Found in deeper tissues and roots

MCQ Questions for Class 11 Medical Biology Photosynthesis In Higher Plants Quiz 1

Photophosphorylation results in the formation of

0%
ATP
0%
NADPH + H $^+$
0%
$C_6H_{12}O_6$
0%
Glucose

Number of Calvin cycles required to generate a molecule of hexose is

0%
2
0%
4
0%
6
0%
8

Explanation

In one cycle one CO

$_2$ is fixed.

So six cycle are required to form hexose as it contains six carbon atoms.

So the correct option is '6'.

The first stable product of photosynthesis in

$C_ 3$ plants is

0%
3- phosphoglyceric acid
0%
Dihydroxyacetone phosphate
0%
Fructose-1, 6- diphosphate
0%
Ribulose-1, 5- diphosphate

Kranz anatomy is an exceptional feature of

0%
C4 plants
0%
CAM plants
0%
All green plants
0%
All lower plants

Explanation

The particularly large cells around the vascular bundles of the C

$_4$ plants are called bundle sheath cells and the leave which possess such anatomy are said to have Kranz anatomy which means wreath with a large number of chloroplasts in it. Example of such plants is maize and sorghum.

So the correct option is 'C

$_4$ plants'.

Photorespiration occurs in

0%
Green photosynthetic parts
0%
All living cells
0%
Mitochondria
0%
Root

Which of the following statements is correct?

0%
Photorespiration is useful process.
0%
C $_4$ plants are more efficient than C $_3$ plants.
0%
C $_3$ plants are more efficient than C $_4$ plants.
0%
Photorespiration is absent in C $_3$ plants but present in C $_4$ plants.

Explanation

$\displaystyle { C }_{ 4 }$ plants are more efficient than

$\displaystyle { C }_{ 3 }$ plants beacuse they have little photorespiration while in

$\displaystyle { C }_{ 3 }$ plants more than half of photsynthetic carbon is lost in photorespiration.

$\displaystyle { C }_{ 4 }$ plants are more efficient in picking up

$\displaystyle { CO }_{ 2 }$ , even in low

$\displaystyle { CO }_{ 2 }$ concentration because of high affinity of

$\displaystyle { CO }_{ 2 }$ with PEP (phosphoenol pyruvic acid).

Which of the following is the site for the Calvin cycle of photosynthesis?

0%
Stroma
0%
Thylakoid
0%
Vacuole
0%
Stomata
0%
Lamella

The site for Calvin cycle is the

0%
Stroma. .
0%
Cytoplasm.
0%
Thylakoid membrane.
0%
Mitochondrial matrix.
0%
Mitochondrial membrane.

Which of the following is incorrect regarding

$C_{4}$ pathway?

0%
It requires more energy than the $C_{3}$ pathway for production of glucose.
0%
It overcomes loss due to photorespiration.
0%
The first formed stable compound is a 3 carbon compound, i.e., oxaloacetic acid.
0%
It is inhibited by high $CO_{2}$ concentration.

Explanation

${_4}$ is the alternative pathway of Calvin cycle (C

${_3}$ cycle) taking place during the dark phase of photosynthesis. In the C

${_4}$ cycle the first stable compound is 4 C compound called as oxaloacetic acid. So, it is called as C

${_4}$ cycle. The primary CO

${_2}$ acceptor is PEP, a 3 carbon compound. Two CO

${_2}$ fixation occur. CO

${_2}$ fixation is fast and more efficient. Fixation of 1 molecule of CO

${_2}$ requires 5 ATP and 3 NADH. This cycle can operate in low CO

${_2}$ concentrations. Also, O

${_2}$ has no inhibitory effect on photosynthesis.

Kranz anatomy is one of the characteristics of the leaves of

0%
Mustard
0%
Potato
0%
Wheat
0%
Sugarcane

Explanation

Kranz anatomy occurs in the chloroplast of C

$_4$ plants such as sugarcane, maize (Zea mays), sorghum etc. It has two types of photosynthetic cell arranged in a specific manner. These are bundle sheath cells that surround the vascular centres, and mesophyll cells that, in turn, surround the bundle sheath cells. Rubisco is localised only within internalised bundle sheath cells which helps in fixation of carbon dioxide.

