$$5'\text{-}AUG\ GAA\ UGC\ UAA\text{-}3'$$

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

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 proteins.

Question 2

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; introduces a premature stop codon.

Question 3

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

Accepted Answer

Redundant

Question 4

If a DNA sequence is 5'-ATG GAA TGC TAA-3', what is the corresponding mRNA sequence?

Accepted Answer

$$5'	ext{-}AUG\ GAA\ UGC\ UAA	ext{-}3'$$

Question 5

A frameshift mutation is most likely to result from which of the following changes?

Accepted Answer

An insertion of one base

Question 6

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

Accepted Answer

RNA polymerase

Question 7

A mutation in a gene results in a protein with a single amino acid change. What type of mutation is this?

Accepted Answer

Missense mutation

Question 8

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

Accepted Answer

Each codon codes for more than one amino acid.

Question 9

Which of the following best explains how a change in genotype can lead to a change in phenotype?

Accepted Answer

A change in DNA sequence alters the mRNA, which can change the amino acid sequence of a protein, affecting its function.

Question 10

Which of the following chromosome mutations involves a segment of a chromosome breaking off, flipping around, and rejoining?

Accepted Answer

Inversion

Question 11

A scientist observes a karyotype with an extra chromosome 21. What type of mutation is this?

Accepted Answer

Aneuploidy

Question 12

Which of the following is a function of mRNA in the cell?

Accepted Answer

It carries genetic information from DNA to the site of protein synthesis.

Question 13

Which of the following codons is a start codon, and what amino acid does it code for?

Accepted Answer

AUG; methionine

Question 14

A mutation changes the DNA sequence from 5'-GAA-3' to 5'-GAG-3'. Both code for glutamic acid. What type of mutation is this?

Accepted Answer

Silent mutation

Question 15

Which of the following best describes a translocation mutation?

Accepted Answer

A segment of a chromosome becomes attached to a different chromosome.

Question 16

Which of the following statements about point mutations is TRUE?

Accepted Answer

Most point mutations are neutral or deleterious.

Question 17

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

Accepted Answer

$$	ext{RNA} ightarrow 	ext{DNA}$$

Question 18

If a gene has the DNA sequence 5'-TAC GGA TTT GCG-3', what is the first three amino acids in the polypeptide produced (use the genetic code)?

Accepted Answer

Met-Gly-Phe

Question 19

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

Accepted Answer

It is ambiguous.

Question 20

A patient’s cancer cells show multiple chromosome duplications and deletions. What is the most likely consequence of these mutations?

Accepted Answer

Deleterious effects on cell function

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

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