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Biochemistry MCQS PAPER SET 7
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1. Important function of cholesterol is to
modulate fluidity
enhance blood circulation
prevent bile salts formation
None of these
2. To stop ATP synthesis which chemical is generally used?
DNSA
2,4 dinitrophenol
DDT
None of the chemical can stop ATP synthesis
3. The enzymes of the TCA cycle in a eukaryotic cell are located in the
nucleus
mitochondria
plasma membrane
lysosomal bodies
4. Citric acid cycle occurs in
cytoplasm
mitochondria
endoplasmic reticulum
golgi bodies
5. Most multi-cellular organisms obtain energy for the synthesis of ATP during oxidative phosphorylation from
high energy phosphate compounds
a proton gradient across the inner mitochondrial membrane
a proton gradient across the cell membrane
a proton gradient across the outer mitochondrial membrane
6. Standard redox potential for a substance is measured under standard condition and is expressed as
mili-Ampere
Volt
without unit
Ohm
7. Most of the enzymes of the citric acid cycle in a eukaryotic cell are located in the
inner mitochondrial membrane
cytosol
mitochondrial matrix
intermembrane space
8. A positive redox potential means substance has
lower affinity for electron
higher affinity for electron
lower affinity for proton
higher affinity for proton
9. The end product of glycolysis is pyruvate, which enters the citric acid cycle after being converted to
acetic acid
acetyl-CoA
acetaldehyde
none of these
10. Energy that is released from glucose during respiration but not transferred to ATP bonds can be detected as
CO2
AMP
ADP
heat
11. Which of the following is involved in energy production?
Generation of proton gradients across membranes
Transport of electrons on organic molecules
Conversion of compounds with high energy to those of low energy
All of the above
12. Which of the following enzyme does not take part in the TCA cycle?
Citrate synthase
Iso-citrate dehydrogenase
Pyruvate dehydrogenase
Malate dehydrogenase
13. The first intermediate in TCA cycle is
succinate
fumerate
citrate
malate
14. Cholesterol can be synthesized de novo in
pancreas
intestine
liver
cell membrane
15. Which one of the following is not the intermediate of Kreb's cycle?
Isocitrate
Succinate
Fumarate
Stearate
16. Which one is not the main protein in electron transport chain?
NADH dehydrogenase
Cytochrome bc1 complex
Cytochrome oxidase
Citrate synthease
17. The FADH2 and NADH produced by the oxidation of one acetyl-CoA results in the synthesis of about-
3 ATPs
6 ATPs
11 ATPs
15 ATPs
18. In eukaryotes, electron transport occurs in
membranes and mitochondria
endoplasmic reticulum
cytoplasm
all of the above
19. The catabolism of sugars and fatty acids is similar because
both of these compounds are funnelled through the TC A/citric acid cycle
both of these compounds generate redox energy during catabolism
both of these compounds generate chemical energy during catabolism
all of the above
20. Which of the following is the reduced form of a temporary electron carrier molecule?
FADH2
ATP
NADP+
CO2
21. Which one of the following is a product of both cyclic and noncyclic photophosphorylation?
NADPH
O2
ATP
Carbohydrate
22. Which of the following represents a correct ordering of the events that occur during the respiration of glucose in the absence of O2?
