Question 1

Which of the following statements best explains why carbon is considered the backbone of organic molecules in living organisms?

Accepted Answer

Carbon is able to form four covalent bonds, including double and triple bonds, enabling complex structures.

Question 2

A patient is exposed to a radioisotope for diagnostic imaging. Which property of radioisotopes makes them useful for this purpose?

Accepted Answer

Radioisotopes emit energy in the form of radiation due to their unstable nuclei.

Question 3

Which equation correctly represents the reversible buffer reaction that helps maintain blood pH?

Accepted Answer

$$\mathrm{$$HCO_3$$^-} + \mathrm{H^+} \rightleftharpoons \mathrm{H_2CO_3}$$

Question 4

Which of the following best describes the difference between covalent and ionic bonds?

Accepted Answer

Covalent bonds involve sharing electrons between atoms, while ionic bonds involve the attraction between oppositely charged ions.

Question 5

A solution has a hydrogen ion concentration of $$1 	imes 10$$^{-4}$$ M. What is its pH?

Accepted Answer

$$4$$

Question 6

Which property of water allows it to help regulate body temperature in humans?

Accepted Answer

Water can absorb and hold a large amount of heat energy with only a modest increase in temperature.

Question 7

Which of the following molecules is a polysaccharide used for energy storage in animals?

Accepted Answer

Glycogen

Question 8

A protein loses its biological function after exposure to high temperature. What is the most likely explanation?

Accepted Answer

The protein underwent denaturation, disrupting its structure.

Question 9

Which of the following best describes the structure of a phospholipid?

Accepted Answer

A glycerol molecule bonded to two fatty acids and a phosphate group.

Question 10

Which of the following is true regarding the flow of genetic information in cells?

Accepted Answer

DNA contains instructions for producing RNA, which then directs protein synthesis.

Question 11

A molecule is described as hydrophobic. What does this mean about its interaction with water?

Accepted Answer

It does not interact with or dissolve in water because it is nonpolar.

Question 12

Which of the following is a correct pairing of nitrogenous bases in DNA?

Accepted Answer

Guanine–Cytosine

Question 13

Which process is responsible for breaking down macromolecules into their monomer subunits by adding water?

Accepted Answer

Hydrolysis

Question 14

A triglyceride molecule is composed of which of the following?

Accepted Answer

Glycerol and three fatty acids

Question 15

Which of the following best describes the role of enzymes in biochemical reactions?

Accepted Answer

Enzymes speed up chemical reactions by lowering activation energy and are not altered or consumed.

Question 16

Which of the following is a correct formula for the hydrolysis of ATP?

Accepted Answer

$$\mathrm{ATP} ightarrow \mathrm{ADP} + \mathrm{P_i} + 	ext{energy}$$

Question 17

Which of the following elements is NOT one of the six most abundant in the human body?

Accepted Answer

Sulfur

Question 18

A molecule of water (H$$_2O) is $$described as polar. What does this mean?

Accepted Answer

The molecule has regions of slight positive and negative charge due to unequal sharing of electrons.

Question 19

Which of the following best explains why free radicals are considered dangerous in biological systems?

Accepted Answer

They have unpaired electrons, making them highly reactive and capable of damaging proteins and DNA.

Question 20

Which of the following statements about dehydration synthesis is correct?

Accepted Answer

It removes the equivalent of a water molecule to link monomers into polymers.

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Study Guide - Practice Questions