Question 1

Which of the following best describes the Central Dogma of molecular genetics?

Accepted Answer

Information flows from DNA to RNA to protein.

Question 2

Which chemical bond links two nucleotides together in a DNA strand?

Accepted Answer

3'-5' phosphodiester bond

Question 3

A DNA molecule is described as 'antiparallel.' What does this mean?

Accepted Answer

The two strands run in opposite 5' to 3' directions.

Question 4

Which of the following is NOT a component of a DNA nucleotide?

Accepted Answer

Amino acid

Question 5

If a segment of DNA has the sequence 5'-ATCG-3', what is the complementary sequence on the opposite strand?

Accepted Answer

3'-TAGC-5'

Question 6

Which nitrogenous base is found in DNA but not in RNA?

Accepted Answer

Thymine

Question 7

What is the main function of the phosphate group in the structure of DNA?

Accepted Answer

It allows the addition of nucleotides to form a macromolecule.

Question 8

Which of the following statements about DNA double helix stability is correct?

Accepted Answer

G-C base pairs are more stable than A-T base pairs.

Question 9

During DNA replication, new nucleotides are added to which end of the growing DNA strand?

Accepted Answer

3' end

Question 10

A mutation changes a cytosine (C) to a thymine (T) in a DNA sequence. Which type of nitrogenous base has been altered?

Accepted Answer

A pyrimidine has been replaced by another pyrimidine.

Question 11

Which of the following best explains why DNA is described as having 'directionality'?

Accepted Answer

The sugar-phosphate backbone has distinct 5' and 3' ends.

Question 12

In the context of the Central Dogma, what is the process called in which information in DNA is used to synthesize mRNA?

Accepted Answer

Transcription

Question 13

Which of the following is a correct pairing of nitrogenous bases in double-stranded DNA?

Accepted Answer

Adenine–Thymine

Question 14

A scientist is analyzing a DNA sample and finds that 30% of the bases are adenine. According to Chargaff's rules, what percentage of the bases should be guanine?

Accepted Answer

$$20\%$$

Question 15

Which structural feature of DNA allows it to be efficiently packaged within the nucleus of a eukaryotic cell?

Accepted Answer

Its ability to form a double helix and wrap around histone proteins

Question 16

Which of the following best describes the backbone of the DNA molecule?

Accepted Answer

Alternating sugars and phosphate groups

Question 17

A patient is diagnosed with a genetic disorder caused by a mutation in the promoter region of a gene. Which process is most likely to be directly affected?

Accepted Answer

Transcription of DNA into mRNA

Question 18

Which of the following statements about the complementarity of DNA is correct?

Accepted Answer

Adenine pairs with thymine, and guanine pairs with cytosine.

Question 19

Which of the following best explains why the bond between G-C base pairs is stronger than that between A-T base pairs?

Accepted Answer

G-C pairs form three hydrogen bonds, while A-T pairs form two.

Question 20

Which of the following is a real-world application of understanding DNA structure in medicine?

Accepted Answer

Developing gene therapies to correct mutations at the DNA level

Introduction to the Central Dogma and DNA Structure

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