MCQ’s of microbiology (Genetics – Part 3)

April 8, 2023

Here, we have prepared some of the mcq’s of microbiology that may be helpful to the students related to microbiology and microbiology related subjects (Genetics).

1) When a mutation occurs in bacteria, the effects are seen on the:

Rate of ATP utilization
Protein synthesized
Rate of nutrient ingestion
ATP taken into the cell

2) A mutation occurring in the cell is most often due to:

Disrupting the genetic code
Eliminating the supply of ATP
Depleting the supply of glucose metabolism
Breaking down enzyme molecules

3) A deletion mutation comes about:

When a segment of DNA reverses its order
When an entire section of chromosome is lost
When a new sequence of nucleotides is added to the chromosome
When a plasmid joins the chromosomal DNA

4) When a purine base is substituted by a pyrimidine or vice versa, the mutation is called:

Transversion
Transition
Inversion
Translocation

5) Genetic material in bacteria is transmitted by all except:

Transformation
Conjugation
Mutation
Transduction

6) A zygote that is partial diploid is called as:

Hemozyzote
Simply zygote
Merozygote
Diploid zygote

7) Transfer of Cell-free or naked DNA from one cell to another is termed as:

Transformation
Conjugation
Transduction
All of the above

8) The process of transformation in bacteria does not require:

A disrupted donor cell
A competent recipient cell
A virus
A series of enzymes

9) Transformation requires the recipient cell to be:

Capable
Actively replicating
In lag phase
Competent

10) The DNA molecule that transforms a bacterium:

Is single stranded
Contains uracil
Has no functional genes
Contains three strands of DNA

11) Griffith (1928) reported the phenomena of transformation first in:

Haemophilus influenza
Pneumococci
E. coli
Bacillus spp.

12) Lederberg & Tatum describes the phenomena of:

Transformation
Fluctuation test
Conjugation
Transduction

13) The process mediated by a plasmid that encodes a mechanism for genetic exchange is:

Conjugation
Transduction
Transformation
None

14) Which of the following is necessary for the process of conjugation in bacteria?

A large concentration of glucose molecules
One live recipient cell and one dead recipient cell
Two live bacteria
Viruses that multiply within bacteria

15) Conjugation does not involve:

Fr
Hfr
Bacteriophage
Plasmids

16) The role of plasmids in conjugation was first described by Lederberg and Tatum in:

Corynebacterium
Pseudomonas
Escherichia coli
Haemophilus influenzae

17) Bacterial conjugation has been observed in numerous:

Spirochetes
Gram positive bacteria
Cyanobacteria
Gram negative bacteria

18) F plasmid of high frequency recombination is a:

Extra-chromosomal
Chromosomal
Mesosomes
Ribosomes

19) When a F factor enters a recipient cell during conjugation, the recipient cell:

Multiplies rapidly
Undergoes lysis
Becomes a donor cell
Develops mitochondria

20) F factor integrates with bacterial chromosomes to form:

RTF
RTF’r
Hfr
F

21) An Hfr bacterium is one that contains:

Many unusual plasmids
Chromosomal material acquired from a recipient cell
A plasmid integrated into its chromosome
The ability to undergo transduction

22) Transfer RNA carries……….. to the………..for the protein synthesis.

mRNA, Ribosomes
Amino acids, mRNA
mRNA, DNA
Amino acids, ribosomes

23) A packet of nucleic acid enclosed in protein best describes a:

Algae
RNA molecule
Bacterium
Virus

24) Which of the following does not possess both DNA and RNA?

Spirochetes
Bacteria
Fungi
Virus

25) The protein rich in basic functions in the packaging of DNA in chromosomes is:

Histones
Hyaluronic acid binding protein
Fibrinogen
Collagen

26) Nucleoproteins are:

Conjugated proteins
Simple proteins
Transport proteins
Derived proteins

27) Proteins present in nucleoproteins are:

Histones
Globulins
Histidine
Albumin

28) Histones are:

Basic protein rich in Lys and/or Arg
Identical to protamines
Bound covalently attached to DNA
Found in high concⁿ in ribosomes

29) Nucleic acid absorbs light at wavelength of 260 nm due to:

Pentose sugars
Proteins
Purines & Pyrimidines
Phosphates

30) Which one of the following statements is not true for a plasmid?

It cannot replicate independently
It is a double stranded DNA
It is a circular DNA
It may transfer in conjugation

31) Plasmid:

Imparts pili formation
Involved in MDR transfer
Imparts capsule formation
All

32) False regarding bacterial plasmid is:

Transmission of different species
Extra chromosomal
Eliminated by treating with radiation
Can cause lysogenic conversion

33) All of the following apply to plasmids except:

They are acquired in transformations
They are self-replicating loops of DNA
They have 10 to 50 genes
They are essential for the survival of a bacterium

34) Plasmids associated with resistance to antibiotics are:

Hfr plasmid
R plasmid
d plasmid
None of above

35) Plasmids associated with resistance to antibiotics are:

D- plasmid
Hfr plasmid
R- plasmid
F + plasmid

36) Drug resistant R- factors are transmitted from strains found:

In developed nation
In immunocompromised patients
On contaminated fomites
On colonized hospital staff

37) A recombination process occurring in bacteria always refers to:

Affect of a physical nature changing the nature of the genes
Acquisition of DNA by an organism
Reversal of microbial mutation
Loss of genes from a cell

38) How many major types of RNA are present in cells?

