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 process by which proteins are synthesized?

  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 proteins are synthesized. It involves the conversion of genetic information from messenger RNA (mRNA) into a sequence of amino acids, which are then linked together to form a protein.

Multiple choice

What is the role of ribosomes in protein synthesis?

  1. They assemble amino acids into a polypeptide chain

  2. They proofread the mRNA sequence for errors

  3. They transport mRNA from the nucleus to the cytoplasm

  4. They regulate the expression of genes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ribosomes are cellular structures that assemble amino acids into a polypeptide chain during protein synthesis. They read the mRNA sequence and use it to determine the order of amino acids in the protein.

Multiple choice

What is the role of tRNA in protein synthesis?

  1. It carries amino acids to the ribosome

  2. It proofreads the mRNA sequence for errors

  3. It transports mRNA from the nucleus to the cytoplasm

  4. It regulates the expression of genes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

tRNA (transfer RNA) molecules carry amino acids to the ribosome during protein synthesis. Each tRNA molecule is specific for a particular amino acid and recognizes the corresponding codon on the mRNA.

Multiple choice

What is the role of chaperones in protein synthesis?

  1. They help fold proteins into their correct conformation

  2. They proofread the mRNA sequence for errors

  3. They transport mRNA from the nucleus to the cytoplasm

  4. They regulate the expression of genes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Chaperones are proteins that help other proteins fold into their correct conformation. They assist in the folding process and prevent misfolding, which can lead to protein aggregation and dysfunction.

Multiple choice

What is the process by which proteins are degraded?

  1. Proteolysis

  2. Transcription

  3. Translation

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

Proteolysis is the process by which proteins are degraded. It involves the breakdown of proteins into smaller peptides or amino acids by enzymes called proteases.

Multiple choice

What is the role of ubiquitin in protein degradation?

  1. It marks proteins for degradation

  2. It proofreads the mRNA sequence for errors

  3. It transports mRNA from the nucleus to the cytoplasm

  4. It regulates the expression of genes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ubiquitin is a small protein that marks other proteins for degradation. When ubiquitin is attached to a protein, it signals to the proteasome, a cellular structure that degrades proteins, to break down the protein.

Multiple choice

What is the name of the RNA molecule that guides the CRISPR-Cas9 complex to the target DNA sequence?

  1. Guide RNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Guide RNA is the RNA molecule that guides the CRISPR-Cas9 complex to the target DNA sequence.

Multiple choice

What are telomeres?

  1. The protective caps at the ends of chromosomes

  2. The segments of DNA that code for proteins

  3. The regions of DNA that control gene expression

  4. The structures that hold chromosomes together
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Telomeres are the protective caps at the ends of chromosomes. They shorten with each cell division, and when they become too short, the cell can no longer divide and dies.

Multiple choice

What is the primary function of transcription in the context of protein synthesis?

  1. To convert DNA into RNA

  2. To assemble amino acids into proteins

  3. To regulate gene expression

  4. To repair damaged DNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Transcription is the process by which the genetic information encoded in DNA is copied into a complementary RNA molecule. This RNA molecule, known as messenger RNA (mRNA), carries the genetic code from the nucleus to the ribosomes, where it is used to direct protein synthesis.

Multiple choice

Which enzyme is responsible for catalyzing the synthesis of RNA during transcription?

  1. DNA polymerase

  2. RNA polymerase

  3. Ligase

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

RNA polymerase is the enzyme responsible for catalyzing the synthesis of RNA during transcription. It unwinds the DNA double helix, reads the DNA sequence, and adds complementary RNA nucleotides to the growing RNA chain.

Multiple choice

What is the template strand during transcription?

  1. The coding strand

  2. The non-coding strand

  3. Both strands

  4. Neither strand
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

During transcription, the non-coding strand of DNA serves as the template strand. RNA polymerase reads the sequence of the non-coding strand in a 5' to 3' direction and synthesizes a complementary RNA molecule in a 5' to 3' direction.

Multiple choice

What is the role of the promoter region 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
A Correct answer
Explanation

The promoter region is a specific DNA sequence located upstream of the transcription start site. It serves as the binding site for RNA polymerase and other transcription factors, which help to initiate transcription.

Multiple choice

What is the process by which RNA polymerase unwinds the DNA double helix during transcription?

  1. Helicase

  2. Ligase

  3. Primase

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

Helicase is an enzyme that unwinds the DNA double helix during transcription. It breaks the hydrogen bonds between complementary DNA nucleotides, allowing RNA polymerase to access the DNA template strand.

Multiple choice

Which of the following is a key difference between transcription and replication?

  1. Transcription uses RNA polymerase, while replication uses DNA polymerase.

  2. Transcription occurs in the nucleus, while replication occurs in the cytoplasm.

  3. Transcription produces a single-stranded RNA molecule, while replication produces two double-stranded DNA molecules.

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

All of the options are key differences between transcription and replication. Transcription uses RNA polymerase, while replication uses DNA polymerase. Transcription occurs in the nucleus, while replication occurs in the cytoplasm. Transcription produces a single-stranded RNA molecule, while replication produces two double-stranded DNA molecules.

Multiple choice

What is the role of introns and exons in transcription?

  1. Introns are transcribed into RNA, while exons are not.

  2. Exons are transcribed into RNA, while introns are not.

  3. Both introns and exons are transcribed into RNA.

  4. Neither introns nor exons are transcribed into RNA.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Exons are the coding regions of a gene that are transcribed into RNA. Introns are the non-coding regions of a gene that are transcribed into RNA but are later removed during RNA processing.