Question 1

Which property of carbon most directly explains its ability to form large, complex, and diverse molecules essential for life?

Accepted Answer

Its four valence electrons allow it to form four covalent bonds with a variety of atoms.

Question 2

A dehydration reaction is crucial in the synthesis of which type of biological molecule?

Accepted Answer

Polymers such as proteins and polysaccharides

Question 3

Which functional group is present in all amino acids and is responsible for their acidic properties?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 4

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have the maximum number of hydrogen atoms and no double bonds, while unsaturated fatty acids have one or more double bonds.

Question 5

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 the hemoglobin protein.

Question 6

Which of the following statements about phospholipids is correct?

Accepted Answer

They have two fatty acid tails and a hydrophilic phosphate head, forming bilayers in water.

Question 7

Which type of bond is responsible for the secondary structure of proteins, such as alpha helices and beta sheets?

Accepted Answer

Hydrogen bonds between the backbone atoms

Question 8

Which of the following best explains why lipids are hydrophobic?

Accepted Answer

They are composed mostly of hydrocarbons, which form nonpolar covalent bonds.

Question 9

A DNA molecule is described as 'antiparallel.' What does this mean?

Accepted Answer

The two sugar-phosphate backbones run in opposite 5' to 3' directions.

Question 10

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

Accepted Answer

Polysaccharide and monosaccharide

Question 11

Which of the following best describes the process of hydrolysis?

Accepted Answer

It adds a water molecule, breaking a bond in a polymer.

Question 12

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

Accepted Answer

Storing genetic information

Question 13

Which of the following statements about ATP (adenosine triphosphate) is correct?

Accepted Answer

ATP releases energy when a phosphate group is removed by hydrolysis.

Question 14

Which of the following best explains why cellulose cannot be digested by most animals, even though it is a polymer of glucose?

Accepted Answer

The glycosidic linkages in cellulose have a different orientation than those in starch, and most animals lack the enzyme to break them.

Question 15

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

Accepted Answer

A nucleotide consists of a nitrogenous base, a pentose sugar (deoxyribose), 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 is a real-life consequence of protein denaturation?

Accepted Answer

A cooked egg white turns from clear to opaque because the proteins lose their native structure.

Question 18

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

Accepted Answer

It ensures that adenine always pairs with thymine and guanine always pairs with cytosine, enabling accurate DNA replication.

Question 19

Which of the following is a correct statement about the structure of steroids?

Accepted Answer

Steroids are composed of four fused carbon rings.

Question 20

A scientist is studying a molecule with the formula $$C_6H_{12}O_6$. Which class of biological molecule does this most likely represent, and what is its primary function in cells?

Accepted Answer

It is a monosaccharide, and its primary function is to provide energy for cellular processes.

Carbon and the Molecular Diversity of Life: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards