Question 1

Which of the following statements best describes the difference between DNA and RNA at the level of their sugar component?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 2

Which of the following bases is found only in RNA and not in DNA?

Accepted Answer

Uracil

Question 3

A nucleotide is composed of which three components?

Accepted Answer

A phosphate group, a pentose sugar, and a nitrogenous base

Question 4

Which property of nucleotides allows for their detection and quantification using spectrophotometry?

Accepted Answer

Their absorption of UV light at around 260 nm

Question 5

What is the significance of the 5' to 3' directionality in nucleic acids?

Accepted Answer

It determines the polarity and sequence in which nucleotides are added during synthesis.

Question 6

According to Chargaff's rules, which of the following equations is correct for double-stranded DNA?

Accepted Answer

$$A = T$$ and $$G = C$$

Question 7

Which of the following best describes the secondary structure of DNA?

Accepted Answer

The three-dimensional arrangement of nucleotide residues, such as the double helix

Question 8

What is the distance between successive base pairs in the B-form DNA double helix?

Accepted Answer

$$0.34 \, 	ext{nm}$$

Question 9

Which enzyme is responsible for relieving supercoiling tension in DNA during replication?

Accepted Answer

Topoisomerase

Question 10

A researcher heats a DNA sample and observes an increase in absorbance at 260 nm. What process is occurring?

Accepted Answer

DNA denaturation (helix-to-random coil transition)

Question 11

Which of the following best describes a palindromic DNA sequence?

Accepted Answer

A sequence that is the same when read in both directions on complementary strands

Question 12

Where are G-quadruplex structures most commonly found in eukaryotic chromosomes?

Accepted Answer

At the telomeres

Question 13

Which of the following is a correct description of the flow of genetic information in a cell?

Accepted Answer

DNA $$\rightarrow$$ RNA $$\rightarrow$$ Protein

Question 14

Which of the following is true regarding the tertiary structure of nucleic acids?

Accepted Answer

It involves long-range 3D interactions such as supercoiling.

Question 15

Which of the following best explains why DNA is considered a strong acid?

Accepted Answer

The phosphate groups undergo primary ionization at low pH.

Question 16

Which of the following is a consequence of the tautomerization of nucleotide bases?

Accepted Answer

It can lead to rare base pairing and mutations during DNA replication.

Question 17

Which form of DNA is most commonly found in cells under physiological conditions?

Accepted Answer

B-form

Question 18

During transcription, which enzyme synthesizes RNA from a DNA template?

Accepted Answer

RNA polymerase

Question 19

Which of the following best describes the role of tRNA in protein synthesis?

Accepted Answer

It carries amino acids to the ribosome and matches them to the mRNA template.

Question 20

Which of the following statements about DNA supercoiling is correct?

Accepted Answer

Topoisomerases can introduce or remove supercoils in DNA.

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