Question 1

Which property of the genetic code allows for multiple codons to specify the same amino acid?

Accepted Answer

The code is degenerate

Question 2

A mutation inserts two nucleotides into a coding sequence. What is the most likely effect on the resulting protein?

Accepted Answer

A frameshift mutation will occur, altering all downstream amino acids

Question 3

Which experimental approach was used to assign specific amino acids to codons by filtering ribosome complexes?

Accepted Answer

Triplet binding assay

Question 4

Given a synthetic mRNA composed only of poly(U), which amino acid will be incorporated into the protein product?

Accepted Answer

Phenylalanine

Question 5

If the codon sequence is 5'-AUG-GUG-UUG-AGC-3', what is the corresponding amino acid sequence?

Accepted Answer

Met-Val-Leu-Ser

Question 6

Which codon serves as the universal start codon for translation in eukaryotes?

Accepted Answer

$$\mathrm{AUG}$$

Question 7

According to the wobble hypothesis, which tRNA anticodon base can pair with more than one mRNA codon base at the third position?

Accepted Answer

Inosine (I)

Question 8

Why is the genetic code described as 'colinear'?

Accepted Answer

Because the linear sequence of codons in a gene corresponds precisely with the linear amino acid sequence of the protein

Question 9

A synthetic mRNA is created with a 1A:5C ratio. What is the probability of the codon CCC appearing?

Accepted Answer

$$\left(\frac{5}{6}\$$right)^3$$ = 57.9\%$$

Question 10

Which of the following is NOT a property of the genetic code?

Accepted Answer

It is overlapping

Question 11

A mutation changes the second base of a codon from U to C. If the original codon specified a hydrophobic amino acid, what is the likely effect?

Accepted Answer

It will likely specify another hydrophobic amino acid

Question 12

Which codons do NOT bind a tRNA and serve as termination signals?

Accepted Answer

$$\mathrm{UAA}$$, $$\mathrm{UAG}$$, $$\mathrm{UGA}$$

Question 13

Which enzyme was used to synthesize artificial mRNAs without a template in early genetic code experiments?

Accepted Answer

Polynucleotide phosphorylase

Question 14

If a codon is changed from UUU to UUC, what is the effect on the encoded protein?

Accepted Answer

There is no change; both code for phenylalanine

Question 15

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

Accepted Answer

Codons for chemically similar amino acids often share the same middle base

Question 16

Which experimental result provided evidence that the genetic code is read in triplets?

Accepted Answer

Insertion or deletion of three nucleotides did not alter the reading frame

Question 17

Which codon is unique in that it both codes for an amino acid and serves as the initiation signal for translation?

Accepted Answer

$$\mathrm{AUG}$$

Question 18

Why do mitochondria in some organisms use a slightly different genetic code?

Accepted Answer

Because the genetic code is not universal in all organisms

Question 19

Which of the following statements about the wobble hypothesis is correct?

Accepted Answer

The third base of the codon is less spatially constrained, allowing one tRNA to recognize multiple codons

The Genetic Code and Transcription: Deciphering the Flow of Genetic Information

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