MCQ Questions for Class 11 Medical Biology Respiration In Plants Quiz 7

The value of R.Q. at the compensation point is

0%
Infinity.
0%
Two.
0%
> 1.
0%
Zero.

Explanation

During aerobic respiration,

$O_2$ is consumed and

$CO_2$ is released. The ratio of the volume of

$CO_2$ evolved to the volume of

$O_2$ consumed in respiration is called the respiratory quotient (RQ) or respiratory ratio. Thus the following expression is used to calculate the value of RQ.
RQ= volume of

$CO_2$ evolved/ volume of

$O_2$ consumed.
At compensation point there is no net evolution of carbon dioxide. Hence, numerator in above expression is zero, giving the value of RQ as zero.

What causes R. Q. to vary?

0%
Respiratory substrates
0%
Light and $O_2$
0%
Respiratory products
0%
Temperature

Explanation

During aerobic respiration,

$O_2$ is consumed and

$CO_2$ is released. The ratio of the volume of

$CO_2$ evolved to the volume of

$O_2$ consumed in respiration is called the respiratory quotient (RQ) or respiratory ratio. The respiratory quotient depends upon the type of respiratory substrate used during respiration. When carbohydrates are used as substrate and are completely oxidised, the RQ will be 1, because equal amounts of

$CO_2$ and

$O_2$ are evolved and consumed, respectively. When fats are used in respiration, the RQ is less than 1. When proteins are respiratory substrates the ratio would be about 0.9.

The value of R.Q. for proteins is

0%
Equal to one.
0%
More than one.
0%
Less than one.
0%
Infinite.

Explanation

During aerobic respiration,

$O_2$ is consumed and

$CO_2$ is released. The ratio of the volume of

$CO_2$ evolved to the volume of

$O_2$ consumed in respiration is called the respiratory quotient (R.Q) or respiratory ratio. The respiratory quotient depends upon the type of respiratory substrate used during respiration. When carbohydrates are used as substrate and are completely oxidised, the RQ will be 1, because equal amounts of

$CO_2$ and

$O_2$ are evolved and consumed, respectively. When fats are used in respiration, the RQ is less than 1. When proteins are respiratory substrates the ratio would be about 0.9.

Respiratory quotient is expressed as which of the following equations?

0%
$O_2/CO_2$
0%
$CO_2/O_2$
0%
$O_2/H_2O$
0%
$CO_2 - O_2$

Explanation

During aerobic respiration,

$O_2$ is consumed and

$CO_2$ is released. The ratio of the volume of

$CO_2$ evolved to the volume of

$O_2$ consumed in respiration is called the respiratory quotient (R.Q) or respiratory ratio. Thus the following expression is used to calculate the value of R.Q.
RQ= volume of

$CO_2$ evolved/ volume of

$O_2$ consumed.

$FADH_2$ is produced in Krebs cycle during the conversion of

0%
isocitrate
0%
$\alpha$ - ketoglutarate
0%
succinate
0%
malate

Explanation

The reactions which help in converting pyruvic acid to carbon dioxide and water in mitochondria are called the Krebs cycle.

$FADH_2$ is produced in Kreb's cycle during the conversion of succinic acid (succinate) to fumaric acid (fumarate) in the presence of enzyme succinate dehydrogenase.

So, the correct answer is option C.

The value of R.Q. for a starved cell is

0%
Zero.
0%
0.8 / less than one.
0%
1 / unit.
0%
Infinite.

Explanation

During aerobic respiration,

$O_2$ is consumed and

$CO_2$ is released. The ratio of the volume of

$CO_2$ evolved to the volume of

$O_2$ consumed in respiration is called the respiratory quotient (RQ) or respiratory ratio. Thus the following expression is used to calculate the value of RQ.
RQ= volume of

$CO_2$ evolved/ volume of

$O_2$ consumed.
The respiratory quotient depends upon the type of respiratory substrate used during respiration. When carbohydrates are used as substrate and are completely oxidised, the RQ will be 1, because equal amounts of

$CO_2$ and

$O_2$ are evolved and consumed, respectively. When fats are used in respiration, the RQ is less than 1. When proteins are respiratory substrates the ratio would be about 0.9.
Under conditions of starvation carbohydrates are not available and proteins or fats are used as cellular fuel and hence the expected value of RQ is less than unity.

Which of the following enzyme is not used in Krebs cycle?

