Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.

 Multiple Choice QuestionsMultiple Choice Questions


Glycolysis occurs in

  • cytosol

  • mitochondria

  • Golgi complex

  • ribosomes



Glycolysis or Embden–Meyerhof–Parnas pathway takes place in cytoplasm. It is a common phase between aerobic and anaerobic respiration. The enzymes occur in cytosol.


The terminal electron acceptor during electron transport system is

  • oxygen

  • cyto a3

  • cyto c

  • plasto quinone



Oxygen is the terminal acceptor of electron in Electron Transport System(ETS), which in the presence of proton forms a water molecule.


R.Q. is always less than one in

  • wheat

  • millets

  • bean

  • castor



Respiratory Quotient is the ratio of the volume of carbon- dioxide evolved to that of oxygen consumed by an organism tissue, or cell in a given time. 

In fats, the value of R.Q. is less than one.


Glycolysis is found in cytoplasm of virtually all types of aerobic/ anaerobic cells. In this process glucose is converted into

  • PEP

  • acetyl CoA

  • pyruvic acid

  • citric acid


pyruvic acid

In the process of glycolysis, one molecule of hexose sugar, i.e. glucose or fructose, a 6C-compound is splitted to form two molecules of a 3C- compound, pyruvic acid (CH3COCOOH).


Which of the following statements regarding mitochondrial membrane is not correct?

  • The outer membrane is permeable to all kinds of molecules

  • The enzymes of the electron transfer chain are embedded in the outer membrane

  • The inner membrane is highly convoluted forming a series of infoldings

  • The inner membrane is highly convoluted forming a series of infoldings


The enzymes of the electron transfer chain are embedded in the outer membrane

In mitochondria, the enzymes of electron transport chain are found in the inner membrane while outer membrane contains enzymes involved in mitochondrial lipid synthesis and those enzymes that convert lipid substrates into forms that are subsequently metabolised in the matrix.
The outer membrane resembles a sieve that is permeable to all molecule of 10,000 daltons mole. weight or less including small proteins.
The inner membrane is impermeable and highly convoluted, forming a series of infoldings, known as cristate, in the matrix space.



Fat, prior to its oxidation associate with

  • cyclic AMP

  • Co- A

  • GMP

  • ATP


Co- A

The respiratory decomposition of fatty acids is known as beta oxidation, which occurs in liver and adipose tissue. Activation of fatty acids takes place, then dehydrogenation of activated fatty acid takes place. It is followed by hydration. The β-hydroxyl acyl derivative is converted to β-keto derivative, which then reacts with Co-A. And it leads to oxidation.


How many ATP are formed by oxidation of one glucose molecular in liver cells ?

  • 36

  • 38

  • 2

  • 8



In liver cells and prokaryotic cells 38 ATP are produced by the complete oxidation of one molecule of glucose.

During glycolysis:

2 ATP directly            - 2 ATP

2 molecules of NADH - 6 ATP

During Pyruvic to Acetyl CoA:

2 molecules of NADH - 6 ATP

Pyruvic acid to Acetyl CoA:

6 molecules of NADH - 18 ATP

2 molecules of FADH - 4 ATP

2 molecules of GTP - 2 ATP

Total number of ATP is 38. Therefore, 38 ATP are produced.


Glycolysis occurs in :

  • cytoplasm

  • nucleus

  • mitochondria

  • both 'a' and 'c



Glycolysis means splitting of glucose. It occurs in the cytoplasm of the cell and yields a small amount of energy and two molecules of pyruvate. It is a common step between aerobic and anaerobic respiration.


The presence of arginase confirms that :

  • urea cycle is operating

  • urea cycle may be operating

  • arginine is being converted into ornithine

  • arginine is being converted into citrulline


arginine is being converted into ornithine

During urea cycle, cytosolic enzyme arginase cleaves arginine to yield urea and ornithine. Ornithine is transported into the mitochondria in order to initiate another round of urea cycle.

Enzymes used in urea cycle are

  1. Carbamoyl phosphate synthase
  2. Ornithine carbamoyltransferase
  3. Arginosuccinate synthase
  4. Arginosuccinate lyase
  5. Arginase


The net gain ATP from complete oxidation of 1 molecule of glucose in eukaryote is

  • 2

  • 4

  • 24

  • 36



There is a total gain of 38 ATP molecules during aerobic respiration. Out of these two molecules of ATP, two are required for transporting the NADH produced in glycolysis (in cytoplasm) into the mitochondria for further oxidation, hence the net gain of ATP is 36 molecules.