Glycolysis; citric acid cycle; oxidative phosphorylation
Glycolysis; oxidative phosphorylation; citric acid cycle
Oxidative phosphorylation; citric acid cycle; glycolysis
Glycolysis; fermentation
23. 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
ETS (electron transfer system in light reactions
C4 pathway
Photosystem II
Calvin cycle
24. NADP+ is reduced to NADPH during
light dependent reactions
photorespiration
calvin cylcle
none of these
25. More ATP is manufactured during __________ than at any other time in all of cellular metabolism.
fermentation
glycolysis
the light reactions of photosynthesis
oxidative phosphorylation
26. Electron transport systems play a vital role in
Calvin cycle
photorespiration
light-dependent reactions
all of these
27. Antenna complexes, electron transport chains, and carbon fixation are all found in
animal cells
bacterial cells
plant cells
association with the reactions of the citric acid cycle
28. Where does the O2 come from that is essential for the proper functioning of oxidative phosphorylation?
Fermentation
Light reactions of photosynthesis
Dark reactions of photosynthesis
Carbon fixation
29. Carbon fixation requires the expenditure of ATP molecules which is generated by
formation of glucose during the Calvin cycle
replenishment of chlorophyll
ETS (electron transfer system) during the light reactions
none of the above
30. A cyclic electron transport process is the characteristic of
photosynthesis
methane oxidation
sulfide oxidation
methane production
31. In oxygenic photosynthesis, the electron donor is
water
oxygen
NADH
NADPH
32. The followings are the products of the light reactions of photosynthesis except
ATP
oxygen
NADPH
glucose
33. The vast majority of the molecules that act as energy carriers to power cellular activities are made in
the nucleus
the Golgi apparatus
the cytosol
the mitochondria and chloroplasts
34. Which of the following statements about energy metabolism is false?
The energy that powers living systems ultimately comes from the sun
All animals in some way rely on plants for their energy
Plants provide the water and CO2 that animals need to carry out respiration
All eukaryotic organisms carry out respiration in the presence of O2
35. In cells having organelles, the steps of the Krebs cycle and the electron transport system occur in the
cell membrane
mitochondria
endoplasmic reticulum
none of these
36. As a result of the photosynthetic process, which product is formed?
Oxygen
Water
Carbon dioxide
Both (a) and (b)
37. A eukaryotic cell that can carry out only fermentation instead of the complete aerobic respiration of glucose
produces less CO2
is lacking in O2
has mitochondria present
all of these
38. What is the maximum absorption wavelength for photosystem I in green plants?
550 nm
600 nm
700 nm
750 nm
39. Carbon dioxide is reduced in
noncyclic photophosphorylation
the Calvin cycle
the light reactions
both light and dark reactions
40. During the light-dependent reactions of photosynthesis, which of the following does not occur?
Splitting of water
Carbon dioxide fixation
Release of oxygen
Absorption of light energy by photosystems
41. Which of the following structures or processes are logically associated with chloroplasts?
Plant cells
Chlorophyll
Thylakoid membranes
All of these
42. In oxygenic photosynthesis, water is split in order to provide the
electrons needed to reduce P680
O2 needed for the dark reactions
electrons needed to reduce NADH
electrons needed for cyclic photophosphorylation
43. Where do the protons come from that make up the proton gradient used in the light reactions of photosynthesis?
Glucose
ATP
H2O
NADPH
44. Oxidative phosphorylation is to respiration as __________ is to photosynthesis
carbon fixation
electron transport chain
light capture by chlorophyll
reduction of NADPH
45. Which of the following serves as a reactant in photosynthesis and a product in cellular respiration?
O2
CO2
Sunlight
ATP
46. Hydrogen (electron) acceptor in the light reactions is
ADP
NADP+
NAD+
FADH
47. The cytochrome c oxidase complex
accepts electrons from cyt c
donates four electrons to O2
pumps protons out of the matrix space
all of these
48. In the Calvin cycle, carbon dioxide is fixed in a reaction with the
ribulose diphosphate
ribulose phosphate
ribose tri phosphate
3-phosphoglyceric acid
49. What do NAD+, NADP+, and FAD+ all have in common?
They are reduced
They have a full complement of electrons
They are oxidized
They are what is used during carbon fixation in photosynthesis
50. In noncyclic photophosphorylation, the ultimate acceptor of electrons that have been produced from the splitting of water is
NADP+
chlorophyll a
carbon dioxide
chlorophyll b
51. The breakdown of glucose occurs by the process known as
glycolysis
fermentation
anaerobic respiration
Krebs cycle
52. The manufacture of ATP in both photosynthesis and respiration is made possible by
the existence of a proton gradient across specific membranes
the action of ATP synthase
energy from the movement of electrons
All of the above
53. The end products of noncyclic photophosphorylation are
O2, ATP and NADPH
carbon dioxide, PGAL (phosphoglyceraldehyde), and H2
water, ADP and NADP+
carbon dioxide, ATP and water
54. In algae, photosynthesis takes place in
choloroplasts
cell membrane
mitochondria
none of the above
55. Which enzyme is involved in carbon-fixation reaction?
NADP reductase
Cytochrome reductase
Ribulose bisphosphate carboxylase
Glycerol kinase
56. 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
O2 to make new H2O
NADPH to make new glucose
pyruvate to make ethanol
electron transport carriers to make O2
57. In the initial step of photosynthesis, sunlight energizes the electron pair of
adenosine triphosphate (ATP)
chlorophyll pigments
water
carbon dioxide
58. Rubisco (RuBP Carboxylase-oxygenase enzyme), glyceraldehyde 3-phosphate, and NADPH all play a role in
the dark reactions of photosynthesis
the breakdown of glucose into CO2
cellular respiration when O2 is present
alcohol fermentation
59. The electrons that are released by the splitting of water during photosynthesis ultimately end up in
ATP
O2
NADPH
rubisco
60. Glycolysis takes places in the __________ and produces __________ , which in the presence of oxygen then enters the __________ .
cytosol; glucose; mitochondrion to complete fermentation
cytosol; pyruvate; mitochondrion to complete fermentation
cytosol; pyruvate; mitochondrion to complete cellular respiration
mitochondrion; pyruvate; chloroplast to complete photosynthesis
61. What process in cellular respiration is essentially the reverse of carbon fixation in photosynthesis?
Glycolysis
Citric acid cycle
Oxidative phosphorylation
Alcohol fermentation
62. What do coenzyme A, CO2, oxaloacetate, and FADH2 all have in common?
They are all components or products of the citric acid cycle
They are part of the dark reactions of photosynthesis
They are part of the reactions of lactic acid fermentation
They are all elements of oxidative phosphorylation
63. 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?
In the water used
In the NADPH
In the carbohydrate produced
In the oxygen given off by the plan
64. Histidine is degraded to α-ketoglutarate and is described as a
gluco amino acid
glucogenic amino acid
ketogenic amino acid
keto-gluco amino acid
65. Which of the following amino acids is considered as both ketogenic and glucogenic?
Valine
Tryptophan
Lysine
None of these
66. A glucogenic amino acid is one which is degraded to
keto-sugars
either acetyl CoA or acetoacetyl CoA
pyruvate or citric acid cycle intermediates
none of the above
67. Which of the following is the best described glucogenic amino acid?
Lysine
Tryptophan
Valine
None of these
68. A person with phenylketonuria cannot convert
phenylalanine to tyrosine
phenylalanine to isoleucine
phenol into ketones
phenylalanine to lysine
69. Oxidative deamination is the conversion of an amino
group from an amino acid to a keto acid
acid to a carboxylic acid plus ammonia
acid to a keto acid plus ammonia
group from an amino acid to a carboxylic acid
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