0

Cellular respiration - class-XI

Attempted 0/57 Correct 0 Score 0

Anaerobic process that takes place after glycolysis is called as

  1. TCA

  2. Calvin cycle

  3. Krebs cycle

  4. Fermentation


Correct Option: D
Explanation:

Anaerobic process after glycolysis is called as fermentation. Fermentation could be defined as a metabolic process, that converts sugar into acids, gases and alcohol. It occurs in yeast and bacteria, but also in oxygen-starved muscle cells, as in the case of lactic acid fermentation.

What is common in common pathway of aerobic respiration

  1. Glycolysis in both aerobic and anaerobic respiration

  2. Krebs cycle common with HMP

  3. Terminal oxidation in both aerobic and anaerobic respiration

  4. Krebs cycle in both aerobic and anaerobic respiration


Correct Option: A
Explanation:

Aerobic respiration is the oxidative breakdown of respiratory substrates with the help of atmospheric oxygen. It takes place in three steps: Glycolysis, Kreb's cycle and electron transport chain. Anaerobic respiration is the breakdown of respiratory substrates in the absence of atmospheric oxygen. The first step of aerobic respiration as well as anaerobic respiration is same and takes place in the cytoplasm of cells. Glycolysis is the common pathway of both the processes in which glucose is broken down anaerobically into two molecules of pyruvic acid. 

Thus, the correct answer is option A. 

Read the following four statements (A-D)
A) In fermentation, less than seven percent of the energy in glucose is released
B) Glycolysis occurs in the cytoplasm of the cell and is present only in anaerobic organisms
C) The number of ATP molecules synthesized in ETS depends on the nature of the electron donor
D) In glycolysis, glucose undergoes coin, complete oxidation to form two molecules pyruvic acid
How Many of the above statements are correct?

  1. 1

  2. 2

  3. 3

  4. 4


Correct Option: B
Explanation:

A) In fermentation, less than seven percent of the energy in glucose is released because only two ATPs are produced at this stage compared to the total number of 32 ATPs in aerobic respiration. The percentage of energy produced is thus (2/32)*100=6.25%.


C) When electrons are transferred from one carrier to next carrier via complexes I to IV in ETS, they are coupled to the production of proton motive force by transport of protons from the lumen to the inner mitochondrial membrane. The number of protons displaced will ultimately determine the number of ATP molecules that will be produced, i.e. for NADH it will be 2.5 and for FADH2 it will be 1.5.


So, the correct option is '2'.

If one triose phosphate completely oxidized inside the prokaryotic cell, then the net gain of ATP of energy is equal to

  1. $5$ ATP

  2. $4$ ATP

  3. $20$ ATP

  4. $19$ ATP


Correct Option: C
Explanation:

If one triose phosphate completely oxidized inside the prokaryotic cell, then the net gain of ATP of energy is equal to the summation of the ATPs produced at different steps. In the glycolysis step 2 ATP and 1 NADH will be produced followed by 1 NADH in the gateway reaction and 1 GTP, 3 NADH and 1 FADH2 in the TCA cycle. This will add up to 20 ATPs.


So, the correct option is '20 ATP'.

The total number of ATP's formed when one molecule of glucose is oxidized to $CO _2$ to $H _2 O $ is

  1. 32

  2. 38

  3. 42

  4. 40


Correct Option: B
Explanation:
One molecule of the glucose that enters in the glycolysis produces 2 molecules pyruvate and 2 molecules of NADH$ _{2}$ and 2 ATP.  2 molecules of pyruvate will form 2 molecules of Acetyl Co-A and this will release 2 NADH$ _{2}$. These 2 Acetyl Co-A will enter into Kreb's cycle and will release 6NADH$ _{2}$, 2FADH$ _{2}$ and 2ATP.
so, the total gain before the ETC (electron transport chain) comes out to be  10NADH$ _{2}$, 2FADH$ _{2}$ and 4ATP.
Now, during the electron transport chain, 
10NADH$ _{2}$ will give 10 X 3=30 ATP
2FADH$ _{2}$ will give 2 X 2= 4 ATP
So, 34 ATP from ETC and 4 ATP from Kreb's cycle will be 38 ATP.
Hence, the correct answer is '38'

Total $ATP$ through aerobic EMP pathway can be

  1. $6$

  2. $10$

  3. $2$

  4. $8$


Correct Option: D
Explanation:

Glycolysis is also known as 'EMP pathway'. It was discovered by three scientist Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas. That's why glycolysis is also known as the EMP pathway. In the EMP pathway, total 8 ATP are produced.

So, the correct answer is '8 ATP'.

