Master Biochemistry Basics: Atoms, Molecules, and More

Question 1

Which chemical bond involves the sharing of electron pairs between atoms?

Accepted Answer

Covalent

Answer

Ionic

Answer

Hydrogen

Answer

Van der Waals

Question 2

Identify the weak acid from the following options:

Accepted Answer

Acetic acid

Answer

Hydrochloric acid

Answer

Sulfuric acid

Answer

Nitric acid

Question 3

What is the primary function of a buffer solution?

Accepted Answer

Maintain a stable pH

Answer

Remove impurities

Answer

Catalyze reactions

Answer

Dissolve solids

Question 4

State the first law of thermodynamics.

Accepted Answer

Energy cannot be created or destroyed.

Answer

Entropy always increases.

Answer

Heat flows from hot to cold.

Answer

Gibbs free energy change is negative for spontaneous reactions.

Question 5

Which reaction is classified as exothermic?

Accepted Answer

Combustion of methane

Answer

Dissolving sodium chloride in water

Answer

Condensation of water vapor

Answer

Melting of ice

Question 6

Distinguish between an atom and a molecule:

Accepted Answer

Atoms are fundamental units, molecules are combinations.

Answer

Molecules are fundamental units, atoms are combinations.

Answer

Atoms and molecules are identical.

Answer

Atoms exist only in elements, molecules only in compounds.

Question 7

Calculate the molar mass of sodium chloride (NaCl).

Accepted Answer

58.44 g/mol

Answer

22.99 g/mol

Answer

35.45 g/mol

Answer

70.90 g/mol

Question 8

Which fundamental particle of matter has a negative charge and an atomic mass of approximately one?

Accepted Answer

Electron

Answer

Proton

Answer

Neutron

Answer

Photon

Question 9

What type of chemical bond results from the electrostatic attraction between ions of opposite charge?

Accepted Answer

Ionic bond

Answer

Covalent bond

Answer

Hydrogen bond

Answer

Van der Waals force

Question 10

Which law of thermodynamics states that energy cannot be created or destroyed, only transferred or transformed?

Accepted Answer

First law

Answer

Second law

Answer

Third law

Answer

Zeroth law

Question 11

Which molecule serves as the basic unit of protein structure?

Accepted Answer

Amino acid

Answer

Glucose

Answer

Fatty acid

Answer

Nucleotide

Question 12

Which factor does NOT influence the strength of an ionic bond?

Accepted Answer

Temperature

Answer

Charge of the ions

Answer

Size of the ions

Answer

Distance between the ions

Question 13

What process describes the movement of water molecules from an area of higher water potential to an area of lower water potential?

Accepted Answer

Osmosis

Answer

Diffusion

Answer

Active transport

Answer

Facilitated diffusion

Question 14

Which biomolecule is the primary energy reserve in most living organisms?

Accepted Answer

Carbohydrates

Answer

Proteins

Answer

Lipids

Answer

Nucleic acids

Question 15

Which type of chemical bond involves the electrostatic attraction between ions with opposite charges?

Accepted Answer

Ionic bond

Answer

Hydrogen bond

Answer

Covalent bond

Answer

Van der Waals force

Question 16

Calculate the pH of a solution with a hydrogen ion concentration of 1 x 10^-7 mol/L.

Accepted Answer

7

Answer

6

Answer

8

Answer

9

Question 17

Which property is NOT characteristic of water?

Accepted Answer

Non-polar molecular structure

Answer

High specific heat capacity

Answer

Acts as a solvent

Answer

Lower density in its solid state

Question 18

What is the primary function of buffers in biological systems?

Accepted Answer

Maintain stable pH levels

Answer

Act as enzyme cofactors

Answer

Provide energy for cellular processes

Answer

Transport ions across cell membranes

Question 19

Which type of molecule is composed of amino acids linked by peptide bonds?

Accepted Answer

Protein

Answer

Carbohydrate

Answer

Lipid

Answer

Nucleic acid

Question 20

What is the primary role of the Krebs cycle in cellular metabolism?

Accepted Answer

Produce reducing equivalents (NADH and FADH2)

Answer

Generate ATP

Answer

Synthesize amino acids

Answer

Degrade carbohydrates

Question 21

Which law of thermodynamics states that the entropy of an isolated system always increases over time?

Accepted Answer

Second law

Answer

First law

Answer

Third law

Answer

Zeroth law

Question 22

What is the conjugate acid of the HPO42- ion?

Accepted Answer

H2PO4-

Answer

H3PO4

Answer

OH-

Answer

PO43-

Question 23

Which component is NOT found in the structure of a nucleotide?

Accepted Answer

Amino acid

Answer

Ribose or deoxyribose

Answer

Phosphate group

Answer

Nitrogenous base