Question 1

Which property of carbon most directly explains its ability to form large, complex, and varied molecules essential for life?

Accepted Answer

Its four valence electrons, allowing it to form four covalent bonds

Question 2

Which of the following best describes a structural isomer?

Accepted Answer

Molecules with the same molecular formula but different covalent arrangements of their atoms

Question 3

A pharmaceutical company discovers that only one enantiomer of a drug is biologically active. What is the most likely explanation for this observation?

Accepted Answer

Organisms are sensitive to subtle variations in molecular shape

Question 4

Which functional group is responsible for the acidic properties of acetic acid, the main component of vinegar?

Accepted Answer

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

Question 5

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

Accepted Answer

A hydrocarbon chain composed only of carbon and hydrogen

Question 6

What is the main difference between cis-trans isomers?

Accepted Answer

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

Question 7

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

Accepted Answer

Amino group $$-\mathrm{NH}_2$$

Question 8

Which functional group is most likely to participate in hydrogen bonding with water, increasing a molecule's solubility?

Accepted Answer

Hydroxyl group $$-\mathrm{OH}$$

Question 9

Which of the following best explains why ATP is an important source of energy for cells?

Accepted Answer

ATP can react with water to release energy by breaking a phosphate bond

Question 10

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

Accepted Answer

An amino acid

Question 11

Which functional group is responsible for stabilizing protein structure through the formation of disulfide bonds?

Accepted Answer

Sulhydryl group $$-\mathrm{SH}$$

Question 12

Which of the following is a correct description of a ketone?

Accepted Answer

A molecule with a carbonyl group within the carbon skeleton

Question 13

Which element has a valence of 3 and is essential for the structure of proteins and nucleic acids?

Accepted Answer

Nitrogen

Question 14

Which functional group is commonly found in DNA and affects gene expression when added to DNA bases?

Accepted Answer

Methyl group $$-\mathrm{CH}_3$$

Question 15

Which of the following best describes the difference between estradiol and testosterone?

Accepted Answer

They have the same carbon skeleton but different functional groups attached

Question 16

Which functional group is most likely to be found in organic phosphates and is essential for energy transfer in cells?

Accepted Answer

Phosphate group $$-\mathrm{OPO}_3$$^{2-}$$

Question 17

Which of the following is NOT a major element of life found in similar percentages among organisms?

Accepted Answer

Calcium

Question 18

A fat molecule is primarily composed of which type of organic molecule?

Accepted Answer

Hydrocarbons

Question 19

Which of the following best explains why hydrocarbons can release a large amount of energy when they undergo reactions?

Accepted Answer

They have many nonpolar covalent bonds between carbon and hydrogen

Question 20

Which functional group is most likely to be found in sugars and is responsible for their classification as aldoses or ketoses?

Accepted Answer

Carbonyl group $$-\mathrm{C}=\mathrm{O}$$

Chapter 4: Carbon – The Backbone of Life

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