0%
Aconitase
0%
Decarboxylase
0%
Aldolase
0%
Fumarase

R.Q. of an actively photosynthesizing tissue is

0%
Infinity.
0%
< 1.
0%
> 1.
0%
Zero.

Explanation

During aerobic respiration, O

$_2$ is consumed and CO

$_2$ is released. The ratio of the volume of CO

$_2$ evolved to the volume of O

$_2$ consumed in respiration is called as the respiratory quotient (RQ) or respiratory ratio. Thus, the following expression is used to calculate the value of RQ.
RQ = volume of CO

$_2$ evolved/ volume of O

$_2$ consumed.
In an actively photosynthesizing tissue, the net volume of carbon dioxide evolved (i.e., volume of carbon dioxide produced in respiration minus that utilised in photosynthesis) is equal to net volume of oxygen (i.e., volume of oxygen consumed in respiration minus that evolved in photosynthesis).

Where does formation of acetyl CoA from pyruvic acid take place?

0%
Mitochondria
0%
Chloroplast
0%
Cytoplasm
0%
Golgi body

The pyruvic acid formed in glycolysis is oxidised to

$CO_{2}$ and

$H_{2}O$ in a cycle is called as

0%
Calvin cycle.
0%
Hill reaction.
0%
Krebs cycle.
0%
Nitrogen cycle.

The value of R.Q. of a succulent plant at night is

0%
< 1.
0%
> 1.
0%
Zero.
0%
Infinite.

Fermentation is represented by which of the following equation?

0%
$C_{6}H_{12}O_{6}\, \rightarrow\, 6CO_{2}\, +_\, 6H_{2}O\, +\, 673 K\, cal$
0%
$C_{6}H_{12}O_{6}\, \rightarrow\, 2C_{2}H_{5}OH\, +\, 2CO_{2}$
0%
$6CO_{2}\, +\, 12H_{2}O\, \rightarrow\, C_{6}H_{12}O_{6}\, +\, 6H_{2}O\, +\, 6O_{2}$
0%
$6CO_{2}\, +\, 6H_{2}O\, \xrightarrow[chlorophyll]{light}\, C_{6}H_{12}O_{6}\, +\, 6O_{2}$

Explanation

In fermentation, say by yeast, the incomplete oxidation of glucose is achieved under anaerobic conditions by sets of reactions where pyruvic acid is converted to

$CO_2$ and ethanol. The enzymes, pyruvic acid decarboxylase and alcohol dehydrogenase catalyse these reactions. Other organisms like some bacteria produce lactic acid from pyruvic acid. In animal cells also, like muscles during exercise, when oxygen is inadequate for cellular respiration pyruvic acid is reduced to lactic acid by lactate dehydrogenase. In both lactic acid and alcohol fermentation not much energy is released; less than seven per cent of the energy in glucose is released and not all of it is trapped as high energy bonds of ATP.

Which of the following scientist discovered the conventional path of anaerobic glycolysis?

0%
Embden, Meyerhof and Parnas
0%
Emerson, Hoffman and Peterson
0%
Embeden, Morrison and Pitcher
0%
Warburg, Dickens and Horecker

Glycolysis gives rise to

0%
8 ATP, 2 NADH $_2$ , 2 Pyruvate.
0%
2 ATP, 2 Co-A, 2 NADH $_2$ .
0%
2 ATP, 2 NADH $_2$ , 2 Pyruvate.
0%
2 ATP, 2 acetate, 2 NADPH $_2$ .

Explanation

In glycolysis, glucose undergoes partial oxidation to form two molecules of pyruvate or pyruvic acid and release 2 ATP and NADH

$_2$ which undergoes oxidation-reduction to release energy.

So the correct option is '2 ATP, 2 NADH

$_2$ , 2 Pyruvate.'

Of the following, the end product of fermentation is

0%
$O_{2}$ .
0%
$N_{2}O$ .
0%
$H_{2}O$ .
0%
$C_{2}H_{5}OH$ .

Explanation

In fermentation, say by yeast, the incomplete oxidation of glucose is achieved under anaerobic conditions by sets of reactions where pyruvic acid is converted to CO

$_2$ and ethanol. The enzymes, pyruvic acid decarboxylase and alcohol dehydrogenase catalyse these reactions. Other organisms like some bacteria produce lactic acid from pyruvic acid. In animal cells also, like muscles during exercise, when oxygen is inadequate for cellular respiration pyruvic acid is reduced to lactic acid by lactate dehydrogenase. The reducing agent is NADH+H+ which is reoxidised to NAD+ in both the processes.

