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Energy output - class-X

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What is ATP?

  1. A hormone

  2. A protein

  3. An enzyme which brings about oxidation

  4. A molecule which contains high energy bond


Correct Option: D
Explanation:

  • Adenosine triphosphate (ATP) is a nucleotide with three phosphates. The ATP is produced by the addition of phosphorous to nucleoside adenosine.
  • The first phosphate is attached by an ester bond. This bond is a normal covalent bond and not a high energy bond. 
  • The two-terminal phosphates are bonded by high energy acid anhydride bonds. 

Thus one molecule of ATP contains two high energy bonds.

ATP stands for which of the following?

  1. Adenosine phosphate

  2. Adenine triphosphate

  3. Adenosine diphosphate

  4. Adenosine triphosphate


Correct Option: D
Explanation:

Chemically ATP is a nucleotide. In fact it is a higher order nucleotide because it contains not one but three phosphates. Compounds made up of (pentose) sugar and a nitrogenous base are called nucleosides. If the base is adenine, the nucleoside will be called adenosine. 

If one phosphate is attached to adenosine through an ester bond then the compound becomes a nucleotide and in this case it is called adenylic acid or adenosine monophosphate.
When second phosphorous is attached to the first phosphorous, through an acid anhydride bond, the nucleotide is called adenosine diphosphate. When third phosphorous is attached to the second phosphate through another acid anhydride bond, the nucleotide is called adenosine triphosphate or ATP.

$\sim P$ in ATP represents

  1. Two bonds with high energy

  2. Two moles of phosphorus

  3. Three atoms of high energy phosphate

  4. None of the above


Correct Option: A
Explanation:
ATP is known as energy currency of the cell and it is a nucleotide formed by the combination of adenine as a nitrogenous base, ribose sugar, and triphosphate. It is found in free cells which breaks to form energy by breaking it's high energy phosphate bonds. The high energy phosphate bonds break to form ADP and AMP. It is a hydrolysis reaction which occurs at extreme pH. It dephosphorylates to provide energy for metabolic function.
ATP has three phosphate out of which one is directly attached to the ribose with phosphate ester bond and it is low energy bond. The bond between two phosphate groups is a phosphoanhydride bond which is considered as high energy bond. So ATP has only two high energy bond phosphoanhydride bond.
So, the correct answer is option A.

Conversion of ATP to ADP releases

  1. Energy

  2. Enzyme

  3. Hormone

  4. Electricity


Correct Option: A
Explanation:

Adenosine Triphosphate or ATP has stored energy in its bond with the third phosphate group. However when required, ATP loses its third phosphate group to release energy and gets converted back to ADP. The energy released is in the form of chemical energy that the cells can use.

So the answer is 'Energy'.

How many ATPs are required by $C _4$ plants in synthesis of one molecule of glucose

  1. 18 ATP

  2. 30 ATP

  3. 12 ATP

  4. None of the above


Correct Option: B
Explanation:

Most of the plants that are adapted to dry tropical regions have the $C _{4}$ pathway. e.g. Sugarcane, Maize, Sorghum,etc. These plants are known as $C _{4}$ plants.For the formation of sugars, $C _{4}$ plants undergo $C _{4}$ cycle as well as $C _{3}$ cycle or Calvin cycle. In these plants double fixation of carbon dioxide occurs.

ATP consumed in $C _{4}$ plants:
$C _{4}$ cycle - 2 ATP per $CO _{2}$ fixed
$C _{3}$ cycle - 3 ATP per $CO _{2}$ fixed 
Total - 5 ATP per $CO _{2}$ fixed
Thus, to form one molecule of glucose or to fix 6 $CO _{2}$, 6 X 5 = 30 ATP are consumed.

One mole of glucose on metabolism, liberate how many kilo calories of energy ?

  1. 180

  2. 80

  3. 160

  4. 380


Correct Option: D
Explanation:

On complete combustion of glucose (1 mole) to CO$ _{2}$ & H$ _{2}$O, approx. 686 kcal of energy is released. When 1 g of glucose respires aerobically by ETS, Glycolysis and  Krebs cycle, around 38 ATP molecules are generated. The terminal group of a mole of ATP has around 10 kcal. Thus, 38 ATP molecules represent a yield of 380 kcal of energy.  

So the correct option is '380'

How many ATP and NADPH molecules are respectively required to make one molecule of glucose through the Calvin cycle?
  1. 3 and 2

  2. 9 and 6

  3. 18 and 12

  4. 12 and 18


Correct Option: C
Explanation:

For every $CO _{2}$ molecule entering the Calvin cycle, $3$ molecules of $ATP$ and $2$ molecules of NADPH are required. To make one molecule of glucose, $6$ turns of the cycles are required 

$(6\times 3 ATP =18 ATP$ and $6\times 2 NADPH=12 NADPH)$.

In                            Out   
$6$ $CO _{2}$ $1\,\, glucose$
$18 ATP$ $18 ADP$
$12 NADPH$  $12 NADP$ So, the correct answer is '

18 and 12'.

If two moles of glucose are oxidized in the body through respiration, the number of moles of ATP produced are.

  1. 19

  2. 38

  3. 57

  4. 76


Correct Option: D
Explanation:
Cellular respiration can be an anaerobic or aerobic respiration, depending on whether or not oxygen is present. Anaerobic respiration makes a total of 2 ATP. Aerobic respiration is much more efficient and can produce up to 38 ATP with a single molecule of glucose.
Anaerobic respiration consists of two steps.
               1. Glycolysis (2 ATP)
               2. Fermentation 
               Total = 2 ATP
Aerobic respiration consists of three steps.
               1. Glycolysis (2 ATP)
               2. Krebs Cycle (2 ATP) 
               3. Electron Transport Chain (34 ATP)
               Total = 38 ATP
If two moles of glucose is oxidized in the body through respiration, the number of moles of ATP produced are 38 x 2 = 76.
So the answer is option D '76'. 

The number of ATP molecules produced during the oxidation of $1$ molecule of glucose is 

  1. $12$

  2. $18$

  3. $32$

  4. $38$


Correct Option: D
Explanation:
1. Glycolysis: 
 C$ _{6}$H$ _{12}$O$ _{6}$ +  2 ATPs  → 2 Pyruvic Acid + 4 H$ _{2}$ + 4 ATPs
2. Formation of Acetyl CoA:
 2 Pyruvic Acid + 2 CoA → 2 Acetyl CoA + 2 CO$ _{2}$ + 2 H$ _{2}$
3. Krebs Cycle:
 2 Acetyl CoA + 3 O$ _{2}$ → 6 H$ _{2}$ + 4 CO$ _{2}$ + 2 ATPs
4. Electron Transport System:
 12 H$ _{2}$+ 3 O$ _{2}$ → 6 H$ _{2}$O + 34 ATPs
Overall Reaction:
C$ _{6}$H$ _{12}$O$ _{6}$ + 6 O$ _{2}$→ 6 CO$ _{2}$ + 6 H$ _{2}$O + 38 ATPs
So, the correct option is '38'.

At the end of Krebs cycle, but before the electron transport chain, the oxidation of glucose has produced a net gain of -

  1. $ 3CO _2 , 5 NADH _2 , 1 FADH _2 , 2 ATP$

  2. $ 6CO _2 , 10 NADH _2 , 2 FADH _2 , 4 ATP$

  3. $ 6CO _2 , 10 NADH _2 , 2FADH _2 , 38 ATP$

  4. None of these


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 molecules of CO$ _{2}$ and 2 NADH$ _{2}$. These 2 Acetyl Co-A will enter into Kreb's cycle and will release 4CO$ _{2}$, 6NADH$ _{2}$, 2FADH$ _{2}$ and 2ATP.

so, the total gain before the ETC comes out to be 6 CO$ _{2}$, 10NADH$ _{2}$, 2FADH$ _{2}$ and 4ATP.
Hence, the correct answer is '6CO$ _{2}$, 10NADH$ _{2}$, 2FADH$ _{2}$, 4ATP'.