So, the correct answer is option D.

In Kranz anatomy, the bundle sheath cells have

0%
Thin walls, many intercellular spaces and no chloroplasts.
0%
Thick walls, no intercellular spaces and a large number of chloroplasts.
0%
Thin walls, no intercellular spaces and several chloroplasts.
0%
Thick walls, many intercellular spaces and few chloroplasts.

The oxygenation activity of RuBisCo enzyme in photorespiration leads to the formation of:

0%
1 molecule of 3-C compound
0%
1 molecule of 6-C compound
0%
1 molecule of 3-C compound and 1 molecule of 2-C compound
0%
2 molecules of 3-C compound

A plant in your garden avoids photorespiratory losses, has improved water use efficiency, shows high rate of photosynthesis at high temperature and has improved efficiency of nitrogen utilisation. In which of the following physiological groups would you assign this plant?

0%
$C_3$
0%
$C_4$
0%
CAM
0%
Nitrogen fixer

Explanation

In C

$_4$ plants, chloroplasts exist not only in the mesophyll cells in the outer part of their leaves but in the bundle sheath cells as well. Instead of direct fixation to RuBisCO in the Calvin cycle, CO

$_2$ is incorporated into a 4-carbon organic acid, which has the ability to regenerate CO

$_2$ in the chloroplasts of the bundle sheath cells. C

$_4$ plants have a competitive advantage over plants possessing the more common C

$_3$ carbon fixation pathway under conditions of drought, high temperatures, and nitrogen or CO

$_2$ limitation. This increased water use efficiency of C

$_4$ grasses means that soil moisture is conserved, allowing them to grow for longer in arid environments.

In light reaction, plastoquinone facilitates the transfer of electrons from

0%
$Cytb_6f$ complex to $PS-I$
0%
$PS-I$ to $NADP^+$
0%
$PS- I$ to $ATP$ synthase
0%
$PS-II$ to $Cytb_6f$ complex

Anoxygenic photosynthesis is characteristic of

0%
Rhodospirillum
0%
Spirogyra
0%
Chlamydomonas
0%
Ulva

Study the pathway given above. In which of the following options, correct words for all the three blanks A, B, and C are indicated?

	A	B	C
1	Carboxylation	Decarboxylation	Reduction
2	Decarboxylation	Reduction	Regeneration
3	Fixation	Transamination	Regeneration
4	Fixation	Decarboxylation	Regeneration

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

Explanation

C $_4$ pathway occurs by the cooperation between bundle sheath cells and mesophyll cells.

1. The first step takes place in the mesophyll cell where the phosphoenolpyruvate carboxylase enzyme catalyzes the formation of oxaloacetate from phosphoenolpyruvate and carbon dioxide. This step A is the fixation of CO

$_2$ .
2. Oxaloacetate reduces to malic acid (C

$_4$ compound) in the presence of malate dehydrogenase enzyme.
3. The malic acid is then transferred to the bundle sheath cell through plasmodesmata.
4. In bundle sheath cells, malic acid is decarboxylated in the presence of the malic enzyme and releases carbon dioxide. Step B in the given flow chart is decarboxylation.
5. By the decarboxylation of malic acid 3 carbon compound i.e., pyruvate is formed. Carbon dioxide enters into the Calvin cycle and pyruvate returns back to the mesophyll cells.
6. In mesophyll cells, pyruvate in the presence of pyruvate phosphate dikinase enzyme regenerates into phosphoenolpyruvate, and the cycle repeats. Step C is the regeneration of phosphoenolpyruvate.

So, the correct answer is option D.

2152952_306730_ans_ce61f4f9a670419f9caf644c2fa4ca15.png

$C_4$ plants have better productivity because

0%
$C_4$ plants absorb more light.
0%
$C_4$ plants absorbs more $CO_2$ .
0%
$C_4$ plants lack photorespiration.
0%
All of the above.

Explanation

Presence of photorespiration is considered as a wasteful and energy consuming process in crop plants which ultimately leads to reduction in final yield of crops. It is estimated that during

$C_3$ photosynthesis, upto 50% of the

$CO_2$ fixed may have to pass through photorespiratory process, thereby resulting in considerable decrease in photosynthetic productivity. In

$C_3$ plants, there is some loss of photosynthetic activity on account of photorespiration which is absent in

$C_4$ plants and hence they have better productivity.

