SATHEE: Biology Master - Quick Revision

Biology Master - Quick Revision

Cell wall is made of cellulose in plants & peptidoglycan in bacteria.
Mitochondria = “Powerhouse”; site of Krebs cycle & oxidative phosphorylation.
RBCs live 120 days, lack nucleus & mitochondria in humans.
Insulin is secreted by β-cells of pancreas; lowers blood glucose.
Haemophilia is X-linked recessive—cross mother → son.
Nitrogenase enzyme (found in Rhizobium) needs anaerobic condition—protected by leghaemoglobin.
Chlorophyll-a has porphyrin head & phytol tail; peak absorption at 660 nm & 430 nm.
ADH (vasopressin) increases water reabsorption in DCT & collecting duct.
Bile contains no enzyme; emulsifies fat via bile salts.
Mendel’s 3:1 ratio is monohybrid dominant : recessive; 9:3:3:1 is di-hybrid.
mRNA has cap (5′-GTP) & tail (3′-poly-A) for stability & translation.
Oxytocin induces uterine contraction & milk ejection—posterior pituitary.
Sickle-cell anaemia is point mutation at 6th codon of β-globin (Glu→Val).
Normal blood pH = 7.35–7.45; maintained by HCO₃⁻ buffer.
Testis descend via inguinal canal; temp 2 °C < body temp for spermatogenesis.
Pulmonary artery is only artery carrying deoxygenated blood.
CCK-PZ hormone from duodenum stimulates pancreas & gall-bladder.
ECG P-wave = atrial depolarisation; T-wave = ventricular repolarisation.
Corpus luteum secretes progesterone to maintain pregnancy; degenerates → menstruation.
Gene therapy first success—ADA-SCID (1990) via retroviral vector.

Formula / Rule	Use
CO₂ assimilation rate = (Rate of photosynthesis – Rate of photorespiration)	Net productivity in C₃ vs C₄ plants
Hardy–Weinberg: p² + 2pq + q² = 1	Calculate allele & genotype frequency
Vital capacity = IRV + TV + ERV	Pulmonary function test
Cardiac output (CO) = Stroke volume (SV) × Heart rate (HR)	Blood flow per minute
Population growth dN/dt = rN(K–N)/K	Logistic growth model
Respiratory quotient (RQ) = CO₂ released / O₂ consumed	Identify substrate oxidised
Nucleic acid % = (A+T)/(G+C) ratio	Taxonomic fingerprint
Water potential (Ψ) = Ψs + Ψp	Predict direction of osmosis
Michaelis constant Km = [S] at ½ Vmax	Enzyme affinity indicator
Net primary productivity (NPP) = Gross PP – Respiratory loss	Ecosystem energy budget

KPCOFGS – King Philip Came Over For Good Soup = Taxonomic hierarchy.
“PALS” – Plasma, Aqueous humour, Lymph, Synovial fluid = Body fluids that are ECF.
“MEN” – Mitochondria, Endoplasmic reticulum, Nucleus = Double-membrane organelles.
“Oh! 4 Girls” – Oxytocin, ADH (vasopressin) both 9 amino-acid peptides from posterior pituitary.
“CARBS” – C₆H₁₂O₆ (glucose) → 6C; “C-arbs” always 1:2:1 ratio.

Error	Correct
Bile is produced by gall bladder	Bile is produced by liver; GB only stores
Photosynthesis occurs only in leaves	Also in green stems, sepals, aerial roots
Xylem transports food	Xylem = water/minerals; phloem = food
All enzymes are proteins	Most are proteins; ribozymes are RNA enzymes
Testosterone is from adrenal cortex	Testosterone is from Leydig cells of testis

Click to expand MCQs

Which is NOT a stop codon?
A. UAA B. UAG C. UGA D. UCA
Ans: D
Match: Vitamin – Deficiency disease
a) B₁₂ b) D c) K d) C
1. Rickets 2) Pernicious anaemia 3) Scurvy 4) Delayed clotting
  Correct pairs:
  A. a-2, b-1, c-4, d-3
  B. a-1, b-2, c-3, d-4
  C. a-4, b-3, c-2, d-1
  D. a-3, b-4, c-1, d-2
  Ans: A
In a dihybrid cross (AaBb × AaBb), probability of aabb is:
A. 1/4 B. 1/8 C. 1/16 D. 3/16
Ans: C
Which hormone peaks at ovulation & triggers LH surge?
A. Progesterone B. Estrogen C. FSH D. Inhibin
Ans: B
C₄ plants show high productivity because they:
A. Lack photorespiration
B. Have PEP-carboxylase with low Km for CO₂
C. Both A & B
D. Operate Calvin cycle at 45 °C
Ans: C