Question 1

Which property of carbon makes it uniquely suited to form the backbone of organic molecules?

Accepted Answer

It can form up to four covalent bonds with other atoms.

Question 2

Which of the following best explains why glucose and fructose, both with the formula $\mathrm{C_6H_{12}O_6}$, have different properties?

Accepted Answer

They are isomers with different arrangements of atoms.

Question 3

A dehydration reaction is used to:

Accepted Answer

Join two monomers to form a polymer, releasing water.

Question 4

Which functional group is found in all amino acids and is responsible for their basic properties?

Accepted Answer

Amino group ($\mathrm{-NH_2}$)

Question 5

Why can humans digest starch but not cellulose, even though both are polymers of glucose?

Accepted Answer

Humans lack the enzymes to break the $\beta$-glycosidic bonds in cellulose.

Question 6

Which of the following statements about lipids is TRUE?

Accepted Answer

They are hydrophobic and store more energy per gram than carbohydrates.

Question 7

A triglyceride is formed by combining:

Accepted Answer

One glycerol and three fatty acids through dehydration reactions.

Question 8

Which of the following best describes the primary structure of a protein?

Accepted Answer

The sequence of amino acids in a polypeptide chain.

Question 9

Which chemical group is non-polar, not reactive, and is responsible for the shapes and functions of organic molecules?

Accepted Answer

Methyl group ($\mathrm{-CH_3}$)

Question 10

Which of the following is a function of nucleic acids in cells?

Accepted Answer

Storing genetic information and directing protein synthesis.

Question 11

A mutation changes a single amino acid in the primary structure of a protein. Which level(s) of protein structure could be affected?

Accepted Answer

All levels: primary, secondary, tertiary, and quaternary.

Question 12

Which of the following best explains why phospholipids are essential for cell membranes?

Accepted Answer

They have hydrophilic heads and hydrophobic tails, forming a bilayer in water.

Question 13

Which of the following pairs is correctly matched with its monomer?

Accepted Answer

Protein – amino acid

Question 14

Which of the following is a real-life consequence of consuming large amounts of saturated fats?

Accepted Answer

Increased risk of cardiovascular disease due to higher cholesterol.

Question 15

Which of the following statements about DNA and RNA is TRUE?

Accepted Answer

DNA is double-stranded and contains thymine; RNA is single-stranded and contains uracil.

Question 16

Which process breaks down polymers into monomers by adding water?

Accepted Answer

Hydrolysis

Question 17

A molecule with the formula $\mathrm{C_{18}H_{36}O_2}$ is most likely a:

Accepted Answer

Fatty acid

Question 18

Which of the following best describes the difference between saturated and unsaturated fatty acids?

Accepted Answer

Saturated fatty acids have no double bonds; unsaturated fatty acids have one or more double bonds.

Question 19

Which of the following is NOT a function of proteins in living organisms?

Accepted Answer

Storing genetic information

Question 20

Which of the following best explains why small differences in molecular structure can have large biological effects, as seen in sex hormones?

Accepted Answer

Small changes in functional groups can alter the molecule's shape and function.

Chapter 3: The Molecules of Cells – Structure and Function of Organic Molecules

Study Guide - Practice Questions