Therefore, the correct answer is option D.

The number of ATP molecules produced from one Krebs cycle is

0%
15
0%
30
0%
38
0%
40

Explanation

Total number of ATP produced during the breakdown of one acetyl-CoA is 12.

The Krebs cycle starts with acetyl-CoA, whereas pyruvic acid is the end product of glycolysis. When one molecule of pyruvic acid is converted to acetyl coA there is the synthesis of one molecule of reduced coenzyme

$NADH_2$ , which yields 3 molecules of ATP during oxidation by mitochondrial electron transport system. Considering these 3 molecules of ATP, the total ATP synthesized by one turn of Krebs cycle is (12+3) i.e., 15 molecules of ATP.

The enzyme which converts glucose to glucose-6-phosphate is

0%
Phosphorylase
0%
Glucose phosphorylase
0%
Hexokinase
0%
Phosphoglucomutase

In the TCA cycle, the conversion of succinyl Co-A to succinic acid requires

0%
Acetyl Co-A + GTP + Pi.
0%
Acetyl Co-A + GDP + Pi.
0%
Co-A + GTP + Pi.
0%
GDP + Pi.

R.Q. is more than one in the case of

0%
Fat
0%
Fructose
0%
Glucose
0%
Organic acid

Which of the following is a 5- carbon compound of Krebs cycle?

0%
Citric acid
0%
Fumaric acid
0%
Oxalosuccinic acid
0%
$\alpha$ -ketoglutaric acid

Product formed by the activity of malic dehydrogenase in the TCA cycle is

0%
Fumaric acid.
0%
Malic acid.
0%
Oxaloacetic acid.
0%
Succinic acid.

Explanation

Malic acid dehydrogenase or malate dehydrogenase is a Krebs cycle enzyme, which converts malic acid into oxaloacetic acid with the simultaneous reduction of one NAD molecule into reduced coenzyme

$NADH_2$ .

The end products of aerobic respiration of glucose is ______________.

0%
$CO_2\, +\, H_2O\, +\, ATP$
0%
$CO_2$ + pyruvic acid
0%
$CO_2$ + ethyl alcohol
0%
$CO_2$ + pyruvic acid + citric acid

How many ATP equivalents are produced by the oxidation of succinate into fumarate?

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

Explanation

Oxidation of succinate to fumarate occurs during Kreb's cycle. This reaction is catalyzed by the enzyme succinate dehydrogenase and is accompanied by the reduction of one molecule of oxidized FAD to reduced FADH ${_2}$ .
The reduced coenzymes produced during the Kreb's cycle are oxidized subsequently by mitochondrial electron transport when ATP is produced. One molecule of reduced FADH ${_2}$ when oxidized by mitochondrial electron transport system results in the synthesis of 2 molecules of ATP.
So, the correct answer is option B.

Total yield in one Krebs cycle is

0%
$3\, FADH_{2},\, 2\, NADH_{2},\, 1\, ATP$ .
0%
$2\, FADH_{2},\, 2\, NADH_{2},\, 2\, ATP$ .
0%
$2\, NADH_{2},\, 1\, FADH_{2},\, 2\, ATP$ .
0%
$3\, NADH_{2},\, 2\, FADH_{2},\, 2\, ATP$ .

Explanation

One turn of Krebs cycle results in the synthesis of 3 molecules of reduced

$NADH_2$ , two molecules of

$FADH_2$ and two molecules of GTP by substrate-level phosphorylation. The GTP is equivalent to ATP.

Substrate-level ATP gain during complete oxidation of 1 molecule of glucose is

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

The chief enzyme found in yeast cells is ________.

0%
Invertase
0%
Maltase
0%
Zymase
0%
Amylase

How many ATP molecules are produced from the complete oxidation of a molecule of active acetate or acetyl CoA ?

0%
38 ATP
0%
15 ATP
0%
12 ATP
0%
4 ATP

Explanation

Glucose undergoes glycolysis to form 2 molecules of pyruvate. The pyruvate molecule is converted to 2 molecules of acetyl-CoA. Each molecule of acetyl-CoA enters the Krebs cycle.

1 NADH (3 ATP) molecule is formed when the isocitrate is converted to oxalosuccinate.

1 NADH (3 ATP) is formed during the conversion of ketoglutarate to succinyl-CoA.

1 GTP/ATP is produced when sunnicyl-CoA is converted to succinic acid.

1 FADH

$_2$ 2 (2 ATP) is produced when succinc acid is converted to fumaric acid.

