R4RIN – MCQs, Mock Tests | Biochemistry Biochemistry MCQS PAPER SET 7

Important function of cholesterol is to

1. modulate fluidity
2. enhance blood circulation
3. prevent bile salts formation
4. None of these

✅ Correct Answer: 1

To stop ATP synthesis which chemical is generally used?

1. DNSA
2. 2,4 dinitrophenol
3. DDT
4. None of the chemical can stop ATP synthesis

✅ Correct Answer: 2

The enzymes of the TCA cycle in a eukaryotic cell are located in the

1. nucleus
2. mitochondria
3. plasma membrane
4. lysosomal bodies

✅ Correct Answer: 2

Citric acid cycle occurs in

1. cytoplasm
2. mitochondria
3. endoplasmic reticulum
4. golgi bodies

✅ Correct Answer: 2

Most multi-cellular organisms obtain energy for the synthesis of ATP during oxidative phosphorylation from

1. high energy phosphate compounds
2. a proton gradient across the inner mitochondrial membrane
3. a proton gradient across the cell membrane
4. a proton gradient across the outer mitochondrial membrane

✅ Correct Answer: 2

Standard redox potential for a substance is measured under standard condition and is expressed as

1. mili-Ampere
2. Volt
3. without unit
4. Ohm

✅ Correct Answer: 2

Most of the enzymes of the citric acid cycle in a eukaryotic cell are located in the

1. inner mitochondrial membrane
2. cytosol
3. mitochondrial matrix
4. intermembrane space

✅ Correct Answer: 3

A positive redox potential means substance has

1. lower affinity for electron
2. higher affinity for electron
3. lower affinity for proton
4. higher affinity for proton

✅ Correct Answer: 2

The end product of glycolysis is pyruvate, which enters the citric acid cycle after being converted to

1. acetic acid
2. acetyl-CoA
3. acetaldehyde
4. none of these

✅ Correct Answer: 2

Energy that is released from glucose during respiration but not transferred to ATP bonds can be detected as

1. CO2
2. AMP
3. ADP
4. heat

✅ Correct Answer: 4

Which of the following is involved in energy production?

1. Generation of proton gradients across membranes
2. Transport of electrons on organic molecules
3. Conversion of compounds with high energy to those of low energy
4. All of the above

✅ Correct Answer: 4

Which of the following enzyme does not take part in the TCA cycle?

1. Citrate synthase
2. Iso-citrate dehydrogenase
3. Pyruvate dehydrogenase
4. Malate dehydrogenase

✅ Correct Answer: 3

The first intermediate in TCA cycle is

1. succinate
2. fumerate
3. citrate
4. malate

✅ Correct Answer: 3

Cholesterol can be synthesized de novo in

1. pancreas
2. intestine
3. liver
4. cell membrane

✅ Correct Answer: 3

Which one of the following is not the intermediate of Kreb's cycle?

1. Isocitrate
2. Succinate
3. Fumarate
4. Stearate

✅ Correct Answer: 4

Which one is not the main protein in electron transport chain?

1. NADH dehydrogenase
2. Cytochrome bc1 complex
3. Cytochrome oxidase
4. Citrate synthease

✅ Correct Answer: 4

The FADH2 and NADH produced by the oxidation of one acetyl-CoA results in the synthesis of about-

1. 3 ATPs
2. 6 ATPs
3. 11 ATPs
4. 15 ATPs

✅ Correct Answer: 3

In eukaryotes, electron transport occurs in

1. membranes and mitochondria
2. endoplasmic reticulum
3. cytoplasm
4. all of the above

✅ Correct Answer: 1

The catabolism of sugars and fatty acids is similar because

1. both of these compounds are funnelled through the TC A/citric acid cycle
2. both of these compounds generate redox energy during catabolism
3. both of these compounds generate chemical energy during catabolism
4. all of the above

✅ Correct Answer: 1

Which of the following is the reduced form of a temporary electron carrier molecule?

1. FADH2
2. ATP
3. NADP+
4. CO2

✅ Correct Answer: 1

Which one of the following is a product of both cyclic and noncyclic photophosphorylation?

1. NADPH
2. O2
3. ATP
4. Carbohydrate

✅ Correct Answer: 3

Which of the following represents a correct ordering of the events that occur during the respiration of glucose in the absence of O2?

1. Glycolysis; citric acid cycle; oxidative phosphorylation
2. Glycolysis; oxidative phosphorylation; citric acid cycle
3. Oxidative phosphorylation; citric acid cycle; glycolysis
4. Glycolysis; fermentation

✅ Correct Answer: 4

The rate of photorespiration in most plants increases at.higher temperatures. Some plants have evolved a somewhat round-about system to deal with this problem. This series of reactions is called

1. ETS (electron transfer system in light reactions
2. C4 pathway
3. Photosystem II
4. Calvin cycle

✅ Correct Answer: 2

NADP+ is reduced to NADPH during

1. light dependent reactions
2. photorespiration
3. calvin cylcle
4. none of these

✅ Correct Answer: 1

More ATP is manufactured during __________ than at any other time in all of cellular metabolism.

