I am single layered, but maintain cellular osmotic pressure

I support the cell, but I am not cell wall I have a body resembling net

I am chemical factory of the cell

MCQ Questions for Class 11 Medical Biology Photosynthesis In Higher Plants Quiz 14

Which one of the following is false about the activities associated with PSI and PSII in noncyclic photophosphorylation?

0%
Water is oxidized in PSII, but not PSI
0%
Photons(light) are needed to activates both PSI and PSII
0%
Photolysis of water formation of ATP $+$ NADPH $+$ H occur
0%
Production of NADPH $+ H^+$ is associated with PSII, not PSI

Who am I?

0%
I am ATP producing factory
0%
I am single layered, but maintain cellular osmotic pressure
0%
I support the cell, but I am not cell wall I have a body resembling net
0%
I am chemical factory of the cell
0%
Leaves are green because of me

Read the following statements.
i) Chloroplasts get aligned with their flat surface parallel to the cell walls to receive optimum light intensity.
ii) Water is the only electron donor in all photosynthetic organisms.
iii) ATP and NADPH are utilised in Carboxylation stage of Calvin cycle.
iv) Bundle sheath cells are characterized by having a large number of chloroplasts and impervious walls.
v) Law of limiting factors was proposed by Blackmann.
Which of the given statements are CORRECT?

0%
(i), (iii) and (iv)
0%
(i), (ii) and (iii)
0%
(iii), (iv) and (v)
0%
(v) only

The total number of ATP produced when one molecule of glucose is partially oxidised into lactic acid is:

0%
2
0%
10
0%
8
0%
36

In cyclic photophosphorylation the lowest energy electrons are driven out from?

0%
$P_{700}$
0%
$P_{680}$
0%
PQ
0%
PC

How many ATP molecules are produced after complete oxidation of one molecule of fructose-1, 6-bis-phosphate ?

0%
40
0%
32
0%
38
0%
44

Which statement is correct for given reaction for photosynthesis?

$2H_2A+CO_2\overset{light}{\rightarrow}2A+CH_2O+H_2O$ .

0%
H donor is oxidisable substrate
0%
$O_2$ evolve from $H_2O$ if reducible compound is $H_2O$
0%
Glucose gain its oxygen from $H_2O$
0%
$(1)$ & $(3)$ both

How many of the given structures are associated with the thylakoid membrane?
PS II, RuBisCO, LHC, PEPcase,

$F_0$ of ATP synthase, cytochromes b & f.

0%
$2$
0%
$3$
0%
$4$
0%
$5$

How many ATP molecules will be produced when one molecule of 3-phosphosphoglyceric acid is completely oxidised :

0%
16
0%
32
0%
64
0%
48

For experiment showing that

$CO_2$ is evolved during respiration process in plants - arrange following steps in proper order.
i) Soak gram seeds in water, overnight. Keep them in conical flask.
ii) Close the conical flask with cork fitted with 'U' tube.
iii) Insert test tube with KOH solution in the conical flask.
iv) Keep the set steady for some time.

0%
i, ii, iii, iv
0%
i, ii, iv, iii
0%
i, iii, ii, iv
0%
i, iii, iv, ii

In how many of the given plants

$C_3$ cycle is present in mesophyll cell?

Wheat, Pea, Maize, Pineapple, Agave, Sorghum, Tomato

0%
Seven
0%
Five
0%
Six
0%
Two

Plants showing

$C_4$ pathway are better than the

$C_3$ plants in

0%
Utilisation of water
0%
Having photorespiration
0%
Producing more yield at very high $CO_2$ concentration
0%
Being sensitive to high temperatures

Chemiosmotic theory of P. Mitchell explains a general mechanism of energy conservation across?

0%
Inner mitochondrial membrane
0%
Thylakoid membrane
0%
Cell wall
0%
More than one option is correct

Find the correct match up:

	Column I		Column II
(A)	Light reaction	(p)	Occures in stroma
(B)	Photophosphorylat ion	(q)	Occures in grana
(C)	Dark reaction	(r)	Tapeivonit
(D)	Parasitic nutriton	(s)	Production of ATP an the presence of light

0%
A-r. B-p, C-s, D-q
0%
A-s, B-q, C-r, D-p
0%
A-p, B-r. C-q. D-s
0%
A-q. B-s, C-p, D-r

Which of the given is not a component of assimilatory power for dark reaction?

