$$\text{Atomic Mass} = \text{Number of Protons} + \text{Number of Neutrons}$$

Question 1

Which of the following best explains why ice floats on liquid water?

Accepted Answer

Ice is less dense than liquid water because hydrogen bonds cause water molecules to spread apart when frozen.

Question 2

Which property of water allows plants to transport water from their roots to their leaves against gravity?

Accepted Answer

Capillary action, which results from cohesion and adhesion of water molecules.

Question 3

Which of the following is a trace element vital to human life, and how do we commonly obtain it?

Accepted Answer

Iodine; obtained from iodized salt and seafood.

Question 4

What is the main difference between an ionic bond and a covalent bond?

Accepted Answer

Ionic bonds involve the transfer of electrons, while covalent bonds involve the sharing of electrons.

Question 5

Which of the following best describes a polar covalent bond?

Accepted Answer

A bond where electrons are shared unequally, resulting in partial charges on the atoms.

Question 6

Which equation correctly represents the calculation of atomic mass?

Accepted Answer

$$	ext{Atomic Mass} = 	ext{Number of Protons} + 	ext{Number of Neutrons}$$

Question 7

Which of the following statements about enzymes is TRUE?

Accepted Answer

Enzymes lower the activation energy required for a chemical reaction to occur.

Question 8

A person who is lactose intolerant lacks which enzyme, and what is the consequence?

Accepted Answer

Lactase; they cannot break down lactose in dairy products.

Question 9

Which of the following is a correct example of dehydration synthesis?

Accepted Answer

Linking two monosaccharides to form a disaccharide and releasing water.

Question 10

Which macromolecule is primarily responsible for storing and transmitting genetic information?

Accepted Answer

Nucleic acids

Question 11

Which of the following best describes the role of valence electrons in chemical bonding?

Accepted Answer

Valence electrons are the outermost electrons and determine how an atom interacts with other atoms.

Question 12

Which of the following is a property of water that helps moderate Earth's climate?

Accepted Answer

High specific heat

Question 13

Which of the following is a correct chemical formula for a compound, and what does it mean?

Accepted Answer

$$\mathrm{H_2O}$$; for every 1 oxygen atom, there are 2 hydrogen atoms.

Question 14

Which of the following best explains why water is a good solvent for many biological molecules?

Accepted Answer

Water is polar, allowing it to dissolve many ions and polar molecules.

Question 15

Which of the following is an example of a polysaccharide used for energy storage in animals?

Accepted Answer

Glycogen

Question 16

Which of the following statements about saturated and unsaturated fats is correct?

Accepted Answer

Saturated fats have no double bonds and are solid at room temperature.

Question 17

Which of the following is a correct description of an isotope?

Accepted Answer

Atoms of the same element with different numbers of neutrons.

Question 18

Which of the following best describes the lock-and-key model of enzyme function?

Accepted Answer

The enzyme's active site is specific to the substrate, allowing only certain molecules to bind.

Question 19

Which of the following is a function of proteins in the body?

Accepted Answer

Transporting molecules through cell membranes.

Question 20

Which of the following best explains why enzymes are sensitive to temperature and pH?

Accepted Answer

Changes in temperature and pH can denature proteins, altering the shape of the enzyme's active site.

General Biology Study Notes: Chemistry of Life, Water, and Macromolecules

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