substrate-level phosphorylation
2016 E.C., Q12 – Why are enzymes considered special molecules in metabolism? Because
2016 E.C., Q24 – Which one of the following determines the cause and effect of lactate production during physical exercise?
2016 E.C., Q20 – Which one of the following alternatives contains only organic molecules: Methane, calcium carbonate, linoleic acid and glucose.
2015 E.C., Q7 – In the aerobic cellular respiration
2015 E.C., Q21 – What happens during the electron transport system of respiration? The
2015 E.C., Q10 – Which one of the following processes of aerobic respiration takes place in the Krebs cycle?
2014 E.C., Q48 – Which of the following processes explains lactate production during anaerobic respiration in animal cells?
2014 E.C., Q44 – Niacin is used to make the coenzyme
2014 E.C., Q96 – In the tropical regions, where there is higher temperature, which one of the following is most likely to take place in the C3 plant's? Rubisco binds with
2014 E.C., Q46 – The hydrogen ions that used to turn the rotor of ATP synthase come from
2014 E.C., Q47 – What triggers fermentation during exercise?
2014 E.C., Q49 – Which one of the following descriptions holds true for the link reaction of respiration?
2013 E.C., Q82 – How does our body synthesize some of the amino acids in our body? From
2013 E.C., Q18 – During alcoholic fermentation, is released when
2013 E.C., Q17 – Suppose two moles of glucose is burned aerobically. How many moles of ATP can be produced by substrate level phosphorylation in Krebs cycle?
2013 E.C., Q16 – Which event of cellular respiration takes place in the cytoplasm eukaryotic cells?
2013 E.C., Q20 – Why do we get tired and fatigued during heavy exercise such as long distance running? It is due to
2013 E.C., Q19 – During anaerobic respiration, reduced NAD is required to
2011 E.C., Q24 – In which part of mitochondria does the Kreb's cycle take place?
2011 E.C., Q89 – Which one is first inhibited if a cell contains excess of ATP?
2011 E.C., Q39 – How many ATP molecules are produced during the complete cellular respiration of one glucose molecule?
2011 E.C., Q77 – Which of the four stages in the aerobic respiration of glucose does NOT produce ATP?
2011 E.C., Q53 – The different steps for complete aerobic respiration are:
2010 E.C., Q45 – In the processes of photosyntheses light is necessary to:
2010 E.C., Q33 – Why is that longer races by athletes must be run slower than shorter than shorter races?
2010 E.C., Q44 – Which of the following takes place under normal conditions as electrons flow down the electron transport chain of the mitochondria?
2010 E.C., Q23 – One of the following groups of plants carry out light dependent and ligh independent reactions of photosynthesis in separate cells of the leaf .
2010 E.C., Q75 – Which of the following molecules can provide the cell the least amount of energy per molecule?
2010 E.C., Q58 – Where is convergence point for the metabolism of the building blocks of carbohydrates lipids and proteins
2010 E.C., Q22 – At which stage is most of the carbon dioxide released during aerobic respiration?
2009 E.C., Q72 – During which stage of aerobic respiration dose oxidative phosphorylatuion occur?
2009 E.C., Q5 – Which of the following laboratory tools is LEAST accurate to measure 1 ml of liquid?
2009 E.C., Q53 – Anaerobic metabolism refers to the generation of ATP:
2009 E.C., Q75 – During anaerobic respiration, what is the gross number of ATP molecules that are produced per glucose molecule?
2009 E.C., Q80 – For which of the following processes is ATP NOT required?
2009 E.C., Q54 – The conversion of one molecule of glucose to two molecule of pyruvate results in the net formation of:
2009 E.C., Q55 – During alcohol fermentation pyruvic acid in the presence of pyruvate decarboxylase is first converted to .
2009 E.C., Q71 – During the Krebs cycle, to which of the following molecule is most of the energy released from food transferred?
2009 E.C., Q52 – Glycolysis occurs in the
2009 E.C., Q32 – Which of the following stage of photosynthesis can take place in the dark?
2008 E.C., Q75 – Which phosphate bond of the ATP is broken when the energy it contain is needed for cellular activity?
2008 E.C., Q74 – which of the following substance is NOT formed when yeasts ferment glucose?
2008 E.C., Q22 – What happens in first reaction of the Krebs cycle during energy transformation?
2008 E.C., Q65 – During which of the following processes in cellular respiration are most of the ATPs formed?
2007 E.C., Q88 – What is the purpose of the in folding of the inner -membrane of the mitochondrion?
2007 E.C., Q64 – When athletes take part in short distance running, how do the cells generate most of the energy that is quickly needed?
2007 E.C., Q71 – Cells immediately use the energy that electrons lose as they pass along the chain of electron carriers to:
2007 E.C., Q5 – Which of the following is a coenzyme
2007 E.C., Q80 – What does the fermentation of glucose by yeast normally yield?
2006 E.C., Q38 – Where exactly in the cell dose the Krebs cycle take place?
2006 E.C., Q79 – During aerobic respiration what is the route through which protons return from the mitochondrial inter-membrane space back to its matrix?
2006 E.C., Q25 – During the krebs cycle which of the following molecule temporarily stores most of the energy released from food molecule
2006 E.C., Q80 – From which of the processes of cellular respiration is the majority of the ATP generated?
2006 E.C., Q36 – If present in the fermentation system which one of the following would negatively affect alcohol production by yeasts?
2006 E.C., Q21 – At which stage is most of the ATP generated in aerobic respiration?
2006 E.C., Q40 – Which of the following substance is NOT necessary for photosyntheseis to take place?
2006 E.C., Q12 – How many net ATP molecule are generated through anaerobic respiration , when a single glucose molecule is change to pyruvate in the human body?
2006 E.C., Q68 – Which of the following groups of plants carry out light dependent and light independent reaction of photosynthesis in separate cells?
2005 E.C., Q24 – During chemiosmosis, what substance diffuses from one side to the other side of the membrane?
2005 E.C., Q91 – In which process is ATP generated during short distance hight speed running ?