Question 1

Which of the following best describes a hydrocarbon?

Accepted Answer

A molecule composed only of carbon and hydrogen atoms.

Question 2

Which of the following is a requirement for a molecule to be considered 'organic' in biological chemistry?

Accepted Answer

It must contain both carbon and hydrogen atoms.

Question 3

Why are hydrocarbons generally insoluble in water?

Accepted Answer

Because hydrocarbons are nonpolar and water is polar, leading to poor interactions between their molecules.

Question 4

What is the valence of carbon, and how does it relate to its ability to form diverse molecules?

Accepted Answer

Carbon has a valence of 4, allowing it to form up to four covalent bonds with other atoms.

Question 5

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 6

Which type of isomerism is illustrated by two molecules that are mirror images of each other but cannot be superimposed?

Accepted Answer

Enantiomers

Question 7

A molecule with the formula $$C_4H_{10}$$ can exist as either butane or isobutane. What type of isomerism does this represent?

Accepted Answer

Structural isomerism

Question 8

Which functional group is present in all amino acids and acts as a base by accepting a proton ($$H^+$$)?

Accepted Answer

Amino group ($$-NH_2$)

Question 9

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

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 10

Which functional group is most directly involved in the transfer of energy within cells, such as in ATP?

Accepted Answer

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

Question 11

Which functional group is associated with cross-linking that stabilizes protein structure, such as in keratin of hair?

Accepted Answer

Sulfhydryl group ($$-SH)$$

Question 12

Which of the following functional groups increases the solubility of organic molecules in water due to its polarity?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 13

A patient is given a drug that is a mixture of two enantiomers. Only one enantiomer is effective, while the other causes side effects. What property of enantiomers explains this difference?

Accepted Answer

Enantiomers have different three-dimensional shapes, allowing them to interact differently with biological molecules such as enzymes and receptors.

Question 14

Which of the following best describes the difference between cis and trans isomers?

Accepted Answer

Cis isomers have substituents on the same side of a double bond, while trans isomers have them on opposite sides.

Question 15

Which of the following statements about the methyl group ($$-CH_3$) is correct?

Accepted Answer

It is nonpolar and often acts to reduce the reactivity of a molecule.

Question 16

A molecule contains both a carbonyl group ($$\u003eC=O) $$and a hydroxyl group ($$-OH) $$attached to the same carbon atom. Which functional group does this describe?

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 17

Which of the following best explains why carbon can form such a wide variety of molecules?

Accepted Answer

Carbon can form four covalent bonds, allowing for branching, rings, and chains.

Question 18

Which two functional groups are found in all amino acids?

Accepted Answer

Amino group ($$-NH_2$) and carboxyl group (-$$COOH$$)

Question 19

A researcher is studying a molecule that contains a phosphate group. Which of the following is a likely function of this molecule in a cell?

Accepted Answer

It is involved in energy transfer, such as in ATP.

Question 20

Which of the following best describes the electron configuration of carbon?

Accepted Answer

$$1s^2$$\ $$2s^2$$\ $$2p^2$$

Chapter 4: Carbon and the Molecular Diversity of Life – Study Guide

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