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 directly involved in the release of energy from ATP during cellular processes?

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

Accepted Answer

Starch has branched chains, while cellulose is always a straight, unbranched polymer.

Question 5

Which process is responsible for breaking down a protein into its individual amino acids?

Accepted Answer

Hydrolysis reaction

Question 6

A patient is diagnosed with sickle-cell disease. Which molecular change is responsible for this condition?

Accepted Answer

A single amino acid substitution in the primary structure of hemoglobin

Question 7

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

Accepted Answer

Their fatty acid chains contain one or more double bonds, causing kinks that prevent tight packing.

Question 8

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

Accepted Answer

Storing genetic information

Question 9

Which of the following statements about phospholipids is correct?

Accepted Answer

They are amphipathic, having both hydrophilic and hydrophobic regions.

Question 10

Which type of isomerism is illustrated by molecules that are mirror images of each other, such as L- and D-amino acids?

Accepted Answer

Enantiomerism

Question 11

A dehydration reaction is used to join two glucose molecules. What is the resulting product and what is released?

Accepted Answer

A disaccharide and a molecule of water ($$H_2O)$$

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

Which of the following is a correct pairing of a functional group and its property?

Accepted Answer

Amino group ($$-\mathrm{NH}_2$$): acts as a base

Question 14

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

Accepted Answer

Humans lack the enzyme to hydrolyze the specific $$\beta-$$glycosidic linkages in cellulose.

Question 15

Which of the following is a correct description of a nucleotide?

Accepted Answer

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

Question 16

Which of the following best describes the quaternary structure of a protein?

Accepted Answer

The association of two or more polypeptide chains into a functional protein

Question 17

Which of the following statements about lipids is FALSE?

Accepted Answer

Lipids are polymers made from fatty acid monomers.

Question 18

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

Accepted Answer

Enzymes speed up chemical reactions by lowering the activation energy.

Question 19

Which of the following is a real-life example of the importance of protein structure?

Accepted Answer

The sickling of red blood cells in sickle-cell disease due to a single amino acid substitution

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

Study Guide - Practice Questions