The energy liberated in the breakdown of glucose molecule is not at all in the form of heat, but a large part of it is converted into chemical energy. What is the chemical form into which the energy is converted to?

  1. GTP

  2. ATP

  3. ADP

  4. NADP


Correct Option: B
Explanation:

The energy in an organism is stored in the form of ATP molecule called Adenosine Triphosphate. It is also considered as the energy currency of the cell and break down of one molecule of glucose in the process of respiration. It occurs mainly in mitochondria gives 38 ATP molecules. Single ATP provides around 30.5 KJ of energy.

So the correct option is 'ATP'.

During the complete oxidation of one sucrose molecule, how many ATP are produced by $FADH _2$ of Krebs cycle?

  1. $24$

  2. $8$

  3. $3$

  4. $4$


Correct Option: B
Explanation:

Sucrose is made up of glucose and fructose. From one molecule of glucose, 38 ATP molecules can be produced during cellular respiration. During Kreb cycle, 2 molecules of FAD are reduced to FADH$ _2$. Now 2 FADH$ _2$ produce 2 x 2 = 4 ATP molecules. Fructose is converted to fructose-6-phosphate by hexokinase enzyme. This fructose-6-phosphate then enters the glycolysis and produces same amount of ATP as glucose molecule does. Hence, it will also produce 4 ATP molecules by FADH$ _2$ of Krebs cycle. Hence, total ATP produced will be 8 molecules phosphorylation by FADH$ _2$ of Krebs cycle.

Thus, the correct answer is '8.'

Which of the following derives maximum energy per molecule of glucose?

  1. Alcoholic fermentation

  2. Lactic acid fermentation

  3. Aerobic respiration in unicellular organisms

  4. Glycolysis in liver cells


Correct Option: C
Explanation:

Aerobic respiration is the process of producing cellular energy involving oxygen. Cells break down food in the mitochondria in a long, multistep process that produces roughly 36 ATP. The first step in is glycolysis, the second is the citric acid cycle and the third is the electron transport system.


So the correct option is 'Aerobic respiration in unicellular organisms'.

The organelle responsible for ATP formation is  

  1. Quantasome

  2. Thylakoid

  3. Chondriosome

  4. Mitochondria


Correct Option: C,D
Explanation:
 Name of the organelle  Function
 Quantasome  These are the particles found in the membrane of thylakoid and in which process of photosynthesis takes place.
 Thylakoid  Carry out the light reactions of photosynthesis
 Chondriosome Another name of a mitochondrion. Responsible for ATP formation
 MItochondria The two stages of respiration take place in the mitochondria. Krebs cycle occurs in the cristae of the mitochondria. Oxidative phosphorylation occurs on the membranes. The energy is released at the end of respiration in the form of ATP.

So, the correct answer is ' Mitochondria and Chondriosome '

In prokaryotic cells, the number of ATP generated form one glucose molecule is _______

  1. $36$

  2. $38$

  3. $34$

  4. $32$


Correct Option: B
Explanation:

In the eukaryotic ell, the aerobic respiration occurs in mitochondria as well as the cytoplasm. The Electron Transport Chain (ETC) that yields the maximum ATPs is located in the inner membrane of the mitochondria. So, the NADH made during the glycolysis in cytoplasm have to be transferred to the mitochondria using the shuttle system and for this, 2 ATPs are consumed. However, in the bacterial cell, since there is no mitochondria, the whole process of respiration occurs within the cytoplasm so no ATP is consumed in transporting across the organelle. Therefore, 38 ATPs are made form one glucose in bacteria while 36 are made in an eukaryotic cell.

Hence, the correct answer is '38'

Energy released by oxidation of one molecule of glucose is -

  1. 800 K.cal

  2. 695 K. cal

  3. 686 K.cal

  4. 700 K.cal


Correct Option: C
Explanation:

When 1 mol (180 g) of glucose reacts with oxygen under standard conditions, 686 kcal of energy is released. 36 ATP synthesised in aerobic respiration. Total free energy stored as high energy phosphate bonds in ATP is therefore 252kcal. The remaining energy is lost. So, the correct option is '686 K.cal'.


How many $NADH+ H^+$ molecules are released from a single Krebs' cycle?

  1. $3$

  2. $6$

  3. $12$

  4. $8$


Correct Option: B

The energy stored in one molecule of NADPH and one molecule of ATP are ....... and ...... respectively.

  1. 52 kcal, 7 kcal

  2. 520 kcal, 70 kcal

  3. 150 kcal, 22 kcal

  4. 650 kcal, 90 kcal


Correct Option: A
Explanation:

Nicotinamide adenine dinucleotide phosphate is abbreviated as NADP, is a cofactor used in anabolic reactions, such as lipid and nucleic acid synthesis, which require NADPH as a reducing agent. It produces 52 kCal of energy from one molecule. Adenosine triphosphate used in cells as a energy currency, often called the molecular unit of currency of intracellular energy transfer. ATP is therefore continuously recycled in organisms: the human body, which on average contains only 250 grams of ATP.  One molecule of ATP produces 7kCal of energy.

How many ATP are synthesized per sucrose molecule(gross synthesis) in aerobic respiration through substrate level phosphorylation?

  1. $10$

  2. $12$

  3. $30$

  4. $76$


Correct Option: C
Explanation:

C- In substrate-level phosphorylation, 2 ATP are synthesized from glycolysis and 2 ATP from Krebs cycle Oxidative phosphorylation that is, 2 × 1.5 ATP or 2 × 2.5 ATP (in malate-aspartate shuttle). Thereby, from the oxidative decarboxylation of pyruvate there shall be 2 NADH+H+ and 6 from Krebs cycle making it – (a) 8 × 2.5 ATP & 2 FADH2 from the Krebs cycle, (b) 2 × 1.5 ATP; thus summing it up to 4 + 3 (or 5) + 20 + 3 = 30 (or 32) ATP per molecule of glucose.

The radiant energy is stored in the form of chemical energy in

  1. NADP

  2. Stored food

  3. RNA

  4. DNA


Correct Option: B
Explanation:

Photosynthesis is an energy conversion process. During photosynthesis green plants trap solar energy and synthesize sugars. Thus light energy present in photons is converted to chemical energy, which is trapped in the bonds of sugar molecules.

Complete oxidation of 1 gm mol of glucose gives rise to ................. calories.

  1. 6860000 

  2. 686000 

  3. 68600 

  4. 6860 


Correct Option: B
Explanation:

At pH 7.0 and temperature 298 K, the standard free energy change of oxidation of glucose is -686 Kilocalories per mole or -2840 Kilojoules per mole. The negative values indicate that oxidation of glucose is an exergonic or energy releasing process.

Common immediate source of energy for cellular activity is

  1. Glucose.

  2. Aldohexose.

  3. ATP.

  4. NAD.


Correct Option: C
Explanation:

Adenosine triphosphate (ATP) is a nucleotide with three phosphates. It is the universal energy currency for all cellular metabolic processes. Endergonic processes are driven by energy input using hydrolysis of ATP. Exergonic processes are coupled to ATP synthesis. 

