Chapter 13 : Photosynthesis in Higher Plants

Why does not photorespiration take place in C4 plants?

Why is RuBisCo enzyme the most abundant enzyme in the world?

What special anatomical features are displayed by leaves of C4 plants?
How do they provide advantage over the structure of C3 plants?

Why is the RuBisCo enzyme more appropriately called RUBP
Carboxylase-Oxygenase and what important role does it play in
photosynthesis?

What are the important events and end products of the light reaction?

Under what conditions are C4 plants superior to C3?

What can we conclude from the statement that the action and absorption
spectrum of photosynthesis overlap? At which wavelength do they show
peaks?

Which property of the pigment is responsible for its ability to initiate the
process of photosynthesis? Why is the rate of photosynthesis higher in
the red and blue regions of the spectrum of light?

Is it correct to say that photosynthesis occurs only in leaves of a plant?
Besides leaves, what are the other parts that may be capable of carrying
out photosynthesis? Justify.

Suppose Euphorbia and Maize are grown in the tropical area.
a. Which one of them do you think will be able to survive under such
conditions?
b. Which one of them is more efficient in terms of photosynthetic
activity?
c. What difference do you think are there in their leaf anatomy?

Why do we believe chloroplast and mitochondria to be semi-autonomous
organelle?

Tomatoes, carrots and chillies are red in colour due to the presence of
one pigment. Name the pigment. Is it a photosynthetic pigment?

A process is occurring throughout the day, in ‘X’ organism. Cells are
participating in this process. During this process ATP, CO2 and water
are evolved. It is not a light dependent process.
a. Name the process.
b. Is it a catabolic or an anabolic process?
c. What could be the raw material of this process?

In what kind of plants do you come across ‘Kranz’ anatomy? To which
conditions are those plants better adapted? How are these plants better
adapted than the plants, which lack this anatomy?

Six turns of Calvin cycle are required to generate one mole of glucose.
Explain.

Find out how Melvin Calvin worked out the complete biosynthetic
pathway for synthesis of sugar.

Explain how during light reaction of photosynthesis, ATP synthesis is a
chemiosmotic phenomenon.

Why does the rate of photosynthesis decrease at higher temperatures?

What conditions enable Rubis CO to function as an oxygenase? Explain
the ensuing process.

In tropical rain forests, the canopy is thick and shorter plants growing
below it, receive filtered light. How are they able to carry out
photosynthesis ?

Photosynthetic organisms occur at different depths in the ocean. Do
they receive qualitatively and quantitatively the same light? How do they
adapt to carry out photosynthesis under these conditions?

If a green plant is kept in dark with proper ventilation, can this plant
carry out photosynthesis? Can anything be given as supplement to
maintain its growth or survival?

How are photosynthesis and respiration related to each other?

Do reactions of photosynthesis called, as ‘Dark Reaction’ need light?
Explain.

Chlorophyll ‘a’ is the primary pigment for light reaction. What are
accessory pigments? What is their role in photosynthesis?

Succulents are known to keep their stomata closed during the day to
check transpiration. How do they meet their photosynthetic CO2
requirements?

What is the basis for designating C3 and C4 pathways of photosynthesis?

Which products formed during the light reaction of photosynthesis are
used to drive the dark reaction?

ATPase enzyme consists of two parts. What are those parts? How are
they arranged in the thylakoid membrane? Conformational change occur
in which part of the enzyme?

Where is NADP reductase enzyme located in the chloroplast? What is
the role of this enzyme in proton gradient development?

Does moonlight support photosynthesis? Find out.

Can girdling experiments be done in monocots? If yes, How? If no, why
not?

a. NADP reductase enzyme is located on _________________.
b. Breakdown of proton gradient leads to release of _________________.

Cyanobacteria and some other photosynthetic bacteria don’t have
chloroplasts. How do they conduct photosynthesis?

Explain the process of bio-synthetic phase of photosynthesis occurring in chloroplast.

How does temperature affect photosynthesis?

Distinguish between photo system – I and Photo system – II

Give advantages of C₄ cycle over C₃ Cycle.

What is kranz anatomy?

Compare between chlorophyll ‘a’ and chlorophyll ‘b’?

Give examples of photosynthetic micro – organisms which also fixes
atmospheric nitrogen?

What is the end product of light reaction?

Explain chlorophyll is an essential photosynthetic pigment?

Briefly explain the chemisomotic hypothesis?

Why are C₄ plant preferred in the tropical region?

What is the advantage of having more than one pigment molecule in a photo
centre?

What is the law of limiting factor?

Explain the role of water in photosynthesis.

Differentiate between respiration and photorespiration.

What is the site for photosynthesis in Opuntia?

Define photosynthesis?

Why photosynthesis important?

(a) suggest some habitats or natural circumstances in which
(i) Light intensity
(ii) CO2 concentration
(iii) temperature might be limiting factors in photosynthesis.
(b) In C4 plants which type of chloroplast is specialized for light reactions and
which for dark reactions?
(c) Why is it an advantage that bundle sheath chloroplast lack grana?

What is the advantage of using chlorella rather than a higher plant?

Explain -There is no oxygen evolution in bacterial photosynthesis.

What are the two main functions of pigments other than chlorophyll in green
leaves?

What are the enzymes that catalyze the dark reaction of carbon fixation
located?

Name the cell – organelles involved in photorespiration.

Name the cell – organelles involved in photorespiration.

Name one plant that carries out photosynthesis at night?

Expand NADP.

Give comparison between the following: (a) C3 and C4 pathways (b) Cyclic and non-cyclic photophosphorylation (c) Anatomy of leaf in C3 and C4 plants

 Figure shows the effect of light on the rate of photosynthesis. Based on the graph, answer the following questions: (a) At which point/s (A, B or C) in the curve is light a limiting factor? (b) What could be the limiting factor/s in region A? (c) What do C and D represent on the curve?

Look at leaves of the same plant on the shady side and compare it with the leaves on the sunny side. Or, compare the potted plants kept in the sunlight with those in the shade. Which of them has leaves that are darker green ? Why?

Why is the colour of a leaf kept in the dark frequently yellow, or pale green? Which pigment do you think is more stable?

Suppose there were plants that had a high concentration of Chlorophyll b, but lacked chlorophyll a, would it carry out photosynthesis? Then why do plants have chlorophyll b and other accessory pigments?

RuBisCO is an enzyme that acts both as a carboxylase and oxygenase. Why do you think RuBisCO carries out more carboxylation in C4 plants?

Even though a very few cells in a C4 plant carry out the biosynthetic – Calvin pathway, yet they are highly productive. Can you discuss why?

By looking at which internal structure of a plant can you tell whether a plant is C3 or C4? Explain.

By looking at a plant externally can you tell whether a plant is C3 or C4? Why and how?