Question 1

Which property of carbon most directly explains its ability to form a vast diversity of stable organic molecules?

Accepted Answer

Its four valence electrons allow it to form up to four covalent bonds with other atoms.

Question 2

A molecule with the formula $$C_5H_{12}$$ can exist as both pentane and 2-methylbutane. What type of isomerism does this illustrate?

Accepted Answer

Structural isomerism

Question 3

Which functional group is responsible for the acidic properties of acetic acid, and what is its general structure?

Accepted Answer

Carboxyl group; $$-COOH$$

Question 4

Why are enantiomers of a drug often biologically distinct in their effects?

Accepted Answer

They are mirror images and only one form may fit the active site of a biological molecule.

Question 5

Which of the following best describes a hydrocarbon?

Accepted Answer

A molecule containing only carbon and hydrogen atoms.

Question 6

A fat molecule contains long hydrocarbon chains. What property do these chains impart to fats?

Accepted Answer

They store large amounts of energy due to the C-H bonds.

Question 7

Which functional group is most likely to form a cross-link that stabilizes protein structure?

Accepted Answer

Sulfhydryl group ($$-SH)$$

Question 8

Which of the following statements about ATP (adenosine triphosphate) is correct?

Accepted Answer

ATP releases energy when a phosphate group is removed by hydrolysis.

Question 9

Which functional group is characteristic of alcohols and is found in ethanol?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 10

A molecule contains both a carbonyl group and a hydroxyl group on the same carbon atom. What is the name of this functional group?

Accepted Answer

Carboxyl group

Question 11

Which of the following best explains why cis-trans isomers have different properties?

Accepted Answer

They differ in the spatial arrangement of atoms around a double bond.

Question 12

Which element is NOT one of the major elements found in living organisms as described in the study materials?

Accepted Answer

Calcium (Ca)

Question 13

Which functional group is most likely to be involved in transferring energy between molecules in cells?

Accepted Answer

Phosphate group ($$-$$OPO_3$$^{2-})$$

Question 14

A molecule with the formula $$C_2H_4$$ has a double bond between its carbon atoms. What is the geometry around each carbon atom in this molecule?

Accepted Answer

Trigonal planar

Question 15

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

Accepted Answer

They are responsible for the unique chemical reactions of each molecule.

Question 16

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

Accepted Answer

It is nonpolar and affects gene expression when attached to DNA.

Question 17

A researcher discovers a new organic molecule with the formula $$C_3H_6O. $$Which functional group could be present if the molecule is a ketone?

Accepted Answer

A carbonyl group ($$\u003eC=O) $$located within the carbon skeleton

Question 18

Which of the following best explains why only one enantiomer of a drug is usually biologically active?

Accepted Answer

Biological receptors are themselves chiral and only recognize one enantiomer.

Question 19

Which of the following functional groups is basic and can accept a proton ($$H^+$$)?

Accepted Answer

Amino group ($$-NH_2$)

Question 20

A molecule contains a phosphate group. Which of the following is a likely property of this molecule?

Accepted Answer

It will have a negative charge and may participate in energy transfer.

Carbon and the Molecular Diversity of Life: Study Notes

Study Guide - Practice Questions