Q: Which of the following is a correct representation of a phosphodiester bond in DNA?

$$\text{C}_3'\text{-O-P-O-C}_5'$$

Question 1

Which of the following statements best describes the antiparallel nature of DNA strands?

Accepted Answer

One DNA strand runs 5' to 3', while the other runs 3' to 5'.

Question 2

Which chemical bond is responsible for holding together the two strands of the DNA double helix?

Accepted Answer

Hydrogen bonds

Question 3

What is the significance of Chargaff's rules in the structure of DNA?

Accepted Answer

They state that the amount of purines equals the amount of pyrimidines in DNA.

Question 4

Which of the following is a correct representation of a phosphodiester bond in DNA?

Accepted Answer

$$	ext{C}_3'	ext{-O-P-O-C}_5'$$

Question 5

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

Accepted Answer

B-DNA

Question 6

A mutation causes the expansion of the trinucleotide 5'-GAA-3' in the first intron of a gene, forming a triple helix that inhibits gene transcription. Which disease is associated with this mechanism?

Accepted Answer

Friedreich's ataxia

Question 7

Which of the following best explains why DNA is more stable than RNA under alkaline conditions?

Accepted Answer

DNA lacks a 2' hydroxyl group on the sugar.

Question 8

Which of the following is NOT a component of a nucleosome?

Accepted Answer

RNA polymerase

Question 9

Which groove of the DNA double helix is most commonly involved in protein-DNA interactions for sequence-specific binding?

Accepted Answer

Major groove

Question 10

Which of the following best describes the difference between a nucleoside and a nucleotide?

Accepted Answer

A nucleotide contains a base, a sugar, and a phosphate group.

Question 11

Which of the following is a unique feature of Z-DNA compared to B-DNA?

Accepted Answer

It is levorotatory (left-handed).

Question 12

Which of the following best explains why the 5' cap and 3' poly(A) tail are important for mRNA?

Accepted Answer

They protect mRNA from exonuclease degradation.

Question 13

Which of the following is true regarding the base pairing in DNA?

Accepted Answer

Guanine pairs with cytosine via three hydrogen bonds.

Question 14

Which of the following is a function of frataxin, the protein affected in Friedreich's ataxia?

Accepted Answer

It binds iron and facilitates the formation of iron-sulfur complexes in mitochondria.

Question 15

Which of the following best describes the role of histone H1 in chromatin structure?

Accepted Answer

It binds to linker DNA and helps seal DNA around the nucleosome core.

Question 16

Which of the following is a distinguishing feature of RNA compared to DNA?

Accepted Answer

RNA contains ribose instead of deoxyribose.

Question 17

Which of the following best explains why the major groove of DNA is important?

Accepted Answer

It allows proteins to recognize specific DNA sequences for gene regulation.

Question 18

Which of the following is a correct statement about the packaging of eukaryotic DNA?

Accepted Answer

Eukaryotic DNA is packaged with histones to form chromatin.

Question 19

Which of the following best describes the difference in base composition between DNA and RNA?

Accepted Answer

DNA contains thymine, while RNA contains uracil.

Question 20

Which of the following is a real-world application of DNA origami technology?

Accepted Answer

In vivo drug delivery for cancer treatment

Nucleic Acids: Structure, Function, and Biological Importance

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