How many ATP forms in aerobic respiration of eukaryotic cell?

  1. 28 ATP

  2. 36 ATP

  3. 20 ATP

  4. 40 ATP


Correct Option: B
Explanation:

Overall production of aerobic reaction is 24 (Krebs cycle) + 6 (oxidative decarboxylation) + 6 (glycolysis), i.e., 36 ATP molecules.

What is the energy coin of a cell?

  1. DNA

  2. RNA

  3. ATP

  4. Minerals


Correct Option: C
Explanation:
  • During cellular metabolism, energy is frequently exchanged between endergonic and exergonic reactions and molecules.
  • The ATP is a universal energy currency, which is used in these cellular energy exchanges.
  • The reason has been that is ATP can be formed easily by the process of phosphorylation of ADP as suggested by the chemiosmotic theory.
  • Further, one molecule of ATP has two terminal high energy acid anhydride bonds, which can break easily to provide energy. 
  • Therefore, ATP can be both formed easily as well as broken easily. 

    Hence, correct option is C.

The number of ATP molecules produced during the production of 1 molecule of acetyl Co-A from 1 molecule of pyruvic acid is

  1. 3 ATP.

  2. 8 ATP.

  3. 36 ATP.

  4. 38 ATP.


Correct Option: A
Explanation:

Pyruvic acid is the end product of glycolysis. It is translocated into mitochondria for complete oxidation to carbon dioxide and water. Inside mitochondria first pyruvic acid is oxidatively decarboxylated into acetyl coA. In this process the three carbon atom containing pyruvic acid is converted to two carbon atom containing acetyl CoA and a molecule of carbon dioxide is released. The acetyl coA is fed into the Kreb's cycle. 

During oxidative decarboxylation of pyruvic acid one molecule of reduced coenzyme $NADH _2$ is synthesized. The reduced coenzyme $NADH _2$ can be metabolised by mitochondrial electron transport system, when one molecule of $NADH _2$ produces 3 ATP molecules by  the process of oxidative phosphorylation.

Chemosynthesizers can convert chemicals into biomass, and many types of chemosynthetic organisms congregate near hydrothermal vents, where chemicals are abundant.
Predict why there would be higher biomass and greater primary production of organisms living in the hydrothermal vent areas, in contrast to the areas outside the vent areas.

  1. The vents release an abundance of chemicals the organisms living there can use in the production of energy molecules.

  2. The heat released from the vents oxidizes chemicals in the water that organisms consume.

  3. It is too cold outside the vent areas, so most of the organisms live within the vent areas.

  4. Predators are rare in the vent areas, so organisms rarely venture out beyond the immediate vent area.


Correct Option: A
Explanation:

Hydrothermal vents are abundant in chemical substances that are released by the core of the earth. These vents are devoid of light and have a temperature of about 350$^o$C. Therefore, this habitat can help only those organisms to survive which do not use light as a source of energy, that is autotrophs of this food chain should be able to synthesize food from chemicals present in the surrounding- example archea while withstanding the extreme temperature

So, the correct answer is 'The vents release an abundance of chemicals the organisms living there can use in the production of energy molecules'

Which organisms are ultimately responsible for obtaining the energy required for life processes?

  1. Anaerobic bacteria

  2. Fungi decomposing dead organisms

  3. Plants undergoing photosynthesis

  4. Animals undergoing respiration


Correct Option: D
Explanation:
Respiration is a catabolic process that leads to formation of ATP molecules from the substrate, that can be utilized for performing various life processes
So, the correct answer is 'Animals undergoing respiration'

Both photosynthesis and cellular respiration are metabolic processes that occur in eukaryotic cells. Each process involves several steps and chemical reactions.
All of the following occur during the processes of photosynthesis and cellular respiration except

  1. The production of large amounts of ATP.

  2. Oxidation-reduction reactions.

  3. The use of multiple enzymes to catalyze reactions.

  4. An electron transport chain.


Correct Option: A
Explanation:

Production of large amount of ATP takes place exclusively during respiration. However a small number of ATP is produced during the light reaction of photosynthesis, which is utilized for fixing or reducing CO$ _2$

So, the correct answer is 'The production of large amounts of ATP'

Which molecule is responsible for storing energy that can be used to do cellular work?

  1. DNA

  2. Fat

  3. ATP

  4. Protein


Correct Option: C
Explanation:

Energy derived from light or chemical compounds is stored in the form of ATP, it is a energy resource compound found across all organisms. Which can be hydrolyzed by the cell to derive energy for all its activities

So, the correct answer is 'ATP'

The enzyme ATP synthase is part of the process required to synthesize ATP from ADP and inorganic phosphate in the mitochondria.

Which of the following conditions would stimulate the synthesis of ATP?

  1. A slowdown of glycolytic activity

  2. Elevated oxygen levels

  3. A build up of the proton gradient

  4. Decreased substrate-level phosphorylation in the cytoplasm


Correct Option: C
Explanation:

A build up of proton gradient in the mitochondrial matrix is used by the ATP synthase to generate ATP from ADP and iP, this is also referred to as PMF or the free energy released by passive movement of protons from the mitochondrial matrix into the cytoplasm.

So, the correct answer is 'A build up of the proton gradient'

One molecule of NADH$ _{2}$ on oxidation yields ............... ATP molecules.

  1. One

  2. Two

  3. Three

  4. Four


Correct Option: C
Explanation:
The NADH$ _2$ and the FADH$ _2$ are produced during the cycles of respiration. These molecules are produced during the glycolysis and the Krebs cycle. These molecules are oxidized in the process of electron transport system. This is the system in which the electrons is donated from one donor to acceptor. These products are oxidized and the protons are used for creating a gradient which is used in the synthesis of ATP. NADH$ _2$ transfers the electrons to the complex I and then transfers the electrons to the complex II. This results in more number of protons which are pumped by ATP synthase. So, the more protons will result in the production of 3 ATPs.
Thus, the correct answer is option C. 

The amount of energy the earth receives from the sun per year is

  1. $15 \times 100^{20} kcal$

  2. $10 \times 10^{30} kcal$

  3. $15 \times 10^{20} kcal$

  4. $15 \times 10^{25} kcal$


Correct Option: C
Explanation:

The sun is considered as the major source of energy. The solar energy is the renewable form of energy and is used for various purposes like generating electricity, working of the solar batteries, etc. The total amount of the energy which is received by the earth from the sun is equal to about 15×10$^{20}$ kcal.

Thus, the correct answer is option C. 

The total amount of energy released from one molecule of glucose on oxidation is about 

  1. $1600 kJ$

  2. $2300 kJ$

  3. $2500 kJ$

  4. $2900 kJ$


Correct Option: D
Explanation:

The glucose molecule is oxidised to form pyruvic acid which is further oxidised to release water and carbon dioxide. When one glucose molecule is completely oxidised, 38 ATP molecules are formed. The energy of the 38 ATP is equal to about 2900 kJ or 686 kcal of energy. The equation of the glucose oxidation is given as 

C$ _6$ H$ _{12}$ O$ _6$ + 6O$ _2$ $\rightarrow$ 6CO$ _2$ + 6H$ _2$O + 2900 kJ energy
Thus, the correct answer is option D. 

How much of the energy released during aerobic respiration is approximately conserved in the form of ATP?

  1. $20\%$

  2. $40\%$

  3. $60\%$

  4. $100\%$


Correct Option: B
Explanation:

Aerobic respiration is a breakdown of organic material in the presence of oxygen. It takes place in the cytoplasm and mitochondria of the cell. During aerobic respiration, the first step is glycolysis in which there is a net formation of eight molecules of ATP and then the link reaction in which the pyruvic acid which is the end product of glycolysis is converted into acetyl CoA. 