0%
Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
0%
Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
0%
Assertion is correct but Reason is incorrect.
0%
Both Assertion and Reason are incorrect.

Explanation

Photosynthetically C

$_4$ plants are more efficient than C

$_3$ plants, because these have Kranz anatomy. Bundle sheath chloroplast are larger agranal and without PS-II activity and perform C

$_3$ cycle.

Which one of the following is wrong in relation to photorespiration?

0%
It occurs in chloroplasts
0%
It occurs in daytime only
0%
It is a characteristic of $C_4$ plants
0%
It is a characteristic of $C_3$ plants

Explanation

$C_4$ plants the RuBisCO is present in bundle sheath cells, in which carbon dioxide is maintained at high concentration and oxygen is not generated in bundle sheath cells. Thus suppressing the photorespiration process.

$C_4$ plants, synthesis of sugars occurs in

0%
Mesophyll cells
0%
Bundle sheath cells
0%
Spongy parenchyma cells
0%
Palisade parenchyma cells.

Explanation

$C_{4}$ plants, the Calvin cycle occurs for the synthesis of sugar. Calvin cycle enzymes such as RubisCo is absent from the mesophyll cell of chloroplast of

$C_{4}$ plants. These enzymes are present in the bundle-sheath cells surrounding the vascular bundles, guard cells and epidermal cells of chloroplasts. So, the Calvin cycle occurs in the bundle-sheath cells. That’s why, in

$C_{4}$ plants, synthesis of sugar occurs in bundle-sheath cells.

Photophosphorylation means synthesis of

0%
ATP from ADP
0%
NADP
0%
ADP from ATP
0%
PGA

Explanation

Photophosphorylation is the process in which light energy is converted into chemical energy through the production of ATP. The process of reduction of

$NADP$ into

$NADP + H^{+}$ may be denoted as electron transport system (ETS). It is the process of formation of ATP from ADP and inorganic phosphate (ip) utilizing light energy. The flow of electrons through ETS is linked to photophosphorylation. Electron transport chain is a series of electron carriers over which electrons pass in a downhill journey releasing energy at every step that is used in generating an electrochemical proton gradient which helps in synthesizing ATP. Based on the path of electrons, associated photophosphorylation can be identified as non-cyclic and cyclic phosphorylation.

Melvin Calvin is well known for the discovery of

0%
EMP pathway
0%
Krebs cycle
0%
Dark reaction of photosynthesis
0%
Light reaction of photosynthesis

Which of the following is a simplified equation of photosynthesis?

0%
${CO_2 +2H _2O \xrightarrow[chlorophyll]{light \,energy}C_5 H_{10} O_4 +H_2 O +O_2}\uparrow$
0%
${CO_2 +2H _2O \xrightarrow[chlorophyll]{light\, energy}(CH_2 O)_n + O_2}\uparrow$
0%
${CO_2 +2H _2O \xrightarrow[chlorophyll]{light\, energy}C_3 H_6 O_3 +CO_2 +O_2}\uparrow$
0%
$6CO_{2} + H_2{O} \xrightarrow\ C_{6}H_{12}O_{6} + 6O_{2}$
0%
$6CO_{2} + 6H_2{O} \xrightarrow\ C_{6}H_{12}O_{6} + 6O_{2}$

Explanation

Photosynthesis is the synthesis of carbohydrates by the conversion of

$C_O2$ and

$H_2O$ under the influence of light energy, which occurs in the chloroplast. The simplified equation of photosynthesis is as follows-
6

$CO_2$ + 6

$H_2O$ ------>

$C_6H_{12}O_6$ + 6

$O_2$ .

It is the balanced equation for photosynthesis.

First acidic compound formed in

${C_4}$ cycle is

0%
OAA
0%
Malic acid
0%
Pyuvic acid
0%
PGA

Dark respiration is

0%
Cellular respiration
0%
Found in deeper tissues and roots
0%
Found only during night
0%
Both B and C

$C_4$ plants, chloroplasts are also found in

0%
Spongy parenchyma
0%
Epidermal cells
0%
Guard cells
0%
Bundle sheath cells.

