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Biology · Textbook solutions

Photosynthesis

Every solved example, exercise, and miscellaneous question, in the order the textbook teaches them. · 29 questions

Exercise

29 q

Q1. Choose correct option

Practice · 10
  1. Choose correct option
    Ex Q1(A)
    A cell that lacks chloroplast does not

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  2. Ex Q1(B)
    Energy is transferred from the light reaction step to the dark reaction step by

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  3. Ex Q1(C)
    Which one is wrong in photorespiration

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  4. Ex Q1(D)
    Non-cyclic photophorylation differs from cyclic photophosphorylation in that former

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  5. Ex Q1(E)
    For fixation of 6 molecules of CO2\text{CO}_2 and formation of one molecule of glucose in Calvin cycle, requires

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  6. Ex Q1(G)
    The head and tail of chlorophyll molecule are made up of

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  7. Ex Q1(H)
    The net result of photo-oxidation of water is release of .................

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  8. Ex Q1(I)
    For fixing one molecule of CO2\text{CO}_2 in Calvin cycle .............. are required

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  9. Ex Q1(J)
    In presence of high concentration of oxygen, RuBP carboxylase converts RuBP to ................

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  10. Ex Q1(K)
    The sequential order in electron transport from PSII to PSI of photosynthesis is

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Q2. Answer the following questions

Practice · 17
  1. Answer the following questions
    Ex Q2(A)
    Describe the light-dependent steps of photosynthesis. How are they linked to the dark reactions?
  2. Ex Q2(B)
    Distinguish between: a. respiration and photorespiration b. absorption spectrum and action spectrum c. cyclic photophosphorylation and non-cyclic photophosphorylation
  3. Ex Q2(C)
    What are the steps that are common to C3\text{C}_3 and C4\text{C}_4 photosynthesis?
  4. Ex Q2(D)
    Are the enzymes that catalyse the dark reactions of carbon fixation located inside the thylakoids or outside the thylakoids?
  5. Ex Q2(E)
    Calvin cycle consists of three phases, what are they? Explain the significance of each of them.
  6. Ex Q2(F)
    Why are the plants that consume more than the usual 18 ATP to produce 1 molecule of glucose favoured in tropical regions?
  7. Ex Q2(G)
    What is the advantage of having more than one pigment molecule in a photocentre?
  8. Ex Q2(H)
    Why does chlorophyll appear green in reflected light and red transmitted light? Explain the significance of these phenomena in terms of photosynthesis.
  9. Ex Q2(I)
    Explain why photosynthesis is considered the most important process in the biosphere.
  10. Ex Q2(J)
    Why is photolysis of water accompained with non-cyclic photophosphorylation?
  11. Ex Q2(K)
    In C-4 plants, why is C-3 pathway operated in bundle sheath cells only?
  12. Ex Q2(L)
    What would have happened if C-4 plants did not have Kranz anatomy?
  13. Ex Q2(M)
    Why does RUBISCO carry out preferentially carboxylation than oxygenation in C4\text{C}_4 plants?
  14. Ex Q2(N)
    What would have happened if plants did not have accessoy pigments?
  15. Ex Q2(O)
    How can you identify whether the plant is C3\text{C}_3 or C4\text{C}_4? Explain / Justify.
  16. Ex Q2(P)
    In C4\text{C}_4 plants, bundle sheath cells carrying out Calvin cycle are very few in number, even then, C4\text{C}_4 plants are highly productive. Explain.
  17. Ex Q2(Q)
    What is functional significance of Kranz anatomy?

Q3. Correct the pathway and name it

Practice · 1
  1. Ex Q3
    Correct the pathway and name it [Figure: two adjoining boxes, 'Mesophyll cell' on the left and 'Bundle Sheath Cell' on the right. An arrow brings CO2\text{CO}_2 in from the top, into the bundle sheath cell, to 'OAA', which sits at the boundary on the bundle sheath side. In the mesophyll cell an arrow curves from 'PEP' to 'OAA'; an arrow runs from 'OAA' back to 'Malic Acid' in the mesophyll cell; from 'Malic Acid' one arrow returns to 'PEP' and another crosses into the bundle sheath cell to 'CO2\text{CO}_2'. Inside the bundle sheath cell is a circular cycle labelled 'C3\text{C}_3 pathway'.]

Q4. Is there something wrong in following schematic...

Practice · 1
  1. Ex Q4
    Is there something wrong in following schematic presentation? If yes, correct it so that photosynthesis will be operated [Figure: a scheme of the light reaction. Light from the sun (a wavy arrow) falls on 'PS-I' on the left. Above PS-I is a 'Primary acceptor' with an arrow pointing down to PS-I and another arrow to 'Cytochrome complex'. Between PS-I and the cytochrome complex an arc turns 'ADP' into 'ATP'. An arrow runs from the cytochrome complex to 'PS-II'. From PS-II an arrow points up to a second 'Primary acceptor', which has an arrow to 'NADP reductase'; below it an arc turns 'NADP+\text{NADP}^+' into 'NADPH'. Along the bottom, 'H2O\text{H}_2\text{O}' has an arrow to '2H++1/2 O2↑+2e−2\text{H}^+ + 1/2\ \text{O}_2 \uparrow + 2\text{e}^-'; a curved arrow goes from the 2H+2\text{H}^+ up to NADP+\text{NADP}^+, and a line from the 2e−2\text{e}^- runs back along the bottom and up into PS-I.]