Explore topic-wise MCQs in Life Sciences.

This section includes 205 Mcqs, each offering curated multiple-choice questions to sharpen your Life Sciences knowledge and support exam preparation. Choose a topic below to get started.

101.

The TCA cycle is regulated by which of the following enzymes?

A. citrate synthase
B. isocitrate dehydrogenase
C. malate dehydrogenase
D. succinate dehydrogenase
Answer» C. malate dehydrogenase
102.

Protein molecules can easily pass into the cell for being utilized for energy production.

A. True
B. False
C. May be
D. Can't say
Answer» C. May be
103.

Age, Gender, Body size and climate determine the

A. growth rate of an individual
B. basal metabolic rate
C. basal hydrolysis rate
D. pressure influence on growth rate
Answer» C. basal hydrolysis rate
104.

Which of the following pathway is common for oxidation of carbohydrates, lipids and amino acids?

A. Calvin cycle
B. Electron transport chain
C. TCA cycle
D. Pentose phosphate pathway
Answer» D. Pentose phosphate pathway
105.

Phosphoenolpyruvate (PEP) is converted to oxaloacetate by the enzyme PEP deaminase.

A. True
B. False
C. May be
D. Can't say
Answer» C. May be
106.

If ΔG of a chemical reaction has a negative value, the reaction

A. releases energy
B. requires energy
C. both (a) and (b)
D. none of these
Answer» B. requires energy
107.

How many oxygen molecules are required in the fermentation of one molecule of glucose to ethanol and CO2?

A. 0
B. 1
C. 2
D. 36
Answer» B. 1
108.

DNA gyrase is a ______________ protein.

A. helix-unwinding
B. helix-destabilizing
C. helix-relaxing
D. helix-winding
Answer» D. helix-winding
109.

Standard free energy change (ΔG) can be expressed as

A. ΔG° = -RTlnkeq
B. ΔG° = RTlnkeq
C. ΔG° = R/Tlnkeq
D. ΔG° = -RT/lnkeq
Answer» B. ΔG° = RTlnkeq
110.

The chromosome of a typical bacterium is ________________

A. circular double-stranded DNA
B. circular single-stranded DNA
C. double-helix DNA
D. single stranded DNA
Answer» B. circular single-stranded DNA
111.

The amount of energy (cal/mole) in an ATP molecule produced by a cell from glucose by fermentation is

A. greater than aerobic metabolism
B. less than aerobic metabolism
C. exactly or approximately equal to aerobic metabolism
D. none of the above
Answer» D. none of the above
112.

In anaerobic respiration, the final electron acceptor can be

A. oxygen
B. nitrate
C. pyruvate
D. acetyl-CoA
Answer» C. pyruvate
113.

Physically tiring jobs may result in basal metabolic rate of

A. 480 kJ
B. 850 kJ
C. 1500 kJ
D. 2050 kJ
Answer» E.
114.

DAHP synthetase catalyzes the condensation of

A. erythrose-4-phosphate
B. phosphoenol pyruvate
C. both (a) and (b)
D. phenylalanine
Answer» D. phenylalanine
115.

How many ATPs are paid back during Pentose phosphate Pathway?

A. 1
B. 3
C. 4
D. 5
Answer» B. 3
116.

Which of the following acts as chemical reductant in bacterial photosynthesis?

A. oxygen
B. water
C. hydrogen sulphide
D. ammonia
Answer» D. ammonia
117.

The region in which bacteriochlorophyll can absorb light is _________

A. ultraviolet region
B. infrared region
C. visible region
D. microwave region
Answer» C. visible region
118.

The enzymes present in glyoxylate cycle are which type of enzymes?

A. reductase enzymes
B. anaplerotic enzymes
C. transferase enzymes
D. hydrolase enzymes
Answer» C. transferase enzymes
119.

Which molecule will combine with the four-carbon oxaloacetate in the TCA cycle to form the six-carbon citrate?

A. lactic acid
B. NADH
C. ATP
D. acetyl-CoA
Answer» E.
120.

An essential process connected with photosynthesis is

A. photolysis
B. synthesis of glucose
C. photophosphorylation
D. electron transfer
Answer» B. synthesis of glucose
121.

Chlorobium sp. is which type of bacteria?

A. Purple Sulphur Bacteria
B. Purple Non-sulphur Bacteria
C. Green Sulphur bacteria
D. Green Non-sulphur bacteria
Answer» D. Green Non-sulphur bacteria
122.

Where are bacteriochlorophyll present in the cell?

A. chloroplast
B. cytoplasm
C. mitochondria
D. membrane
Answer» E.
123.

Most bacterial fermentations yield how many net ATP molecules per molecule of glucose?

A. 1
B. 2
C. 4
D. 6
Answer» C. 4
124.

High energy transfer compounds are capable of

A. accepting large amounts of free energy
B. transferring large amounts of free energy
C. measuring free energy
D. none of the above
Answer» C. measuring free energy
125.

The ribosome of E.coli is made up of which two subunits?

A. 60S and 40S
B. 60S and 30S
C. 50S and 40S
D. 50S and 30S
Answer» E.
126.

In glycolysis, ATP is created by

A. photophosphorylation
B. the chemiosmotic mechanism
C. substrate level phosphorylation
D. the pentose phosphate pathway
Answer» D. the pentose phosphate pathway
127.

