Biochemistry MCQ Quiz Hub

1. Agarose a porous matrix used in various molecular biology technique is made by repetitive units of
maltose
agarobiose
agar
none of these

2. What radioactive molecule is used to end-label an oligonucleotide?
(alpha)-32P-ATP
(alpha)-32P-dUTP
(gamma)-32P-ATP
Any of these

3. Which of the following radioactive element is generally involved in RIA?
Tritium
Carbon-14
Iodine-125
All of these

4. What is approximatively the half life of 32-Phosphorus?
14 days
28 days
42 days
30 days

5. Rocket Immunodiffusion is also known as
gel diffusion
electroimmunodiffusion
double-diffusion
none of these

6. DNA- footprinting is a suitable technique for identifying which of the following?
Particular mRNA in mixture
Particular t-RNA in mixture
Introns within DNA
Protein binding site within DNA

7. What would happen if serum is omitted from the ELISA, but all other steps remain same?
Anti-human Ig-conjugate would not bind and be washed away
The OD values would be nearly the same as the assay control
Both (a) and (b)
Anti-human Ig-conjugate would bind non-specifically to the ELISA plate

8. RAST test (radio allergosorbent test) is often used to detect
antibodies associated with allergies (IgE)
antigen associated with allergies (IgE)
bacteriophages
. None of the above

9. What would happen if the anti-human Ig-conjugate is not washed free of the well before the substrate is added?
The ELISA would not develop when the substrate was added
The ELISA would develop normally
All wells would show uniform over-development due to unbound and excess anti-human Ig enzyme conjugate
None of the above

10. An antigen preparation and an antibody preparation are tested by immunodiffusion. Three bands are found, indicating that
there was more than one antigen
the antibody was impure
the temperature was too high
there was one antibody and one antigen

11. Immunoelectrophoresis techniques are designed to separate the mixture components from each other by using electrophoresis
prior to reaction with antibody
prior to reaction with antigen
after reaction with antibody
after reaction with antigen

12. Which of the following is a positively charged matrix for ion exchange chromatography?
CM cellulose
DEAE cellulose
Phosphocellulose
None of these

13. Which of the following is an immunoelectrophoresis technique?
immunoelectrophoresis
Counterimmunoelectrophoresis
Coimmunoelectrophoresis
Both (a) and (b)

14. Cholesterol is somewhat amphipathic due to
the single hydroxyl along with the hydrocarbon nature of the remainder of the molecule
. the long branched hydrocarbon along with the four hydrocarbon rings
the five-methyl groups along with the hydrocarbon chain
the three six-membered rings along with the single five-membered ring

15. Bacteriorhodopsin
absorbs light and pumps protons
is an integral membrane protein
contains primarily alpha-helical residues
all of the above

16. In active transport, the membrane structure that functions is
cholesterol
integral proteins
carbohydrates
hydrophobic molecules

17. Cholesterol is essential for normal membrane functions because it
plugs up the cardiac arteries of older men
cannot be made by higher organisms
keeps membranes fluid.
spans the thickness of the bilayer

18. The model that is now known to be correct for the structure of biological membrane is
Fluid mosaic model
Page's model
Lac Operon model
Lock and Key model

19. n Fluid mosaic model, the biological membrane can be viewed as
two dimensional solutions of oriented lipids and globular proteins
three dimensional solutions of oriented lipids and globular proteins
two dimensional solutions of oriented lipids and carbohydrate
three dimensional solutions of oriented lipids and carbohydrate

20. Membrane lipids are
hydrophilic
hydrophobic
ampiphillic
none of these

21. Pinocytosis occurs in
all eukaryotic cells
all prokaryotic cells
mitochondria of all cells
none of these

22. Exocytosis is the secretion of proteins
out of the cell across the plasma membrane into the extracellular space
out of the cell across the plasma membrane into the intracellular space
is the uptake of macromolecules from the extracellular space into the cell across the plasma membrane
is the uptake of macromolecules from the intracellular space into the cell across the plasma membrane

23. The membrane proteins that catalyze active transport reactions differ from soluble enzymes as
they are permanently changed during the reaction
the substrates of the reaction are all outside the cell
they do not enhance the rates of reaction
the products of the reaction move in a specific direction

24. The movement of molecules across a membrane by passive transport does not require
an input of metabolic energy
internal energy
vibrational energy
none of these

25. Peptidoglycan is a complex consisting of
oligo-saccharide and protein
polysaccharide and protein
mono-saccharide and protein
aminoacid and carbohydrate

26. The mesosomes may be the sites of
DNA replication and specialized enzymatic reactions
RNA replications and specialized enzymatic reactions
RNA replications and specialized cyclic reactions
None of the above

27. Which of the following is correct?
Peroxisomes have a single boundary membrane
Peroxisomes contain enzymes that degrade fatty acids and amino acids
The byproduct of given reactions in (b) is toxic to cells
All of the above

28. The smooth endoplasmic reticulum (SER) is the site of
phospholipid synthesis
amino acid synthesis
carbohydrate synthesis
protein synthesis

29. Lysozymes are found in
plant cells
animal cells
microbial cells
all of these

30. Biological membranes are like water beds because
they are always moving
they (normally) do not leak their contents
the membrane is thin compared to the enclosed volume
all of the above

31. The plasma membrane is a selectively permeable barrier due to presence of specific transport
proteins
amino acids
carbohydrates
none of these

32. Which type of molecule spans the membrane, from its inner to outer surface according to the Fluid mosaic model of cell membranes?
Cholesterol
Phospholipid
Protein
Carbohydrate