0%
ATP
0%
NADPH
0%
$CO_2$
0%
Both ATP and NADPH

Photo phosphorylation event take place in:

0%
Stroma
0%
Stroma lamella
0%
Grana lamella
0%
2 and 3 both

What is the site of

$C_3$ cycle in

$C_3$ and

$C_4$ plants?

0%
In $C_3$ plant - mesophyll cell and In $C_4$ plant - Bundle sheath cell
0%
In $C_3$ plant - Bundle sheath cell and In $C_4$ plant - mesophyll cell
0%
In $C_4$ plant - Bundle sheath cell and In $C_3$ plant - Bundle sheath cell
0%
In $C_3$ plant - mesophyll cell and In $C_4$ plant - mesophyll cell

Explanation

In $C_4$ plants, the photosynthesis takes place in a chloroplast of a thin-walled mesophyll cell and a 4-carbon acid is handed off to a thick-walled bundle sheath cell where the Calvin cycle occurs.
In $C_3$ plants, a 3-carbon sugar is produced which can diffuse into mesophyll cells, and into the stroma of chloroplasts, where the Calvin cycle takes place.
Hence, the site of $C_3$ cycle or Calvin cycle in $C_3$ plants is mesophyll cell and in $C_4$ plants is bundle sheath cell.

So, the correct answer is 'In

$C_3$ plant - mesophyll cell and In

$C_4$ plant - Bundle sheath cell'.

State whether the following statements are true or false. If false, correct them.
Plants produce oxygen during the process of making their own food.

0%
True
0%
False

Explanation

The given statement is true.

In the process of photosynthesis, plants take in CO

$_2$ (carbon dioxide) from the air and combine it with water absorbed through their roots. They use energy from sunlight to turn these compounds into carbohydrates (sugars) and oxygen, and they release extra oxygen to the air.

In the maize plant,

$CO_2$ fixation occurs in both mesophyll and bundle sheath cells. The enzymes involved in these cells for the process respectively are,

0%
RuBisCO and PEP Kinase
0%
PEP Kinase and Pepsin
0%
RuBisCO and PEP Carboxylase
0%
PEP Carboxylase and RuBisCO

The

$C_4$ plants are photosynthically more efficient than

$C_3$ plants because

0%
The CO $_2$ efflux is not prevented.
0%
They have more chloroplasts.
0%
The CO $_2$ compensation point is more.
0%
CO generated during photorespiration is trapped and recycled through PEP carboxylase.

Explanation

$C_4$ plants are photosynthetically more efficient than

$C_3$ plants. They have lower compensation points and do not show photorespiration. They have more chloroplasts as compared to

$C_3$ plants. They have chloroplasts both in the spongy mesophyll cells and in the bundle sheath cells. The chloroplasts are usually absent from bundle sheath cells but in

$C_4$ plants bundle sheath cells are rich in chloroplast and have unusual type of chloroplasts. These chloroplasts are agranal and have RUBISCO enzyme.

Which is correct link reaction?

0%
Pyruvic acid $+NAD^++$ Co-A $\overset{Pyruvate dehydronase}{\underset{Mg^{++}}{\rightarrow}}$ Acetyl Co-A $+$ NADH $\cdot H^++CO_2$
0%
Pyruvic acid $+FAD^++$ Co-A $\overset{Pyruvate dehydrogenase}{\underset{Mg^++}{\rightarrow}}$ Acetyl Co-A $+$ FADH $\cdot H^++CO_2$
0%
Pyruvic acid $+NADP^++$ Co-A $\overset{Pyruvate dehydrogenase}{\underset{Mg^{++}}{\rightarrow}}$ Acetyl Co-A +NADPH $\cdot H^++CO_2$
0%
Pyruvic acid $+NAD^++$ Co-A $\overset{Pyruvate dehydrogenase}{\underset{Mg^{++}}{\rightarrow}}$ Acetyl Co-A $+$ NADH $\cdot H^+$

