GATE Overflow for GATE ESE - Recent questions and answers in Cell Chemistry and Cell Biology

GATE ES 2026 | Question: 7

Mon, 23 Feb 2026 13:15:36 +0000

The major class of enzymes catalyzing the cleavage of $C-C, C-O, C-N$, or other bonds by elimination, leaving double bonds or rings, or addition of groups to double bonds in any biochemical reactions is $\_\_\_\_$.

lyases
transferases
oxidoreductases
hydrolases

GATE ES 2026 | Question: 28

Mon, 23 Feb 2026 13:14:56 +0000

Which ONE of the following options is CORRECT with respect to sequential breakdown of deoxyribonucleic acid (DNA) into lower-molecular weight compounds?

Deoxyribonucleic acid → $2$-deoxyribose → Nucleosides → Nucleotides
Deoxyribonucleic acid → $2$-deoxyribose → Nucleotides → Nucleosides
Deoxyribonucleic acid → Nucleotides → Nucleosides → $2$-deoxyribose
Deoxyribonucleic acid → Nucleosides → Nucleotides → $2$-deoxyribose

GATE ES 2024 | Question: 35

Mon, 19 Feb 2024 10:24:08 +0000

Which of the following statement$\text{(s)}$ is/are CORRECT?

DNA is composed of nucleotides
Five types of nitrogenous bases occur in DNA
Each phosphate is attached to two deoxyribose units in a single strand of DNA
The ratio of adenine to guanine is always $1: 1$ in a double stranded DNA.

GATE ES 2024 | Question: 33

Mon, 19 Feb 2024 10:24:08 +0000

Enzymes with the class of enzymes are listed in the table.

Enzyme	Class of Enzyme
$\text{(a)}$ Lactate dehydrogenase	$\text{(i)}$ Isomerases
$\text{(b)}$ Alanine racemase	$\text{(ii)}$ Transferases
$\text{(c)}$ Lipase	$\text{(iii)}$ Oxidoreductases
$\text{(d)}$ Hexokinase	$\text{(iv)}$ Hydrolases

Select the correct match(es)

$\text{(a) - (iii); (b) - (i)}$
$\text{(c) - (iv); (d) - (ii)}$
$\text{(a) - (ii); (b) - (iv)}$
$\text{(c) - (iii); (d) - (i)}$

Answered: GATE ES 2023 | Question: 7

Mon, 27 Nov 2023 19:16:08 +0000

i. Dissolved Oxygen (DO) can act as an electron acceptor for aerobic bacteria. This statement is correct because aerobic bacteria use oxygen as the final electron acceptor in their metabolic processes.ii. Nitrite can act as an electron acceptor for aerobic bacteria. This statement is incorrect. Nitrite is not a typical electron acceptor for aerobic bacteria; oxygen is the primary electron acceptor for them.iii. Dissolved Oxygen (DO) can act as an electron acceptor for anaerobic bacteria. This statement is incorrect. Anaerobic bacteria thrive in the absence of oxygen and use alternative electron acceptors like nitrate, sulfate, or carbon compounds.iv. Nitrite can act as an electron acceptor for facultative bacteria. This statement is correct. Facultative bacteria are versatile and can switch between aerobic and anaerobic modes of metabolism. In anaerobic conditions, some facultative bacteria can use nitrite as an electron acceptor.Therefore, (i) is correct, (ii) is incorrect, (iii) is incorrect, and (iv) is correct.

GATE ES 2023 | Question: 5

Tue, 23 May 2023 03:12:46 +0000

Read the following statements

I. Photosynthesis takes place within the chloroplasts of the eukaryotes, whereas the breakdown of complex molecules to yield energy takes place in the cytoplasm and in the mitochondria.

II. Photosynthesis takes place within the chloroplasts of the prokaryotes, whereas the breakdown of complex molecules to yield energy takes place in the cytoplasm and in the mitochondria.

III. All living organisms retain the enzymatic machinery to partially oxidise glucose without the help of oxygen. This breakdown of glucose to pyruvic acid is called glycolysis.

IV. All living organisms retain the enzymatic machinery to completely oxidise glycerol without the help of oxygen. This breakdown of glycerol to citric acid is called glycolysis.

The correct choice is

$\text{I}$ and $\text{III}$ are correct
$\text{II}$ and $\text{IV}$ are correct
$\text{I}$ is correct whereas $\text{III}$ is incorrect
$\text{II}$ is correct whereas $\text{IV}$ is incorrect

GATE ES 2023 | Question: 6

Tue, 23 May 2023 03:12:43 +0000

Read the following statements

i. Aerobic heterotrophic bacteria uses organic matter for carbon source and energy source.
ii. Aerobic heterotrophic bacteria uses carbon dioxide for carbon source and energy source.
iii. Aerobic autotrophic bacteria uses carbon dioxide for carbon source and reduced substances for energy source.
iv. Aerobic autotrophic bacteria uses organic matter for getting energy.

The correct choice is

(i) is correct; (iii) is correct
(iv) is correct; (i) is incorrect
(i) is correct; (iv) is correct
(ii) is correct; (iv) is incorrect

GATE ES 2023 | Question: 22

Tue, 23 May 2023 03:12:22 +0000

The ratio of the moles of $\mathrm{CO}_2$ evolved to the moles of $\mathrm{O}_2$ consumed in respiration also called the respiratory quotient, is calculated for a carbohydrate $\left(\mathrm{C}_6 \mathrm{H}_{12} \mathrm{O}_6\right)$ as substrate and found to be $1$. Under similar conditions, for a fatty acid $\left(\mathrm{C}_{51} \mathrm{H}_{98} \mathrm{O}_6\right)$ as substrate, the respiratory quotient is ____________ (rounded off to two decimal place).

GATE ES 2023 | Question: 27

Tue, 23 May 2023 03:12:17 +0000

Which one of the following statements is NOT correct?

Photophosphorylation is the synthesis of $\text{ATP}$ from $\text{ADP}$ and inorganic phosphate in the presence of light.
The process through which $\text{ATP}$ is synthesized by cells $\text{(in mitochondria and chloroplasts)}$ is called phosphorylation.
The Calvin cycle $\text{(carboxylation, reduction, and regeneration)}$ occurs in all photosynthetic plants ($\text{C3, C4 or any other)}$.
$\text{C3}$ plants have a special type of leaf anatomy, they tolerate higher temperatures, they show a response to high light intensities, have high rate of photosynthesis and reduced rate of photorespiration as compared to $\text{C4}$ plants.

GATE ES 2021 | Question: 8

Tue, 14 Mar 2023 03:44:37 +0000

Which of the following is the terminal electron acceptor in the electron transport chain of aerobic respiration?

Water
$\mathrm{NADH}$
$\mathrm{O}_{2}$
Cytochrome-c

GATE ES 2021 | Question: 18

Tue, 14 Mar 2023 03:44:30 +0000

Which of the following pairing of nucleotide bases is present in double helix DNA?

Thymine - Cytosine
Adenine - Thymine
Cytosine - Adenin
Uracil - Thymine

GATE ES 2021 | Question: 38

Tue, 14 Mar 2023 03:44:01 +0000

Which of the following is/are correct for the process of glycolysis?

There is net decrease in standard Gibbs free energy.
The end product is glyceraldehyde 3-phosphate.
Fist pluase incluces the plosphorylation of the glucose molecule.
It results in the net gain of $\mathrm{NADH}$.