Question 1

Which of the following best describes the central dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

During transcription in eukaryotic cells, which enzyme is responsible for synthesizing the mRNA strand?

Accepted Answer

RNA polymerase

Question 3

Which of the following statements about RNA polymerase is TRUE?

Accepted Answer

RNA polymerase can start a chain from scratch and synthesizes RNA in the 5' → 3' direction.

Question 4

What is the function of the promoter region in DNA during transcription?

Accepted Answer

It is the binding site for RNA polymerase and determines the template strand.

Question 5

Which of the following modifications occur to eukaryotic pre-mRNA before it leaves the nucleus?

Accepted Answer

Addition of a 5' cap and a poly-A tail, and removal of introns

Question 6

A mutation causes a spliceosome to fail to remove introns from pre-mRNA. What is the most likely consequence?

Accepted Answer

The resulting protein will contain extra amino acids not normally present.

Question 7

Which of the following best explains the advantage of alternative RNA splicing?

Accepted Answer

It allows a single gene to encode multiple polypeptides.

Question 8

During translation, what is the role of the tRNA anticodon?

Accepted Answer

It pairs with the complementary codon on mRNA to ensure the correct amino acid is added.

Question 9

Which of the following is TRUE about ribosomes?

Accepted Answer

They facilitate the pairing of mRNA codons with tRNA anticodons and catalyze peptide bond formation.

Question 10

A scientist observes that a single mRNA molecule is being translated by several ribosomes simultaneously. What is this structure called, and what is its significance?

Accepted Answer

Polyribosome; it allows rapid and simultaneous synthesis of multiple copies of a polypeptide.

Question 11

Which of the following codons signals the start of translation in eukaryotic cells?

Accepted Answer

$$\mathrm{AUG}$$

Question 12

What is the correct sequence of events during the elongation phase of translation?

Accepted Answer

Codon recognition, peptide bond formation, translocation

Question 13

Which of the following statements about stop codons is correct?

Accepted Answer

Stop codons signal the end of translation and are recognized by release factors.

Question 14

If a mutation changes the DNA sequence from $$\mathrm{TAC} to$$ $$\mathrm{TAA} in $$the template strand, what is the effect on the resulting protein?

Accepted Answer

Translation will terminate prematurely due to the introduction of a stop codon.

Question 15

Which of the following best describes the function of the 5' cap and poly-A tail added to eukaryotic mRNA?

Accepted Answer

They facilitate mRNA export from the nucleus, protect mRNA from degradation, and help ribosome binding.

Question 16

A patient has a genetic disorder in which their cells cannot produce functional snRNPs. Which process will be directly affected?

Accepted Answer

RNA splicing

Question 17

Which of the following is a direct result of the base-pairing rules during transcription?

Accepted Answer

Adenine in DNA pairs with uracil in RNA.

Question 18

Which of the following best explains why only one DNA strand is used as a template for transcription of a given gene?

Accepted Answer

The promoter sequence determines which strand is used as the template for each gene.

Question 19

Which of the following steps occurs LAST during the process of translation?

Accepted Answer

Release of the completed polypeptide from the ribosome

Question 20

A researcher adds a chemical to cells that prevents the formation of polyribosomes. What is the most likely effect on protein synthesis?

Accepted Answer

Each mRNA will be translated by only one ribosome at a time, reducing the rate of protein production.

Protein Synthesis: From DNA to Functional Protein

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