Hydrogen acceptor in cellular respiration is 

  1. NAD

  2. FAD

  3. NADP

  4. Both A and B


Correct Option: D
Explanation:

NAD (Nicotinamide adenine nucleotide) is an electron carrier. It is reduced by accepting a single hydrogen atom and an electron pair from H$ _2$ atom and other electron freed into the medium. NAD is reduced to NADH in citric acid cycle and glycolysis.
FAD (Flavin adenine dinucleotide) is an electron carrier. It is reduced by accepting a full hydrogen H$ _2$ atom. The FAD is reduced to  FADH$ _2$ in the citric acid cycle.
NADP is also an electron carrier. NADP is reduced into NADPH in the photosynthesis.
So, the correct answer is ' NAD & FAD '.

For glycolysis to continue,all cells require

  1. O2

  2. Mitochondria

  3. ETS

  4. NADP+


Correct Option: A
Explanation:

Glycolysis is the only process of extraction of energy in anaerobic organisms. Thus, It never requires O$ _2$ for its completion. Since the process takes place solely in cytoplasm so never requires any other organelle for its completion. As ETS takes place in mitochondria so it never takes part in glycolysis. For uninterrupted working of glycolysis, we require NADP$^+$ as it is required for the production of NADP$^+$+H$^+$ during conversion of 3-Phosphoglyceraldehyde to 1,3-bisphospho glyceraldehyde. 

So, the correct answer to the question is 'NADP$^+$'.

The net gain of ATP molecules through glycolysis is

  1. 6

  2. 4

  3. 8

  4. 36


Correct Option: C
Explanation:
Although four ATP molecules are produced in the second half, the net gain of glycosis is only two ATP because two ATP molecules are used in the first half of glycosis.
Glycosis produces 2 ATP, 2 NADH, and 2 pyruvate molecules.
2ATP + 2 NADP $\rightarrow$ 8 ATP
So, the correct answer is '8 ATP'.

Glycolysis is a:

  1. Redox process

  2. Aerobic process

  3. Oxidative process

  4. Reductive process


Correct Option: A,B
Explanation:

Glycolysis is a redox as well as an aerobic process. It takes place in presence of oxygen that's why this process is known as an aerobic process. In glycolysis oxidation as well as reduction takes place that's why this process is also known as redox process.


So, the correct answer is 'Glycolysis is a redox as well as an aerobic process'.

Which of the following steps of respiration is amphibolic?

  1. Glycolysis

  2. Oxidative decarboxylation of pyruvate

  3. TCA cycle

  4. Oxidative phosphorylation


Correct Option: A
Explanation:

The term amphibolic is used to describe a biochemical pathway that involves both catabolism and anabolism. These are the most common ways smaller organic molecules can be formed into more complex ones and applies to the formation of carbs, proteins, lipids, and nucleic acids. Other type called reduction reaction, which involves the adding of hydrogens and electrons to a molecule. it gains calories of energy because energy is released when a hydrocarbon bond is split. Pathways of glycolysis are amphibolic pathways because they provide ATP and chemical intermediates to build new cell material. The fundamental metabolic pathways of biosynthesis are similar in all organisms, in the same way, that protein synthesis or DNA structure are similar in all organisms.

So the correct option is 'glycolysis'.

Which of the following is the major regulatory enzyme of Glycolysis?

  1. Hexokinase

  2. phosphofructokinase

  3. aldolase

  4. phosphor-triose-isomerase


Correct Option: A
Explanation:

  • In first step of glycolysis, glucose is converted in to glucose -6- phosphate by the enzyme Hexokinase or Glucokinase.
  • Hexokinase is available for all cell where as Glucokinase acts only for liver cell.
  • It also require magnesium as cofactor.
  • Hexokinase is the major regulatory enzyme of Glycolysis.
Hence, the correct answer is 'Hexokinase'

During respiration, pyruvate is formed ________.

  1. When oxygen takes part in the process

  2. When oxygen does not take part in the process

  3. Irrespective of oxygen taking part in the process

  4. When mitochondria take part in the process


Correct Option: A

Maximum energy is released during conversion of?

  1. Glucose into pyruvic acid

  2. Glucose into ethyl alcohol and $CO _2$

  3. Pyruvic acid into acetyl CoA

  4. Pyruvic acid into $CO _2$ and $H _2O$


Correct Option: A

During the stage in the complete oxidation of glucose are the greatest number of ATP molecules formed from ADP.

  1. Glycolysis

  2. Krebs cycle

  3. Conversion of pyruvic acid to acetyl Co-A

  4. Electron transport chain


Correct Option: A
Explanation:

Glycolysis, part of cellular respiration, is a series of reactions that constitute the first phase of most carbohydrate catabolism, catabolism meaning the breaking down of larger molecules into smaller ones. The word glycolysis is derived from two Greek words and means the breakdown of something sweet. Glycolysis breaks down glucose and forms pyruvate with the production of two molecules of ATP. The pyruvate end product of glycolysis can be used in either anaerobic respiration if no oxygen is available or in aerobic respiration via the TCA cycle which yields much more usable energy for the cell.

