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

What is the function of the transcription termination signal?

  1. To signal the start of transcription

  2. To signal the end of transcription

  3. To regulate gene expression

  4. To proofread the RNA transcript
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The transcription termination signal is a specific DNA sequence that signals the end of transcription. When RNA polymerase encounters this signal, it releases the RNA transcript and dissociates from the DNA template.

Multiple choice

Which of the following is NOT a type of RNA polymerase found in eukaryotic cells?

  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 eukaryotic cells. It is a type of RNA polymerase found in some archaea and bacteria.

Multiple choice

What is the role of transcription factors in transcription?

  1. To initiate transcription

  2. To terminate transcription

  3. To regulate gene expression

  4. To proofread the RNA transcript
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Transcription factors are proteins that bind to specific DNA sequences and regulate gene expression. They can either activate or repress transcription, depending on the specific transcription factor and the context of the DNA sequence.

Multiple choice

What is the process by which RNA polymerase proofreads the RNA transcript during transcription?

  1. Excision repair

  2. Mismatch repair

  3. Base excision repair

  4. Nucleotide excision repair
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

RNA polymerase proofreads the RNA transcript during transcription through a process called mismatch repair. This process involves the removal of incorrectly incorporated nucleotides and their replacement with the correct nucleotides.

Multiple choice

What is the significance of transcription in protein synthesis?

  1. It provides the genetic code for protein synthesis.

  2. It regulates gene expression.

  3. It helps in DNA replication.

  4. It repairs damaged DNA.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Transcription is significant in protein synthesis because it provides the genetic code for protein synthesis. The RNA transcript produced during transcription carries the genetic information from DNA to the ribosomes, where it is used to direct the synthesis of proteins.

Multiple choice

Which of the following is NOT a type of RNA molecule involved in transcription?

  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 not involved in transcription. It is involved in translation, the process by which the genetic code in mRNA is used to direct the synthesis of proteins.

Multiple choice

What is the role of RNA processing in transcription?

  1. To remove introns from the RNA transcript

  2. To add a polyadenylation tail to the RNA transcript

  3. To add a 5' cap to the RNA transcript

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

RNA processing involves a series of modifications to the RNA transcript after transcription. These modifications include the removal of introns, the addition of a polyadenylation tail, and the addition of a 5' cap. These modifications help to protect the RNA transcript and make it more stable and efficient for translation.

Multiple choice

Which of the following is NOT a key step in the process of transcription?

  1. Initiation

  2. Elongation

  3. Termination

  4. Proofreading
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Proofreading is not a key step in the process of transcription. It is a process that occurs during replication to ensure the accuracy of the newly synthesized DNA strand.

Multiple choice

The process by which genetic information from DNA is copied into a complementary RNA molecule is called:

  1. Transcription

  2. Translation

  3. Replication

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

Transcription is the process by which an enzyme called RNA polymerase reads the DNA sequence and synthesizes a complementary RNA molecule.

Multiple choice

Which type of RNA molecule carries the genetic code from the nucleus to the ribosomes for protein synthesis?

  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
A Correct answer
Explanation

Messenger RNA (mRNA) carries the genetic code from the nucleus to the ribosomes, where it serves as a template for protein synthesis.

Multiple choice

The process by which the genetic information in mRNA is converted into a sequence of amino acids is called:

  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 the genetic information in mRNA is converted into a sequence of amino acids, which are the building blocks of proteins.

Multiple choice

The genetic code is composed of:

  1. Codons

  2. Anticodons

  3. Exons

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

The genetic code is composed of codons, which are sequences of three nucleotides that specify a particular amino acid or a stop signal during protein synthesis.

Multiple choice

Which molecule brings the correct amino acid 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) molecules bring the correct amino acids to the ribosome during translation. Each tRNA molecule has an anticodon that recognizes a specific codon on the mRNA.

Multiple choice

The process by which a gene's DNA sequence is copied into a complementary DNA molecule is called:

  1. Transcription

  2. Translation

  3. Replication

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

Replication is the process by which a gene's DNA sequence is copied into a complementary DNA molecule. This process occurs during cell division to ensure that each daughter cell receives a complete copy of the genetic material.

Multiple choice

The process by which a cell regulates gene expression by controlling the transcription of DNA into RNA is called:

  1. Transcriptional regulation

  2. Translational regulation

  3. Post-translational regulation

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

Transcriptional regulation is the process by which a cell regulates gene expression by controlling the transcription of DNA into RNA. This can be achieved through various mechanisms, such as the binding of transcription factors to DNA or the modification of histones.