1. fermentation
2. glycolysis
3. the light reactions of photosynthesis
4. oxidative phosphorylation

✅ Correct Answer: 4

Electron transport systems play a vital role in

1. Calvin cycle
2. photorespiration
3. light-dependent reactions
4. all of these

✅ Correct Answer: 3

Antenna complexes, electron transport chains, and carbon fixation are all found in

1. animal cells
2. bacterial cells
3. plant cells
4. association with the reactions of the citric acid cycle

✅ Correct Answer: 3

Where does the O2 come from that is essential for the proper functioning of oxidative phosphorylation?

1. Fermentation
2. Light reactions of photosynthesis
3. Dark reactions of photosynthesis
4. Carbon fixation

✅ Correct Answer: 2

Carbon fixation requires the expenditure of ATP molecules which is generated by

1. formation of glucose during the Calvin cycle
2. replenishment of chlorophyll
3. ETS (electron transfer system) during the light reactions
4. none of the above

✅ Correct Answer: 3

A cyclic electron transport process is the characteristic of

1. photosynthesis
2. methane oxidation
3. sulfide oxidation
4. methane production

✅ Correct Answer: 1

In oxygenic photosynthesis, the electron donor is

1. water
2. oxygen
3. NADH
4. NADPH

✅ Correct Answer: 1

The followings are the products of the light reactions of photosynthesis except

1. ATP
2. oxygen
3. NADPH
4. glucose

✅ Correct Answer: 4

The vast majority of the molecules that act as energy carriers to power cellular activities are made in

1. the nucleus
2. the Golgi apparatus
3. the cytosol
4. the mitochondria and chloroplasts

✅ Correct Answer: 4

Which of the following statements about energy metabolism is false?

1. The energy that powers living systems ultimately comes from the sun
2. All animals in some way rely on plants for their energy
3. Plants provide the water and CO2 that animals need to carry out respiration
4. All eukaryotic organisms carry out respiration in the presence of O2

✅ Correct Answer: 3

In cells having organelles, the steps of the Krebs cycle and the electron transport system occur in the

1. cell membrane
2. mitochondria
3. endoplasmic reticulum
4. none of these

✅ Correct Answer: 2

As a result of the photosynthetic process, which product is formed?

1. Oxygen
2. Water
3. Carbon dioxide
4. Both (a) and (b)

✅ Correct Answer: 1

A eukaryotic cell that can carry out only fermentation instead of the complete aerobic respiration of glucose

1. produces less CO2
2. is lacking in O2
3. has mitochondria present
4. all of these

✅ Correct Answer: 4

What is the maximum absorption wavelength for photosystem I in green plants?

1. 550 nm
2. 600 nm
3. 700 nm
4. 750 nm

✅ Correct Answer: 3

Carbon dioxide is reduced in

1. noncyclic photophosphorylation
2. the Calvin cycle
3. the light reactions
4. both light and dark reactions

✅ Correct Answer: 2

During the light-dependent reactions of photosynthesis, which of the following does not occur?

1. Splitting of water
2. Carbon dioxide fixation
3. Release of oxygen
4. Absorption of light energy by photosystems

✅ Correct Answer: 2

Which of the following structures or processes are logically associated with chloroplasts?

1. Plant cells
2. Chlorophyll
3. Thylakoid membranes
4. All of these

✅ Correct Answer: 4

In oxygenic photosynthesis, water is split in order to provide the

1. electrons needed to reduce P680
2. O2 needed for the dark reactions
3. electrons needed to reduce NADH
4. electrons needed for cyclic photophosphorylation

✅ Correct Answer: 1

Where do the protons come from that make up the proton gradient used in the light reactions of photosynthesis?

1. Glucose
2. ATP
3. H2O
4. NADPH

✅ Correct Answer: 3

Oxidative phosphorylation is to respiration as __________ is to photosynthesis

1. carbon fixation
2. electron transport chain
3. light capture by chlorophyll
4. reduction of NADPH

✅ Correct Answer: 2

Which of the following serves as a reactant in photosynthesis and a product in cellular respiration?

1. O2
2. CO2
3. Sunlight
4. ATP

✅ Correct Answer: 2

Hydrogen (electron) acceptor in the light reactions is

1. ADP
2. NADP+
3. NAD+
4. FADH

✅ Correct Answer: 2

The cytochrome c oxidase complex

1. accepts electrons from cyt c
2. donates four electrons to O2
3. pumps protons out of the matrix space
4. all of these

✅ Correct Answer: 4

In the Calvin cycle, carbon dioxide is fixed in a reaction with the

1. ribulose diphosphate
2. ribulose phosphate
3. ribose tri phosphate
4. 3-phosphoglyceric acid

✅ Correct Answer: 1

What do NAD+, NADP+, and FAD+ all have in common?

