Q: If a tRNA with the anticodon $$5'\text{UAC}3' is $$present during translation, which mRNA codon will it recognize, and which amino acid will it carry?

It will recognize $$5'\text{AUG}3'$$ and carry methionine.

Question 1

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

Accepted Answer

DNA encodes information that is transcribed into RNA, and RNA encodes information that is translated into proteins.

Question 2

A mutation in the gene encoding homogentisic acid oxidase leads to the accumulation of homogentisic acid, causing alkaptonuria. Which concept does this best illustrate?

Accepted Answer

One gene codes for one enzyme in a metabolic pathway.

Question 3

Which of the following is a direct result of a nonsense mutation in a protein-coding gene?

Accepted Answer

A truncated protein due to the introduction of a premature stop codon.

Question 4

During transcription, which strand of DNA is used as the template for RNA synthesis, and how is this strand selected?

Accepted Answer

The template strand is used, directed by the promoter sequence.

Question 5

Which of the following modifications occurs to eukaryotic pre-mRNA before it is translated?

Accepted Answer

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

Question 6

A mutation that changes a codon from UAU (tyrosine) to UAA (stop) is best classified as which type of mutation?

Accepted Answer

Nonsense mutation

Question 7

Which of the following statements about the genetic code is correct?

Accepted Answer

The genetic code is nearly universal among all organisms.

Question 8

If a tRNA with the anticodon $$5'	ext{UAC}3' is $$present during translation, which mRNA codon will it recognize, and which amino acid will it carry?

Accepted Answer

It will recognize $$5'	ext{AUG}3'$$ and carry methionine.

Question 9

Which of the following best explains why cells do not need 61 different tRNAs for the 61 sense codons?

Accepted Answer

Wobble base pairing allows some tRNAs to recognize multiple codons.

Question 10

A mutation in a splice site causes an intron to remain in the mature mRNA. What is the most likely outcome for the protein product?

Accepted Answer

A nonfunctional or aberrant protein is likely to be made.

Question 11

Which of the following best describes a frameshift mutation?

Accepted Answer

An insertion or deletion that alters the reading frame of the mRNA.

Question 12

Which of the following is a likely effect of a promoter mutation?

Accepted Answer

It may alter the rate of transcription of the gene.

Question 13

Which of the following is true about somatic mutations?

Accepted Answer

They are not passed on to the organism’s offspring.

Question 14

Which of the following best describes the role of aminoacyl-tRNA synthetase in translation?

Accepted Answer

It charges tRNAs with their correct amino acids using ATP.

Question 15

A cell is exposed to a mutagen that causes deamination of cytosine to uracil. If this mutation is not repaired, what will be the result after DNA replication?

Accepted Answer

A G-C base pair will be replaced by an A-T base pair.

Question 16

Which of the following post-translational modifications can regulate protein activity by changing its conformation?

Accepted Answer

Phosphorylation

Question 17

If the DNA encoding a nuclear localization signal (NLS) is inserted into the gene for a cytoplasmic protein, where will the protein be directed?

Accepted Answer

To the nucleus

Question 18

Which of the following best explains why the genetic code is considered redundant but not ambiguous?

Accepted Answer

More than one codon can specify the same amino acid, but each codon specifies only one amino acid.

Question 19

Which of the following is a likely consequence of a transposon inserting into the coding region of a gene?

Accepted Answer

The gene may lose its function due to disruption of the coding sequence.

From DNA to Protein: Gene Expression and Mutation

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