So the correct option is 'glycolysis'.

In glycolysis how many ATP are produced if $O _2$ is supplied?

  1. $2$

  2. $12$

  3. $6$

  4. $8$


Correct Option: A

Glycolysis pathway was invented by

  1. Calvin

  2. Kreb

  3. J.C Bose

  4. None of the above


Correct Option: D
Explanation:

The most common type of glycolysis is the Embden-Meyerhof-Parnas (EMP pathway), which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas. 

Which is required in glycolysis?

  1. ATP, ADP, $NAD^+$, Glucose, cytoplasmic enzymes

  2. $FAD^+$, ADP, ATP, Glucose, cytoplasmic enzymes

  3. $NADP^+$, ATP, GTP, Glucose, cytoplasmic enzymes

  4. $NAD^+$, $NADP^+$, ATP, Glucose, cytoplasmic enzymes


Correct Option: A
Explanation:
  • Glycolysis occurs in the cytoplasm of the cell and is present in all living organisms. In this process, glucose undergoes partial oxidation to form two molecules of pyruvic acid.
  • Glycolysis requires specific ingredients to work. The inputs of glycolysis include a living cell, cytoplasmic enzymes, glucose, and energy transfer molecules nicotinamide adenine dinucleotide (NAD+) and adenosine triphosphate (ATP).ADP.
  • Hence ATP, ADP, $NAD^+$, Glucose, cytoplasmic enzymes are required in glycolysis.
  • So, the correct answer is 'ATP, ADP, $NAD^+$, Glucose, cytoplasmic enzymes'.

EMP is also known as

  1. Glycolysis.

  2. Krebs cycle.

  3. ETS.

  4. Fermentation.


Correct Option: A
Explanation:

Glycolysis is also known as E.M.P. pathway which stands for Embden - Meyerhof - Parnas Pathway, which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas. Glycolysis splits a 6-carbon sugar, glucose, into two molecules of 3-carbon pyruvate in a series of steps, each catalyzed by a particular enzyme. Glycolysis takes place in the cytoplasm (cytosol) of all living cells, not in mitochondria, and does not require the presence of oxygen. Therefore, glycolysis is also known as cytoplasmic respiration. 

1 molecule of glucose and 6 molecules of $O _2$ and 38 ADP combined to form $6 H _2O,\, 6 CO _2$ and 

  1. 38 molecules of ATP

  2. 28 ATP

  3. 38 ADP

  4. 28 ADP


Correct Option: A
Explanation:

During aerobic respiration, one molecule of glucose is oxidized with the help of six oxygen molecules to produce six molecules of carbon dioxide. Six molecules of water are also produced in the process. During aerobic respiration ATP is produced by the processes of substrate level phosphorylation and oxidative phosphorylation. Combined together these processes produce 38 molecules of ATP by phosphorylating 38 molecules of ADP.

Which of the following is incorrect about glycolysis?

  1. Glycolysis converts a single molecule into two molecules of pyruvate.

  2. Glycolysis can produce a net total of 2 ATP for each glucose.

  3. The end product of glycolysis can form ethanol, lactate, or acetyl CoA.

  4. During glycolysis $FADH _{2}$ is produced.

  5. During glycolysis, NADH is produced.


Correct Option: D

Site of glycolysis/EMP is

  1. Chloroplast

  2. Chromosome

  3. Cytoplasm

  4. Nucleus


Correct Option: C
Explanation:

Cellular respiration is stepwise catabolic process that breaks down organic substrates to release energy. The first step in respiration is glycolysis that occurs in the cytoplasm of the living cell. Krebs' cycle and ETS occurs in mitochondria of the cell. So, the answer is 'Cytoplasm'.

In animal cells, the first stage of glucose breakdown is

  1. Krebs cycle

  2. Glycolysis

  3. Oxidative phosphorylation

  4. Electron transport chain


Correct Option: B
Explanation:

Cellular respiration is a complex process that involves multiple pathways. The first step is the glycolysis of glucose which is then followed by Krebs' cycle and ETS in the end. The end products of respiration is CO$ _2$ and H$ _2$O along with release of energy in the form of ATP. Glucose breakdown first starts with glycolysis.

So, the answer is 'Glycolysis'.

Glycolysis is conversion of

  1. Glucose to glycogen

  2. Glycogen to glucose

  3. Glucose to pyruvic acid

  4. Glucose to citric acid


Correct Option: C
Explanation:

The first step of cellular respiration is the process of glycolysis, a process in which there is breakdown of an organic substance like glucose to pyruvic acid. There is stepwise oxidation of the substrate with the release of energy.