1 NADH (3 ATP) is formed when malate is converted to oxaloacetate.

So, the correct answer is 12 ATP. Thus, the correct answer is option C.

How many ATP will be produced during the production of 1 molecule of acetyl CoA from 1 molecule of pyruvic acid?

0%
3 ATP
0%
5 ATP
0%
8 ATP
0%
38 ATP

Explanation

Glycolysis converts one molecule of glucose into two molecules of pyruvic acid in the cell cytoplasm. The pyruvic acid molecules are transported to mitochondria for subsequent oxidation in the aerobic respiration. In mitochondria, each molecule of three carbon atom containing pyruvic acid is metabolised to produce two carbon atom containing acetyl coA. Thus, one molecule of carbon dioxide is released per molecule of pyruvic acid undergoing the reaction which is called as oxidative decarboxylation. The reaction is catalyzed by an enzyme complex pyruvate dehydrogenase (PDH). As this reaction is an oxidation reaction, one molecule of coenzyme NADH is simultaneously reduced to give reduced

$NADH_2$ . When one molecule of reduced coenzyme is oxidised in mitochondrial electron transport chain, three molecules of ATP are produced.

Function of the enzyme aconitase in Krebs cycle is

0%
Citrate $\underrightarrow { \quad \quad Aconitase,\quad { Fe }^{ 2+ }\quad \quad }$ Cis aconitate
0%
Cis aconitate $\underrightarrow { \quad \quad Aconitase \quad \quad }$ Isocitrate
0%
Both (A) and (B)
0%
None of the above

Krebs cycle begins with which of the following reaction?

0%
Citric acid + Acetyl CoA
0%
Oxaloacetic acid + Pyruvic acid
0%
Oxaloacetic acid + Citric acid
0%
Oxaloacetate + Acetyl CoA

More CO

$_{2}$ is evolved than the volume of oxygen consumed when the respiratory substrate is

0%
Fat
0%
Sucrose
0%
Glucose
0%
Organic acid

Explanation

R.Q. is the ratio of carbon dioxide evolved and the oxygen consumed during the process of respiration.

For organic acids as they consume less oxygen due to its adequate presence and gives R.Q. more than one.

$2(COOH)_6 + 0_2\rightarrow 4C0_2 + 2H_20$

RQ = 4 C02/1 02 = 4.0 is for oxalic acid.

SO the correct option is 'Organic acid.'.

The stage up to which glycolysis and fermentation have a common pathway is

0%
Dihydroxyacetone.
0%
3-phosphoglyceradehyde.
0%
Pyruvate.
0%
Glucose-6-phosphate.

During conversion of pyruvic acid into acetyl Co-A, the pyruvic acid is

0%
Oxidised.
0%
Reduced.
0%
Isomerised.
0%
Condensed.

Explanation

The pyruvic acid formed after glycolysis may be completely oxidised into carbon dioxide and water as in aerobic respiration or may be incompletely broken down into ethyl alcohol or lactic acid during fermentation process. For the process of aerobic respiration first pyruvic acid is oxidatively decarboxylated to yield Acetyl CoA. As pyruvic acid is a three carbon atom containing molecule and acetyl CoA is a two carbon atom containing molecule, when one molecule of pyruvic acid is converted to one molecule of acetyl CoA, one molecule of carbon dioxide is released. Hence, it is a decarboxylation reaction. In this reaction one unit of reduced coenzyme

$NADH_2$ is simultaneously synthesized.

Incomplete breakdown of sugars in anaerobic respiration forms

0%
Glucose and $CO_{2}$ .
0%
Alcohol and $CO_{2}$ .
0%
Water and $CO_{2}$ .
0%
Fructose and water.

Significance of Krebs cycle is

0%
Synthesizes ATP.
0%
Carries out aerobic respiration.
0%
Oxidation of glucose.
0%
All of the above.

The respiratory quotient of carbohydrate is

0%
Unity.
0%
Greater than unity.
0%
Less than unity.
0%
Equal to five.

The site of TCA cycle in respiration and ATP synthesis is

0%
Mitochondrial stroma.
0%
Mitochondrial matrix and oxysome.
0%
Cytoplasm.
0%
None of the above.

By aerobic respiration of 1 molecule of PGAL how many ATP get synthesized?

0%
8 ATP
0%
2 ATP
0%
19 ATP
0%
36 ATP

Respiratory quotient of which diet is less than unity?

