Question 1

Which of the following best describes the process of translation in the flow of genetic information?

Accepted Answer

The synthesis of a polypeptide using information in mRNA

Question 2

Francis Crick and Sydney Brenner determined that the genetic code is read in triplets. What is the significance of this finding?

Accepted Answer

Each amino acid is specified by a consecutive, non-overlapping group of three nucleotides

Question 3

Which codon was the first to be identified as coding for a specific amino acid, and which amino acid does it code for?

Accepted Answer

UUU, which codes for phenylalanine

Question 4

What is the role of tRNA during translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches them to the coded mRNA message

Question 5

The 'wobble' effect in the genetic code refers to which of the following phenomena?

Accepted Answer

The ability of a single tRNA to recognize multiple codons due to flexibility at the third codon position

Question 6

Which of the following equations correctly represents the dehydration synthesis reaction that forms a peptide bond between two amino acids?

Accepted Answer

$$\mathrm{Amino\ acid}_1 + \mathrm{Amino\ acid}_2 \rightarrow \mathrm{Dipeptide} + H_2O$$

Question 7

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

Accepted Answer

The genetic code is degenerate, meaning that multiple codons can specify the same amino acid

Question 8

During translation, which site on the ribosome does the initiator tRNA bind to first?

Accepted Answer

P site

Question 9

A mutation changes the codon UAU (tyrosine) to UAA. What is the likely consequence of this mutation?

Accepted Answer

Translation will terminate prematurely because UAA is a stop codon

Question 10

Which of the following best explains why prokaryotes can couple transcription and translation, but eukaryotes cannot?

Accepted Answer

Prokaryotes lack a nuclear envelope, allowing ribosomes to access mRNA as it is being transcribed

Question 11

If a segment of mRNA has the sequence 5'-AUGGCCUAA-3', what is the corresponding amino acid sequence produced during translation?

Accepted Answer

Met-Ala-Stop

Question 12

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

Accepted Answer

Aminoacyl-tRNA synthetase

Question 13

What is the function of release factors during translation?

Accepted Answer

They promote hydrolysis of the bond between the polypeptide and tRNA at the stop codon

Question 14

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

Accepted Answer

Polyribosome (polysome)

Question 15

Which of the following best describes the direction in which mRNA is read during translation?

Accepted Answer

5' to 3'

Question 16

If a tRNA has the anticodon 5'-GAA-3', which mRNA codon will it pair with?

Accepted Answer

5'-CUU-3'

Question 17

Which of the following is a real-world consequence of a mutation that introduces a premature stop codon into a gene?

Accepted Answer

The resulting protein is likely to be shorter and nonfunctional, potentially causing genetic diseases such as cystic fibrosis

Question 18

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 19

During protein synthesis, which bond forms between the carboxyl group of one amino acid and the amino group of the next?

Accepted Answer

Peptide bond

Question 20

A patient has a genetic disorder caused by a single base substitution in a gene. Which of the following best describes a possible molecular consequence?

Accepted Answer

A codon may be changed to a stop codon, resulting in a truncated protein

From Genes to Proteins: Decoding Genetic Information

Guida di studio - Domande di pratica

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