So, the correct answer is 'Glucose to pyruvic acid.'

Glycolysis

  1. Occurs in mitochondria.

  2. Has no connection with ETC.

  3. Reduces 2 molecules of NAD$^+$ per glucose.

  4. Produces no ATP.


Correct Option: C
Explanation:

In glycolysis, glucose undergoes partial oxidation to form two molecules of pyruvic acid in a multi-step process catalyzed by various enzymes. In which 2 ATP molecules are obtained and NAD$^+$ into 2 molecules NADH when 2 moles of 1,3-diphosphoglyceraldehyde converts into two moles of 1,3 diphosphoglyceric acid.

So the correct option is 'Reduces 2 molecules of NAD+ per glucose.'.

The energy releasing metabolic process in which substrate is oxidised without an external electron acceptor is

  1. Fermentation

  2. Aerobic respiration

  3. Photorespiration

  4. Glycolysis


Correct Option: D
Explanation:

Cellular respiration aims at producing energy in the form of ATP and occurs in every living cell. The respiration starts with glycolysis, a stepwise process that oxidises respiratory substrate like glucose. Oxidation is in the form of removal of hydrogen and there is no external electron acceptor present.

So the answer is 'Glycolysis'.

Which of the following is formed from phosphorylation?

  1. Fructose 1,6-bisphosphate

  2. Phosphoglyceric acid

  3. PEP

  4. Pyruvic acid


Correct Option: A
Explanation:

Phosphorylation is the addition of a phosphate group to an organic molecule.

During the glycolysis in the 3rd step, Fructose-6-phosphate is converted into Fructose1,6- bisphosphate. Here one ATP is consumed and converted to ADP as the phosphate group gets attached to the fructose. Here the enzyme used is phosphofructokinase.
So, the correct option is 'Fructose 1,6-bisphosphate'

The other name of glycolysis is

  1. EMP-pathway

  2. TCA-pathway

  3. HMS-pathway

  4. Carbon-pathway.


Correct Option: A
Explanation:

Glycolysis is also known as EMP pathway on the name of the scientist who discovered it and they were Embden, Mayerhoff and Parnas.

So, the correct option is 'EMP pathway'

For bacteria to continue growing rapidly when they are shifted from an environment containing $O _{2}$ to an anaerobic environment, they must

  1. Produce more ATP per mole of glucose during glycolysis

  2. Produce ATP during oxidation of glucose

  3. Increase the rate of glycolysis

  4. Increase the rate of TCA cycle


Correct Option: C
Explanation:

For bacteria to continue growing rapidly when they are shifted from an environment containing O2 to an anaerobic environment, they must increase the rate of glycolysis. Although the amount of ATP produced by anaerobic glycolysis (2) is very less as compared to ATP produced by aerobic glycolysis (38), glycolysis under anaerobic condition is very quick process. It generates ATP very quickly. 

Thus, the correct answer is 'Increase the rate of glycolysis.'

In an eukaryotic cell, glycolysis takes place

  1. In the cytoplasm

  2. Within mitochondrion

  3. On rough ER

  4. Within grana


Correct Option: A
Explanation:

Glycolysis is the splitting of glucose into two pyruvate molecules. It occurs firstly in the cytoplasm and gains a small amount of energy while the other steps occur in the mitochondria where coenzymes and cytochromes are present, it is also the powerhouse of a cell where energy is generated.

So, the correct option is ' in the cytoplasm'.

How many molecules of oxygen are used during the glycolysis of one glucose molecule?

  1. 2

  2. 32

  3. 38

  4. Zero 


Correct Option: D
Explanation:

  • Glycolysis is the process of partial oxidation of glucose into two molecules of pyruvic acid through the enzyme-mediated reaction series.
  • Here two molecules of ATP are utilized. First during the conversion of Glucose to Glucose-6-phosphate and second during the conversion of Fructose-6-phosphate to Fructose-1,6-biphosphate.
  • 4 molecules of ATP are synthesized during 2 substrate based phosphorylated reaction. 
  • First 2 molecules of ATP released during the conversion of 2 molecules of 1,3 bisphosphoglyceric acid to 2 molecules of 3 phosphoglyceric acids. Next 2 molecules are released during the conversion of 2 molecules of phosphoenolpyruvate to 2 molecules of pyruvic acid. 
  • In splitting of one glucose molecule into two pyruvates only the enzymes present in the cytoplasm are used and no oxygen is required. 
  • It is an anaerobic process.
So, the correct option is D ' zero'.
 

Choose the correct answers from the alternatives given :
Which of these processes occurs in the cytosol?

