Cell & Cell Organelles

• Smallest cell: Mycoplasma (0.1–0.3 µm)
• Largest cell: Ovum (egg)
• Longest cell: Nerve cell
• Mnemonic: MOL – Mycoplasma, Ovum, Longest-nerve
• Power house: Mitochondria (oxidative phosphorylation)
• Ribosome: protein factory; 80S (eukaryote), 70S (prokaryote, chloroplast, mitochondria)
• Lysosome: suicidal bag (acid hydrolases)
• Chlorophyll site: thylakoid; pigment: chlorophyll-a (universal)
• Golgi: packaging & secretion; discovered by Camillo Golgi

Genetics

• DNA: deoxyribose; bases A-T, G-C
• RNA: ribose; bases A-U, G-C
• Purines: A, G (2 rings) → Pure As Gold
• Pyrimidines: C, T, U (1 ring) → CUT Py
• mRNA: messenger; tRNA: adaptor (76 nt); rRNA: ribosomal
• Human genome: 23 pairs (46) chromosomes; 22 autosomes + 1 sex pair
• Down syndrome: trisomy 21
• Klinefelter: XXY; Turner: XO

Human Physiology (One-liners)

• Normal blood pH: 7.35–7.45
• RBC lifespan: 120 days; WBC: 3–5 days
• Universal donor: O⁻; universal recipient: AB⁺
• Hemoglobin: 12–16 g/dL (♀), 13.5–17.5 g/dL (♂)
• Heart output: 72 beats/min; cardiac output = stroke vol. × rate ≈ 5 L/min
• Lung capacity: TLC ≈ 6000 mL; IRV 3000, ERV 1100, TV 500 mL
• Pancreas: dual function—insulin (β-cell) & glucagon (α-cell)
• Pepsin: pH 1.5–2; trypsin: pH 8–9
• Vit. K: clotting factor synthesis; Vit. B₁₂: pernicious anemia
• Hormone vs. enzyme: hormone works away, enzyme works on site

Classification

• 5-kingdom (Whittaker): Monera, Protista, Fungi, Plantae, Animalia
• Mnemonic: My Parents Fight Against Monsters
• Binomial nomenclature: Carolus Linnaeus
• Smallest flowering plant: Wolffia
• Largest flower: Rafflesia (corpse flower)
• Amphibian of plant: Bryophyta (need water for fertilization)

Plant Physiology

• C₃: wheat, rice; first product PGA (3-C)
• C₄: maize, sugarcane; first product OAA (4-C), Kranz anatomy
• CAM: pineapple; night CO₂ fixation
• N₂ fixation enzyme: nitrogenase (Mo-Fe protein)
• Hormones: Auxin (apical dominance), Gibberellin (bolting), Cytokinin (delay senescence), ABA (stress, dormancy), Ethylene (ripening)

Diseases & Carriers

• Plasmodium: Anopheles (malaria)
• Dengue: Aedes
• Kala-azar: Sandfly (Phlebotomus)
• Typhoid: Salmonella typhi; Widal test
• Cholera: Vibrio cholerae; rice-water stool
• COVID-19: SARS-CoV-2 (RNA virus)
• AIDS: HIV (retrovirus); T-helper cell target

Rapid-Fire MCQs