Explanation

The particularly large cells around the vascular bundles of

$C_4$ plants is known as bundle sheath cells and leaves with such anatomy is known to have Kranz anatomy. These cells make several layers around the vascular bundles and are characterized by having a large number of chloroplasts, no intercellular spaces and impervious to gaseous exchange.

So the correct option is 'Bundle sheath cells'.

$C_4$ -cycle was discovered by

0%
Hatch and Slack
0%
Calvin
0%
Hill
0%
Arnon

Explanation

$C_{4}$ cycle which is also known as the Hatch-Slack pathway is a cyclic process. It occurs in chloroplasts. It was discovered by two Australian scientists Hatch and Slack. It is found in

$C_{4}$ plants. Carbon dioxide fixation is done in this pathway. The primary

$CO_{2}$ acceptor is a three-carbon molecule phosphoenolpyruvate (PEP) and it is present in mesophyll cells. The enzyme that catalyzes this

$CO_{2}$ fixation is PEP carboxylase or PEPcase. The mesophyll cells of

$C_{4}$ plants lack the enzyme RuBisCO. The 4-carbon oxaloacetic acid (OAA) is formed in the mesophyll cells which is further converted into the malic acid or aspartic acid and then transported into bundle sheath cells. In the bundle sheath cells, these

$C_{4}$ acids are broken down to release

$CO_{2}$ and a three-carbon molecule.

Light energy is used in photosynthesis for

0%
Breakdown of $H_2O$
0%
Breakdown of $CO_2$
0%
Activation of chlorophyll
0%
Breakdown of $C_6H_{12}O_6$

The enzyme that catalyses carbon dioxide fixation in

$C_4$ plants is

0%
RuBP carboxylase
0%
PEP carboxylase
0%
Carbonic anhydrase
0%
Carboxydismutase

Explanation

Most of the plants that are adapted to dry tropical regions have the

$C_{4}$ pathway. These plants are called

$C_{4}$ plants. Sugarcane, Maize, Sorghum, Corn, etc., are the examples of these plants. Carbon fixation in these plants occurs through Hatch and Slack pathway. It is also known as

$C_{4}$ pathway. It is a cyclic process. It occurs in chloroplasts. It was discovered by two Australian scientists Hatch and Slack. Carbon dioxide fixation is done in this pathway. The primary

$CO_{2}$ acceptor is a three-carbon molecule phosphoenolpyruvate (PEP) and it is present in mesophyll cells. The enzyme that catalyzes this

$CO_{2}$ fixation is PEP carboxylase or PEPcase. The mesophyll cells of

$C_{4}$ acids are broken down to release

$CO_{2}$ and a three-carbon molecule.

The first carbon dioxide acceptor in

$C_4$ plants is

0%
Phosphoenolpyruvate
0%
Ribulose 1, 5-diphosphate
0%
Oxalo-acetic acid
0%
Phosphoglyceric acid

Explanation

Most of the plants that are adapted to dry tropical regions have the

$C_{4}$ pathway. These plants are called

$C_{4}$ plants. Sugarcane, Maize, Sorghum, Corn, etc. are the examples of these plants. In these plants, double fixation of carbon dioxide occurs by

$C_{4}$ pathway. The first

$CO_{2}$ acceptor is a three-carbon molecule phosphoenolpyruvate (PEP) and it is present in mesophyll cells. The enzyme that catalyzes this

$CO_{2}$ fixation is PEP carboxylase or PEPcase. The mesophyll cells of

$C_{4}$ acids are broken down to release

$CO_{2}$ and a three-carbon molecule.

ATP synthesis during light reaction is

0%
Oxidative phosphorylation
0%
Photolysis
0%
Photophosphorylation
0%
Phosphorylation

$C_4$ plants are also known as

0%
Calvin type
0%
Calvin-Bassham type
0%
Hatch and Slack type
0%
Emerson type

Explanation

Most of the plants that are adapted to dry tropical regions have the

$C_{4}$ pathway. These plants are called

$C_{4}$ plants. Sugarcane, Maize, Sorghum, Corn, etc., are the examples of these plants. These plants are also known as Hatch and Slack type because they operate Hatch-Slack pathway. It is a cyclic process. It occurs in chloroplasts. It was discovered by two Australian scientists Hatch and Slack. Carbon dioxide fixation is done in this pathway. The primary

$CO_{2}$ acceptor is a three-carbon molecule phosphoenolpyruvate (PEP) and it is present in mesophyll cells. The enzyme that catalyzes this

$CO_{2}$ fixation is PEP carboxylase or PEPcase. The mesophyll cells of

$C_{4}$ acids are broken down to release

$CO_{2}$ and a three-carbon molecule.