  1. Krebs cycle

  2. Glycolysis

  3. Electron transport system

  4. Transition reaction


Correct Option: B
Explanation:

The process of cellular respiration occurs into three steps :

  1. Glycolysis
  2. Krebs cycle 
  3. Terminal oxidation
Glycolysis is the basic step of respiration where glucose is broken down into two molecules of pyruvate which occurs in the cytoplasm and does not require oxygen while other processes like Krebs cycle, electron transport system and transition reaction occurs in the mitochondria of the cell.
So, the correct option is ' Glycolysis'.

The inner membrane of mitochondrion is very selective in respect to entering, molecule. Name a molecule that regularly enters in it

  1. Pyruvic acid

  2. Glucose

  3. ATP

  4. Oxaloacetic acid


Correct Option: A
Explanation:

Cellular respiration occurs firstly in the cytoplasm and then in mitochondria. Glycolysis occurs in the cytoplasm in which glucose breaks into two pyruvates which are transported to mitochondria through an inner mitochondrial membrane which performs the Krebs cycle. This pyruvate regularly enters the mitochondria to start the Krebs cycle and complete cellular respiration.

So, the correct option is ' pyruvic acid'. 

Choose the correct answers from the alternatives given :
Glycolysis takes place in

  1. eukaryotic cells only

  2. cyanobacteria only

  3. anaerobic bacteria

  4. virtually all cells


Correct Option: D
Explanation:

Glycolysis is the foremost step in the process of cellular respiration which breakdown glucose molecule to extract energy. It is the part of the metabolism of nearly all the cells and organisms as it is the basic process, it does not require oxygen hence it is anaerobic. it occurs in the cytoplasm of both prokaryotes as well as eukaryotes.

So, the correct option is ' Virtually all cells'.

State whether the following statements are true or false.
In a eukaryotic cell glycolysis takes place within the mitochondria, whereas in a prokaryotic cell in the cytoplasm.

  1. True

  2. False


Correct Option: B
Explanation:
  • The process of glycolysis takes place in both prokaryotic and eukaryotic animals as a part of the respiration process to provide the cell with energy.
  • The process of glycolysis always takes places in the cytoplasm of any cell where it occurs for 2 reasons. 
  • First the enzymes that are required for the process are present in the cytoplasm and secondly any of the membrane bound organelles such as mitochondria are nit present in prokaryotic organisms so if the glycolysis was taking place in mitochondria then the prokaryotes won't be able to preform it.
  • Only the reactions of the aerobic respiration such as Kerb's cycle and oxidative phosphorylation takes place in mitochondria to produce ATP.
  • Therefore the sentence above is FALSE and the option 'False' is correct.

Choose the correct answers from the alternatives given :
The rate of glycolysis is

  1. stimulated by ATP

  2. stimulated by oxygen

  3. inhibited by ADP

  4. stimulated by ADP


Correct Option: D
Explanation:
  • For the glycolysis to start the glucose molecule is firstly to be converted to Glucose 6 phophaste after that only will the reaction proceed for which ATP is required which is converted to ADP after the conversion.
  • So when the amount of the ATP in the cell is reduced and the amount of ADP is increased the process is to be started to provide the cell with the required ATP.
  • So the receptors of the cells or the gene that regulate the process of glycolysis are somewhat stimulated by the presence of increased amount of ADP as there are other factors also which control the process of glycolysis such as the amount of ATP, Pyruvic acid etc.
  • Therefore it can be said that the ADP is one of the stimulating factors for the Glycolysis process.
  • Therefore the correct answer is option 'stimulated by ADP'.

Choose the correct answers from the alternatives given :
Which metabolic pathway is common to both the aerobic and anaerobic catabolism of sugar?

  1. Synthesis of acetyl CoA from pyruvic acid

  2. Glycolysis

  3. Krebs cycle

  4. Electron transport chain


Correct Option: B
Explanation:

  • First part for both type of respiration aerobic and anaerobic is glycolysis where the sugar is broken down to pyruvic acid.
  • Glycolysis takes place in the cytoplasm of the cells and does not require for the presnece of any organelles.
  • So both kind of organisms are able to perform glycolysis whether they perform aerobic or anaerobic reactions.
  • Thus it can be said that in both kind of respiration glycolysis is a common process which provides substrate for further reactions in both kind of respiration. Pyruvic acid which converts to acetyl coA and takes part in kerb cycle while pyruvic acid converts to lactic acid or alcohol in fermentation reaction.
  • Therefore the correct answer is option 'Glycolysis'.










Choose the correct answers from the alternatives given :
Glycolysis starts and ends m the 

  1. cytoplasm

  2. plasma membrane

  3. nucleus

  4. mitochondrion


Correct Option: A
Explanation:
  • The whole process of glycolysis takes place in the cytoplasm it does not require any membrane bound organelles to perform the reaction.
  • GLycolysis is the main process to obtain energy in the prokaryotic organisms where there are no membrane bound organelles present and glycolysis is the only source of obatining energy.
  • Therefore the enzymes and substrate required for the process of glycolysis are present in the cytoplasm and the whole reaction takes place in the cytoplasm.
  • Therefore the answer 'cytoplasm' is correct.