This reaction leads to the formation of six molecules of ATP but these are not included in the Krebs cycle. This is acetyl CoA enter the Krebs cycle, which results in the formation of 30 molecules of ATP.
So, the net formation of ATP is 38 ATP and this round off to 40% of the total energy that is conserved as ATP.
So, the correct option is '40%'

The synthesis of ATP in photosynthesis and respiration is essentially an oxidation-reduction process involving removal of energy from 

  1. Oxygen

  2. Phytochrome

  3. Cytochrome

  4. Electrons


Correct Option: D
Explanation:

Synthesis of ATP in photosynthesis as well as respiration is possible by the help of several oxidation and reduction reactions. This can be termed as redox reactions. This involves the excitation of electrons from ground state to excited state and vice - versa. ATP is called as the energy currency of cell.

Which one of the following is energy currency of the cell?

  1. Phosphate

  2. ATP

  3. ADP

  4. AMP


Correct Option: B
Explanation:

The major energy currency molecule of the cell is ATP. This complex  molecule is critical for all life froms, the simplest to the most complex. It is one of the end products of photophosphorylation, cellular respiration and fermentation and used by enzymes and structural proteins in many cellular processes.

In photosynthesis energy from light reaction to dark reaction is transferred in the form of 

  1. ADP

  2. ATP

  3. RUDP

  4. Chlorophyll


Correct Option: B
Explanation:

ATP is the energy currency. Assimilatory power is the power of plants in the form of ATP and NADPH to obtain food in the form of carbohydrates from the reduction of $CO _2$ during photosynthesis.

Usable energy available from respiration is

  1. 10%

  2. 30%

  3. 40%

  4. 50%


Correct Option: D
Explanation:

One mole of glucose on complete oxidation to carbon dioxide and water produces about 690,000 calories. About 10,000 calories are needed to form the high energy phosphate bonds in one mole of ATP. 36 or 38 moles of ATP formed in respiration process will trap 360,000 or 380,000 calories. The remaining 330, 000 or 310,000 calories are lost as heat. Thus about 52% of the energy released from glucose is trapped in ATP. 

Thus, the correct answer is option D. 

Number of ATP molecules formed during complete oxidation of fructose 1, 6-diphosphate is 

  1. 20

  2. 32

  3. 36

  4. 40


Correct Option: D
Explanation:

Fructose-1, 6-bisphosphate is formed during glycolysis as an intermediate product when glucose-1,6-bisphosphate is converted into fructose-1, 6-bisphosphate and enzme phosphofructokinase is used for this. Fructose generally results in the formation of a higher amount of energy after oxidation and in this case, it is more than glucose.

So, the correct option is '40'

The net gain of energy from one gram mole of glucose during aerobic respiration is

  1. 2 ATP

  2. 4 ATP

  3. 38 ATP

  4. 40 ATP.


Correct Option: C
Explanation:

If a cell is undergoing aerobic respiration then it will first undergo glycolysis which is the first breakdown of glucose in the cell and then Krebs cycle.

The net gain of ATP in glycolysis is 8 and the net gain of ATP in Krebs cycle including the substrate phosphorylation and oxidative phosphorylation is 30. So, the total gain of ATP is 38 from one molecule of glucose.
So, the correct option is '38 ATP'

Common immediate source of energy in cellular activity is 

  1. DNA

  2. ATP

  3. RNA

  4. NAD.


Correct Option: B
Explanation:

ATP stands for adenosine triphosphate. The energy released by oxidation of organic molecules is transferred into high energy phosphate bonds of ATP, which can be readily utilised when a cell needs energy. One of the three phosphates of ATP is broken down to release energy. Thus, ATP is the intermediate energy transferring compound. 

So, the correct option is  'ATP'

The amount of energy given by one mole of ATP is

  1. 7.3 kcal

  2. 721 kcal

  3. 7600 kcal

  4. 1000 kcal


Correct Option: A

Energy currency (reservoir) of the cells is

  1. AMP

  2. ATP

  3. ENA

  4. DNA


Correct Option: B
Explanation:

ATP or adenosine triphosphate is considered to be the energy currency of the cell as it has three high energy phosphate bonds.

When the cell needs energy on of the first bond of the ATP is broken down and energy is used for cellular needs.
In the entire body wherever energy or heat generation takes place it results in the conservation of energy in the form of ATP so that the minimum amount of heat is lost and the body can store ATP for future use.
So, the correct option is 'ATP'

Oxidation of a molecule of acetyl CoA produces

  1. 12 ATP

  2. 15 ATP

  3. 6 ATP

  4. 19 ATP.


Correct Option: A
Explanation:

The acetyl CoA produced from pyruvic acid as a result of link reaction enters Krebs' cycle by forming citric acid from oxaloacetic acid. When 1 molecule of acetyl CoA completes 1 round of Krebs' cycle, it produces 3 NADH+H+, 1 FADH2 and 1 ATP. So after going through ETS, a total of 12 ATP is yielded ( 3*3  + 1*2  + 1 ).

So the answer is '12ATP'.

Maximum amount of energy/ATP is liberated on oxidation of

  1. Fats

  2. Proteins

  3. Starch

  4. Vitamins


Correct Option: A
Explanation:
Fats are complex molecules composed of fatty acids and glycerol. The body needs fats for growth and energy.
Fats are the slowest source of energy but the most energy-efficient form of food. Each gram of fat supplies the body with about 9 grams of energy. 
The oxidation of fats releases the maximum amount of energy.
So, the correct option is 'Fats'

Number of ATP molecules which can be built on complete oxidation of pyruvic acid is

  1. 6

  2. 2

  3. 15

  4. 30


Correct Option: C
Explanation:

The breakdown glucose takes place during glycolysis in which there is a net gain of 8 ATP. The pyruvic acid so formed undergoes oxidative decarboxylation and thus forms acetyl CoA. This reaction leads in the formation of 2 NADH₂ molecules. It results in the formation of 6 ATP.

Therefore if the complete oxidation of pyruvic acid takes place when there is a net gain of 15 ATP.
So, the correct option is '15ATP'

Out of 36 ATP molecules produced per glucose molecule during respiration

  1. 2 are produced outside glycolysis and 34 during respiratory chain

  2. 2 are produced outside mitochondria and 34 inside mitochondria

  3. 2 during glycolysis and 34 during Krebs cycle

  4. All are formed inside mitochondria


Correct Option: B
Explanation:

2 ATP from glycolysis which takes place in the cytoplasm and other cellular respiration processes takes place in mitochondria which gives 34 ATP.

So, the correct option is '2 are produced outside mitochondria and 34 inside mitochondria.'

Energy released in aerobic respiration is higher than the one available from anaerobic respiration by

  1. 8 times.

  2. 18 times.

  3. 28 times.

  4. 36 times.


Correct Option: B
Explanation:

Aerobic respiration produces 36 ATP and anaerobic respiration makes on 2 ATP with a single molecule of glucose.

So the correct option is '18 times.'

Maximum energy becomes available per mole of glucose when it is metabolised through

  1. Glycolysis in skeletal muscle of a sprinter.

  2. Fermentation into ethanol by yeast.

  3. Fermentation into methanol by enteric bacteria.

  4. Aerobic respiration.


Correct Option: D
Explanation:

Cells performing aerobic respiration synthesize much more ATP, but not as part of glycolysis. 

