Q: A virus uses reverse transcriptase to synthesize DNA from its RNA genome. Which direction does the genetic information flow in this case?

$\text{RNA} \rightarrow \text{DNA}$

Question 1

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

Accepted Answer

Genetic information flows from DNA to RNA to proteins.

Question 2

Beadle and Tatum’s experiments with Neurospora crassa led to which important biological hypothesis?

Accepted Answer

The one-gene, one-enzyme hypothesis.

Question 3

A mutation changes a single base in a DNA sequence, resulting in a different amino acid in the protein. What type of mutation is this?

Accepted Answer

Missense mutation

Question 4

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

Accepted Answer

It is ambiguous, with some codons coding for more than one amino acid.

Question 5

If a DNA sequence is 5'-TACGGT-3', what is the corresponding mRNA sequence produced during transcription?

Accepted Answer

$5'	ext{-}AUGCCA	ext{-}3'$

Question 6

Which enzyme is responsible for synthesizing RNA from a DNA template during transcription?

Accepted Answer

RNA polymerase

Question 7

A mutation that does not change the amino acid sequence of a protein is called:

Accepted Answer

Silent mutation

Question 8

Which codon signals the start of translation in nearly all organisms?

Accepted Answer

$AUG$

Question 9

A scientist observes that a mutation in a regulatory region of DNA does not change the protein sequence but alters the amount of protein produced. What is the most likely explanation?

Accepted Answer

The mutation affects gene expression.

Question 10

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

Accepted Answer

If several codons specify the same amino acid, the first two bases are usually identical.

Question 11

A virus uses reverse transcriptase to synthesize DNA from its RNA genome. Which direction does the genetic information flow in this case?

Accepted Answer

$	ext{RNA} ightarrow 	ext{DNA}$

Question 12

Which of the following is a real-world example of a beneficial mutation?

Accepted Answer

A mutation that increases an organism’s ability to survive and reproduce in its environment.

Question 13

Which process interprets the nucleotide 'language' of mRNA into the amino acid sequence of a protein?

Accepted Answer

Translation

Question 14

A point mutation changes a codon from $UAC$ (tyrosine) to $UAA$ (stop). What is the consequence of this mutation?

Accepted Answer

Nonsense mutation

Question 15

Which of the following best describes the relationship between genotype and phenotype?

Accepted Answer

Genotype is the sequence of bases in DNA, and phenotype is the product of the proteins produced.

Question 16

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

Accepted Answer

Ambiguous

Question 17

A frameshift mutation is most likely to result from:

Accepted Answer

An insertion or deletion of one or two bases

Question 18

Which experimental result would support the one-gene, one-enzyme hypothesis?

Accepted Answer

A single gene mutation prevents the synthesis of a specific enzyme in a metabolic pathway.

Question 19

If a codon in mRNA is $5'	ext{-}GAA	ext{-}3'$, what amino acid does it code for?

Accepted Answer

Glutamic acid (Glu)

Question 20

Which of the following is an example of a neutral mutation?

Accepted Answer

A mutation that does not affect the amino acid sequence or the organism’s fitness.

How Genes Work: The Central Dogma, Genetic Code, and Mutations

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