Choose the correct answers from the alternatives given :
Select the true statement

  1. glycolysis produces equal numbers of ATP molecules regardless of the presence or absence of oxygen

  2. more ATP molecules are produced per molecule of glucose when glycolysis occurs in aerobic conditions

  3. more ATP molecules are produced per molecule of glucose wvhen glycolysis occurs in anaerobic conditions

  4. none of the above are true


Correct Option: A
Explanation:


  • As the reaction of glycolysis takes place in the cytoplasm of cell where it can proceed in the absence of oxygen molecule. 
  • It does not require the presence of oxygen of to proceed further.
  • It will produce 4 ATP molecules and use 2 molecules of ATP, which gives the cell the net gain of 2 ATP at the end of the glycolysis process.
  • Presence of oxygen or absence of oxygen does not hinder the process of glycolysis and prodution of ATP by glycolysis.
  • Therefore the answere option 'glycolysis produces equal numbers of ATP molecules regardless of the presence or absence of oxygen' is true.

State whether the following statements are true or false.
Glycolysis and fermentation are thought to be older processes than the electron transport system and the Krebs cycle 

  1. True

  2. False


Correct Option: A
Explanation:

The initial processes for energy generation by prokaryotes included anaerobic processes such as Glycolysis and Fermentation. The latter happening of endosymbiosis was the major revolution in bringing up aerobic respiration with the advent of mitochondria within the cells.

Before that, the energy generation was an anaerobic process without using oxygen in Glycolysis and Fermentation.
So, the correct option is 'True'.

State whether the following statements are true or false.
The most efficient pathway for ATP production in animal cells is by glycolysis.

  1. True

  2. False


Correct Option: B
Explanation:
  • Glycolysis is the pathway were one molecule of glucose is broken down to 2 molecules of pyruvate by the phosphorylation and dephosphorylation reactions.
  • 2 molecules of ATP are used in phosphorylation reaction of glycolysis. First while conversion of glucose to glucose-6-phosphate and the second one during conversion of fructose to fructose1,6-biphosphate.
  • While 4 ATP molecules are produced in the dephosphorylation reaction. 2 ATP are produced while conversion of  1,3 bisphosphoglyceric acid to 3-phosphoglyceric acid and another 2 ATP during conversion of phosphophenolepyruvate to pyruvic acid.
  • So the net gain of ATP at the end of one glycolysis reaction is 2. SO glycolysis is not a efficient pathway for the production of ATP in animal cells, in turn it is a part of the chain of reaction which take place before aerobic or anaerobic respiration in animal cells.
  • Glycolysis provided the reaction of aerobic and anaerobic respiration with the substrates to carry the reaction further and produce ATPs in mitochondria where the prominent reactions for production of energy in animal cell takes place.
  • Glycolysis takes place in the cytoplasm of the cell and the product of the glycolysis is transported to the mitochondria.
  • Therefore Glycolysis is not the most efficient pathway for ATP production. So the sentence above is FALSE and therefore the option 'False' is correct.

Choose the correct answers from the alternatives given :
Which of the following does not form during glycolysis?

  1. NADH

  2. ATP

  3. Pyruvate

  4. $FADH _2$


Correct Option: D
Explanation:
  • NADH is formed in the glycolysis after the reaction of conversion Glyceradehyde 3 phosphate to 3 phosphoglyeric acid when electrons re released and are accepted by the NAD.
  • ATP is formed  while conversion of 1,3 bisphosphoglyceric acid to phospoglyceric acid and also while conversion of phosphophenol to pyruvic acid.
  • And pyruvate is the end product of the glycolysis.
  • FADH is the product which is formed  during the the kerb cycle while formation of succunic acid to malic acid.
  • Thereofte the correct answer is '$FADH _2$'
During complete metabolism of glucose, the number of ATP formed is
  1. 2