Explanation

Pyruvate, which is formed by the glycolytic catabolism of carbohydrates in the cytosol, after it enters mitochondrial matrix undergoes oxidative decarboxylation by a complex set of reactions catalyzed by pyruvic dehydrogenase.
The reactions catalyzed by pyruvic dehydrogenase require the participation of several coenzymes, including NAD+ and Coenzyme A.
Pyruvic acid $+NAD^++$ Co-A $\overset{Pyruvate dehydronase}{\underset{Mg^{++}}{\rightarrow}}$ Acetyl Co-A $+$ NADH $\cdot H^++CO_2$ .
The acetyl co-A formed in the above reaction enters the Krebs cycle. Hence this reaction is considered as connecting link between the glycolysis and Krebs cycle.
So, the correct answer is 'Pyruvic acid $+NAD^++$ Co-A $\overset{Pyruvate dehydronase}{\underset{Mg^{++}}{\rightarrow}}$ Acetyl Co-A $+$ NADH $\cdot H^++CO_2$ '.

The enzyme RuBP caboxylase

0%
Activity occurs in $C_3$ and $C_4$ plants
0%
In present in inner thylakoid membrane
0%
Is low temperature sensitive enzyme
0%
Shows greater affinity for $O_2$ than for $CO_2$

Who proposed the chemiosmotic theory of oxidative phosphorylation?

0%
Krebs
0%
Gibbs
0%
Mitchell
0%
Dixons

The ratio between 3- carbon and 2- carbon intermediates having -

$NH_{2}$ group formed in photosynthetic oxidation cycle is

0%
1:1
0%
2:1
0%
3:2
0%
3:4

Explanation

Photorespiration is a process in plant which is otherwise called as photosynthetic oxidation cycle. It attempts to reduce the consequences of a wasteful oxygenation reaction by the enzyme RuBisCO. The ratio between 3-carbon intermediates (serine and glycerate) and 2-carbon (glycine) having NH

$_{2}$ group formed in photosynthetic oxidation cycle is 2:1.

Select the incorrect matched pair with regard to

$C_{4}$ cycle.

(a)	Primary $CO_{2}$ fixation product	-	PGA
(b)	Site of initial carboxylation	-	Mesophyll cells
(c)	Primary $CO_{2}$ acceptor	-	PEP
(d)	$C_{4}$ plant	-	Maize
(e)	Location of enzyme RuBisCO	-	Bundle sheath cells

0%
(a)
0%
(b)
0%
(c)
0%
(d)
0%
(e)

Explanation

PEP carboxylase catalyzes carboxylation of phosphoenolpyruvate (PEP, the primary acceptor of

$CO_2$ ) to form four carbon compound oxaloacetate in mesophyll cells of

$C_4$ plants. Initial carboxylation reaction of

$C_4$ cycle takes place in mesophyll cell wherein oxaloacetate is converted into the intermediate malate. Malate is transported to bundle-sheath cell and is decarboxylated to produce pyruvate and

$CO_2$ . Rubisco present in bundle sheath cells then carries out fixation of released carbon dioxide. Maize is a

$C_4$ with characteristic kranz anatomy consisting of mesophyll and bundle sheath cells. Thus, the correct answer is option A.

Artiplex spongiosa is a

0%
${C_3 }$ plant
0%
${C_ 4 }$ plant
0%
CAM plant
0%
All of the above

Explanation

Artiplex spongiosa is a

$C_4$ plant where PEP carboxylase fixes bicarbonate in the mesophyll cells of the leaf and the resulting four-carbon compound, malate, is shuttled into the bundle sheath cells where it releases CO for fixation by RuBisCO. Thus, option B is correct.

The electron transport chain of photosynthetic process is

0%
In the stroma of the chloroplast
0%
Bound to the thylakoid membranes
0%
Present in the outer membranes of the chloroplast
0%
Present on mitochondria

For the synthesis of one glucose molecule, the number of ATP required are

0%
9 ATP for ${C_3}$ cycle and 20 ATP for ${C_4}$ cycle.
0%
18 ATP for ${C_3}$ cycle and 30 ATP for ${C_4}$ cycle.
0%
22 ATP for ${C_3}$ cycle and 35 ATP for ${C_4}$ cycle.
0%
24 ATP for ${C_3}$ cycle and 36 ATP for ${C_4}$ cycle.

