Molecular Basis of Inheritance

Molecular Basis of Inheritance

DNA Structure

• DNA is a polymer of deoxyribonucleotide monomers.

• Most DNA is double-stranded with base pairs (A-T and G-C) via hydrogen bonds.

• It forms a double helix structure.

DNA Replication

• Follows the semi-conservative model: each new DNA molecule comprises one parental and one daughter strand.

• Involves primases for RNA primer creation; DNA polymerases for nucleotide addition.

• Leading strand synthesized continuously; lagging strand in Okazaki fragments.

• Telomeres shorten with cell division due to incomplete replication.

Chromatin Packing

• Chromatin consists of DNA and proteins, forming nucleosomes.

• Further packing leads to higher-order structures, affecting gene activity; tightly packed chromatin reduces transcription efficiency.

Telomeres and Aging

• Telomeres protect DNA ends but shorten with replication; linked to aging.

• Telomerase extends telomeres, active in germline cells but linked to cancer in somatic cells.

Conclusion

• Understanding DNA replication and chromatin structure is vital for genetics and cell biology.

• Telomere dynamics have implications in aging and cancer research.