Question 1

Which of the following best describes the bond formed in the hydrogen molecule (H₂) as shown in the second image?

Accepted Answer

Covalent bond, where electrons are shared between atoms

Question 2

A solution has a hydrogen ion concentration $$[H^+] of$$ $$10^{-8} M. $$What is the pH of this solution?

Accepted Answer

$$pH = 8$$

Question 3

Which of the following best explains why ice is less dense than liquid water?

Accepted Answer

Hydrogen bonds in ice are more stable and keep water molecules further apart

Question 4

Which of the following is a correct description of a glycosidic bond?

Accepted Answer

A bond formed between two monosaccharides

Question 5

Which functional group is characterized by the formula $$-COOH$$ and is acidic in nature?

Accepted Answer

Carboxyl group

Question 6

What is the main difference between saturated and unsaturated fats?

Accepted Answer

Saturated fats have only single bonds between carbon atoms; unsaturated fats have one or more double bonds

Question 7

Which of the following amino acids is classified as basic?

Accepted Answer

Lysine

Question 8

Which property of water allows coastal areas to maintain moderate temperatures?

Accepted Answer

High specific heat

Question 9

What is the [OH⁻] concentration in a solution with $$[H^+] = 10$$^{-8}$$ M at 25°C? (Given: $$[H^+][OH^-] = $$10^{-14})$$

Accepted Answer

$$[OH^-] = 10$$^{-6}$$ M

Question 10

Which of the following best describes a condensation (dehydration synthesis) reaction?

Accepted Answer

A reaction that joins monomers to form polymers by removing water

Question 11

Which of the following is an example of a structural polysaccharide?

Accepted Answer

Cellulose

Question 12

Which of the following best describes an enantiomer?

Accepted Answer

Molecules that are mirror images of each other

Question 13

Which of the following is a trace element essential for life?

Accepted Answer

Iron

Question 14

Which type of bond is shown in the third image (sodium and fluorine)?

Accepted Answer

Ionic bond

Question 15

What is the difference in hydrogen ion concentration between a solution with pH 4 and one with pH 6?

Accepted Answer

The pH 4 solution has 100 times more $$[H^+]$$ than the pH 6 solution

Question 16

Which of the following best describes a peptide bond?

Accepted Answer

A bond between two amino acids

Question 17

Which of the following is a characteristic of the phosphate functional group?

Accepted Answer

It is involved in energy transfer, such as in ATP

Question 18

Which of the following best explains why morphine can mimic endorphins in the body (as shown in the last image)?

Accepted Answer

Morphine has a similar three-dimensional shape to endorphins, allowing it to bind to the same receptors

Question 19

Which of the following is true about the backbone of DNA and RNA molecules?

Accepted Answer

It is made of alternating phosphate and sugar groups

Question 20

Which of the following best describes a polar covalent bond?

Accepted Answer

A bond where electrons are shared unequally, creating partial charges

Biology 121 – Foundational Concepts and Molecular Structures Study Guide

Study Guide - Practice Questions