Question 1

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

Accepted Answer

DNA → RNA → Protein

Question 2

Sir Archibald Garrod was the first to propose a link between genes, proteins, and metabolic disease. Which disorder did he study that led to the concept of 'inborn errors of metabolism'?

Accepted Answer

Alkaptonuria

Question 3

Beadle and Tatum’s experiments with Neurospora supported which hypothesis about gene function?

Accepted Answer

One gene, one enzyme

Question 4

In eukaryotic cells, what is the correct sequence of events for gene expression?

Accepted Answer

Transcription → RNA processing → Translation

Question 5

Which of the following statements about transcription is TRUE?

Accepted Answer

RNA polymerase synthesizes RNA in the 5' to 3' direction.

Question 6

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this, and what is the likely result?

Accepted Answer

Nonsense mutation; translation is terminated early

Question 7

Which of the following modifications occur to eukaryotic pre-mRNA before it becomes mature mRNA?

Accepted Answer

Addition of a 5' cap and a poly-A tail

Question 8

What is the function of the spliceosome during RNA processing?

Accepted Answer

It removes introns and joins exons together.

Question 9

Which of the following best explains why the genetic code is described as 'universal'?

Accepted Answer

The same codons specify the same amino acids in nearly all organisms.

Question 10

A tRNA molecule is charged with the amino acid leucine. Its anticodon is 3'-AAG-5'. Which mRNA codon will it recognize during translation?

Accepted Answer

5'-CUU-3'

Question 11

Which of the following is a consequence of a frameshift mutation caused by the insertion of a single nucleotide within the coding region of a gene?

Accepted Answer

The reading frame is altered, changing all downstream amino acids.

Question 12

Which enzyme is responsible for attaching the correct amino acid to its corresponding tRNA?

Accepted Answer

Aminoacyl-tRNA synthetase

Question 13

During translation, which site on the ribosome holds the tRNA carrying the growing polypeptide chain?

Accepted Answer

P site

Question 14

Which of the following best describes a missense mutation?

Accepted Answer

A mutation that changes one amino acid to another

Question 15

A researcher introduces a chemical mutagen into a bacterial culture. Which of the following outcomes would best indicate that the chemical is a mutagen?

Accepted Answer

The bacteria show increased rates of genetic mutations.

Question 16

Which of the following is TRUE about translation in prokaryotes compared to eukaryotes?

Accepted Answer

Translation in prokaryotes can begin before transcription is finished.

Question 17

A mutation in the promoter region of a gene most likely affects which process?

Accepted Answer

The initiation of transcription

Question 18

Which of the following is a post-translational modification that may be required for a protein to become functional?

Accepted Answer

Cleavage of a polypeptide chain

Question 19

If a gene contains the sequence 5'-ATG GAA TGA-3' on the coding strand, what is the sequence of the mRNA transcribed from this gene?

Accepted Answer

5'-AUG GAA UGA-3'

Question 20

Which of the following best explains why a silent mutation does not affect the phenotype of an organism?

Accepted Answer

It does not change the amino acid sequence of the protein.

Gene Expression: From Gene to Protein – Transcription, Translation, and Mutations

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