Question 1

Which of the following statements best describes the difference between an element and a compound?

Accepted Answer

An element is a pure substance made of only one type of atom, while a compound is a substance composed of atoms of two or more different elements.

Question 2

A patient is injected with a radioactive isotope for a PET scan. Which property of the isotope is most important for this diagnostic procedure?

Accepted Answer

The isotope emits radiation that can be detected by imaging equipment.

Question 3

Which of the following best explains why oxygen is more electronegative than hydrogen in a water molecule?

Accepted Answer

Oxygen has more protons in its nucleus, resulting in a stronger pull on shared electrons.

Question 4

Which of the following is true regarding the structure of an atom?

Accepted Answer

Protons and neutrons are found in the nucleus, while electrons orbit in the electron cloud.

Question 5

A sodium atom (Na) loses one electron to become a sodium ion (Na+). What is the resulting charge and why?

Accepted Answer

The sodium ion has a +1 charge because it has one more proton than electron.

Question 6

Which of the following best describes a dehydration synthesis reaction?

Accepted Answer

A reaction in which two molecules are joined together with the removal of a water molecule: $$AH + BOH \rightarrow AB + H_2O$$

Question 7

Which of the following statements about pH is correct?

Accepted Answer

A solution with a pH less than 7 is acidic and has more hydrogen ions ($$H^+) $$than hydroxide ions ($$OH^-).$$

Question 8

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

Accepted Answer

All of the above

Question 9

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

Accepted Answer

A saturated fatty acid has no double bonds in its hydrocarbon tail, while an unsaturated fatty acid has one or more double bonds.

Question 10

Which of the following is true about the structure of DNA?

Accepted Answer

DNA consists of two complementary strands held together by hydrogen bonds between nitrogenous bases.

Question 11

A patient’s blood pH is measured at 7.2. Which physiological state does this indicate, and what is a potential consequence if the pH drops below 7?

Accepted Answer

Acidosis; a pH below 7 can result in a coma.

Question 12

Which of the following best explains why humans cannot obtain energy from cellulose?

Accepted Answer

Humans lack the enzymes to break the specific bonds between glucose molecules in cellulose.

Question 13

Which of the following is a correct statement about peptide bonds?

Accepted Answer

A peptide bond is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another.

Question 14

Which of the following best describes the process of phosphorylation?

Accepted Answer

The addition of a phosphate group to another molecule, often storing or transferring energy.

Question 15

Which of the following is a correct example of a reversible reaction in the human body?

Accepted Answer

$$A + B \leftrightarrow AB$$

Question 16

Which of the following best describes the role of ATP in the cell?

Accepted Answer

ATP stores and provides energy for cellular processes through high-energy phosphate bonds.

Question 17

Which of the following is a correct statement about the quaternary structure of proteins?

Accepted Answer

It involves interactions between two or more polypeptide subunits to form a functional protein complex.

Question 18

Which of the following best explains why enzymes are essential for life?

Accepted Answer

Enzymes lower the activation energy required for biochemical reactions, allowing them to occur rapidly at body temperature.

Chapter 2: The Chemical Level of Organization – Study Notes

Study Guide - Practice Questions