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Multiple choice question for engineering

Set 1

1. What happens in hypochromicity?
a) When DNA is in bound form, there is decrease in absorption of UV light
b) When DNA is in bound form, there is increase in absorption of UV light
c) When DNA is in unbound form, it is more stable
d) When DNA is in unbound form, there is decrease in absorption of UV light

View Answer

Answer: a [Reason:] It describes the decrease in absorbance of UV light in a double stranded DNA.

2. What happens in hyperchromicity?
a) When DNA is in bound form, there is decrease in absorption of UV light
b) When DNA is in bound form, there is increase in absorption of UV light
c) When DNA is in unbound form, it is more stable
d) When DNA is in unbound form, there is increase in absorption of UV light

View Answer

Answer: d [Reason:] It describes the increase in absorption of UV light in a single stranded DNA.

3. Which of the following is true about tm?
a) It can be termed as renaturation temperature
b) The higher the content of G ≡ C base pairs, the higher the tm
c) The higher the content of A = T base pairs, the higher the tm
d) The higher the content of G ≡ C base pairs, the lower the tm

View Answer

Answer: b [Reason:] Tm is the melting temperature or denaturation temperature.

4. Which of the following is false?
a) The stability of an RNA-DNA hybrid is generally intermediate between that of RNA and DNA
b) RNA duplexes are more stable than DNA duplexes
c) DNA duplexes are more stable than RNA duplexes
d) DNA duplexes are less stable than RNA- DNA hybrid

View Answer

Answer: c [Reason:] RNA duplexes are more stable than DNA duplexes.

5. DNA denaturation is measured by absorbance at
a) 220nm
b) 230nm
c) 250nm
d) 260nm

View Answer

Answer: d [Reason:] At 260nm absorbance, DNA denaturation is measured.

6. Which of the following is false about denaturation?
a) Disruption of hydrogen bonds
b) Disruption of phosphodiester linkage
c) Loss of helical structure of DNA
d) It is resulted as a result of change in pH or increase in temperature

View Answer

Answer: b [Reason:] Phosphodiester linkages are not broken by denaturation.

7. Which of the following nucleotides is not present in RNA?
a) AMP
b) GMP
c) CMP
d) TMP

View Answer

Answer: d [Reason:] Thymidine monophosphate is present in DNA.

8. Which of the following nucleotides is not present in DNA?
a) AMP
b) GMP
c) CMP
d) UMP

View Answer

Answer: d [Reason:] Uridine monophosphate is present in RNA.

9. Which of the following is false?
a) RNA does not obey Chargaff’s rule
b) DNAs can be identified by Orcinol color reaction
c) In RNA OH group is present at 2’ position
d) Alkali hydrolyses RNA to 2’3’-cyclic diesters

View Answer

Answer: b [Reason:] RNAs can be identified by Orcinol color reaction.

10. Which of the following involves in carrying genetic information from DNA for protein synthesis?
a) m-RNA
b) t-RNA
c) r-RNA
d) sn-RNA

View Answer

Answer: a [Reason:] Messenger RNA carries genetic information from DNA for protein synthesis.

Set 2

1. Number of hydrogen bonds between adenine and thymine?
a) 1
b) 2
c) 3
d) 4

View Answer

Answer: b [Reason:] A = T is the notation for bonding between A and T.

2. Number of hydrogen bonds between guanine and cytosine?
a) 1
b) 2
c) 3
d) 4

View Answer

Answer: c [Reason:] G≡C is the notation for bonding between G and C.

3. Which ratio is constant for DNA?
a) A + G / T + C
b) A + T / G + C
c) A + C / U + G
d) A + U / G + C

View Answer

Answer: a [Reason:] The molar concentration of purine bases A and G is equal to the molar concentration of pyrimidine bases T and C because one of each type makes up a base pair. Because of base pairing rules, A = T and G = C. The specific A – T and G – C content varies from species to species. But in any one species the ratio is constant.

4. According to Chargaff’s rule, in a DNA molecule
a) The amount of adenine and thymine is equal to the amount of guanine and cytosine
b) The amount of adenine and guanine is equal to the amount of thymine and cytosine
c) The amount of adenine and uracil is equal to the amount of guanine and cytosine
d) The amount of adenine and guanine is equal to the amount of uracil and cytosine

View Answer

Answer: a [Reason:] According to Chargaff’s rule, whatever the amount of adenine, it is equal to the amount of thymine and same is the case with guanine and cytosine.

5. Arrangement of nucleotides in DNA can be seen by
a) Ultracentrifuge
b) X-Ray crystallography
c) Light microscope
d) Electron microscope

View Answer

Answer: b [Reason:] It is a scientific method used to determine the arrangement of atoms of a crystalline solid in a three dimensional space.

6. Which of the following leads to disruption of nucleosomal structure?
a) Acetylation
b) Carboxylation
c) Phosphorylation
d) Methylation

View Answer

Answer: d [Reason:] Methylation denatures nucleosomal structure.

