Photosynthesis in Higher Plants NCERT

Photosynthesis is important because:
I. It is the primary source of all food on earth.
II. It is responsible for the release of oxygen into the atmosphere by green plants.

Julius von Sachs provided evidence for:
I. production of glucose when plants grow
II. location of green substance in plants in special bodies
Which of the following will be true in light of the information given above?
A. Glucose produced during photosynthesis is usually stored as cellulose in plants.
B. The ‘green substance’ refers to chlorophyll.
C. ‘Special bodies’ refer to chloroplasts in the plant cells.

Consider the given two statements:
Statement I: Water molecules appear on both side of the equation for photosynthesis in higher plants.
Statement II: The water molecules that enter the reaction are not the same molecules that emerge from the reaction

Joseph Priestley \(
\text { (1733-1804) }
\) in \(
1770
\) performed a series of experiments that revealed the essential role of air in the growth of green plants. Priestley observed that a candle burning in a closed space – a bell jar, soon gets extinguished (Figure a, b, c, d). Similarly, a mouse would soon suffocate in a closed space. He concluded that a burning candle or an animal that breathe the air, both somehow, damage the air. But when he placed a mint plant in the same bell jar, he found that the mouse stayed alive and the candle continued to burn.

The conclusions that can be drawn from these experiments will be:
I. Plants restore to the air whatever breathing animals and burning candles remove.
II. Sunlight is essential to the plant process that somehow purifies the air fouled by burning candles or breathing animals.

C.B van Niel proved that:

The correct and complete equation for the process of photosynthesis in higher plants will be:

\(
\begin{array}{ll}
\text{1.} & 6CO_2 + 12H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2 + 6H_2O \\
\text{2.} & 6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2 \\
\text{3.} & CO_2 + H_2O + \text{light energy} \rightarrow [CH_2O] + O_2 \\
\text{4.} & C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O \\
\end{array}
\)

In the chloroplast:
Statement I: The membrane system is the site of enzymatic reactions leading to synthesis of sugar.
Statement II: The stroma is responsible for trapping the light energy and also for the synthesis of ATP and NADPH.

Consider the given two statements:
I: Carbon reactions during photosynthesis in higher plants are called as dark reactions.
II: They occur in darkness and they are not light dependent.

The absorption spectrum in the given diagram will be of:

\(
\begin{array}{|l|l|}
\hline \text { 1. Chlorophyll a } & \text { 2. Chlorophylld } \\
\hline \text { 3. Carotenoids } & \text { 4. Retinol } \\
\hline
\end{array}
\)

The wavelengths of light most useful in photosynthesis are:

The relationship between photosynthesis and respiration can be best described as:

Match each item in COLUMN I with one in COLUMN II and select the correct match from the codes given:

\(
\begin{array}{|l|l|l|l|}
\hline & \text { COLUMN I } & & \text { COLUMN II } \\
\hline \text { A } & \text { Chlorophyll a } & \text { P } & \text { Bright or blue-green } \\
\hline \text { B } & \text { Chlorophyll b } & \text { Q } & \text { Yellow-green } \\
\hline \text { C } & \text { Xanthophylls } & \text { R } & \text { Yellow } \\
\hline \text { D } & \text { Carotenoids } & \text { S } & \text { Yellow to yellow-orange } \\
\hline
\end{array}
\)

Codes:-

\(
\begin{array}{|l|l|l|l|l|}
\hline & \text { A } & \text { B } & \text { C } & \text { D } \\
\hline 1 . & \text { P } & \text { Q } & \text { R } & \text { S } \\
\hline 2 . & \text { Q } & \text { R } & \text { S } & \text { P } \\
\hline 3 . & \text { R } & \text { S } & \text { P } & \text { Q } \\
\hline 4 . & \text { S } & \text { P } & \text { Q } & \text { R } \\
\hline
\end{array}
\)

The accessory pigments of photosynthesis:
I. Include Carotenoids and Xanthophylls but not Chlorophyll b.
II. Enable a wider range of wavelength of incoming light to be utilised for photosynthesis.
III. Protect Chlorophyll a from photo-oxidation.

The correct statements about photosynthesis include:
I. the light-dependent reactions can occur only in the light, the light-independent reactions only in the dark
II. photorespiration is more efficient at producing glucose than is photosynthesis
III. the light-dependent reactions produce the energy-rich compounds that are used to run the light-independent reactions.

The splitting of water during oxygenic photosynthesis in higher plants:
I. is associated with PS II
II. releases one molecule of oxygen on splitting of two water molecules
III. releases protons and oxygen in the thylakoid lumen

The given diagram shows the scheme of :-

The ‘light reaction’ of photosynthesis in higher plants does not include:

In Section 11.7, NCERT says that “immediately after light becomes unavailable, the biosynthetic process continues for some time and then stops”. Why does it stop after some time?

Identify the correct statement regarding the functioning of photosystem II?

The products of non-cyclic photophosphorylation include:

In the Z-scheme, transfer of electrons starts from:

The ATP synthase consists of two parts where:

Chemiosmosis in chloroplasts is possible because of:

Consider the given two statements:
Statement I: When only PS I is functional, the electron is circulated within the photosystem and the phosphorylation occurs due to cyclic flow of electrons.
Statement II: Cyclic photophosphorylation also occurs when only light of wavelengths beyond 680 nm are available for excitation.

