Gene Expression

Question 1

What is the central dogma of molecular biology? (gene expression)

Answer 1

The central dogma describes the flow of genetic information from DNA to RNA to proteins.

Question 2

What are the two main processes involved in gene expression?

Answer 2

Transcription and Translation

Question 3

What is a codon?

Answer 3

A sequence of three nucleotides in mRNA that corresponds to a specific amino acid or a stop signal during protein synthesis. Codons are part of the genetic code and are essential for translating the genetic information from DNA into proteins.

Question 4

Where does transcription occur in eukaryotic cells?

Answer 4

In the nucleus

Question 5

What is the role of RNA polymerase in transcription?

Answer 5

RNA polymerase binds to the promotoer region of a gene and synthesizes a complementary RNA strand from the DNA template.

Question 6

What are the three stages of transcription?

Answer 6

Initiation, Elongation, and termination.

Question 7

What is a promoter?

Answer 7

A promoter is a non-coding DNA sequence where transcription factors bind to initiate transcription.

Question 8

What is the function of transcription factors?

Answer 8

Transcription factors help position RNA polymerase at the promoter and regulate the transcription of genes.

Question 9

What is the difference between mRNA and tRNA?

Answer 9

mRNA carries the genetic information from DNA to the ribosome, while tRNA (transfer RNA) brings amino acids to the ribosome during protein synthesis.

Question 10

What is the significance of codons in mRNA?

Answer 10

Codons are triplets of nucleotide bases in mRNA that specify which amino acid will be added during translation.

Question 11

What happens during the elongation stage of transcription?

Answer 11

RNA polymerase moves along the DNA template, unwinding the DNA and adding RNA nucleotides to the growing RNA strand.

Question 12

What is the termination sequence in transcription?

Answer 12

A specific sequence of nucleotides that signals RNA polymerase to stop transcription and release the newly synthesized RNA.

Question 13

How does the genetic code ensure redundancy?

Answer 13

The genetic code is redundant because multiple codons can code for the same amino acid, which helps mitigate the effects of mutations.

Question 14

What is the role of ribosomes in translation?

Answer 14

Ribosomes facilitate the coupling of tRNA anticodons with mRNA codons, enabling the addition of amino acids to the growing polypeptide chain.

Question 15

What are the three stages of translation?

Answer 15

Initiation, Elongation, and Termination.

Question 16

What is the function of the release factor in translation?

Answer 16

The release factor binds to the stop codon in the A site of the ribosome, causing the disassembly of the ribosome and the release of the newly synthesized polypeptide.

Question 17

What is transcription?

Answer 17

Transcription is the process by which genetic information in DNA is copied into a complementary RNA molecule, specifically messenger RNA (mRNA).

Question 18

What role does RNA polymerase play in transcription?

Answer 18

RNA polymerase is the enzyme that binds to the promoter region of a gene, unwinds the DNA, and synthesizes the mRNA transcript in a 5’ to 3’ direction.

Question 19

What is translation?

Answer 19

Translation is the process by which the sequence of codons in mRNA is read by ribosomes to synthesize a polypeptide chain, ultimately folding into a functional protein.

Question 20

What is the function of ribosomes in protein synthesis?

Answer 20

Ribosomes facilitate the coupling of tRNA anticodons with mRNA codons, enabling the addition of amino acids to the growing polypeptide chain.

Question 21

What is the role of transfer RNA (tRNA) in translation?

Answer 21

tRNA molecules bring specific amino acids to the ribosome, matching their anticodon with the corresponding codon on the mRNA to ensure the correct sequence of amino acids in the protein.

Question 22

How is gene expression regulated?

Answer 22

Gene expression is regulated by various factors, including transcription factors that bind to specific DNA sequences, influencing the binding of RNA polymerase and the rate of transcription.