  2. 12

  3. 36

  4. 44


Correct Option: C
Explanation:
There is a gain of $2$ ATP molecules during glycolysis and $2$ ATP(GTP) molecules during double Krebs cycle. A total of $10$ ${NADH} _{2}$ molecules are formed in aerobic respiration. Thus, the net gain from complete oxidation of a molecule of glucose in muscle and nerve cells is 36 ATP molecules ($10$ ${NADH} _{2}=30 ATP, 2{FADH} _{2}=4 ATP$, four formed by substrate-level phosphorylation in glycolysis and Krebs' cycle and two consumed in transport of the ${NADH} _{2}$ molecules into mitochondria). In aerobic prokaryotes, heart, liver and kidneys, $38$ ATP molecules are produced per glucose molecule oxidised. passage of ATP molecules from inside of mitochondria to the cytoplasm is through facilitated diffusion.
Thus, there is a net gain of $36$ or $38$ ATP molecules depending upon the type of aerobic respiration.
[Note: $1{NADH} _{2}=3ATP$ and $1{FADH} _{2}=2ATP$].
So the correct answer is '36'.
Which of the following statements regarding metabolic pathways is incorrect?
  1. Many of the steps of glycolysis can run in reverse

  2. Starch, sucrose or glycogen must be hydrolysed before it can enter the glycolysis.

  3. After fats are digested, glycerol enters glycolysis by forming DHAP.

  4. After fat digestion, fatty acids can no longer participate in cellular respiration.


Correct Option: D
Explanation:

After fats are digested into fatty acids and glycerol, the following products can take place in cellular respiration.

So, the correct option is 'After fat digestion, fatty acids can no longer participate in cellular respiration.'.

The balance sheet for ATP production in glycolysis has been given below. Select the option which correctly fills up the blanks for P,Q,R and S. ['X' stands for 'nil'].

Steps ATP Utilisation ATP Production
1. $Glucose\rightarrow Glucose-6-phosphate$ P X
2. $Fructose-6-phosphate\rightarrow Fructose-1, 6-bisphosphate$ 1 Q
3. $1,3-bisphosphoglyceric acid\rightarrow 3-Phospho-glyceric acid$ X R
4. $2-Phosphoenol pyruvic acid\rightarrow Pyruvic acid$ S 2
  1. P-1; Q-X; R-X; S-2

  2. P-1; Q-X; R-2; S-X

  3. P-2; Q-1; R-X; S-1

  4. P-X; Q-1; R-2; S-X


Correct Option: B
Explanation:
During glycolysis, the conversion of glucose into glucose-6-phosphate requires the utilization of one ATP molecule and no ATP molecules are produced. Similarly, there is no production of ATP molecules during the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate and only one ATP molecule is utilized. Also, during the conversion of 1,3−bisphosphoglycericacid to 3−Phospho−glycericacid and that of 2−Phosphoenolpyruvicacid to pyruvic acid, tow molecules each of ATP as utilized and no ATP is produced.

So, the correct answer is 'P-1; Q-X; R-2; S-X'.
Which of the following conversions involve ATP synthesis during glycolysis?
  1. Glucose$\rightarrow$Glucose-6-phosphate

  2. Fructose-6-phosphate$\rightarrow$Fructose-1,6-biphosphate

  3. 1,3-bisphosphoglyceric acid (BPGA) $\rightarrow$ 3-phosphoglyceric acid (PGA)

  4. All of these


Correct Option: C
Explanation:

In the energy conserving phase of glycolysis, the conversion of BPGA to PGA is catalyzed by phosphoglycerate kinase. The phosphate on carbon 1 is transferred to a molecule of ADP, yielding ATP and 3-phosphoglycerate. This type of ATP synthesis, traditionally referred to as substrate-level phosphorylation, involves the direct transfer of a phosphate group from a substrate molecule to ADP, to form ATP.
$1,3-bisphosphoglycerate+ADP\overset{Phosphoglycerate kinase}{\underset{{Mg}^{2+}}{\rightleftharpoons}}3-phosphoglycerate+ATP$

How much energy is gained directly during glycolysis from one molecule of glucose?

  1. 34 kJ

  2. 72 kJ

  3. 68 kJ

  4. 50 kJ


Correct Option: C
Explanation:

Glycolysis produces 2 ATP, 2 NADH,2 pyruvate molecules. It is the aerobic catabolic breakdown of glucose, which produces energy of 68KJ in form of ATP, NADH, and pyruvate, which itself enters a citric acid cycle to produce more energy.

So, the correct option is '68KJ'.

The enzymatic machinery to partially oxidise glucose into pyruvic acid without the help of oxygen.

  1. Present in prokaryotic as well as eukaryotic organisms

  2. Occurs in mitochondrial matrix of eukaryotes

  3. Produces four ATP as net gain

  4. More than one option is correct


Correct Option: A
Explanation:
The enzymatic machinery to partially oxidise glucose into pyruvic acid without the help of oxygen.
 Ans is A
Present in prokaryotic as well as eukaryotic organisms both. 
In eukaryotic  cell like muscle and RBC and many of the prokaryotic cell use this process. 

The major reason that glycolysis is not as energy productive as respiration is that?

