Tag: bio-chemistry

Questions Related to bio-chemistry

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

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

  1. 18 ATP

  2. 30 ATP

  3. 12 ATP

  4. None of the above

Show answer
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 ?

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

  1. 180

  2. 80

  3. 160

  4. 380

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

  1. 3 and 2

  2. 9 and 6

  3. 18 and 12

  4. 12 and 18

Show answer
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.

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

  1. 19

  2. 38

  3. 57

  4. 76

Show answer
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 

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

  1. $12$

  2. $18$

  3. $32$

  4. $38$

Show answer
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 -

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

  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

Show answer
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?

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

  1. GTP

  2. ATP

  3. ADP

  4. NADP

Show answer
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?

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

  1. $24$

  2. $8$

  3. $3$

  4. $4$

Show answer
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?

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

  1. Alcoholic fermentation

  2. Lactic acid fermentation

  3. Aerobic respiration in unicellular organisms

  4. Glycolysis in liver cells

Show answer
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  

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

  1. Quantasome

  2. Thylakoid

  3. Chondriosome

  4. Mitochondria

Show answer
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 '