Explanation

Since every

$CO_2$ molecule has to be fixed twice, first by 4-carbon organic acid and second by RuBisCO, the

$C_4$ pathway uses more energy than the

$C_3$ pathway. The

$C_3$ pathway requires 18 molecules of ATP for the synthesis of one molecule of glucose, whereas the

$C_4$ pathway requires 30 molecules of ATP.

This energy debt is more than paid for by avoiding losing more than half of photosynthetic carbon in photorespiration as occurs in some tropical plants, making it an adaptive mechanism for minimizing the loss.

As compared to a C

$_{3}$ -plant, how many additional molecules of ATP are needed for net production of one molecule of hexose sugar by C

$_{4}$ -plants -

0%
Zero
0%
Six
0%
Two
0%
Twelve

$C_{4}$ photosynthesis does not occur in

0%
Zea mays
0%
Saccharum munja
0%
Saccharum officinarum
0%
Euphorbia splendens

Explanation

Plants exhibiting characteristic kranz anatomy are

$C_4$ plants. Spatial separation of carbon dioxide fixation and RUBISCO activity in mesophyll and bundle sheath cells of

$C_4$ plants respectively avoids photorespiration by concentrating

$CO_2$ in bundle sheath cells to scale down the oxygenase activity of RUBISCO and increase the RUBISCO efficiency. Zea mays and Saccharum spp are

$C_4$ plant while Euphorbia splendens is a CAM plant that reduces water loss by opening the stomata at night only. So, the correct answer is option D.

The glycolate metabolism occurs in

0%
Lysosomes
0%
Ribosomes
0%
Glyoxysomes
0%
Peroxisomes

Photosynthesis consists of essentially two biological reaction systems, one followed by the other. The second of these systems do which of the following?

0%
Fixes $CO_{2}$
0%
Traps light energy
0%
synthesizes starch
0%
Works only in the presence of light

Explanation

The photosynthesis is consists of two biological reaction systems are light dependent and light independent reactions. The CO $_2$ is fixed in this system.
The plant uses light energy to generate NADPH and ATP. The chemical bonds in these compounds store the energy and are used during the light independent phase.
The light independent phasen the ATP and NADPH generated in the light phase utilised to make C-C bonds of carbohydrates from carbon dioxide and water, with the RuBP.
Six molecules of carbon dioxide enter the cycle, which in turn produces one molecule of glucose or sugar.

So, the correct answer is option A.

Which of the following statement is true with regard to the light reaction of photosynthetic mechanism in plants?

0%
Chlorophyll a occurs with peak absorption at 680 nm in photosystem I and at 700 nm in photosystem II.
0%
Magnesium and sodium ions are associated with photolysis of water molecules.
0%
${O_2}$ is evolved during cyclic photophosphorylation.
0%
Photosystems I and II are both involved in non-cyclic photophosphorylation.
0%
Both ATP and ${NADPH_2}$ are formed during cyclic photophosphorylation.

Explanation

PSII have molecules of chlorophyll a arranged with a geometry to facilitate absorption of shorter wavelength, higher energy photons then photosystem I. Photosystem II have absorption peak of approximately 680 nanometers while PS I reaction center has absorption peak of 700 nm. Photosystem II has P680 reaction center with associated Mn atoms. These Mn atoms are associated with an enzyme that splits water under sunlight (photolysis). Cyclic photophosphorylation is non-oxygenic photosynthesis in which electrons are passed from P700 of PS-I, via electron transfer chain, to back to P700 with the formation of ATP. Electrons are not passed to NADP reductase; no

$NADPH_2$ is formed. Inorganic compounds, not water, serve as energy/electron source and oxygen is not released. Noncyclic photophosphorylation includes the flow of electron from PSII through quinone, cyt

$b_6$ f complex and plastocyanin to NADPH via PSI; it does not return to PSII and includes both PSI and PSII. Thus, the correct answer is option D.

