Question 1

Which of the following best explains why unsaturated fatty acids have lower melting points than saturated fatty acids?

Accepted Answer

The double bonds in unsaturated fatty acids create kinks, preventing tight packing and lowering the melting point.

Question 2

A sample of bacterial DNA contains 13% adenine. According to Chargaff’s Rules, what percentage of guanine would you expect in this DNA?

Accepted Answer

37%

Question 3

Which of the following is a defining structural feature of phospholipids that allows them to form bilayers in biological membranes?

Accepted Answer

They contain a polar phosphate head and two nonpolar fatty acid tails.

Question 4

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

Accepted Answer

Fatty acid

Question 5

In the central dogma of biology, which process is responsible for synthesizing proteins from RNA?

Accepted Answer

Translation

Question 6

Which of the following best describes the difference between DNA and RNA sugars?

Accepted Answer

DNA contains deoxyribose, which lacks an OH group at the 2' carbon, while RNA contains ribose with an OH group at the 2' carbon.

Question 7

Which of the following is true about the structure of a steroid molecule?

Accepted Answer

It consists of four fused carbon rings.

Question 8

A triacylglycerol sample is tested for melting point. The results show that sample A has the lowest melting point, sample B the highest, and sample C is intermediate. Which sample most likely contains the highest proportion of saturated fatty acids?

Accepted Answer

Sample B

Question 9

Which of the following best describes a phosphodiester bond?

Accepted Answer

A bond joining the phosphate group of one nucleotide to the sugar of another nucleotide.

Question 10

Which nitrogenous bases are classified as purines?

Accepted Answer

Adenine and guanine

Question 11

Which of the following is a function of ATP in cells?

Accepted Answer

It stores and transfers energy for cellular processes.

Question 12

Which of the following statements about the backbone of nucleic acids is correct?

Accepted Answer

It consists of repeating phosphate and sugar units.

Question 13

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

Accepted Answer

Adenine pairs with thymine, and cytosine pairs with guanine.

Question 14

Which of the following is a characteristic of lipids that distinguishes them from carbohydrates?

Accepted Answer

Lipids have a 1:2 ratio of carbon to hydrogen and contain very little oxygen.

Question 15

Which of the following is NOT a function of nucleic acids in cells?

Accepted Answer

Catalyzing metabolic reactions

Question 16

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

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 17

A mutation causes a change in the sequence of bases in a DNA molecule. Which process will be directly affected by this mutation according to the central dogma?

Accepted Answer

Transcription

Question 18

Which of the following is a real-world consequence of a defect in phospholipid synthesis in human cells?

Accepted Answer

Impaired cell membrane integrity and function

Question 19

Which of the following best explains why cholesterol is classified as a lipid?

Accepted Answer

It contains long hydrocarbon chains and is insoluble in water.

Question 20

Which of the following equations correctly represents the formation of a phosphodiester bond between two nucleotides?

Accepted Answer

$$\mathrm{Nucleotide}_1 + \mathrm{Nucleotide}_2 \rightarrow \mathrm{Dinucleotide} + \mathrm{H}_2\mathrm{O}$$

Lipids and Nucleic Acids: Structure, Function, and Biological Importance

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