Question 1

Which of the following statements best explains why the mass of an object remains constant regardless of its location, while its weight can change?

Accepted Answer

Mass is the amount of matter in an object, while weight depends on the gravitational pull acting on that mass.

Question 2

A radioactive isotope of iodine ($$^{131}\mathrm{I}) is $$commonly used in medical diagnostics. What property makes this isotope useful for such applications?

Accepted Answer

It emits radiation as it decays, which can be detected to trace biological processes.

Question 3

How many neutrons are present in an atom of sodium ($$\mathrm{Na}) $$with an atomic number of 11 and an atomic mass of 23?

Accepted Answer

$$23 - 11 = 12$$ neutrons

Question 4

Which of the following best describes why only electrons are involved in chemical reactions?

Accepted Answer

Electrons are located in the outer shells and can be gained, lost, or shared to form bonds.

Question 5

A solution has a pH of 4. What is the concentration of hydrogen ions ($$[\mathrm{H}^+]) $$compared to a solution with a pH of 6?

Accepted Answer

It is 100 times greater.

Question 6

Which of the following molecules is most likely to be hydrophobic?

Accepted Answer

A hydrocarbon chain such as a fatty acid tail

Question 7

Which of the following best explains why water is an excellent solvent for ionic compounds?

Accepted Answer

Water is a polar molecule, allowing it to surround and separate ions.

Question 8

Which of the following is a correct description of a buffer in biological systems?

Accepted Answer

A buffer resists changes in pH by absorbing or releasing $$\mathrm{H}^+$$ ions.

Question 9

Which of the following best describes the difference between a saturated and an unsaturated fat?

Accepted Answer

Saturated fats have no double bonds between carbon atoms, making them solid at room temperature.

Question 10

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

Accepted Answer

Carboxyl group ($$-\mathrm{COOH})$$

Question 11

Which level of protein structure is directly affected by a single amino acid substitution, such as in sickle-cell anemia?

Accepted Answer

Primary structure

Question 12

What type of chemical reaction is responsible for joining two monosaccharides to form a disaccharide?

Accepted Answer

Dehydration reaction

Question 13

Which of the following best describes the role of hydrogen bonds in the structure of proteins?

Accepted Answer

They stabilize secondary structures such as alpha helices and beta sheets.

Question 14

Which of the following statements about cellulose is correct?

Accepted Answer

It is a polysaccharide that provides structural support in plant cell walls.

Question 15

A molecule with the formula $$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 is $$classified as which of the following?

Accepted Answer

A monosaccharide

Question 16

Which of the following best explains why phospholipids form bilayers in water?

Accepted Answer

They have hydrophilic heads and hydrophobic tails, causing them to arrange with heads facing water and tails away from water.

Question 17

Which of the following is a real-life example of hydrolysis?

Accepted Answer

Digestion of starch into glucose in the small intestine

Question 18

Which of the following best describes the difference between an aldose and a ketose sugar?

Accepted Answer

An aldose has a carbonyl group at the end of the carbon chain, while a ketose has it within the chain.

Question 19

Which of the following is a function of cholesterol in animal cells?

Accepted Answer

It helps maintain fluidity of cell membranes.

The Chemistry of Life: Atoms, Molecules, and Macromolecules

Study Guide - Practice Questions

Study Guide - Flashcards