  1. $NAD^+$ is regenerated by alcohol or lactate production, without the high-energy electrons passing through the electron transport chain

  2. It is the pathway common to fermentation and respiration

  3. It does not take place in a specialized membrane-bound organelle

  4. Pyruvate is more reduced than $CO _2$; it still contains much of the energy from glucose


Correct Option: B
Explanation:

Glycolysis, part of cellular respiration, is a series of reactions that constitute the first phase of most carbohydrate catabolism. Catabolism means the breaking down of larger molecules into smaller ones. The word glycolysis is derived from two Greek words and means the breakdown of something sweet. Glycolysis breaks down glucose and forms pyruvate with the production of two molecules of ATP. The pyruvate end product of glycolysis can be used in either anaerobic respiration if no oxygen is available or in aerobic respiration via the TCA cycle which yields much more usable energy for the cell.  When oxygen is present, NADH can pass its electrons into the electron transport chain, regenerating NAD$^+$ for use in glycolysis. When oxygen is absent, cells may use other, simpler pathways to regenerate NAD$^+$ these pathways, NADH donates its electrons to an acceptor molecule in a reaction that doesn’t make ATP but does regenerate NAD$^+$ so glycolysis can continue. This process is called fermentation.

So the correct option is 'It is the pathway common to fermentation and respiration'.

Energy releasing process in which substrate is oxidised without an external electron acceptor is

  1. Aerobic respiration.

  2. Fermentation.

  3. Photorespiration.

  4. Glycolysis.


Correct Option: D
Explanation:

During glycolysis process the substrate pyruvic acid is formed from glucose is then oxidized into lactic acid in muscles by pyruvic acid, decarboxylase and alcohol dehydrogenase.

So the correct option is 'Glycolysis.'

Which of the following is incorrect for glycolysis?

  1. It produces ATP

  2. It uses ATP

  3. End products are CO$ _2$ and H$ _2$O

  4. None of the above.


Correct Option: C
Explanation:

During the process of glycolysis, ATP is utilized and produced but the carbon dioxide and water are not the end products.

So the correct option is 'End products are CO$ _2$ and H$ _2$O.'

NADH is produced in

  1. Photosystem II

  2. Photosystem I

  3. Glycolysis

  4. Both A and B


Correct Option: C
Explanation:

NADH is essentially produced only during the cellular respiration and it gets oxidised to release energy in the form of ATP. Glycolysis is a part of cellular respiration and leads to production of NADH. However, photosystem I and II produce NADPH rather than NADH as energy carriers. So the answer is 'Glycolysis'.

Which group of scientists discovered glycolysis?

  1. Embden, Merrison and Pitches

  2. Embden, Meyerhof and Parnas

  3. Emerson, Hoffman and Peterson

  4. Avery, Macleod and Mc Carthy


Correct Option: B
Explanation:

Glycolysis takes place in the liquid part of the cytoplasm i.e. cytosol. The most common type of glycolysis is the Embden–Meyerhof–Parnas (EMP pathway), which was discovered by Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas. 

So the correct option is 'Embden, Meyerhof and Parnas.'

What occurs in glycolysis?

  1. Fixation.

  2. Reduction.

  3. Dehydrogenation.

  4. Oxidation.


Correct Option: D
Explanation:

Glycolysis takes place in the cytosol of cytoplasm without the involvement of oxygen. The by-product of glycolysis is pyruvate which entered into mitochondria and oxidized oxygen to carbon dioxide.

So the correct option is 'Oxidation.'

In glycolysis, enzyme enolase produces

  1. Phosphoglyceric acid

  2. Phosphoenol pyruvate

  3. Phosphoglyceraldehyde

  4. Pyruvate


Correct Option: B
Explanation:

In glycolysis, the respiratory substrate glucose is oxidised to pyruvic acid to release energy. The enzyme enolase converts phosphoglycerate to phosphoenol pyruvate with the release of H$ _2$O. So, the correct answer is 'Phosphoenol pyruvate'.

Glycolysis is part of

  1. Only anaerobic respiration

  2. Krebs cycle

  3. Only aerobic respiration

  4. Both aerobic and anaerobic respiration.


Correct Option: D
Explanation:

There is no utilization oxygen is seen in the process of glycolysis which takes place in the cytoplasm and it is an anaerobic process. After finishing the glycolysis the cell needs to respirate through aerobic respiration in the presence of oxygen. Aerobic reactions occur in the mitochondria which require oxygen.

So the correct option is 'Both aerobic and anaerobic respiration'.

Anaerobic respiration takes place in
  1. mitochondrion

  2. nucleus

  3. cytoplasm

  4. vacuole


Correct Option: C
Explanation:
Anaerobic respiration (both glycolysis and fermentation) takes place in the fluid portion of the cytoplasm whereas the bulk of the energy yield of aerobic respiration takes place in the mitochondria. So, the correct answer is "Cytoplasm."
- Hide questions