Question 1

Which of the following statements best describes the location and properties of electrons in an atom?

Accepted Answer

Electrons orbit the nucleus within the electron cloud and are much lighter than protons.

Question 2

A carbon atom has an atomic number of 6. What does this indicate about its structure?

Accepted Answer

It has 6 protons and 6 electrons.

Question 3

Which element is essential for oxygen transport and energy capture in the human body?

Accepted Answer

Iron

Question 4

Radioisotopes are used in PET scans to detect cancer. Which property of radioisotopes makes them useful for this purpose?

Accepted Answer

They emit subatomic particles that can be tracked using imaging.

Question 5

What is the maximum number of electrons that can be held in the first electron shell of an atom?

Accepted Answer

Two

Question 6

Which of the following best explains why atoms with unfilled valence shells are chemically reactive?

Accepted Answer

They seek to fill their valence shell by gaining, losing, or sharing electrons.

Question 7

Which of the following is both a molecule and a compound?

Accepted Answer

H$$_2O$$

Question 8

An atom that loses two electrons will become:

Accepted Answer

A cation with a charge of $$+2$$

Question 9

Which type of chemical bond involves the sharing of electrons between atoms?

Accepted Answer

Covalent bond

Question 10

Water is considered a polar molecule because:

Accepted Answer

The oxygen atom has a greater electronegativity than the hydrogen atoms, resulting in partial charges.

Question 11

Which of the following reactions is represented by the equation $$AB + H_2O \rightarrow AH + BOH$$?

Accepted Answer

Hydrolysis (decomposition)

Question 12

A solution with a pH of 5 is best described as:

Accepted Answer

Acidic

Question 13

What is the main storage polysaccharide in the human body?

Accepted Answer

Glycogen

Question 14

Which of the following statements about cellulose is correct?

Accepted Answer

Cellulose serves as a source of fiber in the human diet.

Question 15

Which lipid molecule is a primary component of plasma membranes?

Accepted Answer

Phospholipid

Question 16

A peptide bond is formed between:

Accepted Answer

The carboxyl group of one amino acid and the amino group of another.

Question 17

Which level of protein structure is determined by the sequence of amino acids in a single polypeptide?

Accepted Answer

Primary structure

Question 18

What happens to a protein when it is denatured?

Accepted Answer

It unfolds and loses its functional three-dimensional shape.

Question 19

Which nitrogenous base is found only in RNA and not in DNA?

Accepted Answer

Uracil

Question 20

Which high-energy compound is most important for energy storage in the human body?

Accepted Answer

Adenosine triphosphate (ATP)

Chapter 2: The Chemical Level of Organization – Study Notes

Study Guide - Practice Questions