$_4$ plants have .......... carboxylations.

0%
One
0%
Two
0%
Three
0%
Four.

In a green cell, the enzyme catalase is localised in

0%
Peroxisomes
0%
Chloroplasts
0%
Lysosomes
0%
Vacuoles

Hatch and Slack who discovered alternate method of carbon fixation were from

0%
England
0%
Australia
0%
America
0%
New Zealand

Explanation

Hatch and Slack who discovered an alternate method of carbon fixation were from Australia. Hatch-Slack pathway is a cyclic process. It occurs in chloroplasts. It is also known as

$C_{4}$ pathway because it is found in

$C_{4}$ plants. Carbon dioxide fixation is done in this pathway. The primary

$CO_{2}$ acceptor is a three-carbon molecule phosphoenol pyruvate (PEP) and it is present in mesophyll cells. The enzyme that catalyzes this

$CO_{2}$ fixation is PEP carboxylase or PEPcase. The mesophyll cells of

$C_{4}$ acids are broken down to release

$CO_{2}$ and a three-carbon molecule.

The entire reactions of

$C_4$ pathway take place in

0%
Mesophyll and bundle sheath
0%
Vascular bundle and palisade tissue
0%
Mitochondria and peroxisomes
0%
Bundle sheath and endoplasmic reticulum

Explanation

Most of the plants that are adapted to dry tropical regions have the

$C_{4}$ pathway. These plants are called

$C_{4}$ plants. Sugarcane, Maize, Sorghum, etc., are the examples of these plants. In these plants, double fixation of carbon dioxide occurs. The entire reactions of

$C_{4}$ pathway take place in mesophyll and bundle sheath. Kranz anatomy is found in leaves of

$C_{4}$ plants. The

$C_{4}$ pathway requires the presence of two types of cells i.e., mesophyll cells and bundle sheath cells. The particularly large cells around the vascular bundles of

$C_{4}$ plants are called bundle sheath cells, these cells may form several layers around the vascular bundles, they are characterized by having a large number of chloroplasts, grana are absent, thick walls impervious to gaseous exchange and no extracellular spaces. The mesophyll cells of

$C_{4}$ acids are broken down to release

$CO_{2}$ and a three-carbon molecule.

In photorespiration the number of ATP and NADPH synthesised are respectively

0%
1 and 3
0%
2 and 3
0%
3 and 4
0%
0 and 0.

Explanation

Photorespiration is a process which involves loss of fixed carbon as

$CO_{2}$ in plants in the presence of light. It is initiated in chloroplasts. This process does not produce ATP or NADPH and is a wasteful process. Photo-respiratory reactions are operated in chloroplasts, mitochondria, and peroxisomes. Loss of

$CO_{2}$ occurs in mitochondria. Photorespiration occurs usually when there is the high concentration of oxygen. Under such circumstances, RuBisCO, the enzyme that catalyzes the carboxylation of RuBP during the first step of Calvin cycle, functions as an oxygenase. Some

$O_{2}$ does not bind to RuBisCO and hence

$CO_{2}$ fixation is decreased. The RuBP binds with

$O_{2}$ to form one molecule of PGA (3C compound) and phosphoglycolate (2C compound) in the pathway of photorespiration. There is neither the synthesis of sugar nor of ATP. Rather, it results in the release of

$CO_{2}$ with the utilization of ATP. It leads to a 25 percent loss of the fixed

$CO_{2}$ .

$O_{2}$ is first utilized in chloroplasts and then in peroxisomes.

