Question 1

Which element is the most abundant in living systems (excluding water) and serves as the main component of carbohydrates, proteins, nucleic acids, and lipids?

Accepted Answer

Carbon

Question 2

Organic molecules are defined as chemical compounds that contain:

Accepted Answer

Carbon and Hydrogen

Question 3

Which of the following best explains why carbon is an excellent building block for biological molecules?

Accepted Answer

It can form up to four covalent bonds, allowing for diverse molecular structures.

Question 4

Which of the following is NOT a way that carbon backbones can vary in organic molecules?

Accepted Answer

Type of peptide bond

Question 5

A hydrocarbon is best described as:

Accepted Answer

A molecule containing only carbon and hydrogen atoms

Question 6

Which of the following molecules is NOT considered organic?

Accepted Answer

CO2 (carbon dioxide)

Question 7

Which functional group is NOT present in the molecule shown below?

$$\mathrm{HO{-}C(=O){-}CH(NH_2$){-}CH_2OH}$$

Accepted Answer

Sulfhydryl

Question 8

Which of the following is NOT a functional group commonly found in biological molecules?

Accepted Answer

-H_2O (water)

Question 9

Which functional group is shown below?

$$\mathrm{R{-}COOH}$$

Accepted Answer

Carboxyl

Question 10

A molecule with the formula $$\mathrm{C_2H_6O}$$ could be either ethanol or dimethyl ether. This is an example of which concept?

Accepted Answer

Isomerism

Question 11

Which of the following best describes the difference between a ketone and an aldehyde functional group?

Accepted Answer

A ketone has a carbonyl group in the middle of a carbon chain, while an aldehyde has it at the end.

Question 12

Which of the following molecules is a hydrocarbon?

Accepted Answer

C2H6 (ethane)

Question 13

Which property of carbon allows it to form molecules with different shapes such as straight chains, branched chains, and rings?

Accepted Answer

Ability to form four covalent bonds

Question 14

Which of the following best describes a methyl group?

Accepted Answer

A carbon atom bonded to three hydrogen atoms ($$\mathrm{-CH_3$})$$

Question 15

A molecule contains both an amino group ($$\mathrm{-NH_2$}) $$and a carboxyl group ($$\mathrm{-COOH}). $$This molecule is most likely:

Accepted Answer

An amino acid

Question 16

Which of the following is a real-life example of a molecule with a ring form carbon backbone?

Accepted Answer

Benzene ($$\mathrm{C_6H_6})$$

Question 17

Which functional group is responsible for the acidic properties of amino acids?

Accepted Answer

Carboxyl group ($$\mathrm{-COOH})$$

Question 18

Which of the following best explains why hydrocarbons are generally insoluble in water?

Accepted Answer

They are nonpolar and cannot form hydrogen bonds with water.

Question 19

Which of the following functional groups is commonly found in ATP and is involved in energy transfer?

Accepted Answer

Phosphate group ($$\mathrm{-PO_4$^{2-}})$$

Question 20

A molecule with the formula $$\mathrm{C_6H_{12}O_6$}$$ can exist as both a straight-chain and a ring form. This is an example of which property of carbon?

Accepted Answer

Ability to form different backbone structures

Carbon and the Molecular Diversity of Life: Study Notes

Study Guide - Practice Questions

Study Guide - Flashcards