As compared to a

${C_3}$ -plants how many additional molecules of ATP are needed for net production of one molecule of a hexose sugar by

${C_4}$ -plants

0%
2
0%
6
0%
0
0%
12

In Panicum maximum and Chloris gayana the

${C_4}$ pathway is ........... type.

0%
PEP-CK
0%
${NADP\pm Me}$
0%
${NAD\pm Me}$
0%
All of the above

Explanation

There is three variation of the basic

$C_4$ pathway, which principally differ in the

$C_4$ acid transported into the bundle sheath cells (malate or aspartate) and in the manner of decarboxylation.

The enzyme that catalyzes decarboxylation in bundle-sheath cells differs. In maize and sugarcane, the enzyme is NADP-malic enzyme; in millet, it is a NAD-malic enzyme and, in Panicum maximum and Chloris gayana, it is PEP carboxykinase.

So, the correct answer is option A.

In the following dark reaction of photosynthesis,

${6CO_2+6 H_2 O +A+12 NADPH +H\rightarrow C_6H_{12}O_6+6O_2+B+18 NADP}$ , A and B stand for

0%
18 ADP, 18 ATP
0%
12 ATP, 18 ATP
0%
18 ATP, 18 ADP
0%
12 ATP, 12 ADP

Explanation

In dark reaction of photosynthesis, 18 ATP molecules and 12

$NADPH_2$ molecules are utilized, which are produced during light reactions. Thus, A and B are 18 ATP and 18 ADP respectively.

Which of the following plant is efficient converter of solar energy, whose net productivity is 2 - 4 kg/

${m^2}$ /yr or even higher?

0%
Wheat
0%
Rice
0%
Sugarcane
0%
Bajra

Explanation

$C_4$ plants are more efficient than

$C_3$ plants, because

$C_3$ plants undergo photorespiration. The Kranz anatomy helps in

$C_4$ metabolism and thus no wastage of energy for photorespiration. Sugarcane is a

$C_4$ plant. So, it has higher productivity.

So, the correct answer is option C.

Which step of non cyclic photosphorylation is blocked by DCMU?

0%
Flow of $e^-$ between PS I to FD
0%
Flow of $e^-$ between cyto $b_6$ to cyto f
0%
Flow of $e^-$ between PC to PS I
0%
Flow of $e^-$ between PS II to PQ

The correct sequence of cell organelles participating in photorespiration is

0%
Chloroplast - Peroxisome - Mitochondria
0%
Chloroplast - Vacuole - Peroxisome
0%
Chloroplast - Golgi bodies - Mitochondria
0%
Chloroplast - Rough endoplasmic reticulum - Dictyosomes

Z-scheme of electrons transfer involves

0%
Bundle sheath cells
0%
PS-I
0%
PS-II
0%
Both (B) and (C)

Explanation

Z-scheme is a diagrammatic representation of the electron flow in non-cyclic phosphorylation, showing the change in energy potential of the electrons. The electrons lost by

$P_{680}$ (PS-II) are taken up by

$P_{700}$ (PS-I) and do not get back to

$P_{680}$ i.e., unidirectional and hence, it is called non- cyclic phosphorylation. The electrons pass through the primary acceptor, plastoquinone (PQ), cytochrome complex, plastocyanin (PC) and finally to P700. The electrons given out by P700 are taken up by primary acceptor and are ultimately passed on to NADP. The electrons combine with H+ and reduce NADP to

$NADPH_2$ .

The exceptional difference between

${C_3}$ and

${C_4}$ plants is exhibited by phenomenon

0%
Photosynthesis
0%
Photorespiration
0%
Transpiration
0%
Crassulacean metabolism

Explanation

$C_3$ plants,

$CO_2$ is pumped directly into the Calvin cycle, leaving rubisco exposed to

$O_2$ . Rubisco in a

$C_3$ will take up

$O_2$ rather than

$CO_2$ to undergo photorespiration. Photorespiration occurs under low concentrations of

$CO_2$ and high concentrations of

$O_2$ .

$C_4$ plants capture carbon dioxide in their mesophyll cells forming oxaloacetate. This oxaloacetate is then converted to malate and is transported into the bundle sheath cells, where oxygen concentration is low to avoid photorespiration.
Photosynthesis and transpiration occurs in both

$C_3$ and

$C_4$ plants. Crassulacean metabolism does not occur in both

$C_3$ and

$C_4$ plants.

