Biology

Molecular Genetics

917 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

Which of the following statements regarding the process of translation in organisms is INCORRECT?

  1. The basic process of protein production is addition of one amino acid at a time to the end of a protein.

  2. Each amino acid added is matched to a three nucleotide subsequence of the mRNA.

  3. The ribosome molecules translate this code to a specific sequence of amino acids.

  4. The mRNA carries genetic information encoded as a ribonucleotide sequence from the chromosomes to the ribosomes.

  5. The basic process of protein production is addition of an amino acid occurs at the N-terminus of the peptide.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Addition of an amino acid occurs at the C-terminus of the peptide and thus translation is said to be amino-to-carboxyl directed.

Multiple choice

Which of the following types of genes is a transcription factor in the circadian pacemaker of mammal's heart particularly human beings?

  1. Bmal1 gene

  2. Clock gene

  3. Per gene

  4. Tim gene

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

Clock, also known as Circadian Locomotor Output Cycles Kaput, is a transcription factor in the circadian pacemaker of mammals. It affects both the persistence and period of circadian rhythms by its interactions with the gene Bmal1.

Multiple choice

What is the function of mRNA?

  1. Formation of ribosomes acting as site for protein synthesis

  2. Transfer of activated amino acids to the site of protein synthesis

  3. To carry the genetic information of DNA into protoplasm and translate them into the language of protein

  4. To act as a carrier of hereditary material

  5. To help in rRNA synthesis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It is a function of mRNA.

Multiple choice

Which of the following is not a step of translation?

  1. Attachment of RNA polymerase to initiation site

  2. Activation of amino acids

  3. Transfer of amino acid to tRNA

  4. Initiation of polypeptide chain

  5. Formylation of methionine
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It causes unwinding of DNA, leading to mRNA synthesis.

Multiple choice

Virus consists of

  1. nucleic acid and protein

  2. nucleic acid

  3. orotein

  4. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Viruses are simple infectious agents consisting of genetic material (either DNA or RNA nucleic acid) enclosed in a protein coat called a capsid. Some viruses also have an outer lipid envelope. This minimal structure allows them to replicate only inside host cells.

Multiple choice

Which one of the following has ssRNA?

  1. TMV

  2. T2-bacteriophage

  3. Polio Virus

  4. CMV
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tobacco mosaic virus (TMV) is a rigid rod-shaped ssRNA-containing virus that causes distortion and blistering of leaves in a wide range of plants.

Multiple choice

The largest subunit of prokaryotic ribosomes is

  1. 30S

  2. 40S

  3. 50S

  4. 60S
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Prokaryotic ribosomes have 70S structure composed of large (50S) and small (30S) subunits. The 50S is the larger subunit. Eukaryotic ribosomes have 80S structure with 60S and 40S subunits. The S (Svedberg) unit measures sedimentation rate, not molecular weight, so the numbers don't add up mathematically.