33. Which of the following is correct?
Membranes form boundaries around the cell and distinct subcellular components
Membranes act as selectively permeable barrier
Membranes contain varying amount of lipid and protein and some contain small amount of carbohydrates
All of the above

34. In membranes, lipids are
glycerophospholipids
sphingolipids
sterols
all of these

35. Which of the following is not found in membranes?
Glycoproteins
Glycolipids
Nucleic acids
Phospholipids

36. Because DNA is a highly charged polyanion, its stability to heat denaturation
does not depend on hydrophobic interactions
increases with increasing salt
is independent of G - C content
decreases with increasing salt

37. The sugar in RNA is __________ , the sugar in DNA is __________
deoxyribose, ribose
ribose, deoxyribose
ribose, phosphate
ribose, uracil

38. Nucleoside is a pyrimidine or purine base
covalently bonded to a sugar
ionically bonded to a sugar
hydrogen bonded to a sugar
none of the above

39. In gel electrophoresis, what fragments will move most quickly through a gel?
Large fragments
Small fragments
Large genome
None of these

40. Which pyrimidine base contains an amino group at carbon 4?
Cytosine
Thymine
Uracil
Adenine

41. Nucleotide bases and aromatic amino acids absorb light respectively at
280 and 260 nm
260 and 280 nm
270 and 280 nm
260 and 270 nm

42. The glycosidic bonds in DNA and RNA
connect the sugar to the base
can be hydrolyzed by OH- ion
stabilize Watson-Crick H-bonds
are free to rotate over about 180°

43. Nucleic acids can be analyzed experimentally by their
molecular weight
absorption of visible light
absorption of uv light
none of these

44. Thymidine
can participate in hydrophobic interactions due to its methyl group
is replaced by uracil in RNA
normally forms two hydrogen bonds with adenosine
all of the above

45. A nucleotide consists of
a sugar, a base and a phosphate
a sugar and a phosphate
paired bases
a sugar, a base and three phosphates

46. A five carbon sugar lacking a hydrogen at the number 2 carbon is found in
DNA
RNA
mRNA
rDNA

47. The unfavourable free energy associated with not satisfying a hydrogen bond after formation of the double helix is approximately
10 kJ/mol
20 kJ/mol
25 kJ/mol
30 kJ/mol

48. The most stabilizing force for nucleic acids is
hydrogen bonds
electrostatic bond
Van der Waals
conformational entropy

49. A purine with an amine (NH2) group on the 6th carbon is
adenine
cytosine
thymine
guanine

50. Which of the following is found on RNA but not DNA?
Uracil
Deoxyribose
Phosphate
Adenine

51. Which of the following is a purine?
Cytosine
Adenine
Thymine
Uracil

52. Which of the following techniques was carried out by Nirenberg and Matthaei in 1961 to determine the first codon?
In vitro synthesis of a polypeptide using UUUUU
Labeled peptide binding to a ribosome
Mixed co-polymer mRNA synthesis
none of the above

53. Bacterial protein called catabolic activator protein (CAP) is an example of
negative control of gene expression
positive control of gene expression
second type of positive control of gene expression
none of the above

54. How many different codons are possible?
3
20
64
An infinite number

55. The genetic code is
universal
universal except for rare exceptions in mitochondria and some protozoa
species-specific
kingdom-specific

56. Which of the following has been used as an evidence that primitive life forms lacked both DNA and enzymes?
RNA can both code genetic information and act as a catalyst
DNA and enzymes are only present in the most advanced cells
Advanced cells lack RNA
All of the above

57. Crick demonstrated that the genetic code involved three bases and suggested that the code was degenerated. What experimental technique Crick conducted to suggest genetic code degeneration?
Gel electrophoresis
Density gradient centrifugation
Frameshift mutagenesis
Restriction digests of the rII gene

58. Codon that specify the amino acids often differs in the
first base
second base
third base
none of these

59. In some organelles in eukaryotes, the genetic code for some codons
differs from that used in prokaryotes
are same
are partially same
none of the above

60. The codons which do not specify an amino acid are called
initiation code
termination code
propagation code
none of these

61. The genetic code is degenerated. Which of the following codons represents the principle of degeneracy?
UAA and UAC
AUG and AUA
CAU and CAC
UUA and UUC

62. The sequence of one strand of DNA is: 5' ATTGCCA 3', what is the sequence of the other strand?
5' TAACGGT 3'
5' TGGCAAT 3'
5' ATTGCCA 3'
. 5' UAAGCCU3'

63. In prokaryotes, AUG encodes
methionine
N-formyl methionine
a stop codon
alanine

64. How many amino acids will be encoded by 5' GAU GGU UGA UGU 3' sequence?
One
Two
Three
Four

65. In protein synthesis in prokaryotes
the initiating amino acid is N- formyl methionine
the initiating amino acid is methionine
the initiating amino acid is phenyl alanine
none of the above

66. AUG codes for methionine act as a
initiation code
elongation code
termination code
propagation code

67. Translation begins
at the replication fork
on the lagging strand
at the start codon
in nucleus

68. The complex of RNA polymerase, DNA template and new RNA transcript is called
transcription bubble
replication bubble
a translation bubble
none of these

69. RNA polymerase in prokaryotes has a removable
alpha subunit
beta subunit
both (a) and (b)
sigma subunit

70. Promoters for tRNAs are located
upstream from the start codon
downstream from the start codon
both (a) and (b)
none of these