So the correct option is 'Aerobic respiration'.

In aerobic respiration one glucose produces

  1. $8 NADH + 2 FADH _2 + 2 ATP$

  2. $12 NADH + 2 FADH _2 + 38 ATP$

  3. $12 NADH + 30 ATP + H _2O$

  4. $10 NADH + 2 FADH _2 + 2 ATP + 2 GTP$


Correct Option: D
Explanation:
| Process |  Site |  Energy Release | | --- | --- | --- | |  Glycolysis(breakdown of glucose into pyruvic acid) |  In cytoplasm |  2 ATP 2 NADH | | Decarboxylation(conversion of pyruvic acid into Acetyl co enzyme) | mitochondria |  2 ATP | |  Citric Acid Cycle(Oxidation of acetyl co enzyme)(when the cycle runs twice) | mitochondria |  8 NADH 2 FADH 2 GTP   | |  Total |   |  10+28=38 |
So the correct option is  $ 10NADH$+ $2 FADH _2$ +$2ATP$+ $2GTP$

Oxidation of one molecule of glucose in aerobic respiration produces

  1. 2 ATP

  2. 30 ATP

  3. 36 ATP

  4. 38 ATP


Correct Option: D
Explanation:
 Product  Molecule  ATP
 Glycolysis  2 ATP2NADH  8ATP
 Krebs cycle NADH  3 (in two cycle)  18 ATP
 FADH$ _2$  2 (in two cycle)  4 ATP
 GTP  2 (in two cycle)  2ATP
 Oxidative decarboxylation  2 NADH (in two cycle)  6ATP
 Total    38

ATP molecules formed on complete oxidation of 40 moles of glucose

  1. 3040

  2. 380

  3. 190

  4. 1520


Correct Option: D
Explanation:

One mole of glucose produce=38 ATP molecules

40 moles of glucose produce=38X40=1520
So the correct option is '1520'.

Number of ATP molecules produced from 1 glucose molecule in aerobic respiration

  1. 38

  2. 32

  3. 30

  4. 28


Correct Option: A
Explanation:
 Product  Molecule  ATP
 Glycolysis  2 ATP2NADH  8ATP
 Krebs cycle NADH  3 (in two cycle)  18 ATP
 FADH$ _2$  4 (in two cycle)  4 ATP
 GTP  2 (in two cycle)  2ATP
 Oxidative decarboxylation  2 NADH (in two cycle)  6ATP
 Total    38

What does the following equation represent 

  1. $C _6H _{12}O _6 + 2 NAD + 2 ADP + 2 Pi 2CH _3.CO.COOH + 2 NADH _2 + 2 ATP$

  2. Complete glycolysis

  3. Complete aerobic respiration

  4. Complete anaerobic respiration

  5. Complete fermentation


Correct Option: A

The energy consumed during the conversion of ADP into ATP is 

  1. 73000 cal/mole

  2. 686000 cal/mole

  3. 8000 cal/mole

  4. 7300 cal/mole


Correct Option: D
Explanation:

Adenosine-5'-triphosphate (ATP) is comprised of an adenine ring, a ribose sugar, and three phosphate groups. ATP is often used for energy transfer in the cell. ATP synthase produces ATP from ADP or AMP + Pi. The energy consumed during the conversion of ADP into ATP is 7300 cal/mole.

Net gain of ATP in prokaryotes from a molecule of glucose when oxidized is

  1. 40

  2. 38

  3. 36

  4. 34


Correct Option: B
Explanation:

A total 38 ATP molecules (2 ATP molecules from glycolysis, 2 from Kreb's cycle and 34 from electron transport system) are produced per molecule of glucose oxidised in aerobic prokaryotes. Whereas, the net gain in most of the eukaryotes is 36 ATP molecules (as 2 ATP molecules are consumed intransporting $NADH _2$ into mitochondria). 

A single ATP produce 

  1. -7.3 kcal

  2. 10 kcal

  3. 12 kcal

  4. 100 kcal


Correct Option: A
Explanation:

ATP stands for adenosine triphosphate. It is complex molecule that contains the nucleoside adenosine and a tail consisting of three phosphates. It is the primary energy currency. A single ATP produce -7.3 kcal.

How many ATP are formed from NADPH$^{+}$ to NAD$^{+}$?

  1. 2 ATP

  2. 3 ATP

  3. 6 ATP

  4. 4 ATP


Correct Option: B
Explanation:

$NAD^+$ and $NADP^+$ are coenzymes, that function in oxidation-reduction reactions. 3 ATP are formed from the conversion of  $NADPH^+$ to $NAD^+$.

 Energy produced during aerobic respiration of glucose 

  1. 637 kcal

  2. 640 kcal

  3. 686 kcal

  4. 693 kcal


Correct Option: C
Explanation:

 Aerobic respiration takes place through a series of reactions such as Glycolysis, Oxidative decarboxylation of pyruvates, Citric acid cycle and Oxidative phosphorylation. Being efficient in extracting chemical energy, the total free energy produced during the process is 686 kcal. Thus, the correct answer is option C.

The net gain of energy from one molecule of glucose during aerobic respiration is 

  1. 2 ATP

  2. 36 ATP

  3. 38 ATP

  4. 15 ATP


Correct Option: C
Explanation:

38 molecules can be made per oxidised glucose molecule during cellular respiration. It is possible by the yield of ATP molecules from Krebs cycle, glycolysis and electron transport system. 

The net gain of ATP from one molecule of glucose in aerobic respiration is

  1. 18 ATP

  2. 38 ATP

  3. 60 ATP

  4. 80 ATP


Correct Option: B
Explanation:

If the food substances in living cells are oxidized in presence of oxygen, it is called aerobic respiration. It is the step-wise complete breakdown of the respiratory substrates like glucose into simpler molecules like $CO _2$ and water with the release of ATP. It is mostly seen in eukaryotic type of organisms. Each glucose molecule on complete oxidation gives 38 ATP molecules. 

How many PGAL are produced by glycolysis of 3 molecules of glucose? How many ATP are released by respiration of these PGAL till formation of $O _2$ and $H _2O$?

  1. 4 PGAL-80 ATP

  2. 6 PGAL-160 ATP

  3. 4 PGAL40 ATP

  4. 6 PGAL-120 ATP


Correct Option: D
Explanation:

Glycolysis of one molecule of glucose produces 2 PGAL, thus of three molecules will produce 6 PGAL.
Respiration of one molecule of glucose or 2 PGAL produces 38 ATP molecules, thus, of 6 PGAL will produce 114 ATP molecules. Out of the given options 120 ATP is the nearest correct answer. Thus the correct answer is option D.

Which of the following is not an electron transferring molecule?

  1. ATP

  2. NAD$^{+}$

  3. Fe-S protein

  4. Co-enzyme Q


Correct Option: A
Explanation:

Adenosine triphosphate is a nucleoside triphosphate used in cells as a coenzyme. It is often called the molecular unit of currency of intracellular energy transfer. ATP transports chemical energy within cells for metabolism. It is one of the end products of photophosphorylation, cellular respiration and fermentation and used by enzymes and structural proteins in many cellular processes, including biosynthetic reactions, motility and cell division. One molecule of ATP contains three phosphate groups.

Complete oxidation of 1 gm mole of glucose yields

  1. 686 cal

  2. 6860 cal

  3. 68600 cal

  4. 686000 cal


Correct Option: D
Explanation:

Complete oxidation of 1 gm mole (180 g) of glucose yields 686 Kcal, that is 686000 cal of energy. It means, 1 g of glucose oxidizes to produce 3.8 Kcal.

