🔬 Biology Exam Review – Multiple Choice (40 Questions)

Which reaction stores energy in the form of ATP?
A. Exergonic
B. Endergonic
C. Hydrolysis
D. Fermentation

Which of the following reactions releases energy?
A. Condensation
B. Endergonic
C. ATP synthesis
D. ATP hydrolysis

What do enzymes do in a chemical reaction?
A. Change the equilibrium
B. Increase the activation energy
C. Speed up reactions by lowering the activation energy
D. Act as substrates

In competitive inhibition, the inhibitor:
A. Binds to an allosteric site
B. Changes enzyme shape permanently
C. Competes with the substrate for the active site
D. Inhibits only DNA polymerase

Which of the following involves the intake of small droplets of fluid by a cell?
A. Phagocytosis
B. Pinocytosis
C. Endocytosis
D. Exocytosis

Which macromolecule is made of monosaccharides?
A. Lipids
B. Proteins
C. Carbohydrates
D. Nucleic acids

Which functional group gives amino acids their acidic properties?
A. Hydroxyl (-OH)
B. Phosphate (-PO₄³⁻)
C. Methyl (-CH₃)
D. Carboxyl (-COOH)

What type of bond links sugars in carbohydrates?
A. Peptide
B. Hydrogen
C. Glycosidic
D. Phosphodiester

Which of the following best represents the secondary structure of a protein?
A. Order of amino acids
B. Folding into alpha-helices and beta-sheets
C. Overall 3D shape
D. Multiple polypeptide chains linked together

Which level of protein structure involves interactions between R-groups?
A. Primary
B. Secondary
C. Tertiary
D. Quaternary

Phosphodiester bonds are found in:
A. Proteins
B. Carbohydrates
C. DNA and RNA backbones
D. Lipids

Which process occurs first in cellular respiration?
A. Glycolysis
B. Krebs cycle
C. Chemiosmosis
D. ETC

Which molecule is produced during glycolysis?
A. NADPH
B. Pyruvate
C. CO₂
D. Acetyl-CoA

What is the final electron acceptor in the ETC of aerobic respiration?
A. NAD+
B. Oxygen
C. Carbon dioxide
D. Glucose

Chemiosmosis is the movement of:
A. Electrons through a protein
B. Protons across a membrane to power ATP synthesis
C. ATP into the mitochondria
D. CO₂ out of cells

Which of the following occurs in the mitochondrial matrix?
A. Glycolysis
B. Calvin cycle
C. Krebs cycle
D. Light reactions

Which stage of photosynthesis produces glucose?
A. Light reactions
B. Calvin cycle
C. Chemiosmosis
D. Photolysis

Which enzyme is responsible for synthesizing RNA during transcription?
A. DNA polymerase
B. RNA polymerase
C. Helicase
D. Ligase

A mutation that replaces one amino acid with another is a:
A. Frameshift mutation
B. Silent mutation
C. Missense mutation
D. Nonsense mutation

A mutation that changes a codon into a stop codon is a:
A. Frameshift mutation
B. Missense mutation
C. Silent mutation
D. Nonsense mutation

Which enzyme unwinds DNA during replication?
A. DNA polymerase
B. Ligase
C. Helicase
D. RNA polymerase

DNA and RNA differ because:
A. DNA contains uracil
B. RNA has deoxyribose
C. RNA is double-stranded
D. RNA has uracil instead of thymine

Which base pairs with cytosine in DNA?
A. Thymine
B. Adenine
C. Guanine
D. Uracil

The role of the anticodon on tRNA is to:
A. Start transcription
B. Bind to a ribosome site
C. Match a codon on mRNA
D. Terminate translation

Where does translation occur?
A. Nucleus
B. Ribosome
C. Golgi apparatus
D. Mitochondrion

Which part of cellular respiration makes the most ATP?
A. Glycolysis
B. Krebs cycle
C. ETC + Chemiosmosis
D. Fermentation

Which process splits water and releases oxygen in photosynthesis?
A. Calvin cycle
B. Light-dependent reactions
C. Glycolysis
D. Krebs cycle

The lac operon is an example of:
A. Protein synthesis
B. Post-translational modification
C. Gene regulation in prokaryotes
D. DNA replication

How does temperature affect enzymes?
A. They work faster as temperature decreases
B. Too high a temperature can denature them
C. All enzymes work best at 0°C
D. Enzymes become inactive at room temperature

Which process breaks down polymers into monomers using water?
A. Condensation
B. Dehydration
C. Hydrolysis
D. Phosphorylation

ATP is mainly used in cells to:
A. Store DNA
B. Break down enzymes
C. Provide energy for cellular work
D. Act as an enzyme

Which solution has equal solute concentrations inside and outside a cell?
A. Hypotonic
B. Hypertonic
C. Isotonic
D. Osmotic

Which type of molecule is made of glycerol and fatty acids?
A. Protein
B. Carbohydrate
C. Triglyceride
D. Nucleic acid

Where does osmosis occur?
A. In DNA replication
B. In ribosomes
C. Across a selectively permeable membrane
D. In the nucleus

Codons are found on:
A. DNA
B. tRNA
C. mRNA
D. rRNA

Which ribosomal site holds the growing polypeptide chain during translation?
A. E site
B. A site
C. P site
D. Z site

Which of the following best describes diffusion?
A. Active transport of molecules
B. Movement of molecules from high to low concentration
C. Requires ATP
D. Only occurs in plants

Which bonds hold the nitrogenous bases of DNA together?
A. Peptide bonds
B. Hydrogen bonds
C. Phosphodiester bonds
D. Ionic bonds

Which of the following contains ribose sugar?
A. DNA
B. Protein
C. RNA
D. ATP only

Which type of molecule contains both a phosphate group and nitrogen base?
A. Amino acid
B. Nucleotide
C. Fatty acid
D. Disaccharide