🔬 Biology Exam Review – Multiple Choice (40 Questions)

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

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

  3. 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

  4. 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

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

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

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

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

  9. 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

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

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

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

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

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

  15. 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

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

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

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

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

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

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

  22. 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

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

  24. 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

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

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

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

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

  29. 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

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

  31. 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

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

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

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

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

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

  37. 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

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

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

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