Thus, the correct answer is option D.

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

  1. Glycolysis

  2. Krebs cycle

  3. Electron transport chain

  4. Conversion of pyruvic acid to acetyl CoA


Correct Option: C
Explanation:

In glycolysis 4 ATP and 2NADH2 molecules are formed. These 2NADH2  molecules go to electron transport chain. In oxidative decarboxylation no ATP molecule is formed but two molecules of 2NADH2  are formed from two molecules of pyruvate. These two NADH2 go to electron transport chain. In Kreb's cycle 2 ATP, 6NADH2 and 2FADH2 molecules are formed from two molecule of acetyl Co-A. These NADH2 and 2FADH2  go to electron transport chain. In electron transport chain all 2NADH2   and 2FADH2  pass to electron carriers and yield 3 ATP and 2 ATP molecules per 2NADH2   and 2FADH2  respectively. Thus,  4 ATP are formed in glycolysis, 2 ATP in Krebs cycle and 34 ATP from electron transport chain. 40 ATP and 2 ATP molecules are used during glycolysis. So, net gain of ATP molecules during one complete oxidation of a glucose molecule is 38 ATP.


So, the correct answer is 'Electron transport chain'.

The rate of respiration undergoes a sharp rise followed by a when certain fruits ripen. This phenomenon is known as ____________.

  1. Climatic rise

  2. Climatic fall

  3. Climacteric rise

  4. Anaerobiosis


Correct Option: A

Out of $38$ ATP molecule how many ATP are formed by substrate level phosphorylation by aerobic respiration of $1$ glucose?

  1. $2$

  2. $3$

  3. $4$

  4. Zero


Correct Option: A
Explanation:

Substrate level phosphorylation involves the conversion of 1,3 bisphosphoglycerate to 3 phosphoglycerate producing ATP.

For 1 molecule of glucose, 2 (1,3 bisphosphoglycerate) are formed, hence 2 ATP are formed.  

Number of ATP molecules formed during aerobic respiration in break down of one glucose molecule via malate aspartate shuttle is 

  1. 38

  2. 18

  3. 28

  4. 4


Correct Option: A

For the synthesis of 1 ATP in oxidative phosporylation how many ${H}^{+}$ required?

  1. $3$

  2. $2$

  3. $4$

  4. $1$


Correct Option: C
Explanation:

For synthesis of 1 ATP, 4 H+ are required. ATP synthase synthesizes 1 ATP for every 4 H+ that passes through it. 

During aerobic respiration, all the ATPs are synthesized as a result of _______________.

  1. Oxidative phosphorylation

  2. Oxidative and substrate level phosphorylation

  3. Substrate level phosphorylation

  4. Oxidative and phosphorylation


Correct Option: A

How many oxygen atoms are utilised during aerobic oxidation of one molecule of acetyl-Co-A?

  1. Three

  2. Four

  3. Two

  4. Six


Correct Option: A

How many ATP molecules are synthesized in complete aerobic respiration of dipeptide molecule during Amphibolic pathway?

  1. $30\ ATP$

  2. $60\ ATP$

  3. $15\ ATP$

  4. $36\ ATP$


Correct Option: A

If $4$ molecules of glucose are synthesized during photosynthesis, how many ATP molecules are released and how many molecules of ATP are utilized respectively?

  1. $8 ATP, 72 ATP$

  2. $2 ATP, 18 ATP$

  3. $8 ATP, 36 ATP$

  4. $4 ATP, 36 ATP$


Correct Option: A
Explanation:
For the synthesis of one molecule of glucose by photosynthesis, 2 ATP molecules are released and 18 ATP molecules are utilized. 18 ATP molecules are utilized in the sense that in most of the plants the mode of CO$ _2$ fixation is C$ _3$ cycle or Calvin cycle. In C$ _3$ cycle for each molecule of CO$ _2$ to be fixed, 3 ATP are required. Thus, for the synthesis of one Glucose molecule, 6 CO$ _2$ molecules are fixed. Thus, 18 ATP molecules in total are utilized for the formation of one Glucose molecule.
Hence, for the synthesis of 4 glucose molecules in photosynthesis,
ATP molecules released = 4 × 2 = 8
ATP molecules utilized = 4 × 18 = 72.
So, the correct answer is A.

Choose the correct answers from the alternatives given :
In eukaryotes complete oxidation of a glucose molecule results in the net gain of how many ATP molecules?

  1. 2

  2. 4

  3. 36

  4. 38


Correct Option: D
Explanation:

Complete oxidation of glucose occurs through three steps : 

  1. Glycolysis
  2. Krebs cycle
  3. Terminal oxidation
During glycolysis glucose changes to pyruvic acid gaining total energy as 2 ATP molecules and 2 molecules of NADH$ _2$ then later on in Krebs cycle 30 ATP molecules and 2 FADH$ _2$ are produced. One NADH$ _2$ produces 3 ATP molecules while one FADH$ _2$ produces two ATP molecules. Therefore in complete oxidation of one molecule of glucose, a total of 38 ATP's are gained.
So, the correct option is ' 38'. 


In aerobic cellular respiration, most of the ATP is synthesized during:

  1. Electron transport

  2. Glycolysis

  3. Krebs cycle

  4. Oxidation of pyruvic acid


Correct Option: C
Explanation:

Cellular respiration occurs in three steps :

  1. Glycolysis 
  2. Krebs cycle 
  3. Terminal oxidation 
Glycolysis is the breakdown of glucose into two molecules of pyruvate where 2 NADH and 2 ATP molecules are formed which in total is 8 ATP molecules as 1 NADH = 3 ATP, While in Krebs cycle reaction occurs in mitochondria where 10 NADH molecules, 2 FADH, and 4 ATP molecules are formed, in total 38 ATP molecules are formed .
So, the correct option is ' Krebs cycle'.

Choose the correct answers from the alternatives given :
Which one of the following is the energy currency of the cell?

  1. AMP

  2. ADP

  3. ATP

  4. NADP


Correct Option: C
Explanation:

ATP ( Adenosine triphosphate ) is the energy currency of the cell, it helps in the completion of all the metabolic processes by utilization of its phosphorus molecule. It is generated by mitochondria. One molecule of ATP releases around 30.5 kJ /mol of energy.

So, the correct option is ' ATP'.

Choose the correct answers from the alternatives given :
Of the 36 ATP molecules that are produced during the complete breakdown of glucose, most are due to the action of 

  1. substrate-level phosphorylation

  2. electron transport system

  3. chemiosmotic phosphorylation

  4. both (b) and (c)


Correct Option: D
Explanation:
  • Substrate level phosphorylation is the part of glycolysis reaction whihc will give the cell 2 molecules of ATP at the end of the reaction.
  • Electron transport system is the transport system that is present in the mitochondrial membrane where it transports the electrons and hydronium ions from NADH and FAD through various complex of the chain.
  • In chemiosmotic phosphorylation the $F _1$-$F _0$ complex is used for the synthesis of one molecule of ATP for every 2 hydronium ion that is transported through the complex from the intermembrane matrix.
  • For each NADH transported through the chain 3 times 2 hydronium ions are released which means every molecule of NADH produces 3 molecules of ATP. For every FADH molecules passed 2 times 2 hydronium are released which means that every molecule of FADH gives 2 ATP molecules.
  • Therefore when per pyruvic acid after going under kerb cycle gives 4 NADH and 1 FADH molecule that gives the cell with  12 ATP and 2 ATP molecules respectively per cycle.
  • Therefore ETS and the chemisomotic phosphorylation give the major contribution in the formation of ATP i.e. 15 ATP per cycle.
  • Therefore the answer option 'both (b) and (c)' is correct.

