Question 1

Which property of carbon is MOST responsible for the diversity of organic molecules found in living organisms?

Accepted Answer

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

Question 2

Which of the following best explains why visible light does not break the covalent bonds in organic molecules?

Accepted Answer

Visible light has a longer wavelength and therefore less energy than is required to break C—C bonds.

Question 3

A molecule with the formula $$C_2H_2$$ contains what type of bond between the two carbon atoms?

Accepted Answer

A triple bond

Question 4

Which functional group is most likely to confer a negative charge to a biological molecule at neutral pH?

Accepted Answer

Carboxyl group

Question 5

How many stereoisomers are possible for a molecule with three asymmetric carbon atoms?

Accepted Answer

$$2^3 = 8$

Question 6

Which property of water is MOST responsible for its ability to moderate temperature changes in living organisms?

Accepted Answer

Its high specific heat

Question 7

Why are hydrocarbons generally insoluble in water?

Accepted Answer

They are nonpolar and cannot form hydrogen bonds with water.

Question 8

Which of the following best describes the permeability of a biological membrane to ions such as $$Na^+$$ and $$Cl^-$$?

Accepted Answer

Impermeable; ions require transport proteins to cross the membrane.

Question 9

Which process is responsible for the breakdown of biological polymers into their monomers?

Accepted Answer

Hydrolysis

Question 10

During the synthesis of a protein, what is the role of tRNA?

Accepted Answer

It activates amino acids by coupling them to a carrier molecule.

Question 11

Which of the following is an example of a supramolecular structure?

Accepted Answer

A ribosome

Question 12

Which type of noncovalent interaction is primarily responsible for the association of nonpolar groups within a protein's interior?

Accepted Answer

Hydrophobic interactions

Question 13

A protein is denatured by heat and then slowly cooled. What is most likely to happen if the protein does NOT require molecular chaperones?

Accepted Answer

It will spontaneously refold into its native conformation and regain function.

Question 14

Which of the following best describes the amphipathic nature of membrane phospholipids?

Accepted Answer

They have both a hydrophilic head and two hydrophobic tails.

Question 15

Which of the following is a direct consequence of the polarity of water molecules?

Accepted Answer

Water molecules form hydrogen bonds with each other.

Question 16

Which of the following statements about the hierarchical assembly of cellular structures is TRUE?

Accepted Answer

It allows for quality control by discarding defective components before higher-level assembly.

Question 17

Which of the following best explains why sodium chloride ($$NaCl) $$dissolves readily in water?

Accepted Answer

Water molecules form hydration shells around the ions, decreasing their chances of reassociation.

Question 18

Which of the following is NOT a property of water that is critical for life?

Accepted Answer

Low heat of vaporization

Question 19

Which of the following statements about the self-assembly of biological structures is correct?

Accepted Answer

The information for folding and assembly is inherent in the polymers themselves.

Question 20

Which of the following best describes the difference between informational and structural macromolecules?

Accepted Answer

Informational macromolecules have a nonrandom sequence of monomers that carries information, while structural macromolecules do not.

The Chemistry of the Cell: Foundations for Cell Biology

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