Question 1

Which of the following statements best explains why carbon is the backbone of organic molecules?

Accepted Answer

Carbon has four valence electrons, allowing it to form up to four covalent bonds with other atoms.

Question 2

A molecule with the formula $C_6H_{12}O_6$ is classified as which type of large organic molecule?

Accepted Answer

Carbohydrate

Question 3

Which property of hydrocarbons makes them a major component of fossil fuels?

Accepted Answer

They contain only carbon and hydrogen, making them nonpolar and energy-rich.

Question 4

Which functional group is responsible for making amino acids act as bases?

Accepted Answer

Amino group

Question 5

A triglyceride molecule is formed by joining three fatty acids to a glycerol backbone. Which type of reaction is responsible for this process?

Accepted Answer

Dehydration synthesis

Question 6

Which of the following best describes the difference between geometric (cis-trans) isomers?

Accepted Answer

They have the same covalent bonds but differ in the spatial arrangement around a double bond.

Question 7

Which of the following functional groups is most likely to make a molecule more hydrophilic and increase its solubility in water?

Accepted Answer

Carboxyl group

Question 8

A mutation causes a protein to lose its sulfhydryl (–SH) groups. What is the most likely consequence?

Accepted Answer

The protein will lose its ability to form disulfide bridges, affecting its stability.

Question 9

Which of the following is true about isomers?

Accepted Answer

Isomers have the same molecular formula but different structural arrangements, leading to different properties.

Question 10

Which of the following best explains why phosphates are important in biological molecules?

Accepted Answer

Phosphate groups store and transfer energy, as seen in ATP and nucleic acids.

Question 11

Which of the following molecules is most likely to be nonpolar and hydrophobic?

Accepted Answer

Methane ($CH_4$)

Question 12

A scientist discovers two molecules with the same molecular formula $C_5H_{12}$ but different branching patterns. What type of isomers are these?

Accepted Answer

Structural isomers

Question 13

Which functional group is most likely to act as an acid by donating a proton ($H^+$) in solution?

Accepted Answer

Carboxyl group ($-COOH$)

Question 14

Which of the following best describes the role of methyl groups in organic molecules?

Accepted Answer

They help turn on or off gene expression by attaching to DNA.

Question 15

Which of the following statements about nucleic acids is correct?

Accepted Answer

Nucleic acids are made of nucleotides, each containing a sugar, a nitrogen base, and a phosphate group.

Question 16

Which of the following is a correct statement about the relationship between carbon skeleton length and the number of possible isomers?

Accepted Answer

The number of isomers increases with the size of the carbon skeleton.

Question 17

Which of the following best explains why lipids are generally hydrophobic?

Accepted Answer

Lipids are composed mostly of long hydrocarbon chains, which are nonpolar.

Question 18

Which of the following is a property of the carboxyl group that affects the behavior of amino acids?

Accepted Answer

It acts as an acid and donates $H^+$ ions.

Question 19

Which of the following best describes the role of double bonds in hydrocarbon chains?

Accepted Answer

Double bonds make the chain more flexible and increase the number of possible geometric isomers.

Question 20

A molecule contains a carboxyl group and an amino group. Which type of molecule is this most likely to be?

Accepted Answer

Amino acid

Organic Molecules and Functional Groups in General Biology

Study Guide - Practice Questions