Photorespiration is also called

0%
$C_2$ cycle
0%
$C_3$ cycle
0%
$C_4$ cycle
0%
$C_5$ cycle

Explanation

Photorespiration is a process which involves loss of fixed carbon as

$CO_{2}$ in plants in the presence of light. It is also known as

$C_{2}$ cycle. It is initiated in chloroplasts. This process does not produce ATP or NADPH and is a wasteful process. Photo-respiratory reactions are operated in chloroplasts, mitochondria, and peroxisomes. Loss of

$O_{2}$ does not bind to RuBisCO and hence

$CO_{2}$ fixation is decreased. The RuBP binds with

$O_{2}$ to form one molecule of PGA (3C compound) and phosphoglycolate (2C compound) in the pathway of photorespiration. Rather, it results in the release of

$CO_{2}$ with the utilization of ATP. It leads to a 25 percent loss of the fixed

$CO_{2}$ .

$O_{2}$ is first utilized in chloroplasts and then in peroxisomes.

$C_4$ -pathway initial carbon dioxide fixation occurs in chloroplasts of

0%
Guard cells
0%
Mesophyll
0%
Bundle sheath
0%
All the above

Explanation

$C_{4}$ pathway is called so because it is found in

$C_{4}$ plants. It is a cyclic process. It is also known as a Hatch-Slack pathway. In

$C_{4}$ pathway, initial carbon dioxide fixation occurs in chloroplasts of mesophyll because primary

$CO_{2}$ acceptor phosphoenolpyruvate (PEP) is present in the mesophyll. PEP (phosphoenolpyruvate) is a three-carbon molecule. The enzyme that catalyzes this

$CO_{2}$ fixation is PEP carboxylase or PEPcase. The mesophyll cells of

$C_{4}$ acids are broken down to release

$CO_{2}$ and a three-carbon molecule.

Photorespiration requires this activity by an enzyme

0%
Hydrolase
0%
Oxygenase
0%
Carboxylase
0%
ATPase

Explanation

Photorespiration is a process which involves loss of fixed carbon as

$CO_{2}$ occurs in mitochondria. Photorespiration occurs usually when there is the high concentration of oxygen. Photorespiration requires this activity by an enzyme oxygenase. Under such circumstances, RuBisCO, the enzyme that catalyzes the carboxylation of RuBP during the first step of Calvin cycle, functions as an oxygenase. Some

$O_{2}$ does not bind to RuBisCO and hence

$CO_{2}$ fixation is decreased. The RuBP binds with

$O_{2}$ to form one molecule of PGA (3C compound) and phosphoglycolate (2C compound) in the pathway of photorespiration. Rather, it results in the release of

$CO_{2}$ with the utilization of ATP. It leads to a 25 percent loss of the fixed

$CO_{2}$ .

$O_{2}$ is first utilized in chloroplasts and then in peroxisomes.

3-phosphoglyceric acid as first

$CO_2$ fixation product in algal photosynthesis was discovered by

0%
Priestley
0%
Ingenhousz
0%
Calvin
0%
Sachs

Explanation

3-phosphoglyceric acid as first

$CO_{2}$ fixation product in algal photosynthesis was discovered by Calvin. He used radioactive

$^{14}C$ in algal photosynthetic studies. This led to the discovery that the first

$CO_{2}$ fixation product was a three-carbon organic acid. He also helped to mark out the complete biosynthetic pathway, hence it is named as Calvin Cycle. The first stable product identified was 3-phosphoglyceric acid (PGA), hence it is named as

$C_{3}$ pathway. Calvin cycle occurs in all photosynthetic plants whether they have

$C_{3}$ or

$C_{4}$ pathway.

Kranz anatomy is not seen in (i) Maize (ii) Sorghum (iii) Tomato.

0%
i and ii
0%
ii only
0%
i only
0%
iii only

Explanation

Kranz anatomy is found in leaves of

$C_{4}$ plants. The

$C_{4}$ pathway requires the presence of two types of cells i.e. mesophyll cells and bundle sheath cells. The particularly large cells around the vascular bundles of

$C_{4}$ plants is called Kranz anatomy. 'Kranz' means wreath and is a reflection of the arrangement of cells. So, Kranz anatomy is not seen in tomato as it is not a

$C_{4}$ plant.

