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 eukaryotic gene expression, which of the following modifications occurs to precursor mRNA before it becomes mature mRNA?

Accepted Answer

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

Question 3

Which enzyme is responsible for catalyzing the attachment of amino acids to their corresponding tRNAs?

Accepted Answer

Aminoacyl-tRNA synthetase

Question 4

A tRNA with the anticodon 3'-UGG-5' would carry which amino acid?

Accepted Answer

Threonine (Thr)

Question 5

Which of the following statements about ribosomes is TRUE?

Accepted Answer

The ribosome is a ribozyme, and its catalytic activity is due to rRNA.

Question 6

In bacteria, what is the significance of the formation of a polyribosome (polysome)?

Accepted Answer

It enables multiple ribosomes to simultaneously translate a single mRNA, increasing protein yield.

Question 7

Which of the following best explains the 'wobble hypothesis' proposed by Crick?

Accepted Answer

The third position of the codon allows nonstandard base pairing, enabling one tRNA to recognize multiple codons.

Question 8

Which of the following steps occurs during the elongation phase of translation?

Accepted Answer

A new aminoacyl-tRNA enters the A site, and a peptide bond forms between amino acids.

Question 9

What is the role of the E site in the ribosome during translation?

Accepted Answer

It is the site where tRNAs without amino acids exit the ribosome.

Question 10

Which of the following is a key difference between translation in bacteria and eukaryotes?

Accepted Answer

In eukaryotes, transcription and translation are separated in space and time.

Question 11

Which of the following best describes the function of mRNA vaccines, such as those for COVID-19?

Accepted Answer

They introduce mRNA that is translated into viral proteins, triggering an immune response.

Question 12

Which of the following is NOT a post-translational modification?

Accepted Answer

Addition of a poly-A tail to mRNA

Question 13

Which of the following statements about tRNA structure is correct?

Accepted Answer

The CCA sequence at the 3' end is the binding site for amino acids.

Question 14

Which of the following events occurs during the termination phase of translation?

Accepted Answer

A release factor binds to the stop codon, causing the polypeptide to be released.

Question 15

Which of the following equations correctly represents the energy requirement for attaching an amino acid to tRNA?

Accepted Answer

$$\mathrm{Amino\ acid} + \mathrm{tRNA} + \mathrm{ATP} ightarrow \mathrm{Aminoacyl	ext{-}tRNA} + \mathrm{AMP} + \mathrm{PP_i}$$

Question 16

A mutation prevents the addition of a 5' cap to eukaryotic mRNA. What is the most likely consequence?

Accepted Answer

The mRNA will not be exported from the nucleus and will be rapidly degraded.

Question 17

Which of the following best explains why there are fewer tRNAs than codons?

Accepted Answer

Some tRNAs can recognize multiple codons due to wobble base pairing at the third codon position.

Question 18

Which of the following is a function of molecular chaperones during protein synthesis?

Accepted Answer

They speed up the folding of newly synthesized proteins.

Question 19

Which of the following best describes the role of the large ribosomal subunit during translation?

Accepted Answer

It is where peptide bonds are formed between amino acids.

Question 20

A scientist introduces a mutation that prevents the formation of the poly-A tail on eukaryotic mRNA. What is the most likely effect on gene expression?

Accepted Answer

The mRNA will be rapidly degraded and less protein will be produced.

Transcription, RNA Processing, and Translation: Central Dogma and Protein Synthesis

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