AQA A2 Biology B11 Photosynthesis Kerboodle Answers

This page contains the AQA A2 Biology B11 Photosynthesis Questions and kerboodle answers for revision and understanding.This page also contains the link to the notes and video for the revision of this topic.
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C11.1 An overview of Photosynthesis AQA A2 Biology B11 Photosynthesis Kerboodle Answers

  1. Answer: Water, Carbon Dioxide,Light.
  2. Answer: Oxygen and Glucose.
3.Answer: a. The light-dependent reaction occur in thylakoid. b.The light-independent reaction occur in stroma. 4.Answer: a.)NADP,ATP and oxygen are the products of light dependent reaction. b.) sugar and other organic molecules are the products of light independent reaction. C11.2 The light-dependent reaction AQA A2 Biology B11 Photosynthesis Kerboodle Answers 
  • Answer: In photosynthesis, the light-dependent reactions take place on the thylakoid membranes.
Answer: If chlorophyll molecules continuous absorb light energy then electrons must be replaced.
  • These replacement electrons are provided from water molecules.
  • They are split using light energy.
  • This photolysis of water yields protons.
  • These protons pass out of the thylakoid space through the ATP synthase channels and are taken up by an electron carrier called NADP.
  • The reduced NADP is important because it is a further source of chemical energy to the plant.
  • The oxygen by-product from photolysis of water is either used in respiration or diffuses out of the leaf as a waste product of photosynthesis.
  • The Equation for this process is:
Answer: a. Reduction.
  • Reduction.
  • Oxidation.
  C11.3 The Light-indpendent reactions AQA A2 Biology B11 Photosynthesis Kerboodle Answers 
Answer:RuBP is ribulose biphosphate. It is formed by taking a phosphate, coming from the splitting of ATP, and joining it with RuP, changing RuP (ribulose phospate) into RuBP. RuBP is then able to join with CO2 and form an unstable 6C molecule which is the basis for the dark reaction.
  • Answer: Reduced NADP from the light-dependent reaction is used to reduced glycerate 3-phosphate to triose phosphate TP using energy supplied bt ATP.
 
  • Answer: Apart from the reduced NADP Most triose phosphate molecules are used to regenerate ribulose bisphosphate using ATP from the light-dependent reaction.
  • Answer: In the stroma of chloroplast in photosynthetic organisms
Practice Questions
  • Answer:i) So it/CO2 is not a limiting factor (on growth/photosynthesis)
(ii)Answer: So any difference is due to iron (deficiency)(iii) Answer: Amount of triose phosphate/TP will be similar/same/low (at start)(b)Answer: 1. (Less) ATP produced;
  • (Less) reduced NADP produced;
  • ATP/reduced NADP produced during lightdependent reaction;
  • (Less) GP to triose phosphate/TP
 (c) Answer: 1. Less triose phosphate converted to RuBP;
  • CO2 combines with RuBP;
During  photosynthesis, carbon dioxide reacts with ribulose biphosphate (RuBP) to form two molecules of glycerate 3-phosphate(GP).This reaction is catalysed by the enzyme Rubisco. Rubisco can als catalyse a reaction between RuBP and oxygen to form one molecule of GP and one  molecule of phosphoglycolate. Both the reactions catalysed by Rubisco are shown in fig. 1
  • (i) Where exactly in a cell is the enzyme Rubisco found? (1 mark)
Answer: Stroma (of chloroplasts); (ii) Use the information provided to give the number of carbon atoms in one molecule of carbon dioxide of phyosphoglycolate. (1 mark)Answer: 2
  • Scientists investigated the effect of different concentrations of oxygen on the rate of absorption of carbon dioxide by leaves of soya bean plants. Their results are shown in figure 2.
Answer:
  • As oxygen (concentration) increases less Rubisco/RuBP reacts/binds with carbon dioxide;
  • Competitive inhibition / competition between oxygen and carbon dioxide for rubisco/enzyme/active site;
  • Less RuBP formed/regenerated (to join with carbon dioxide);
(c)Answer: 1. Less glycerate 3-phosphate/GP produced;
  • (Less) triose phosphate to form sugars/protein/organic (product)/any named photosynthetic product;
  • Less RuBP formed/regenerated;
  • A scientist investigated the uptake of radioactively labeled carbon dioxide in chloroplasts. She used three tubes, each containing different components of chloroplasts .She measured the uptake of carbon dioxide in each of these tubes. Her results are shown in the table:
  • Answer: Ribulose bisphosphate/RuBP
 
Answer: ATP and reduced NADP are produced in grana/thylakoids/ present in A/both tubes; 
Answer: 1. 4 000;
  • Light-dependent reaction does not occur /ATP and reduced NADP are not produced;
 
  • Answer: (Less) GP converted to TP;
  • (Less) TP converted to RuBP;
 
  • Answer: No/less ATP / ATP produced (during electron transport);
  • No/less reduced NADP / reduced NADP produced (during electron transport);
 4 (a) Answer: 1. High concentration of carbon dioxide linked with night/darkness;
  • No photosynthesis in dark/night / light required for photosynthesis/light-dependent reaction;
  • (In dark) plants (and other organisms) respire;
  • In light net uptake of carbon dioxide by plants/plants use more carbon dioxide than they produce/ rate of photosynthesis greater than rate of respiration;
  • Decrease in carbon dioxide concentration with height; 6. At ground level fewer leaves/less photosynthesising tissue/more animals/less light
 (b)Answer: 1. Carbon dioxide combines with ribulose bisphosphate/RuBP;
  • To produce two molecules of glycerate 3- phosphate/GP;
  • Reduced to triose phosphate/TP;
  • Requires reduced NADP; 5. Energy from ATP;
 
  • Answer:
  • Microorganisms are saprobionts/saprophytes;
  • Secrete enzymes (onto dead tissue) / extracellular digestion;
  • Absorb products of digestion/smaller molecules/named relevant substance;
  • Respiration (by microorganisms) produces carbon dioxide;
  • Carbon dioxide taken into leaves;
  • Through stomata
 
  • (i)Answer: Temperature and light;
 (ii) Answer: Increase in temperature causes increase in rate of photosynthesis / uptake of carbon dioxide; Increase in light/ more/medium/high light (intensity) causes increase in rate of photosynthesis / uptake of carbon dioxide; Answer: 2.75 – 2.81 (mg g-1 hr-1 ) 
  • Answer: Growth will decrease (at higher temperature);
  • Rate of respiration will increase at higher temperature;
  • Photosynthesis decreases as limited by light/ as there is less light;
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