Biology

Molecular Genetics

851 Questions

Molecular genetics explores the mechanisms of genetic information transfer, including DNA replication, transcription, and translation. It is a core component of biology syllabi. These concepts frequently appear in general science sections of major competitive exams.

DNA replicationTranscription processTranslation processRNA typesCentral dogma

Molecular Genetics Questions

Multiple choice

What is Readseq?

  1. Tool which helps to read and translate nucleotide sequence

  2. Tool which converts sequence in one format to another

  3. Database which helps to download nucleotide sequence

  4. Tool which reads the nucleotide sequences
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

These are various formats of sequence file. Each tool is designed to accept the input sequence in the specific formats. Readseq tool is used to convert sequence from one format to another.

Multiple choice

NADP is_____.

  1. a coenzyme

  2. an enzyme

  3. a part of tRNA

  4. a part of sRNA

  5. a vitamin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A coenzyme is a substance that works with an enzyme to initiate or aid the function of the enzyme.

Multiple choice

Which of the following is regarded as the link between the living and the non-living?

  1. RNA

  2. Virus

  3. Amoeba

  4. Bacteria
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A virus is non living and relies solely on the 'host' for survival. Viruses are so primitive that many scientists consider them to be both living and nonliving things. By itself, a virus is a lifeless particle that cannot reproduce. But inside a living cell, a virus becomes an active organism that can multiply hundreds of times.

Multiple choice

The influenza virus contains ________.

  1. DNA

  2. RNA

  3. both DNA and RNA

  4. either DNA or RNA

  5. proteins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Influenza, commonly known as the flu, is an infectious disease of birds and mammals caused by RNA viruses of the family Orthomyxoviridae.

Multiple choice

TMV genes are _________.

  1. double stranded RNA

  2. single stranded DNA

  3. double stranded DNA

  4. proteinaceous

  5. polyribonucleotides
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Tobacco mosaic virus is made up of polyribonucleotides, i.e. single stranded RNA molecule.

Multiple choice

The enzyme called lysozyme is synthesised by __________.

  1. host cell of a virus under the control of its genome

  2. host cell of a virus under the control of viral genome

  3. virus under the control of its own genome

  4. virus under the control of the host genome

  5. both virus and host
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lysozyme is synthesised by host cell under the control of viral genome. These are glycoside hydrolases.

Multiple choice

The ras oncogene contributes to the development of cancers by

  1. coding for a transcription factor being synthesised in enormous amount in the body

  2. coding for an anti-apoptotic protein in the cell

  3. coding for an enzyme known as GTPase switch protein, which cannot be turn off in its mutated form

  4. coding for a abbreviated form of a growth factor receptor, which is continually active
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The ras gene codes for a GTPase switch protein, which forms part of a growth factor signalling pathway. Stimulation of this protein through an occupied growth factor receptor causes it to activate by exchanging a molecule of GDP for GTP. The activated ras protein then activates downstream proteins, which ultimately activates transcription factors. Normally, the ras signal is self limiting because the protein has intrinsic GTPase activity. So, it hydrolyses its bound GTP to GDP, switching the signal off.

Multiple choice

Which of the following characterises an oncogene?

  1. It is a predominantly expressed mutation providing growth or survival advantage to the cell.

  2. It codes for a mutated form of a protein which creates fractions of a signal transduction pathway.

  3. It codes for a protein which restricts the cell from apoptosis.

  4. It codes for a specific protein, which controls cell cycle in a cell.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An oncogene is a mutated form of a normal cellular gene (the proto-oncogene) which codes for a protein which is either controlled abnormally so that it is expressed in abnormally large amounts or has gained activity so that it is more active than the normal protein.

Multiple choice

Ribosome is the site where mRNA binds and protein is synthesised by the process of translation.

In which of the following comments about 3’ poly(A) tail of mRNA, is the above statement FALSE?

  1. It is not indispensable for protein synthesis.

  2. In the nucleus, it is added to the primary transcript.

  3. It takes part during translation, by aligning eukaryotic mRNA on the ribosome.

  4. It helps to increase the stability and lifespan of mRNA.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It takes part during translation, by aligning eukaryotic mRNA on the ribosome. The mRNA is aligned to the ribosome by 7-methylguanosine cap. The 3’ poly(A) tail of mRNA is responsible for its stability and long lifespan.

Multiple choice

Ribosome is the site where mRNA binds and protein is synthesised by the process of translation.

According to “Wobble Hypothesis”, which of the following abnormal base pairings might be found?

  1. A - U

  2. G - U

  3. C - I

  4. G - T
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

G - U. According to “Wobble Hypothesis”, the codons of mRNA are degenerate, i.e. there are more codons on the mRNA than the number of amino acids. The codon–anticodon base pairing is relaxed at the third base, which allows G to pair with U, which does not generally happen.