NEET Revision Kit: Rapid Recall

1. The "Bond" Identity

  • Peptide bond: Proteins (formed by dehydration/condensation).
  • Glycosidic bond: Sugars/Polysaccharides (formed by dehydration/condensation).
  • Phosphodiester bond: DNA/RNA backbone (links nucleotides).
  • Hydrogen bonds: Stabilize DNA base pairs and protein secondary structure (α-helix, β-sheet).

2. The "Secondary Metabolite" Cheat Sheet (NCERT Table)

  • Drugs: Vinblastine, Curcumin.
  • Toxins: Abrin, Ricin.
  • Lectins: Concanavalin A.
  • Alkaloids: Morphine, Codeine.

3. Enzyme Core Facts (High-Yield)

  • Holoenzyme = Apoenzyme (protein part) + Cofactor (non-protein part).
  • Competitive inhibition: Malonate inhibits Succinic dehydrogenase (malonate resembles succinate).
  • Vmax remains unchanged
  • Km increases (apparent Km increases)
  • Inorganic catalysts: Often work at high temperatures.
  • Enzymes: Usually show maximum activity near optimum temperature; many are denatured at high temperature (thermophiles are exceptions).

4. DNA Data (Watson–Crick B-DNA)

  • A=T (2 H-bonds), G≡C (3 H-bonds).
  • Pitch: 34 A˚\mathring{A}.
  • Rise per base pair: 3.4 A˚\mathring{A}.
  • Base pairs per turn: 10.

5. The "Lipid" Trap (NCERT Concept)

  • Lipids are micromolecules (low molecular weight) but appear in the acid-insoluble fraction (retentate) because they form membrane vesicles that do not pass through the filter cloth.