Question 1

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

Accepted Answer

Its tetravalence, allowing it to form four covalent bonds with other atoms

Question 2

Which of the following best describes a hydrocarbon?

Accepted Answer

A molecule containing only carbon and hydrogen atoms

Question 3

What is the molecular geometry of methane ($$CH_4) $$and why?

Accepted Answer

Tetrahedral, because carbon forms four bonds directed to the corners of a tetrahedron

Question 4

Which statement about isomers is correct?

Accepted Answer

Isomers have the same molecular formula but different structures and properties

Question 5

Which type of isomerism is responsible for the difference between cis and trans forms of a molecule?

Accepted Answer

Geometric (cis-trans) isomerism

Question 6

Thalidomide is a drug with two enantiomers. What is the significance of enantiomers in biological systems?

Accepted Answer

One enantiomer can be biologically active while the other is inactive or harmful

Question 7

Which functional group is present in all amino acids and is responsible for their basic properties?

Accepted Answer

Amino group ($$-NH_2$)

Question 8

Which functional group is found in alcohols and is responsible for their ability to form hydrogen bonds with water?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 9

Which of the following molecules is a hydrocarbon?

Accepted Answer

Methane ($$CH_4)$$

Question 10

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

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 11

Which functional group is found in thiols and is important for forming disulfide bonds in proteins?

Accepted Answer

Sulfhydryl group ($$-SH)$$

Question 12

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

Accepted Answer

It is nonpolar and can affect gene expression when attached to DNA

Question 13

Which functional group is present in ATP and is crucial for energy transfer in cells?

Accepted Answer

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

Question 14

Which of the following is a structural isomer of butane ($$C_4H_{10}$$)?

Accepted Answer

Isobutane

Question 15

Which type of isomerism is illustrated by the difference between estradiol and testosterone?

Accepted Answer

Functional group isomerism

Question 16

A molecule has the formula $$C_2H_6O. $$Which of the following statements is true?

Accepted Answer

It can exist as two structural isomers: ethanol and dimethyl ether

Question 17

Which functional group is most likely to be found in a molecule that acts as a base in biological systems?

Accepted Answer

Amino group ($$-NH_2$)

Question 18

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

Accepted Answer

The inflexibility of double bonds causes atoms to be arranged differently in space

Question 19

Which functional group is most likely to increase the solubility of an organic molecule in water?

Accepted Answer

Hydroxyl group ($$-OH)$$

Question 20

A patient is prescribed thalidomide for treatment. Why is it important for the physician to consider the drug's enantiomers?

Accepted Answer

One enantiomer can cause severe birth defects while the other is therapeutic

Carbon and the Molecular Diversity of Life: Structure, Isomerism, and Functional Groups

Study Guide - Practice Questions