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 is a type of RNA polymerase found in eukaryotes?

  1. RNA polymerase I

  2. RNA polymerase II

  3. RNA polymerase III

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Eukaryotes have three types of RNA polymerase: RNA polymerase I, RNA polymerase II, and RNA polymerase III, each with specific roles in transcribing different types of RNA molecules.

Multiple choice

What is the function of the promoter region in a gene?

  1. Binding site for transcription factors

  2. Site of transcription initiation

  3. Region of DNA that is transcribed

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The promoter region is a region of DNA located upstream of the transcription start site that contains binding sites for transcription factors, serves as the site of transcription initiation, and is part of the DNA that is transcribed.

Multiple choice

Which of the following is a type of RNA molecule that is involved in regulating gene expression?

  1. MicroRNA (miRNA)

  2. Small interfering RNA (siRNA)

  3. Long non-coding RNA (lncRNA)

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

MicroRNA (miRNA), small interfering RNA (siRNA), and long non-coding RNA (lncRNA) are all types of RNA molecules that can regulate gene expression through various mechanisms.

Multiple choice

What is the process by which a gene is turned off or its expression is reduced?

  1. Transcriptional repression

  2. Translational repression

  3. Gene silencing

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Transcriptional repression, translational repression, and gene silencing are all mechanisms by which gene expression can be turned off or reduced.

Multiple choice

What is the role of introns in eukaryotic genes?

  1. Coding sequences for proteins

  2. Non-coding sequences that are removed during RNA processing

  3. Regulatory sequences that control gene expression

  4. All of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Introns are non-coding sequences within eukaryotic genes that are removed during RNA processing (splicing) and are not part of the final mature RNA molecule.

Multiple choice

Which of the following is a type of post-transcriptional modification that can affect gene expression?

  1. Splicing

  2. Polyadenylation

  3. Capping

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Splicing, polyadenylation, and capping are all types of post-transcriptional modifications that can affect gene expression by altering the stability, localization, and translation of RNA molecules.

Multiple choice

What is the role of transcription factors in gene expression?

  1. Binding to DNA and regulating transcription initiation

  2. Synthesizing RNA molecules

  3. Proofreading RNA molecules

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

Transcription factors are proteins that bind to specific DNA sequences and regulate transcription initiation by either promoting or repressing the binding of RNA polymerase to the promoter region.

Multiple choice

What is the process by which a protein is synthesized from an mRNA molecule?

  1. Transcription

  2. Translation

  3. Replication

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

Translation is the process by which a protein is synthesized from an mRNA molecule. During translation, the mRNA molecule is read by ribosomes, which use the genetic code to assemble amino acids into a polypeptide chain.

Multiple choice

Which of the following is a type of RNA molecule that carries amino acids to the ribosome during translation?

  1. Messenger RNA (mRNA)

  2. Transfer RNA (tRNA)

  3. Ribosomal RNA (rRNA)

  4. Small nuclear RNA (snRNA)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Transfer RNA (tRNA) is a type of RNA molecule that carries amino acids to the ribosome during translation. Each tRNA molecule is specific for a particular amino acid and recognizes the corresponding codon on the mRNA molecule.

Multiple choice

What is the role of the ribosome in protein synthesis?

  1. Synthesizing mRNA molecules

  2. Transcribing DNA molecules

  3. Assembling amino acids into a polypeptide chain

  4. Proofreading the amino acid sequence
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The ribosome is a complex structure that assembles amino acids into a polypeptide chain during protein synthesis. It reads the mRNA molecule and uses the genetic code to determine the order of amino acids in the protein.

Multiple choice

What is a 'gene'?

  1. A region of DNA that codes for a protein.

  2. A region of DNA that codes for a non-coding RNA.

  3. A region of DNA that is involved in regulating gene expression.

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A 'gene' is a region of DNA that codes for a protein, a non-coding RNA, or is involved in regulating gene expression.

Multiple choice

What is a 'genome'?

  1. The complete set of genetic information in an organism.

  2. The complete set of genes in an organism.

  3. The complete set of proteins in an organism.

  4. The complete set of non-coding RNAs in an organism.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A 'genome' is the complete set of genetic information in an organism. This includes the genes, the non-coding RNAs, and the regulatory elements that control gene expression.

Multiple choice

What is the enzyme responsible for transcribing DNA into RNA?

  1. DNA polymerase

  2. RNA polymerase

  3. Helicase

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

RNA polymerase is the enzyme responsible for synthesizing RNA from a DNA template.

Multiple choice

Which of the following is not a type of RNA polymerase found in eukaryotes?

  1. RNA polymerase I

  2. RNA polymerase II

  3. RNA polymerase III

  4. RNA polymerase IV
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

RNA polymerase IV is not found in eukaryotes. It is found in some bacteria and archaea.

Multiple choice

What is the template strand in transcription?

  1. The coding strand

  2. The non-coding strand

  3. Either strand can be the template strand

  4. It depends on the organism
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In most cases, the non-coding strand of DNA serves as the template strand for transcription.