39) Which statement is not true for rRNA?

Constitutes about 15 % of the total cellular RNA
Constitutes about 80 % of the total cellular RNA
Most stable among the RNA, found in ribosomes
Also called insoluble RNA

40) Enzyme made up from rRNA is called:

Protease
Endonuclease
Ribozyme
Ribulose -5 isomerese

41) mRNA is complementary copy of:

tRNA
rRNA
A single strand of DNA
None of the above

42) Which one of the following statement about mRNA is incorrect?

Sugar moiety in mRNA is D-ribose
mRNA has a 3-poly-A sequence:
Polynucleotide chain of mRNA is longer than that of DNA
mRNA exist as single-stranded molecules

43) Which RNA has clover leaf structure?

hnRNA
tRNA
TRNA
mRNA

44) Anticodon region is an important part of the:

rRNA
mRNA
hnRNA
tRNA

45) Anticodon is present in:

mRNA
tRNA
rRNA
hnRNA

46) Transfer RNA molecules exist in the metabolizing cell in the:

Mitochondrion
Nucleus
Cytoplasm
Golgi body

47) Number of tRNA present in cells is.

48) The number of nucleotides on tRNA usually ranges from:

1,600-2,500
73-93
9,00-1,500
3,200-5,500

49) Which one of the following bases is not found in tRNA?

Uracil
Adenine
Thymine
Pseudouridine

50) Which of the following RNA contains thymidine?

Ribosomal RNA
Transfer RNA
Messenger RNA
Eukaryotic RNA

51) Which class of RNA characteristically contains unusual purines and pyrimidines?

rRNA
mRNA
tRNA
16 S RNA

52) Which type of RNA has the highest percentage of modified base?

mRNA
tRNA
rRNA
snRNA

53) According to Cloverleaf model of which one of the arm contains a stem but not a loop?

Acceptor arm
D arm
Anticodon arm
TwC arm

54) In tRNA, the amino acid molecule attaches to

5′ end
3′ terminal and of -CCA sequence
DHU loop
TWC loop

55) The 5′ end of tRNA consists:

Either G or C
Either A or T
Either A or U
Either A or C

56) In tRNA, the ribosome recognition site is present on:

Anticodon loop
Amino acid attachment site
TWC loop
Synthetase site

57) Chargaff’s rule states:

(A+G) = (T+C)
C+C=A+C
A/T =G/C
A+T=G+C

58) The nucleic acid was analyzed and found to contain 32% adenine, 18% guanine, 17% cytosine and 33% thymine. The nucleic acid must be:

Single-stranded DNA
Double stranded DNA
Double-stranded RNA
Single-stranded RNA

59) Which form of DNA is usually found under physiological conditions?

B-DNA
E-DNA
Z-DNA
A-DNA

60) Which form of DNA can form left handed helical structure?

B-DNA
A-DNA
C-DNA
Z-DNA

61) At the physiological pH, the DNA molecules are:

Negatively charged
Positively charged
Neutral
Amphipathic

62) Which is true for DNA?

It is acid stable
It is alkali stable
It is alkali labile
All of these

63) On complete hydrolysis of DNA we will get all of the following except:

Adenosine
Deoxy-pentose sugar
Phosphoric acid
Purine bases

64) A sequence of bases that reads the same in both directions on opposite strands of the DNA is called:

Replicon
Operon
Codon
Pallindrome

65) Pallindromic DNA has potential to form:

Cruciform structure
Hairpin structure
Both a and b
None

66) A short sequence of bases that are repeated hundreds of times in eukaryotic DNA is called

Repetitive DNA
Satellite DNA
Both a and b
Pallindromic DNA

67) The DNA base composition (i. e. moles % G+C value) values for various organism ranges from:

15-20
5-10
23 to 75
20-50

68) All of the following apply to the DNA of bacteria except:

The DNA is a single, closed loop
The DNA contains histone proteins
The DNA is concentrated in the nucleoid
The DNA contains the genetic code

69) Bacterial DNA is:

Single stranded
Double stranded
Both a & b
None

70) The mitochondrial DNA is:

Single stranded linear
Single stranded circular
Double stranded circular
Double helix

71) Biological task of DNA is.

Storage of genetic information
Transmission of genetic information to off-springs
Direction of cellular activity through transcription & translation
All of the above

72) RNA normally exists as:

Double stranded circular molecule
Double stranded molecule
Double stranded helical molecule
Single stranded molecule

73) RNA is:

Alkali stable
Alkali labile
Both a and b
None

74) Which is not true of RNA?

It is a genetic material of some viruses
There are more unusual bases in RNA than in DNA
Pairing of bases is only in the helical region
Pairing of bases is throughout the length of molecule

75) Which one of the following nitrogenous bases is not a constituent of deoxy-ribonucleotides?

