Question 1

Which of the following statements best describes an element in the context of biology?

Accepted Answer

An element is a substance made up of only one kind of atom, which cannot be broken down into other substances.

Question 2

Which four elements make up approximately 96% of the human body’s mass?

Accepted Answer

Oxygen, Carbon, Nitrogen, Hydrogen

Question 3

A patient presents with an enlarged thyroid gland due to iodine deficiency. What type of element is iodine considered in biological systems?

Accepted Answer

Trace element

Question 4

Which of the following best describes a molecule?

Accepted Answer

A molecule is a combination of two or more atoms bonded together.

Question 5

Which of the following is a compound?

Accepted Answer

CO$$_2$$

Question 6

Atoms are composed of which three types of subatomic particles?

Accepted Answer

Neutrons, electrons, and protons

Question 7

Where are protons and neutrons located within an atom?

Accepted Answer

In the nucleus

Question 8

Which statement about electron shells is correct?

Accepted Answer

Atoms tend to fill their outermost electron shells by interacting with other atoms.

Question 9

What type of chemical bond is formed when electrons are transferred from one atom to another?

Accepted Answer

Ionic bond

Question 10

In a water molecule (H$$_2O$$), why does oxygen have a partial negative charge?

Accepted Answer

Oxygen attracts shared electrons more strongly than hydrogen.

Question 11

Which of the following best explains why water has a high specific heat capacity?

Accepted Answer

Hydrogen bonds between water molecules absorb heat before breaking.

Question 12

Which property of water is most critical for the transport of nutrients in living organisms?

Accepted Answer

Water’s cohesion due to hydrogen bonding

Question 13

A solution is made by dissolving table salt (NaCl) in water. In this scenario, which is the solute?

Accepted Answer

Sodium chloride (NaCl)

Question 14

Which equation correctly represents the chemical reaction for the combustion of methane?

Accepted Answer

$$\mathrm{CH_4$ + 2O_2 \rightarrow CO_2$ + 2H_2O}$$

Question 15

Which statement about chemical reactions is true?

Accepted Answer

Chemical bonds are broken and new ones are formed, but matter is neither created nor destroyed.

Question 16

Which of the following best describes a polar molecule?

Accepted Answer

A molecule with an uneven distribution of electrical charge, resulting in partial positive and negative regions.

Question 17

Which of the following substances would most likely increase the concentration of H$$^+$$ ions in an aqueous solution?

Accepted Answer

An acid

Question 18

If the pH of a solution changes from 7 to 5, how does the concentration of H$$^+$$ ions change?

Accepted Answer

It increases by a factor of 100.

Question 19

Which of the following is true about the pH scale?

Accepted Answer

The pH scale is logarithmic, with each unit representing a tenfold change in H$$^+$$ concentration.

Question 20

Which of the following best explains why sodium chloride (NaCl) forms from sodium and chlorine atoms?

Accepted Answer

Sodium transfers an electron to chlorine, resulting in oppositely charged ions that attract each other.

Basic Chemistry for Biology: Study Notes

Study Guide - Practice Questions