7. One of the following nucleic acids has a left handed helix
a) M-RNA
b) T-RNA
c) A-DNA
d) Z-DNA

View Answer

Answer: d [Reason:] Z-DNA is left handed and B-DNA is right handed helix.

8. Which of the following statements is not true about RNA?
a) Does not have a double stranded structure
b) Thymine is present
c) Does not obey Chargaff’s rule
d) The sugar contained in RNA is a ribose

View Answer

Answer: b [Reason:] Thymine is present in DNA.

9. Which of the following is true about Z-DNA helix?
a) It has alternating GC sequences
b) It is a permanent conformation of DNA
c) It tends to be found at the 3’ end of the genes
d) It has fewer base pairs per turn than B-DNA

View Answer

Answer: a [Reason:] It is a temporary conformation of DNA It has more base pairs per turn than B-DNA.

10. Which of the following statements is true?
a) The template strand matches the sequence of the RNA transcript
b) The two strands of DNA run parallel to each other
c) G-C bonds are much more resistant to denaturation than A-T rich regions
d) The common form of DNA is left handed

View Answer

Answer: c [Reason:] The two strands of DNA run antiparallel to each other. The common form of DNA is B-DNA which is right handed.

Set 3

1. The proposal of chemiosmotic hypothesis was by
a) Peter D. Mitchell
b) Charles Darwin
c) Mendele
d) Alfred Russell

View Answer

Answer: a [Reason:] Peter D. Mitchell was the one to propose chemiosmotic hypothesis.

2. ATP synthesis by chemiosmosis is by
a) ATP dehydrogenase
b) Gyrase
c) ATP synthase
d) Dehydrogenase

View Answer

Answer: c [Reason:] ATP synthase synthesizes ATP by chemiosmosis.

3. The measure of potential energy stored as combination of proton and voltage gradients across membrane is termed as
a) Proton motive force
b) Electron motive force
c) Molecule motive force
d) Ion motive force

View Answer

Answer: a [Reason:] The measure of potential energy stored as combination of proton and voltage gradients across membrane is termed as proton motive force.

4. The transport of acyl co-A for oxidation using a shuttle involves formation of the intermediate
a) Acyl coenzyme A
b) 3 acetyl co-A
c) Acyl cartinine
d) None

View Answer

Answer: c [Reason:] The intermediate acyl cartinine is formed in the transport of acyl co-A for oxidation using a shuttle.

5. Three identical β subunits of the F1 complex during ATP synthesis have
a) Different affinities for ATP and ADP
b) Similar affinities for ADP and ATP
c) Different affinities for ADP but not ATP
d) Different affinities for ATP but not ADP

View Answer

Answer: a [Reason:] The conformational differences among β subunits extend to differences in their ATP/ADP-binding sites.

6. The acyl co-A formed in the cytosol is transported to
a) Mitochondrial matrix
b) Microsomes
c) ER
d) Remains in cytosol

View Answer

Answer: a [Reason:] The acyl co-A formed in the cytosol is transported to mitochondrial matrix.

7. Every cycle of β-oxidation produces
a) 1 FAD, 1 NAD+ and 2 CO2 molecules
b) 1 FADH2, 1 NADH and 1 acetyl co-A
c) 1 FADH2, 1 NAD+ and 1 acetyl co-A
d) 1 FAD, 1 NADH and 2 CO2 molecules

View Answer

Answer: b [Reason:] Every cycle of β-oxidation produces 1 FADH2, 1 NADH and 1 acetyl co-A.

8. Membrane potential and proton gradient
a) Cancel one another when uncouplers are present
b) Reinforce one another when respiratory inhibitors are present
c) Are sufficient, separately to make ATP from ADP + Pi
d) Are required to make ATP

View Answer

Answer: d [Reason:] Membrane potential and proton gradient are both required to make ATP.

9. Long-chain fatty acids are oxidized step-wise in one carbon units starting from
a) Carboxyl end
b) Aliphatic end
c) a and b
d) None

View Answer

Answer: a [Reason:] Long-chain fatty acids are oxidized step-wise in one carbon units starting from carboxyl end.

10. Maximum energy per gram on oxidation is yielded from
a) Starch
b) Fat
c) Glycogen
d) Protein

View Answer

Answer: b [Reason:] Fat yields maximum energy per gram on oxidation.

Set 4

1. Uridylylation and deuridylylation of PII are brought about by a single enzyme
a) Uridylyltransferase
b) Adenylyltransferase
c) Glutamate synthase
d) Dinitrogenase

View Answer

Answer: a [Reason:] Uridylylation and deuridylylation of PII are brought about by a single enzyme, uridylyltransferase.

2. Dinitrogenase reductase is a
a) Monomer
b) Dimer
c) Trimer
d) Tetramer

View Answer

Answer: b [Reason:] Dinitrogenase reductase is a dimer of two identical subunits.

