Explore topic-wise MCQs in Biology.

This section includes 302 Mcqs, each offering curated multiple-choice questions to sharpen your Biology knowledge and support exam preparation. Choose a topic below to get started.

1.

Assertion (A) : DNA finger printing has became a powerful tool to establish paternity and identity of criminal in rape and assault cases.
Reason (R) : Trace evidences such as hair, saliva and dried semen are adequate for DNA analysis.
Codes

A. Bot A and B are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer» B. Both A and R are true but R is not the correct explanation of A.
2.

Assertion (A) : Insect resistance transgenic cotton has been produced by inserting Bt gene.
Reason (R) : The Bt gene is derived from a bacterium.
Code

A. Both A and R are true and R is the Correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer» C. A is true but R is false.
3.

Assertion (A) : In human being the female play a major role in determining the sex of the offspring.
Reason (R) : Women have two X - chromosomes.
Codes

A. Both A and Rare true and R is the correct explanation of A.
B. Both A and R are true but R is not a correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer» E.
4.

Assertion (A) : Dolly was the first cloned mammal.
Reason (R) : Dolly was produced by invitro fertilization.

A. Both A and R are true and R is correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer» E.
5.

Mendel's law apply only when

A. Characters are linked
B. Parents are pure breeing
C. F
D. monohybrid ratio shows two type of individuals
E. First pair of contrasting characters is dependent upon other pairs
Answer» C. F
6.

Which of the following professional are more likely to run the risk of a permanent change in their cell's DNA ?
1. Rescarchers using carbon 14 isotope
2. X - ray technicia
3. Cola miner
4. Dyer and painter
Code

A. 2 alone
B. 1, 2 and 3
C. 1, 2 and 4
D. 1, 3 and 4
Answer» D. 1, 3 and 4
7.

Which one of the following statements is correct ?
Cretinism is human disorder which is due to the under secretion of

A. Adrenalin harmone
B. Cortisone harmone
C. Glucagon harmone
D. Thyroxin harmone
Answer» E.
8.

In the context of genetic disorders, consider the following
A women suffer from colour blindness while her husband does not suffer from it. They have a son and a daughter. In this context, which one of the following statements is most probably correct ?

A. Both children suffer from colour blindness
B. Daughter suffer from colour blindness while son does not suffer from it
C. Both children do not suffer from colour blindness
D. Son suffers from colour blindness while daughter does not suffer from it.
Answer» E.
9.

Mendel's law of independent assortment is based on F2 ratio of

A. 1 : 2 : 1
B. 9 : 3 : 3 : 1
C. 2 : 1
D. 3 : 1
Answer» C. 2 : 1
10.

Match List_I with List_II and select the correct answer using the codes given below:
List-IList-II
F. Theory of mutation1.Beadle and Tatum
G. Theory of evolution2.Jacob and Monod
H. One gene one enzyme hypothesis3.Darwin
J. Operon concept4.De Vries
Codes
FGHJ
A.3412
B.4312
C.4312
D.3421

A. A.
B. B.
C. C.
D. D.
Answer» C. C.
11.

Stem and loop structures are

A. proteins that help partially denatured enzymes to recover their native configuration
B. structures in DNA caused by inverted repeats
C. structures at the ends of linear eukaryotic DNA molecules
D. the bonds between adjacent DNA nucleotides in the same strand
Answer» C. structures at the ends of linear eukaryotic DNA molecules
12.

An mRNA transcript of a gene contains

A. a start codon
B. a stop codon
C. a terminator
D. all of these
Answer» E.
13.

Enzymes?reverse 'transcriptase' is coded by

A. Gag gene
B. Pol gene
C. Tat gene
D. Vif gene
Answer» C. Tat gene
14.

Differentiation of four different bases in automated sequencing systems is that each base has

A. different radioactive tag
B. cytosine at start
C. unique antibody bound to it
D. distinctive fluorescent tag
Answer» E.
15.

