Question 1

Which of the following statements best describes the difference between DNA and RNA at the molecular level?

Accepted Answer

DNA contains deoxyribose sugar, while RNA contains ribose sugar.

Question 2

Which of the following bases is a purine found in both DNA and RNA?

Accepted Answer

Adenine

Question 3

What is the primary reason nucleotides are considered strong acids?

Accepted Answer

The primary ionization of the phosphate group at pH values close to 1.0.

Question 4

Which property of nucleotides allows for their detection and quantification in laboratory settings?

Accepted Answer

Their absorption of ultraviolet light at around 260 nm.

Question 5

Which of the following best describes a phosphodiester linkage in nucleic acids?

Accepted Answer

A bond between the phosphate group of one nucleotide and the 3' hydroxyl group of another.

Question 6

Given the DNA sequence 5'-ACGT-3', what is the complementary sequence?

Accepted Answer

3'-TGCA-5'

Question 7

Which of the following is true regarding the secondary and tertiary structures of nucleic acids?

Accepted Answer

Tertiary structure includes supercoiling and cruciforms.

Question 8

According to Chargaff's rules, which equation correctly represents the base composition of DNA?

Accepted Answer

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

Question 9

How many base pairs are there per turn in the B-form DNA double helix?

Accepted Answer

10 bp/turn

Question 10

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

Accepted Answer

$$0.34 \AA$$

Question 11

Which feature of the DNA double helix is shown by the space-filling model?

Accepted Answer

The close packing of atoms and the presence of major and minor grooves.

Question 12

Which model of DNA replication is supported by experimental evidence?

Accepted Answer

Semiconservative replication

Question 13

Which form of DNA is most commonly found in cells?

Accepted Answer

B-form

Question 14

What is the role of topoisomerases in DNA structure?

Accepted Answer

They modify the state of DNA supercoiling.

Question 15

Which statement best describes the migration of DNA molecules during agarose gel electrophoresis?

Accepted Answer

Smaller or more compact DNA molecules migrate more rapidly.

Question 16

Which of the following is a common conformation of single-stranded RNA molecules?

Accepted Answer

Random coil with regions of internal complementarity

Question 17

What structural feature allows tRNA molecules to fold into their tertiary structure?

Accepted Answer

Intramolecular complementarity

Question 18

Which of the following describes a palindromic DNA sequence?

Accepted Answer

A sequence that is the same when read in both directions.

Question 19

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

Accepted Answer

In telomeres at the ends of linear DNA molecules

Question 20

What is the result of heating double-stranded DNA above its melting temperature?

Accepted Answer

Denaturation into two higher energy single strands

Nucleic Acids: Structure, Properties, and Biological Functions

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