Question 1

Which of the following statements best explains why carbon is the backbone of biological macromolecules?

Accepted Answer

Carbon can form up to four covalent bonds, allowing for large, complex, and varied molecules.

Question 2

Which functional group is responsible for the negative charge and energy transfer properties of ATP?

Accepted Answer

Phosphate group ($$-\mathrm{OPO}_3$$^{2-}$$)

Question 3

A molecule with the formula $$C_6H_{12}O_6$ is classified as which type of biomolecule?

Accepted Answer

Monosaccharide

Question 4

Which process is used to break down a polymer into its monomers, and what molecule is required for this reaction?

Accepted Answer

Hydrolysis; water is added

Question 5

Which of the following best describes the difference between starch and cellulose?

Accepted Answer

Starch has branched chains, while cellulose is always a straight chain due to different glycosidic linkages.

Question 6

Which of the following is a correct pairing of a macromolecule and its monomer?

Accepted Answer

Carbohydrate – Monosaccharide

Question 7

A patient is diagnosed with sickle-cell disease. Which level of protein structure is directly affected by the mutation causing this disease?

Accepted Answer

Primary structure

Question 8

Which of the following statements about phospholipids is correct?

Accepted Answer

They have hydrophilic heads and hydrophobic tails, forming bilayers in water.

Question 9

Which type of isomerism is responsible for the difference between cis and trans fatty acids, and why is this biologically significant?

Accepted Answer

Cis-trans isomerism; it affects the shape and function of the molecule, influencing membrane fluidity.

Question 10

Which of the following best explains why unsaturated fats are liquid at room temperature while saturated fats are solid?

Accepted Answer

Unsaturated fats have double bonds that create kinks, preventing tight packing.

Question 11

Which of the following is NOT a function of proteins in living organisms?

Accepted Answer

Storing genetic information

Question 12

Which of the following best describes the structure of DNA?

Accepted Answer

A double helix with antiparallel sugar-phosphate backbones and complementary base pairing

Question 13

A dehydration reaction is used to join two glucose molecules. What is the resulting molecule and what bond is formed?

Accepted Answer

Maltose; glycosidic linkage

Question 14

Which of the following best explains why cellulose cannot be digested by humans?

Accepted Answer

Humans lack the enzyme to hydrolyze the $$\beta-1$$,4 glycosidic linkages in cellulose.

Question 15

Which of the following is a correct description of a nucleotide found in DNA?

Accepted Answer

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

Question 16

Which of the following best describes the role of enzymes in biological systems?

Accepted Answer

They speed up dehydration and hydrolysis reactions without being consumed.

Question 17

Which of the following is true about the quaternary structure of proteins?

Accepted Answer

It involves the interaction of two or more polypeptide chains to form a functional protein.

Question 18

Which of the following best explains the importance of complementary base pairing in DNA?

Accepted Answer

It ensures accurate replication and transmission of genetic information.

Question 19

Which of the following is a real-world consequence of a single amino acid substitution in a protein, as seen in sickle-cell disease?

Accepted Answer

Red blood cells become sickle-shaped and can block blood vessels, causing pain and organ damage.

Question 20

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

Accepted Answer

A nucleoside contains a nitrogenous base and a pentose sugar; a nucleotide also contains one or more phosphate groups.

Chapter 3: Carbon and the Molecular Diversity of Life – Study Notes

Study Guide - Practice Questions