1. They are reduced
2. They have a full complement of electrons
3. They are oxidized
4. They are what is used during carbon fixation in photosynthesis

✅ Correct Answer: 3

In noncyclic photophosphorylation, the ultimate acceptor of electrons that have been produced from the splitting of water is

1. NADP+
2. chlorophyll a
3. carbon dioxide
4. chlorophyll b

✅ Correct Answer: 3

The breakdown of glucose occurs by the process known as

1. glycolysis
2. fermentation
3. anaerobic respiration
4. Krebs cycle

✅ Correct Answer: 1

The manufacture of ATP in both photosynthesis and respiration is made possible by

1. the existence of a proton gradient across specific membranes
2. the action of ATP synthase
3. energy from the movement of electrons
4. All of the above

✅ Correct Answer: 4

The end products of noncyclic photophosphorylation are

1. O2, ATP and NADPH
2. carbon dioxide, PGAL (phosphoglyceraldehyde), and H2
3. water, ADP and NADP+
4. carbon dioxide, ATP and water

✅ Correct Answer: 1

In algae, photosynthesis takes place in

1. choloroplasts
2. cell membrane
3. mitochondria
4. none of the above

✅ Correct Answer: 1

Which enzyme is involved in carbon-fixation reaction?

1. NADP reductase
2. Cytochrome reductase
3. Ribulose bisphosphate carboxylase
4. Glycerol kinase

✅ Correct Answer: 3

Assume the combined processes of photosynthesis and cellular respiration, the electrons that start as part of H2O at the beginning of the light reactions end up attaching to

1. O2 to make new H2O
2. NADPH to make new glucose
3. pyruvate to make ethanol
4. electron transport carriers to make O2

✅ Correct Answer: 1

In the initial step of photosynthesis, sunlight energizes the electron pair of

1. adenosine triphosphate (ATP)
2. chlorophyll pigments
3. water
4. carbon dioxide

✅ Correct Answer: 2

Rubisco (RuBP Carboxylase-oxygenase enzyme), glyceraldehyde 3-phosphate, and NADPH all play a role in

1. the dark reactions of photosynthesis
2. the breakdown of glucose into CO2
3. cellular respiration when O2 is present
4. alcohol fermentation

✅ Correct Answer: 1

The electrons that are released by the splitting of water during photosynthesis ultimately end up in

1. ATP
2. O2
3. NADPH
4. rubisco

✅ Correct Answer: 3

Glycolysis takes places in the __________ and produces __________ , which in the presence of oxygen then enters the __________ .

1. cytosol; glucose; mitochondrion to complete fermentation
2. cytosol; pyruvate; mitochondrion to complete fermentation
3. cytosol; pyruvate; mitochondrion to complete cellular respiration
4. mitochondrion; pyruvate; chloroplast to complete photosynthesis

✅ Correct Answer: 3

What process in cellular respiration is essentially the reverse of carbon fixation in photosynthesis?

1. Glycolysis
2. Citric acid cycle
3. Oxidative phosphorylation
4. Alcohol fermentation

✅ Correct Answer: 2

What do coenzyme A, CO2, oxaloacetate, and FADH2 all have in common?

1. They are all components or products of the citric acid cycle
2. They are part of the dark reactions of photosynthesis
3. They are part of the reactions of lactic acid fermentation
4. They are all elements of oxidative phosphorylation

✅ Correct Answer: 1

If the oxygen is labeled in CO2 and provide this CO2 to a plant, where it is expected to find this labeled oxygen after the plant had undergone photosynthesis?

1. In the water used
2. In the NADPH
3. In the carbohydrate produced
4. In the oxygen given off by the plan

✅ Correct Answer: 3

Histidine is degraded to α-ketoglutarate and is described as a

1. gluco amino acid
2. glucogenic amino acid
3. ketogenic amino acid
4. keto-gluco amino acid

✅ Correct Answer: 2

Which of the following amino acids is considered as both ketogenic and glucogenic?

1. Valine
2. Tryptophan
3. Lysine
4. None of these

✅ Correct Answer: 2

A glucogenic amino acid is one which is degraded to

1. keto-sugars
2. either acetyl CoA or acetoacetyl CoA
3. pyruvate or citric acid cycle intermediates
4. none of the above

✅ Correct Answer: 3

Which of the following is the best described glucogenic amino acid?

1. Lysine
2. Tryptophan
3. Valine
4. None of these

✅ Correct Answer: 3

A person with phenylketonuria cannot convert

1. phenylalanine to tyrosine
2. phenylalanine to isoleucine
3. phenol into ketones
4. phenylalanine to lysine

✅ Correct Answer: 1

Oxidative deamination is the conversion of an amino

1. group from an amino acid to a keto acid
2. acid to a carboxylic acid plus ammonia
3. acid to a keto acid plus ammonia
4. group from an amino acid to a carboxylic acid

✅ Correct Answer: 3