So, the correct answer is option B.

In addition to the 12 molecules of

$NADPH_2$ the energy required for the synthesis of one mole of hexose by

$C_3$ and

$C_4$ pathway is

0%
18 molecules of ATP
0%
30 molecules of ATP
0%
18 and 30 molecules of ATP respectively
0%
30 and 18 molecules of ATP respectively

Explanation

$C_3$ plants 3 molecules of ATP and 2 molecules of

$NADPH_2$ are required per carbon atom fixed into sugars making the total requirement to produce one molecule of hexose sugar as 18 molecules of ATP and 12 molecules of

$NADPH_2$ . In

$C_4$ plants 5 molecules of ATP and 2 molecules of

$NADPH_2$ are required per carbon atom fixed into sugars making the total requirement to produce one molecule of hexose sugar as 30 molecules of ATP and 12 molecules of

$NADPH_2$ .

Which of the following is the evidence to show that oxygen released in photosynthesis comes from water?

0%
Isotopic oxygen $(O^{18})$ supplied as $H_2O$ appears in the $O_2$ released in photosynthesis.
0%
Activated chloroplast in water releases $O_2$ if supplied potassium ferrocyanide or some other reducing agent in the absence of $CO_2$ .
0%
Photosynthetic bacteria use $H_2S$ and $CO_2$ to make carbohydrates, $H_2S$ and sulphur.
0%
All of the above.

Explanation

Ruben and Kamen in 1941 using Chlolerra a green alga proved it by using isotopes of oxygen $^{18}O$ in water and gave the result that oxygen is released by green plants is obtained by photolysis ow water.
Robin Hill showed that isolated chloroplast present with an electron acceptor and potassium ferricyanide release oxygen without the absorption of water. Hence proved carbon dioxide does not provide it.
In 1930, C.B. Van Niel proved that sulphur bacteria use H $_2$ S and release sulphur

So the correct option is 'All of the above.'

The conversion of PGA to PGAL during Calvin cycle is a process of

0%
Reduction
0%
Oxidation
0%
Hydroxylation
0%
Isomerization

Explanation

In Calvin cycle, the carboxylation step is achieved by the enzyme, ribulose- 1,5-bisphosphate carboxylase/oxygenase, also known as RuBisCO (rubisco). This enzyme combines carbon dioxide dissolved in the cytosol with ribulose- 1,5-bisphosphate (RuBP) to produce 3-phosphoglycerate (3-PGA). The 3-phosphoglycerate kinase adds a phosphate from ATP to the 3-PGA to make 1,3-bisphosphoglycerate. Then NADP (glyceraldehyde-3-phosphate dehydrogenase) removes hydrogen from NADPH and adds it to the 1,3-bisphosphoglycerate to make glyceraldehyde-3-phosphate (PGAL). So, PGAL is formed by the addition of H

$_{2}$ atom and hence this reaction is called as a reduction reaction.

Which of the following statements correctly describes the light reactions and dark reactions taking place during photosynthesis?
(i) Light reactions occur in grana thylakoids whereas dark reactions occur in stroma of chloroplasts.
(ii) Light reactions generate ATP and

$\displaystyle NADPH_{2}$ whereas dark reactions consume ATP and

$\displaystyle NADPH_{2}$ .
(iii) Oxygen is released as a by-product during the light reactions as well as dark reactions.
(iv) Light reactions take place in the presence of light and dark reactions are independent of the products formed during light reactions.

0%
(i) and (ii)
0%
(iii) and (iv)
0%
(i), (ii) and (iv)
0%
(ii), (iii) and (iv)

Explanation

Photosynthesis consists of a set of light and dark reactions. In the light reactions, the energy from sunlight is utilized in the photochemical reduction of

$H_2O$ so that oxidizing agent

$NADP^+$ is reduced to

$NADPH$ . Dark reactions occur all the time and not just the dark.