A yeast or fungal cell produces how many net ATP molecules per molecule of glucose when completely oxidized?

A. 32
B. 34
C. 36
D. 38
Answer» D. 38
128.

The enzymes for glycolysis are located

A. on the inner surface of the cell membrane
B. on the inner membrane of the mitochondrion
C. on the outer membrane of the chloroplast
D. in the cytoplasm
Answer» E.
129.

In aerobic respiration, the terminal electron acceptor is

A. oxygen
B. nitrogen
C. hydrogen
D. nitrate
Answer» B. nitrogen
130.

The acquisition energy by glucose fermentation requires

A. substrate-level phosphorylation
B. electron transport of electrons from NADH
C. long-chain fatty acid oxidation
D. the enzyme formic-hydrogen lyase
Answer» B. electron transport of electrons from NADH
131.

Free energy change (ΔG) of a reaction is referred as the amount of energy

A. liberated during reaction
B. taken up during reaction
C. liberated or taken up during reaction
D. none of these
Answer» D. none of these
132.

Which of the following intermediates of TCA cycle act as amino acid precursors?

A. oxaloacetic acid
B. succinic acid
C. citric acid
D. acetyl CoA
Answer» B. succinic acid
133.

The role of bacteriophyll in an oxygenic photosynthesis is to

A. reduce ferridoxin directly
B. reduce NADP directly
C. use light energy to energize an electron
D. transfer electrons to an intermediate in the sulfide oxidation pathway
Answer» D. transfer electrons to an intermediate in the sulfide oxidation pathway
134.

In photosynthesis by green plants, algae, cyanobacteria which of the following acts as terminal electron acceptor?

A. Water
B. Oxygen
C. NADP+
D. FAD+
Answer» D. FAD+
135.

Organisms can synthesize ATP by oxidative phosphorylation when they

A. ferment
B. oxidize glucose to pyruvate
C. pass electrons from the oxidation of chlorophyll through an electron transport system
D. pass electrons to oxygen through an electron transport system containing cytochromes
Answer» E.
136.

Which force drives the flagellar rotation in bacteria?

A. ATP
B. protonmotive force
C. electrons
D. water gradient
Answer» C. electrons
137.

The final product of Calvin cycle is _________

A. RuBP
B. Glucose
C. Dihydroxy acetone phosphate
D. Glyceraldehyde-3-phosphate
Answer» E.
138.

The dark reaction in photosynthesis is governed by __________

A. CO2, temperature, and light
B. CO2, light, and water
C. water, temperature, and CO2
D. oxygen, water, and temperature
Answer» B. CO2, light, and water
139.

Which of the following has no detectable ATPase activity?

A. cilia
B. eukaryotic flagella
C. bacterial flagella
D. endoflagella
Answer» D. endoflagella
140.

Which of the following steps during electron transfer in anoxygenic photosynthesis is the ATP production step?

A. Ferredoxin to ubiquinone
B. ubiquinone to cyt b
C. cyt b to cyt f
D. cyt f to excited bacteriochlorophyll
Answer» D. cyt f to excited bacteriochlorophyll
141.

Which pathway will result in the production of four carbon dioxide molecules, two ATP molecules, NADH2 and FADH2?

A. glycolysis
B. Krebs cycle
C. Calvin cycle
D. electron transport system
Answer» C. Calvin cycle
142.

For each glucose molecule broken down, there are______________number of reduced coenzymes to be oxidized.

A. 12
B. 8
C. 6
D. 4
Answer» B. 8
143.

Hexose monophosphate pathway is also known as

A. phosphogluconate pathway
B. oxaloacetate pathway
C. malate pathway
D. fumerate pathway
Answer» B. oxaloacetate pathway
144.

Entner - Doudoroff pathway is not found in

A. aerobic prokaryotes
B. anaerobic prokaryotes
C. Both (a) and (b)
D. eukaryotes
Answer» E.
145.

Which of the following enzyme removes the RNA primer with its 5’-nuclease activity?

A. DNA polymerase I
B. DNA polymerase II
C. DNA polymerase III
D. RNA polymerase
Answer» B. DNA polymerase II
146.

Aerobic catabolism of glucose yields how much energy (ATP synthesized) relative to glucose fermentation?

A. Slightly less
B. About the same
C. Twice as much
D. More than 10 times as much
Answer» E.
147.

Aerobic respiration differs from anaerobic respiration in which of the following respects?

A. Anaerobic respiration is glycolysis
B. Aerobic respiration requires the electron transport chain
C. The final electron acceptors are different
D. Aerobic respiration produces less ATP
Answer» D. Aerobic respiration produces less ATP
148.

How many molecules of glucose-6-phosphate are regenerated in pentose-phosphate pathway?

A. 3
B. 2
C. 5
D. 4
Answer» D. 4
149.

Which one of the following is produced in the greatest numbers during one turn of the Krebs cycle?

A. NADH
B. Acetyl-CoA
C. FADH2
D. ATP
Answer» B. Acetyl-CoA
150.

The specific enzyme/(s) of the glyoxylate cycle is/are

A. isocitrate lyase
B. malate synthase
C. both (a) and (b)
D. anaplerotic
Answer» D. anaplerotic