Tag: bio-chemistry

Questions Related to bio-chemistry

Mitochondrial electron transport chain is

  1. Cyclic phosphorylation.

  2. Oxidative phosphorylation.

  3. Noncyclic phosphorylation.

  4. Photooxidation.


Correct Option: B
Explanation:

The electron is transferred from NADH to oxygen in mitochondria con­sists of four multi-protein complexes is coupled to the synthesis of ATP from ADP and inorganic phosphate (Pi) which is called as oxidative phosphorylation. 

So the correct option is 'Oxidative phosphorylation.'

Coenzyme $NAD^+$ and FAD are connected with respiratory reactions as they

  1. Are involved in each step of ATP synthesis.

  2. Function in Krebs cycle and terminal oxidative phosphorylation.

  3. Act as hydrogen carrier.

  4. Are reducing agents.


Correct Option: C
Explanation:

NAD and FAD plays a major role in cellular respiration,  They carry the H+ and electrons to Electron Transport Chain to convert ADP + Pi ATP.

So the correct option is 'Act as a hydrogen carrier.'

Glyceraldehyde phosphate is oxidised in glycolysis. The hydrogen atom and electron liberated cause

  1. Oxidation of NAD$^+$.

  2. Reduction of NAD$^+$.

  3. Change in oxaloacetic acid.

  4. Formation of methane.


Correct Option: B
Explanation:

Glyceraldehyde-3-phosphate is oxidized by the coenzyme nicotinamide adenine dinucleotide (NAD). NAD+ is an oxidizing agent - it accepts electrons from other molecules and becomes reduced.

So the correct option is 'Reduction of NAD+'.

Which of the following is a biological uncoupler of oxidative phosphorylation?

  1. Thermogenin.

  2. 2, 4-Dichlorophenoxyacetic acid.

  3. 2, 4-Dinitrophenol.

  4. Ethylene diaminotetra-acetic acid.


Correct Option: A
Explanation:

Brown adipose tissue is rich in mitochondria, containing an uncoupling protein (thermogenin) that uncouples oxidation and phosphorylation of adenosine diphosphate, reduces ATP production, and consequently enhances thermogenesis.

So the correct option is 'Thermogenin'.

Identify the wrong statement.

  1. Proton motive force drives the uniport.

  2. Movement of NO$ _3$ ions in cotransport is against their own concentration gradient.

  3. Azides inhibit the process of respiration.

  4. ATPase serves as proton-translocating carrier protein.


Correct Option: A

In mechanism, photophosphorylation is very similar to

  1. substrate-level phosphorylation

  2. oxidative phosphorylation

  3. Calvin cycle

  4. glycolysis


Correct Option: B
Explanation:

Oxidative phosphorylation is the process in which ATP is formed by the transfer of electrons from NADH or FADH 2 to O 2 by a series of electron carriers. The sunlight-driven production of ATP from ADP and inorganic phosphate is called photophosphorylation.

So, the correct option is, 'oxidative phosphorylation'.

FAD acts as an electron acceptor in between

  1. fumaric and mallic acid

  2. succinic and fumaric acid

  3. malic and oxaloacetic acid

  4. citric and isocitric acid


Correct Option: B

Name the chemical formula.
C$ _{16}$H$ _{32}$O$ _2$

  1. Palmitic acid

  2. Stearic acid

  3. Glycerol

  4. Galactose


Correct Option: A
Explanation:

Palmitic acid or hexadecanoic acid was discovered by Edmond Fremy. It is commonly found in plants, animals and microorganisms.Its chemical formula is CH$ _3$(CH$ _2$)$ _{14}$COOH.It is a saturated fatty acid.

Which of the following is not an essential unsaturated fatty acid


  1. Oleic acid

  2. Linoleic acid

  3. Linolenic acid

  4. Stearic acid


Correct Option: D

What is a cholesterol?

  1. Phospholipid

  2. Wax

  3. Steroid

  4. Triglyceride


Correct Option: C
Explanation:

Steroids are crystallisable lipids having four hydrocarbon rings consisting of three cyclohexane and one cyclopentane ring and a long hydrocarbon side chain. Fatty acids are absent. In animals, sterols are precursors of steroid hormones and vitamin D. Cholesterol is a sterol of animal systems which forms bile salts, is a component of plasma membrane and hormones.