$NADPH^+$ and ATP produced in light reactions lead to the reductive synthesis of carbohydrate from

$CO_2$ and

$H_2O$ . The site of photosynthesis is the chloroplast, which is under the surface of the leaf. The light reactions occur on the thylakoid membrane and the dark reactions occur within the stroma.

${CO_2}$ acceptor during the dark reaction of

${C_3}$ photosynthesis is

0%
RUBP.
0%
PEP.
0%
NADPH.
0%
ATP.

Explanation

The carbon-fixing reaction of photosynthesis involves a cyclic series of reactions, often called as the Calvin cycle or

$C_3$ pathway. In carboxylation or fixation, three molecules of

$CO_2$ combine with three molecules of 5C compound called ribulose-1, 5- bisphosphate (RuBP), which is the acceptor molecule of

$CO_2$ , giving rise to an unstable 6- carbon compound. Carboxylation of a molecule of

$CO_2$ to RuBP is catalyzed by the enzyme RuBP carboxylase or Rubisco. The resulting 6C compound is highly unstable. This molecule quickly breaks down to give two molecules of 3-phosphoglycerate (3PG), also called phosphoglyceric acid (PGA).

The structure known as peroxisome is associated with

0%
Photosynthesis.
0%
Respiration.
0%
Photorespiration.
0%
Photophosphorylation.

Explanation

Photorespiration (also known as the oxidative photosynthetic carbon cycle, or

$C_2$ photosynthesis) is a process in plant metabolism which attempts to reduce the consequences of a wasteful oxygenation reaction by the enzyme RuBisCO. Peroxisome, mitochondria and chloroplast is involved in this process.

Chemical reaction that takes place during the dark reaction of photosynthesis is called as

0%
Photolysis.
0%
Hydrolysis.
0%
Binding of carbon dioxide with RUBP.
0%
Nitrogen fixation.

The number of ATP required in excess to assimilate atmospheric

$CO_2$ to four molecules of triose phosphates in

$C_4$ plants as compared to

$C_3$ plants is

0%
30
0%
36
0%
60
0%
8

Explanation

For one glucose molecule, 6 turns of C

$_3$ cycle are required for producing 12 molecules of triose, out of which 2 will be used for glucose. For 6 cycles, 18 ATP are required. ATP produced in one cycle is 18/6=3. If there are 4 molecules required for glucose formation, 4 cycles should take place. So, 3 x 4 = 12 ATP required for 4 molecules of triose.

Similarly, for one glucose molecule, 6 turns of C

$_4$ cycle are required for producing 12 molecules of triose, out of which 2 will be used for glucose. For 6 cycles, 30 ATP are required. ATP produced in one cycle is 30/6=5. If there are 4 molecules required for glucose formation, 4 cycles should take place. So, 5 x 4 = 20 ATP required for 4 molecules of triose.

So, there are 20-12 = 8 molecules of ATP required in excess.

Thus, the correct answer is option D.

Who described

$C_4$ pathway for first time?

0%
Hatch and Slack
0%
Robert Hill
0%
Hans Krebs
0%
Melvin Calvin

Explanation

$\textbf{Correct Option A}$

$\textbf{Solution}$

$\bullet$ The C4 pathway was first described by hatch and slack in the year 1966. This is C4 cycle is a pathway of carbon dioxide fixation.

$\bullet$ This pathway is designed in such a way so that carbon dioxide can efficiently be fixed at lower concentrations and the plants that use this pathway are known as C4 plants.

$\bullet$ It is a cyclic process which occurs in the chloroplast of the plant cells. This pathway is called a C4 pathway because the first product that is obtained after the carbon fixation is a 4 carbon compound.

$\bullet$ Normal plants produce 3 carbon compound at the end of the carbon fixation process and they are called C3 plants. Some of the examples of C4 plants are Amaranthus, Zea, panicum.

$\bullet$ So the correct option is A.

CBSE Questions for Class 11 Medical Biology Photosynthesis In Higher Plants Quiz 14 - MCQExams.com

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Practice Class 11 Medical Biology Quiz Questions and Answers

CBSE Questions for Class 11 Medical Biology Photosynthesis In Higher Plants Quiz 14 - MCQExams.com

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Practice Class 11 Medical Biology Quiz Questions and Answers

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