3. Dinitrogenase is a
a) Monomer
b) Dimer
c) Trimer
d) Tetramer

View Answer

Answer: d [Reason:] Dinitrogenase is a tetramer with two copies of two different subunits, containing both iron and molybdenum.

4. The reaction of glutamate and NH4+ to yield glutamine is catalyzed by
a) Uridylyltransferase
b) Adenylyltransferase
c) Glutamate synthase
d) Glutamine synthase

View Answer

Answer: d [Reason:] Glutamine synthase catalyzes the reaction of glutamate and NH4+ to yield glutamine.

5. An intermediate of the citric acid cycle that undergoes reductive amination with glutamine as nitrogen donor is
a) α-ketoglutarate
b) Glutamine
c) NADPH
d) H+

View Answer

Answer: a [Reason:] α-ketoglutarate is the intermediate of the citric acid cycle that undergoes reductive amination with glutamine as nitrogen donor.

6. Which of the following catalyzes reactions that incorporate nitrogen derived from glutamine?
a) Glutamine amidotransferase
b) Adenylyltransferase
c) Glutamate synthase
d) Glutamine synthase

View Answer

Answer: a [Reason:] Glutamine amidotransferase catalyzes reactions that incorporate nitrogen derived from glutamine.

7. Conversion of nitrogen to ammonia or nitrogenous compounds is termed as
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation

View Answer

Answer: a [Reason:] Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called as nitrogen assimilation. Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called as nitrification. Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called as denitrification.

8. Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called as
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation

View Answer

Answer: d [Reason:] Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called as nitrification. Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called as denitrification. Conversion of nitrogen to ammonia or nitrogenous compounds is termed as nitrogen fixation.

9. Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called as
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation

View Answer

Answer: b [Reason:] Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called as denitrification. Conversion of nitrogen to ammonia or nitrogenous compounds is termed as nitrogen fixation. Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called as nitrogen assimilation.

10. Nitrate is reduced and ultimately produces N2 through a series of intermediate gaseous nitrogen oxide products is called as
a) Nitrogen fixation
b) Nitrification
c) Denitrification
d) Nitrogen assimilation

View Answer

Answer: c [Reason:] Conversion of nitrogen to ammonia or nitrogenous compounds is termed as nitrogen fixation. Formation of organic nitrogen compounds like amino acids from inorganic nitrogen compounds is called as nitrogen assimilation. Ammonia or ammonium is oxidized to nitrite followed by the oxidation of nitrite to nitrate is called as nitrification.

Set 5

1. Which of the following amino acids are exclusively ketogenic?
a) Leucine
a) Asparagine
c) Threonine
d) Proline

View Answer

Answer: a [Reason:] Only two amino acids, leucine and lysine are exclusively ketogenic.

2. Which of the following are exclusively glucogenic?
a) Arginine
b) Leucine
c) Lysine
d) Threonine

View Answer

Answer: a [Reason:] Leucine and lysine are exclusively ketogenic. Threonine is both ketogenic and glucogenic.

3. Which of the following yield acetyl co-A via aceto-acetyl co-A?
a) Leucine
b) Isoleucine
c) Threonine
d) Alanine

View Answer

Answer: a [Reason:] Leucine, lysine, phenylalanine and tryptophan yield acetyl co-A via aceto-acetyl co-A.

4. Which of the following yield acetyl coA directly?
a) Phenylalanine
b) Isoleucine
c) Lysine
d) Alanine

View Answer

Answer: b [Reason:] Isoleucine, leucine, threonine and tryptophan yield acetyl coA directly.

5. Which of the following produce pyruvate?
a) Leucine
b) Isoleucine
c) Lysine
d) Alanine

View Answer

Answer: d [Reason:] The amino acids producing pyruvate are alanine, cysteine, glycine, serine, threonine and tryptophan.

6. Which of the following produce α-ketoglutarate?
a) Leucine
b) Threonine
c) Methionine
d) Proline

View Answer

Answer: d [Reason:] Arginine, glutamate, glutamine, histidine and proline produce α-ketoglutarate.

7. Which of the following produce succinyl co-A?
a) Leucine
b) Isoleucine
c) Arginine
d) Alanine

View Answer

Answer: b [Reason:] Isoleucine, methionine, threonine and valine produce succinyl co-A.

8. Fumarate is produced from four carbon atoms of
a) Tyrosine
b) Isoleucine
c) Threonine
d) Alanine

View Answer

Answer: a [Reason:] Four carbon atoms of phenylalanine and tyrosine give rise to fumarate.

9. Which of the following produce oxaloacetate?
a) Aspartate
b) Isoleucine
c) Threonine
d) Alanine

View Answer

Answer: a [Reason:] Asparagine and aspartate produce oxaloacetate.

10. The branched chain amino acid is not
a) Leucine
b) Isoleucine
c) Valine
d) Alanine

View Answer

Answer: d [Reason:] Isoleucine, leucine and valine are the branched chain amino acids.