Uracil
Guanine
Adenine
Thymine

76) Which base is not present in normal DNA or RNA?

Uracil
Guanine
Thymine
Theophylline

77) The hereditary substance in all microbial cells is:

DPN
DNA
ATP
AMP

78) Gene is:

mRNA
Anticodon
A segment of DNA molecule
A complete DNA molecule

79) The gene as a unit of recombination is called as:

Cistron
Recon
Muton
None of these

80) The gene as a unit of function is known as:

Recon
Cistron
Muton
None of these

81) The concept of one-gene, one-enzyme hypothesis was clearly demonstrated by:

Jacob & Monad
Beadle and Tatum
Laveran
John Marshall

82) DNA is composed of:

Phosphoric acid, ribose sugar & nitrogen bases
Phosphoric acid, deoxyribose sugar & nitrogen bases
Phosphoric acid, histone proteins & ribose sugar
Phosphoric acid, ribulose sugar & purine

83) Which compound has double helical structure?

Ribonucleic acid
Collagen
Deoxyribonucleic acid
Cholesterol

84) Double helical structure of DNA was proposed by:

Chargaff
Watson and Crick
Stahl and Messelson
Hargobind Khorana

85) In the double helix arrangement of DNA in the chromosome, base cytosine stands opposite the base:

Cytosine
Thymine
Guanine
Adenine

86) Which one of the following pairs does not usually occur in DNA?

U-A
G-C
T-A
C-G

87) The character of the nitrogenous base of DNA determines:

Sequence of folding of protein
Base pairing and Sequence
Reactively with acid
Structure of the double helix

88) Two strands of double helical DNA are linked by:

Peptide bonds
Glycosidic bonds
Hydrogen bonds
Phosphodiester bonds

89) DNA double helix is bound by:

Van der waal forces
Disulphide linkage
Hydrogen bond
Covalent bond

90) DNA molecule contains how many nucleotides?

100-300
500-1000
1000-9000
10000 – 15000

91) What is the distance of one turn of helical structure of DNA according to Watson-Crick model?

2.00 nm
3.40 nm
0.54 nm
0.70 nm

92) According to Watson – Crick Model, how many base pairs are present in each turn of helical structure of B- DNA?

12
10
11
None

93) The term ‘nucleic acid to replace ‘nuclein’ was introduced by:

Altmann
Benzer
Miescher
Zacharis

94) Nucleic acids are:

Communication molecules
Structural molecules
Information molecules
Second messengers

95) Which are the three chemical components of nucleic acids?

Phosphate group, nitrogenous base, ribose
Nitrogenous base, hexose, phosphate group
Phosphate group, carboxyl group, hydrophobic side chain
Carboxyl group, amino group, R group

96) The chemical units of nucleic acids are:

Amino acids
NAD and FAD
Nucleotides
Enzyme molecules

97) Nucleotide contains:

Sugar, phosphate
Base, sugar
Base, sugar, phosphate
Base, sugar, phosphate, protein

98) Components of nucleosides are:

Nitrogenous base & Pentose sugar
Nitrogenous base and protein
Pentose sugar& phosphate
Nitrogenous base, sugar & phosphate

99) Nucleotides in a single strand are linked to one another in nucleic acids by:

Disulphide bond
Hydrogen bond
Glycosidic bond
Phosphodiester bond

100) Which carbon of the pentose is in ester linkage with the phosphate in a nucleotide?

C₁
C₄
C₅
C₃

101) All the following biologically important nucleotides are not present in nucleic acids except.

AMP
GTP
ATP
NAD

102) Ribose & deoxyribose differ in structure around a single carbon, namely:

103) 2-Deoxy-D-ribose is a constituent of:

RNA
DNA
Inulin
Dextrin

104) Who first identified the purine and pyrimidine bases?

Kossel
Miescher
Fisher
Fuelgen

105) An example of purine base is:

Cytosine
Adenine
Uracil
Thymine

106) Thymine is a:

Vitamin
Basic amino-acid
Pyrimidine base
Purine base

107) All of the following refer to both cytosine and thymine except:

Both are nitrogenous bases
Both are pyrimidine molecules
Both may be found in DNA
Both may be found in RNA

108) The base present in DNA but absent in RNA is:

Thymine
Guanine
Uracil
Cytosine

109) Which of the following bases is a constituent of RNA but not DNA?

Thymine
Guanine
Cytosine
Uracil

REFERENCES:

i) https://www.mcqbiology.com/2013/01/mcq-on-microbiology.html

ii) https://pgblazer.com/mcq/microbiology-mcq/

iii) http://www.dspmuranchi.ac.in/pdf/Blog/MCQ%20is%20microbiology%20.pdf

iv) https://openstax.org/books/microbiology/pages/1-multiple-choice

v) https://www.prometricmcq.com/microbiology-mcqs/

MCQ’s of microbiology (Genetics – Part 3)

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Shailesh Koirala

I am Shailesh Koirala

MCQ’s of microbiology (Genetics – Part 3)

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Shailesh Koirala