Tag: carbohydrate metabolism

Questions Related to carbohydrate metabolism

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

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. Three

  2. Four

  3. Two

  4. Six

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Correct Option: A

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

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. $30\ ATP$

  2. $60\ ATP$

  3. $15\ ATP$

  4. $36\ ATP$

Show answer
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?

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. $8 ATP, 72 ATP$

  2. $2 ATP, 18 ATP$

  3. $8 ATP, 36 ATP$

  4. $4 ATP, 36 ATP$

Show answer
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?

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. 2

  2. 4

  3. 36

  4. 38

Show answer
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:

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. Electron transport

  2. Glycolysis

  3. Krebs cycle

  4. Oxidation of pyruvic acid

Show answer
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?

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. AMP

  2. ADP

  3. ATP

  4. NADP

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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 

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. substrate-level phosphorylation

  2. electron transport system

  3. chemiosmotic phosphorylation

  4. both (b) and (c)

Show answer
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

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. oxygen

  2. transition reaction

  3. glycolysis

  4. Krebs cycle

Show answer
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
bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. $73 Kcal \,{mol}^{-1}$

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

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

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

Show answer
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?

bio-chemistry carbohydrate metabolism energy output living organisms and energy production respiration in cell

  1. $180$

  2. $360$

  3. $1440$

  4. $3040$

Show answer
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.