Which hormone regulates blood sugar? A. Thyroxine B. Insulin C. Adrenaline D. Melatonin Explanation: Insulin lowers blood glucose levels.
Which process converts glucose to pyruvate? A. Krebs cycle B. Glycolysis C. Electron transport D. Fermentation Explanation: Glycolysis breaks glucose into pyruvate.
Which structure regulates passage of substances into cell? A. Nucleus B. Cell membrane C. Mitochondria D. Ribosome Explanation: Plasma membrane controls transport.
Which base is found in RNA but not DNA? A. Thymine B. Cytosine C. Uracil D. Guanine Explanation: RNA uses uracil instead of thymine.
Which amino acid is acidic? A. Lysine B. Arginine C. Aspartic acid D. Alanine Explanation: Aspartic acid has acidic side chain.
Which functional group defines ketones? A. -CHO B. -CO- C. -COOH D. -OH Explanation: Ketones contain carbonyl group within chain.
Which is an example of nucleophilic substitution? A. Addition to alkene B. SN1 reaction C. Elimination reaction D. Oxidation Explanation: SN1 involves nucleophile replacing leaving group.
Which molecule is nonpolar? A. NH₃ B. H₂O C. CO₂ D. SO₂ Explanation: Linear geometry cancels dipoles.
Which is strongest oxidizing agent? A. F₂ B. Cl₂ C. Br₂ D. I₂ Explanation: Fluorine has highest reduction potential.
Which element has highest electronegativity? A. Oxygen B. Fluorine C. Nitrogen D. Chlorine Explanation: Fluorine is most electronegative element.