KTUYSBeta
Log inSign up

Cheat sheet · Class 12 · CBSE · Science Biology

Molecular Basis of Inheritance cheat sheet

The whole chapter on one page: key formulas, facts and the points to remember, for quick revision before a test.

CBSE Class 12 · Biology

Cheat sheet

Chapter 4Molecular Basis of Inheritance

Central dogma: DNA → RNA → Protein.

1. DNA

  • Double helix (Watson & Crick); antiparallel strands.
  • Chargaff: A = T, G = C.
  • One turn: 10 bp, 3.4 nm.
  • Packaging: nucleosome (histone octamer + 200 bp).

2. Experiments

Griffith

transforming principle (Streptococcus).

Avery, MacLeod, McCarty

DNA is the transforming principle.

Hershey–Chase

DNA is genetic material (³²P, ³⁵S).

Meselson–Stahl

semi-conservative replication (¹⁵N).

3. Replication, Transcription, Translation

ProcessKey facts
ReplicationDNA polymerase (5′ → 3′); leading and lagging (Okazaki) strands; ligase
TranscriptionRNA polymerase; promoter, structural gene, terminator; eukaryotes: splicing, capping, tailing
Translationribosome reads codons; tRNA brings amino acids; AUG start; UAA, UAG, UGA stop

4. Gene Regulation

  • Lac operon: inducible; lactose binds repressor → genes switched on.
  • Genes z, y, a code for β-galactosidase, permease, transacetylase.

5. Key Points

  • Genetic code: triplet, degenerate, universal, non-overlapping.
  • Human Genome Project: ~20 000 genes.
  • DNA fingerprinting uses VNTRs.
  • Reverse transcription in retroviruses.

Remember: DNA structure | 4 experiments | replication → translation | lac operon

Molecular Basis of Inheritance: questions and notes

More Class 12 · CBSE · Science Biology cheat sheets

Practise Molecular Basis of Inheritance

Sign up free to practise the full chapter. Questions you get wrong come back until you've mastered them.

Start practising free

Free to start · No credit card needed