Non-cyclic photophosphorylation results in production of

0%
ADP
0%
ATP
0%
NADPH
0%
ATP and NADPH

Explanation

Non-cyclic phosphorylation is a type of photophosphorylation in which flow of electrons is non-cyclic. It results in the production of ATP and NADPH. It involves both Photosystem I and Photosystem II. These two photosystems work in series, first PS II and then PS I. The two photosystems are connected through an electron transport chain.

$NADPH$ is synthesized by this kind of electron flow. Electrons are transferred from the PS II and then passed on to the pigments of PS I. Then, electrons get excited and transferred to another acceptor. These electrons are then moved downhill again to a molecule of

$NADP^{+}$ . The addition of these electrons results in the formation of

$NADPH$ . This whole scheme is known as Z scheme.

Photorespiration produces

0%
Sugar but not ATP
0%
ATP but no sugar
0%
Both ATP and Sugar
0%
Neither ATP nor sugar

Explanation

Photorespiration is a process which involves loss of fixed carbon as

$CO_{2}$ in plants in the presence of light. It is initiated in chloroplasts. This process does not produce ATP or NADPH and is a wasteful process. It does not even produce any sugar. Photo-respiratory reactions are operated in chloroplasts, mitochondria, and peroxisomes. Loss of

$O_{2}$ does not bind to RuBisCO and hence

$CO_{2}$ fixation is decreased. The RuBP binds with

$O_{2}$ to form one molecule of PGA (3C compound) and phosphoglycolate (2C compound) in the pathway of photorespiration. Rather, it results in the release of

$CO_{2}$ with the utilization of ATP. It leads to a 25 percent loss of the fixed

$CO_{2}$ .

$O_{2}$ is first utilized in chloroplasts and then in peroxisomes. It decreases photosynthetic output.

Which of the following scientist is best known for his work on photosynthesis?

0%
Peter Debye
0%
Erwin Mueller
0%
Melvin Calvin
0%
Leonardo de Vinci

Cyclic photophosphorylation forms

0%
NADPH
0%
ATP
0%
ATP and NADPH
0%
ATP, NADPH and $O_2$

PEP is primary

$CO_{2}$ acceptor in

0%
$C_{4}$
0%
$C_{3}$
0%
$C_{2}$
0%
both $C_{3}$ and $C_{4}$ plants

Explanation

$C_{4}$ plants, initial fixation of

$CO_{2}$ or carboxylation occurs in mesophyll cells. The chloroplasts of mesophyll cells possess enzyme PEP carboxylase (or PEP case) for initial fixation of

$CO_{2}$ .The primary acceptor of

$CO_{2}$ is phosphoenol pyruvate or PEP. It combines with

$CO_{2}$ in the presence of PEP carboxylase (or PEP case) to form oxaloacetic acid or oxallocetate (OAA). So, the correct answer is 'C4'.

Which of the following is concerned with carbon dioxide fixation?

0%
Krebs' cycle
0%
Calvin cycle
0%
Orhithine cycle
0%
Glycolysis

Explanation

When carbon dioxide is reduced to simple organic compound, then it is called carbon dioxide fixation. Melvin Calvin helped to mark out the complete biosynthetic pathway; hence it is called as Calvin cycle. The first stable product identified was 3-phosphogyceric acid (PGA), hence it is also named as

$C_{3}$ pathway. Calvin cycle occurs in all photosynthetic plants whether they have

$C_{3}$ or

$C_{4}$ pathway. Calvin cycle occurs in three stages: - carboxylation, reduction, and regeneration.

Identify the false statements and rewrite them correctly by changing the first or the last word only.
Dark reaction of photosynthesis occurs during night time.

0%
True
0%
False

The fixation and reduction of

$CO_{2}$ occur in presence of

0%
ATP
0%
ATP and NADPH
0%
NADPH, chlorophyll and water
0%
ATP, NADPH and light

Explanation

The fixation and reduction of

$CO_2$ occurs in the presence of ATP and NADPH molecules. The ATP and NADPH molecules are synthesised in light reaction and used in the dark reaction for carbohydrate synthesis.

CBSE Questions for Class 11 Medical Biology Photosynthesis In Higher Plants Quiz 1 - 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 1 - MCQExams.com

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Practice Class 11 Medical Biology Quiz Questions and Answers

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