Question 1

Which of the following statements best explains why carbon is the backbone of most biological molecules?

Accepted Answer

Carbon can form four strong covalent bonds, allowing for large, complex molecules.

Question 2

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

Accepted Answer

Carboxyl group ($$-COOH)$$

Question 3

A molecule with the formula $$C_2H_5OH is $$classified as which type of organic compound?

Accepted Answer

An alcohol

Question 4

Which of the following elements is NOT one of the six most abundant elements in living organisms (CHNOPS)?

Accepted Answer

Calcium ($$Ca)$$

Question 5

At physiological pH (about 7.4), what is the predominant form of the amino and carboxyl groups in amino acids?

Accepted Answer

Amino group is protonated ($$-NH_3$^+$$), carboxyl group is deprotonated ($$-COO^-).$$

Question 6

Which statement best describes the relationship between the strength of covalent bonds and the atomic mass of the elements involved?

Accepted Answer

Lighter elements form stronger covalent bonds.

Question 7

Which of the following is a correct pairing of a monomer and its corresponding polymer?

Accepted Answer

Nucleotide – Nucleic acid

Question 8

Which property distinguishes living things from inanimate matter at the molecular level?

Accepted Answer

Propensity for self-replication

Question 9

Which of the following is a trace element essential for life, but present in much lower abundance than CHNOPS elements?

Accepted Answer

Iron ($$Fe)$$

Question 10

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

Accepted Answer

Amino group ($$-NH_2$)

Question 11

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

Accepted Answer

A sugar, a phosphate group, and a nitrogenous base

Question 12

Which of the following is a correct statement about the periodic table and biochemistry?

Accepted Answer

A small number of elements (CHNOPS) make up the majority of living matter.

Question 13

Which of the following is a correct example of a functional group and its effect on molecular properties?

Accepted Answer

Adding a hydroxyl group to ethane forms ethanol, which is liquid at room temperature.

Question 14

Which of the following statements about water in biological systems is correct?

Accepted Answer

Water is the most abundant molecule in most living organisms.

Question 15

Which of the following best describes the role of enzymes in biological systems?

Accepted Answer

Enzymes catalyze chemical reactions, increasing reaction rates.

Question 16

Which of the following is a correct statement about the organization of living things?

Accepted Answer

Living things are highly organized and composed of simple molecules that interact in complex ways.

Question 17

Which of the following is a correct example of a polymer and its monomer?

Accepted Answer

Polysaccharide – Monosaccharide

Question 18

Which of the following best explains the quote by Jacques Monod: 'Anything found to be true of E. coli must also be true of elephants'?

Accepted Answer

All living organisms share the same basic biochemical principles.

Question 19

Which of the following is a correct statement about the role of electron transfer in living systems?

Accepted Answer

All life relies on the transfer of electrons between molecules to capture energy.

Question 20

Which of the following is a correct description of the zwitterionic form of an amino acid at physiological pH?

Accepted Answer

The amino group is positively charged ($$-NH_3$^+) $$and the carboxyl group is negatively charged ($$-COO^-).$$

Biochemistry Foundations: Elements, Biomolecules, and Molecular Principles

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