A specific __________ factor helps RNA polymerase bind to late promoters and transcribe late genes.

A. sigma
B. beta
C. delta
D. gamma
Answer» B. beta
16.

Which of the following type of recombination does not require homologous sequences and is important for the integration of viral genomes into bacterial chromosomes?

A. Mutagenic recombimation
B. Site-specific recombination
C. Replicative recombination
D. General recombination
Answer» C. Replicative recombination
17.

Between two chromosomes exchange of 'gene' is called as

A. Interaction
B. Mutation
C. Recombination
D. Point mutation
Answer» D. Point mutation
18.

Which of the following transport bacterial DNA to other bacteria via bacteriophages?

A. Conjugation
B. Transduction
C. Transformation
D. Translation
Answer» C. Transformation
19.

The DNA sequences of rRNA genes can be used to

A. assess relatedness of eukaryotes but not prokaryotes
B. obtain a tentative identification of a new microorganism
C. predict the pulsed field gel pattern of a microorganism
D. predict whether a bacteria will be gram-positive or gram-negative
Answer» C. predict the pulsed field gel pattern of a microorganism
20.

R factors involved in plant-microbe interactions are

A. plant proteins
B. bacterial proteins
C. essential for transfer of DNA to plant cells
D. also called opines
Answer» B. bacterial proteins
21.

The mutation which will not affect the length of a protein is,

A. nonsense mutation
B. missense mutation
C. frameshift mutation
D. all of these
Answer» C. frameshift mutation
22.

Which of the following statement(s) is/are true in regards to F+ x F- mating events?

A. DNA is transferred from F- to F+ cells
B. DNA is transferred from F+ to F- cells
C. No DNA is transferred because F- cells are unable to perform conjugation
D. No DNA is transferred because F+ cells are unable to perform conjugation
Answer» C. No DNA is transferred because F- cells are unable to perform conjugation
23.

Which of the following modified amino acid is used at the starting of most prokaryotic proteins?

A. N-formylserine
B. N-formylmethionine
C. N-formylleucine
D. N-formylalanine
Answer» C. N-formylleucine
24.

A mutagen is defined as

A. an enzyme that repairs mutations
B. a chemical or physical agent that induces mutations
C. an inhibitor of gene modification
D. a molecule which stabilizes DNA thus prevents mutations from occurring
Answer» C. an inhibitor of gene modification
25.

Substitutions that prematurely stops synthesis of protein, by generating stop codon, called as

A. Missense mutation
B. Nonsense mutation
C. Frameshift mutation
D. Alternation
Answer» B. Nonsense mutation
26.

The cloning step in PCR/sequencing analysis of microbial communities is necessary for

A. the amplification process
B. preventing contamination by outside DNA
C. separating the different rRNA gene sequences in the mixture
D. none of these
Answer» D. none of these
27.

Frame shift mutation may occur as a result of

A. formation of a thymine-dimer
B. deamination of cytosine to uracil
C. conversion of guanine to xanthine
D. none of the above
Answer» E.
28.

Process of mating through which two bacterial cells transfer their DNA, a cell acts as a host while other as recipient, process is known as

A. Transduction
B. Transformation
C. Conjugations
D. Mating
Answer» D. Mating
29.

Which of the following plamids do not possess information for self transfer to another cell?

A. Cryptic plasmids
B. Conjugative plasmids
C. Non-conjugative plasmids
D. None of these
Answer» D. None of these
30.

The chromosomal genes, possessing fertility factor is known as

A. R factor
B. F prime factor
C. HFr
D. F factor
Answer» C. HFr
31.

Which of the following is a product of transcription?

A. mRNA
B. tRNA
C. rRNA
D. all of these
Answer» E.
32.

The efficiency of amplification in PCR in later cycles is reduced due to

A. reduction in substrate concentration
B. insufficient enzyme and time to synthesize mass quantity of DNA
C. build up of PCR product which competes with primers for hybrid formation
D. all of these
Answer» E.
33.