Choose the correct answers from the alternatives given :
The greatest contributor of electrons to the electron transport system is

  1. oxygen

  2. transition reaction

  3. glycolysis

  4. Krebs cycle


Correct Option: D
Explanation:
  • Electron transport system is the transport system that is present in the mitochondrial membrane where it transports the electrons and hydronium ions from NADH and FAD through various complex of the chain.
  • In chemiosmotic phosphorylation the $F _1$-$F _0$ complex is used for the synthesis of one molecule of ATP for every 2 hydronium ion that is transported through the complex from the intermembrane matrix.
  • For each NADH transported through the chain 3 times 2 hydronium ions are released which means every molecule of NADH produces 3 molecules of ATP. For every FADH molecules passed 2 times 2 hydronium are released which means that every molecule of FADH gives 2 ATP molecules.
  • Therefore when per pyruvic acid after going under kerb cycle gives 4 NADH and 1 FADH molecule that gives the cell with  12 ATP and 2 ATP molecules respectively per cycle.
  • Therefore it can be said that kerb cycle is the major contributor to the electron that are provides to the ETS for the production of ATP.
  • Therefore option 'Krebs cycle' is the correct answer.
Amount of energy released during hydrolysis of a high energy bond of ATP is
  1. $73 Kcal \,{mol}^{-1}$

  2. $0.73 Kcal \,{mol}^{-1}$

  3. $3.4 Kcal\, {mol}^{-1}$

  4. $7.3 Kcal \,{mol}^{-1}$


Correct Option: D
Explanation:
Adenosine triphosphate(ATP) is the energy currency of the cell. It is the most important energy carrier which carries energy in the two terminal phosphate bonds(called as high energy bonds or energy-rich bonds). Equal amounts of usable energy are released per mole of ATP or ADP hydrolysis:
$ATP+{H} _{2}O\rightleftharpoons ADP+Pi+7.3Kcal{\,\,mol}^{-1}$
$ADP+{H} _{2}O\rightleftharpoons AMP+Pi+7.3Kcal{\,\,mol}^{-1}$
So the correct answer is '$7.3 Kcal \,{mol}^{-1}$'.

How many ATP molecules will be generated in a plant system during complete oxidation of $40$ molecules of glucose?

  1. $180$

  2. $360$

  3. $1440$

  4. $3040$


Correct Option: C
Explanation:

$36 $ ATP molecules are produced during complete oxidation of one molecule of glucose.
So, $40$ molecules of glucose will produce $(36 \times 40) ATP= 1440$ ATP.

So the correct option is C.

Which one of the following equations represents the Aerobic respiration?

  1. $6CO _2\,+\,6H _2O\,\rightarrow \,C _6H _{12}O _6\,+\,6O _2$

  2. $C _6H _{10}O _2\,+\,6O _2\,\rightarrow\,6CO _2\,+\,5H _2O\,+\,674Kcal$

  3. $C _6H _{12}O _6\,+\,6O _2\,\rightarrow\,6CO _2\,+\,6H _2O\,+\,674Kcal$

  4. $C _6H _{12}O _2\,+\,6O _2\,\rightarrow\,6H _2CO _3$


Correct Option: C

The net yield of ATP, except substrate-level phosphorylation, from Krebs cycle per glucose molecule is

  1. $12$

  2. $24$

  3. $22$

  4. $36$


Correct Option: C
Explanation:

From one molecule of glucose, 38 ATP molecules can be produced during cellular respiration. Glycolysis produces net 2 ATP molecules by substrate level phosphorylation. Kreb cycle produces 2 ATP molecules by substrate level phosphorylation. About 34 ATP are produced from oxidative Phosphorylation. During Kreb cycle, 6 molecules of NAD$^+$ are reduced to NADH and 2 molecules of FAD are reduced to FADH$ _2$. Now 6 NADH produce 6 x 3 = 18 ATP molecules. Similarly, 2 FADH$ _2$ produce 2 x 2 = 4 ATP molecules. Hence, total 18 + 4 = 22 molecules of ATP are produced per glucose molecule from Kreb cycle except substrate level phosphorylation.

Thus, the correct answer is '22.'

If one triose phosphate completely oxidized inside prokaryotic cell than gain of ATP of energy equal to?

  1. $5$ ATP

  2. $4$ ATP

  3. $20$ ATP

  4. $19$ ATP


Correct Option: D
Explanation:

Triose phosphate is another name of glyceraldehyde 3- phosphate

Total NADH and ATP are produced in the cycle are as follows as -

 Name of process  Gain of ATP
 Glycolysis: glyceraldehyde 3- phosphate $\rightarrow$pyruvate  1 NADH ( each NADH is equal to 3 ATP) + 1 ATP3ATP+ 1ATP = 4ATP
 Oxidative decarboxylation pyruvate $\rightarrow$acetyl CoA  1 NADH = 3 ATP
 Tricarboxylic acid cycle  3NADH +1 FADH (each FADH is equal to 2ATP) + 1 GTP(equivalent to ATP) =  12 ATP

Total gain of ATP, when one triose phosphate is completely oxidised =  4 ATP =3 ATP =12 ATP $\rightarrow$  19 ATP

So, the correct answer is ' 19 ATP '

Mark the incorrect statement

  1. The breaking of c-c bonds of complex organic molecules by oxidation cells leading to the release of a lot of energy is called cellular respiration

  2. Initial stage of cellular respiration takes place in cytoplasm

  3. Incomplete oxidation of pyruvate by stepwise removal of all the hydrogen atoms leaving 3 molecules of CO2

  4. TCA cycle starts with condensation of acetyl group with OAA and water to yield citric acid


Correct Option: A
Explanation:

Aerobic respiration is comprised by

1) The complete oxidation of pyruvate by stepwise removal of all hydrogen atoms leaving 3 molecules of CO$ _2$. 
2) The passing of the electrons removed as apart of the hydrogen atoms to molecular O$ _2$with the simultaneous synthesis of ATP.
So, the incorrect statement is ' Incomplete oxidation of pyruvate by stepwise removal of all hydrogen atoms leaving 3 molecules of CO$ _2$'.
rest all are correct statements w.r.t. Respiration. 

Out of $36$ ATP molecules produced per glucose molecule during respiration.

  1. $2$ are produced outside glycolysis and $34$ during respiratory chain

  2. $2$ are produced outside mitochondria and $34$ inside mitochondria

  3. $2$ during glycolysis and $34$ during Krebs cycle

  4. All are formed inside mitochondria


Correct Option: B
Explanation:

Cellular respiration is a set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions, which break large molecules into smaller ones, releasing energy in the process, as weak so-called "high-energy" bonds are replaced by stronger bonds in the products. Respiration is one of the key ways a cell releases chemical energy to fuel cellular activity.  The chemical energy stored in ATP (its third phosphate group is weakly bonded to the rest of the molecule and is cheaply broken allowing stronger bonds to form, thereby transferring energy for use by the cell) can then be used to drive processes requiring energy. Since the cellular respiration happens inside mitochondria, and glucose being given out as a by-product, glucose is produced inside and outside mitochondria.

So the correct option is '2 are produced outside mitochondria and 34 inside mitochondria'.

Complete oxidation of a molecule of glucose yields?

