Question 1

Which molecule is primarily responsible for directing cellular functions by storing and transmitting genetic information?

Accepted Answer

DNA

Question 2

How does the structure of DNA allow it to serve as a template for its own replication?

Accepted Answer

The double helix structure allows complementary base pairing, enabling each strand to serve as a template for a new strand.

Question 3

Which of the following best explains why fats provide more energy per gram than carbohydrates?

Accepted Answer

Fats have more carbon-hydrogen bonds, which release more energy when oxidized.

Question 4

Which of the following is a key structural difference between DNA and RNA?

Accepted Answer

DNA contains deoxyribose and thymine, while RNA contains ribose and uracil.

Question 5

A scientist is analyzing a nucleic acid and finds it contains uracil and is usually single-stranded. What is the most likely identity of this molecule?

Accepted Answer

RNA

Question 6

Which type of bond links nucleotides together in the backbone of DNA and RNA?

Accepted Answer

Phosphodiester bond

Question 7

If a DNA strand has the sequence 5'-GGAACACACTGTGAA-3', what is the sequence of its complementary strand?

Accepted Answer

3'-CCTTGTGTGACACTT-5'

Question 8

Which of the following best describes the amphipathic nature of phospholipids?

Accepted Answer

They have both hydrophilic heads and hydrophobic tails.

Question 9

What is the main function of mRNA in the cell?

Accepted Answer

To carry genetic instructions from DNA to ribosomes for protein synthesis.

Question 10

Which of the following statements about saturated and unsaturated fats is correct?

Accepted Answer

Saturated fats have only single bonds between carbon atoms and are solid at room temperature.

Question 11

Which of the following best explains why RNA is generally less stable than DNA?

Accepted Answer

RNA contains a hydroxyl group at the 2' position of ribose, making it more reactive.

Question 12

Which of the following is NOT a function of steroids in biological systems?

Accepted Answer

Catalyzing chemical reactions

Question 13

A mutation changes a cytosine (C) to a thymine (T) in a DNA sequence. What type of base pairing will now occur at this position during DNA replication?

Accepted Answer

Adenine (A) will pair with thymine (T) instead of guanine (G) pairing with cytosine (C).

Question 14

Which of the following best describes the 'central dogma' of molecular biology?

Accepted Answer

DNA is transcribed to RNA, which is translated to protein.

Question 15

Which of the following equations correctly represents the energy content of fats and carbohydrates?

Accepted Answer

$$9 \ \mathrm{kcal/g}$$ for fats and $$4 \ \mathrm{kcal/g}$$ for carbohydrates

Question 16

Which of the following is a real-world application of DNA information in understanding human history?

Accepted Answer

Tracing human ancestry and migration patterns using DNA sequence data.

Question 17

Which of the following best describes the structure of a phospholipid bilayer in biological membranes?

Accepted Answer

Hydrophilic heads face outward toward water, and hydrophobic tails face inward away from water.

Question 18

Which of the following is a correct statement about the role of ribosomal RNA (rRNA)?

Accepted Answer

rRNA is a structural and catalytic component of ribosomes, facilitating protein synthesis.

Question 19

Which of the following best explains why phospholipids are essential for cell membrane structure?

Accepted Answer

Their amphipathic nature allows them to form bilayers that separate the cell from its environment.

Molecular Information and the Role of Nucleic Acids in Cellular Function

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