0%
Carbohydrate
0%
Fats
0%
Organic acid
0%
Sugar

In the process of respiration, the largest amount of energy is produced during

0%
Anaerobic respiration.
0%
Krebs cycle and oxidative phosphorylation.
0%
Glycolysis.
0%
None of the above.

Which of the following connects glycolysis to Krebs cycle?

0%
Acetyl CoA
0%
Ribozyme
0%
Cytochrome oxidase
0%
N- acetyl glucosamine

Which of the following accepts terminal electron during aerobic respiration?

0%
Molecular $O_{2}$
0%
Molecular $H_{2}$
0%
Molecular $CO_{2}$
0%
$NADPH_{2}$

Explanation

Although the aerobic process of respiration takes place only in the presence of oxygen, the role of oxygen is limited to the terminal stage of the process. Yet, the presence of oxygen is vital, since it drives the whole process by removing hydrogen from the system. Oxygen acts as the final electron acceptor. It accepts electrons from cytochrome

$a$ -

$a_3$ and forms water molecule.

How many ATPs are directly formed during glycolysis cycle of by 6 molecule of glucose?

0%
24
0%
32
0%
36
0%
38

Which of the following is not an intermediate in Krebs cycle?

0%
Acetic acid
0%
Succinyl coenzyme A
0%
Malic acid
0%
Citric acid

Explanation

The TCA (Krebs) cycle starts with the condensation of acetyl group with oxaloacetic acid (OAA) and water to yield citric acid. The reaction is catalysed by the enzyme citrate synthase and a molecule of CoA is released. Citrate is then isomerised to isocitrate. It is followed by two successive steps of decarboxylation, leading to the formation of alpha ketoglutaric acid and then succinyl CoA. During the conversion of succinyl CoA to succinic acid, a molecule of GTP is synthesised. Succinic acid is converted to fumaric acid, fumaric to malic acid and finally malate to oxaloacetic acid. Thus oxaloacetate is regenerated for another round of Krebs cycle. There are three points in the cycle where

$NAD^+$ is reduced to

$NADH +$

$H^+$ and one point where FAD is reduced to FADH

${_2}$ . Acetic acid is not an intermediate of Krebs cycle.

Thus, the correct answer is option A.

The enzyme of yeast which converts glucose into ethyl alcohol is called as

0%
Diastase
0%
Invertase
0%
Zymase
0%
Maltase

Glycolysis is the conversion of

0%
Glucose to glycogen.
0%
Glycogen to glucose.
0%
Glucose to pyruvic acid.
0%
Glucose to citric acid.

Alcoholic fermentation takes place in the presence of

0%
Maltase.
0%
Zymase.
0%
Amylase.
0%
Invertase.

Explanation

$\textbf{Correct Option B}$

$\textbf{Solution}$

$\bullet$ $\textbf{Option A}$ Maltese is an enzyme which help in catalyzing the hydrolysis process of the disaccharide maltose to simple sugar glucose.

$\bullet$ $\textbf{Option B}$ Zymase is an enzyme is obtained from yeast and it helps in catalyzing the process of breakdown of sugar in alcoholic fermentation which produces ethanol and carbon dioxide as by products.

$\bullet$ $\textbf{Option C}$ Amylase is an enzyme which helps in the catalyst of hydrolyzing process of starch into sugar.

$\bullet$ $\textbf{Option D}$ Invertase is an enzyme which catalyzes the breakdown of sucrose into fructose and glucose.

So, the correct option is B.

A respiratory cycle where

$NADH_{2}$ is produced is the

0%
Calvin cycle.
0%
Krebs cycle.
0%
EMP pathway.
0%
HMP shunt.

Explanation

Krebs cycle forms the second step in respiration where

$NADH_2$ and

$FADH_2$ are produced. It is a cyclic chain of reactions that starts and ends with oxaloacetate.

Fermentation is an

0%
Aerobic respiration
0%
Incomplete oxidation
0%
Excretory process
0%
None of the above

Which of the following is true about Krebs cycle?

0%
GTP / ATP is formed
0%
Decarboxylation
0%
Acetyl CoA acceptor is OAA
0%
All of the above

CBSE Questions for Class 11 Medical Biology Respiration In Plants Quiz 7 - MCQExams.com

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Practice Class 11 Medical Biology Quiz Questions and Answers

CBSE Questions for Class 11 Medical Biology Respiration In Plants Quiz 7 - MCQExams.com

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Practice Class 11 Medical Biology Quiz Questions and Answers

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