  1. $15$ ATP molecules

  2. $2$ ATP molecules

  3. $36$ ATP molecules

  4. $8$ ATP molecules


Correct Option: C
Explanation:

Oxidation is a chemical process that, loosely defined, involves removing electrons from particular areas of a molecule. In biochemical processes, oxidation generally results in the release of energy. The glucose molecule contains stored energy in its bonds, just as other nutrient molecules do, including starch, proteins and fats. When you consume food that contains glucose, you digest the food and absorb the glucose into your bloodstream. From there, cells take up the glucose and either store it for later use or chemically burn it to provide energy. Oxidation of glucose is analogous to burning wood in many ways: It releases chemical energy. The complete aerobic oxidation of glucose is coupled to the synthesis of as many as 36 molecules of ATP.

So the correct option is '36 ATP molecules'.

Number of ATP obtained at the end of Kreb's cycle?

  1. $2$ ATP

  2. $4$ ATP

  3. $36$ ATP

  4. $38$ ATP


Correct Option: D

How many ATP molecules will be produced when one molecule of $3$-phosphophoglyceric acid is completely oxidised?

  1. $16$

  2. $17$

  3. $32$

  4. $20$


Correct Option: A

The incremental oxidation of 1 molecule of glucose during cellular respiration produces 30 molecules of ATP according to the balanced equation:
$C _6H _{12}O _6+6O _2+30ADP+30P _i\rightarrow 6H _2O+6CO _2+30ATP$
ATP is then hydrolyzed by cells for a variety of biochemical processes.
Changes in free energy between glucose oxidation and ATP hydrolysis were compared. The table below illustrates the data collected:

Reaction Change in Free Energy ($\triangle G$)
Glucose Oxidation -686 kcal/mol
ATP Hydrolysis -13 kcal/mol

Which statement best explains the data?

  1. Both glucose oxidation and ATP hydrolysis, are exergonic because they have negative $\triangle G$ values.

  2. Both glucose oxidation and ATP hydrolysis, are exergonic because their products have more free energy than their reactants.

  3. Both glucose oxidation and ATP hydrolysis, are endergonic because they have negative $\triangle G$ values.

  4. Both glucose oxidation and ATP hydrolysis, are endergonic because their products have less free energy than their reactants.


Correct Option: A
Explanation:

Both ATP and Glucose oxidation are energy releasing or exergonic processes as the value of $\delta$G is negative

So, the correct answer is 'Both glucose oxidation and ATP hydrolysis, are exergonic because they have negative G△G values'

Respiratory substrate yielding maximum number of ATP molecules is

  1. Ketogenic amino acids

  2. Glucose

  3. Amylose

  4. Glycogen


Correct Option: B
Explanation:

The process of glycolysis in respiration requires glucose as the primary substrate to be oxidised. Any other substrate is first converted to glucose before it can enter glycolysis. Certain substrates like ketogenic amino acids, amylose, glycogen need to be converted to glucose first at a cost of some energy in the form of ATP. Hence their net yield of ATP is less than that of glucose as a substrate.

So the answer is 'Glucose'.

Total number of ATP molecules produced per glucose molecule in eukaryotic cell is

  1. 38

  2. 36

  3. 24

  4. 12


Correct Option: B
Explanation:

In eukaryotic cells, Complete breakdown of one glucose molecule in to carbon dixoide and water using oxygen produces 36 ATP molecules.

So the correct option is '36'.

One $NADH _2 / NADPH _2$ yields

  1. 2 ATP

  2. 3 ATP

  3. 12 ATP

  4. 6 ATP


Correct Option: B
Explanation:

One NADH$ _2$/NADPH$ _2$ yields 3 ATP during electron transport chain process.

So the correct option is '3 ATP.'

Metabolism of one palmitic acid yields 

  1. 36 ATP

  2. 56 ATP

  3. 129 ATP

  4. 48 ATP


Correct Option: C
Explanation:

Oxidation of palmitic acid yields 7 NADH + 7 FADH2 + 8 acetyl-CoA in 7 cycles of mitochondrial beta-oxidation. Every acetyl-CoA yields 3 NADH + 1 FADH2 + 1 GTP (=ATP) during Krebs cycle. An average production of 3 ATP/NADH and 2 ATP/FADH2 using the respiratory chain, We get  131 ATP molecules. However, you have to use 2 ATP molecules for the initial activation of every fatty acid that is going to be oxidized in the mitochondria.

So the correct option is '129 ATP'.

Direct ATP yield during Krebs cycle per glucose molecule is

  1. 2

  2. 8

  3. 30

  4. 38


Correct Option: A
Explanation:

During the Krebs cycle, the net yield obtained was 6 molecules of NADH + H+, 2 molecules of FADH2, 4 carbon dioxide molecules, and two molecules of ATP. 

So the correct option is '2.' 

How many ATP molecules are released when one molecule of glucose is oxidised in our liver cells?

  1. 36

  2. 38

  3. 2

  4. 8


Correct Option: B
Explanation:

38 ATP molecules are produced for the oxidation of one molecule of glucose. 2 from glycolysis, 2 from the Citric acid cycle, and about 34 from the electron transport system.

So the correct option is '38.'

How many ATPs are formed per glucose molecule in Krebs cycle?

  1. 2

  2. 24

  3. 6

  4. 28


Correct Option: D
Explanation:

During the process of Krebs cycle 2 molecules of ATP, 8 molecules of NADH and 2 molecules of FADH2 were produced per molecule of glucose. A total of 28 ATPs are produced during Krebs cycle per a glucose molecule.

So the correct option is '28.'

From the oxidation of one molecule of palmitic acid (fatty acid), the number of ATP molecules gained as net are

  1. $131$

  2. $129$

  3. $38$

  4. $142$


Correct Option: B
Explanation:

The oxidation of fatty acid occurs in the following step in mitochondria:

1. activation of fatty acid
2. beta-oxidation
3. Kreb's cycle
Palmitic acid is made up of 16 carbons, so going by the formula C$ _{2n}$, then 2n=16 for palmitic acid, hence, n=8. So, 8 acetyl Co-A are produced. Now, n-1 will be the number of NADH and FADH$ _{2}$ produced, so, n-1=7 for palmitic acid. Hence, there will be 7 FADH$ _{2}$ and 7 NADH.
Now, 1 NADH gives 3 ATP, so 7 NADH will give 21 ATP
          1 FADH$ _{2}$ gives 2 ATP, so 7  FADH$ _{2}$ will give 14 ATP
          1 Acetyl Co-A through Kreb's cycle gives 12 ATP, so 8 Acetyl Co-A will give 96 ATP.
Hence, a total of 131 ATP will be formed. But 2 ATPs have been used in the activation of the fatty acid in the first step so, 131-2=129 ATPs as net will be formed. 
Hence, the correct answer is '129'

In aerobic respiration,if 38 molecules of ATP are produced,then the number of ATP produced in glycolysis (X), pyruvate to acetyl- CoA (Y) and Krebs cycle (Z) will be

  1. X- 2,Y-6,Z-30

  2. X-8,Y-6,Z-24

  3. X-8,Y-10,Z-24

  4. X-2,Y-12,Z-24


Correct Option: A
Explanation:
  •  Glycolysis: (2 ATP)
ATP formation by substrate phosphorylation = 4 ATP
ATP consumed in Glycolysis = 2 ATP 
  •  Pyruvate to Acetyl CoA: (2 NADH$ _{2}$ = 6 ATP) 
  • Kreb's Cycle: (30 ATP)
ATP formation by substrate phosphorylation = 2 ATP
ATP formation by oxidative phosphorylation = 28 ATP
So, the correct option is 'A) X- 2, Y - 6 ,Z-30'.
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