A nonsense mutation introduced into the DNA sequence of a gene may

A. cause premature termination of the mRNA
B. shorten the length of the protein encoded by the gene
C. have no effect on the transcript or protein made
D. cause a shift in reading frame
Answer» C. have no effect on the transcript or protein made
34.

The term used for acquisition of naked DNA from its environment and its incorporation in their genome by a bacterium is

A. transformation
B. lysogenic conversion
C. conjugation
D. transduction
Answer» B. lysogenic conversion
35.

Recognition/binding site of RNA polymerase is called

A. receptor
B. promoter
C. facilitator
D. terminator
Answer» C. facilitator
36.

Which of the following defines an open reading frame (ORF)?

A. A sequence of genome in bacteriophage
B. The sequence of a complete genome
C. A plasmid vector used in genome sequencing
D. A possible gene predicted by DNA sequencing
Answer» E.
37.

Inability to replicate, in certain viruses, providing an ultimae advantage in the

A. Gene therapy
B. Drug therapy
C. Physiotherapy
D. Chemotherapy
Answer» B. Drug therapy
38.

In viral 'gene' expression first step is synthesis of

A. Messenger RNA
B. Transfer RNA
C. Ribosomal RNA
D. Proteins
Answer» B. Transfer RNA
39.

'Gag' and 'pol' are viral

A. Function unit
B. Nucleocapsid
C. Structural proteins
D. Subunits
Answer» D. Subunits
40.

Inverted repeat sequences at each end and a gene encoding transposase is contained in which of the following transposable element?

A. Composite transposon
B. Insertion element
C. Virus
D. Plasmid
Answer» C. Virus
41.

The plasmids can be eliminated from a cell by the process known as

A. curing
B. breaking
C. fixing
D. expulsion
Answer» B. breaking
42.

Transfer of 'DNA' mediated by bacteriophage is called as

A. Transduction
B. Transformation
C. Conjugations
D. Mating
Answer» B. Transformation
43.

Which of the following statement defines a replicon?

A. A DNA molecule that encodes pili for conjugation
B. A DNA molecule that is able to replicate and be maintained
C. A DNA template which is used in transcription
D. The enzyme responsible for transposition
Answer» C. A DNA template which is used in transcription
44.

What is the term used for a segment of DNA with one or more genes in the centre and the two ends carrying inverted repeat sequences of nucleotides?

A. Plasmid
B. Transposon
C. Insertion sequence
D. None of these
Answer» C. Insertion sequence
45.

Genetic material of bacteria is composed of, a single-stranded

A. Linear DNA
B. Ladder like DNA
C. Coiled DNA
D. Circular DNA
Answer» E.
46.

In therapeutic process, nucleic acid is delivered in patient's cell as a drug to recover a disease, process is known as

A. Drug therapy
B. Physiotherapy
C. Gene therapy
D. Chemotherapy
Answer» D. Chemotherapy
47.

The template for PCR is

A. RNA
B. single stranded DNA
C. double stranded DNA
D. none of these
Answer» D. none of these
48.

Which of the following statement describes plasmids?

A. Another name for a protoplast
B. A complex membrane structure that covers the chromosome of bacteria
C. Small, circular DNA molecules that can exist independently of chromosomes commonly found in bacteria
D. None of the above
Answer» D. None of the above
49.

The expression of gene X (which has promoter Px) is to be monitored. A gene fusion construction for carrying this work will

A. have Px but not the rest of the X coding region
B. have the promoter of lacZ or some other reporter gene
C. allow to monitor the expression of all genes with a promoter similar in sequence to Px
D. give the same information as from a microarray
Answer» B. have the promoter of lacZ or some other reporter gene
50.

Which of the following type of recombination does not require homologous sequences and is utilized by mobile genetic elements that move about chromosomes?

A. Mutagenic recombimation
B. Site-specific recombination
C. Replicative recombination
D. General recombination
Answer» D. General recombination