The ATP synthase complexes in a plant cell are located:
I. in the thylakoid membrane
II. in the plasma membrane
III. in the inner mitochondrial membrane

Regarding the thylakoid membrane:
I. Plastoquinone is located within the membrane
II. Plastocyanin is located on the inner lumen side of the membrane
III. NADP reductase is located on the stroma side of the membrane

Consider the given two statements:
Statement I: \(
\mathrm{CF}_1
\) particle of ATP synthase makes ATP molecules.
Statement II: \(
\mathrm{CF}_1
\) particle of ATP synthase is embedded in the thylakoid membrane and forms a transmembrane channel that carries out facilitated diffusion of protons across the membrane.

This is an intext question in Section 11.7.1 NCERT. How many carbon atoms does the primary carbon dioxide acceptor have in \(
\mathrm{C}_3 \) photosynthesis?

The \(
\mathrm{C}_3 \) pathway:

Consider the following two statements regarding RuBisCO:
I. When carbon dioxide is the substrate, the product of the carboxylase reaction is finally two molecules of glycerate-3-phosphate.
II. When molecular oxygen is the substrate, the products of the oxygenase reaction are two molecules of phosphoglycolate.

\(
\begin{array}{|l|l|}
\hline \text { 1. Only I is correct } & \text { 2. Only II is correct } \\
\hline \text { 3. Both I and II are correct } & \begin{array}{l}
\text { 4. Both I and II are } \\
\text { incorrect }
\end{array} \\
\hline
\end{array}
\)

Which of the following must occur in the biochemical pathway of Calvin cycle?

Identify the incorrect statement regarding the light independent reactions in photosynthesis:

The number of turns of Calvin cycle required to produce one molecule of Glyceraldehyde-3 phosphate is:

This is based on the Table 13.1 in NCERT. Identify the correctly matched rows:

\(
\begin{array}{|l|l|l|l|}
\hline
& & \text{C}_3 \text{ Plants} & \text{C}_4 \text{ Plants} \\
\hline
\text{I.} & \text{Productivity} & \text{Low} & \text{High} \\
\hline
\text{II.} & \text{CO}_2 \text{ Compensation Point} & \text{Low} & \text{Low } \\
\hline
\text{III.} & \text{Temperature Optimum} & 20\text{–}25^{\circ} \mathrm{C} & 30\text{–}45^{\circ} \mathrm{C} \\
\hline
\end{array}
\)

\(
\begin{array}{|l|l|}
\hline \text { 1. Only I and II } & \text { 2. Only I and III } \\
\hline \text { 3. Only II and III } & \text { 4. I, II and III } \\
\hline
\end{array}
\)

Identify the correct statements regarding RuBisCO:
I. It catalyzes the carboxylation of \(
\mathrm{CO}_2 \) to ribulose 1,5 bisphosphate.
II. It initiates photorespiration when the \(
\mathrm{CO}_2 \) / \(
\mathrm{O}_2\) ratio is low.
III. It catalyzes the reduction of two molecules of PGAL to form glucose.

Identify Incorrectly matched pair:-

\(
\begin{array}{|l|l|l|}
\hline \text { 1. } & \text { PS I } & \text { P700 is reaction center } \\
\hline \text { 2. } & \text { RuBP } & 5 \text { carbon compound } \\
\hline \text { 3. } & \text { PS II } & \text { P680 is reaction center } \\
\hline \text { 4. } & \text { C }_3 \text { plants } & \text { Kranz anatomy } \\
\hline
\end{array}
\)

The \(
\mathrm{C}_3 \)and \(
\mathrm{C}_4 \) photosynthesis pathway are so called because the initial carbon fixation product in them are respectively:

The following diagram shows the \(
\mathrm{C}_4 \) photosynthetic carbon cycle. A and B can respectively be:

Identify the incorrect statement regarding the comparison of \(
\mathrm{C}_4 \) plants to the \(
\mathrm{C}_3 \) plants:

In Hatch and Slack pathway:
I. The \(
\mathrm{C}_4 \) acid OAA is formed in the mesophyll cells.
II. Malic acid or aspartic acid are transported to the bundle sheath cells.
III. \(
\mathrm{C}_4 \) acids are broken down to release carbon dioxide and a 3 carbon molecule in mesophyll cells.
IV. The 3 carbon molecule is transported back to the bundle sheath cell where it is converted to PEP again.

\(
\mathrm{C}_4 \) plants are special. Which of the following will be true for \(
\mathrm{C}_4 \) plants?

a. They have a special type of leaf anatomy
b. They tolerate higher temperature
c. They show a response to high light intensities
d. They lack a process called photorespiration
e. They have greater productivity of biomass

In Section 11.9, NCERT states that photorespiration is a wasteful process. Why is it so?

When the ratio, \(
\mathrm{CO}_2 \) : \(
\mathrm{O}_2 \) is nearly equal, RuBisCO

In the photorespiratory pathway:
I. there is no synthesis of sugars
II. there is release of carbon dioxide with the utilization of ATP
III. ATP is synthesized but NADPH is not synthesized

Consider the given two statements:
Statement I: Despite the presence of a green leaf, optimal light and carbon dioxide conditions, the plant may not photosynthesize if the temperature is very low.
Statement II: If a chemical process is affected by more than one factor, then its rate will be determined by the factor which is nearest to its minimal value.