Lec 3 DNA Replication and Telomeres

Telomeres

Repetitive DNA sequences at chromosome ends.

Telomerase

Enzyme that extends telomeres in cells.

3' Hydroxyl Group

End of DNA strand with a hydroxyl group.

DNA Polymerase

Enzyme that synthesizes new DNA strands.

Cellular Senescence

Process where cells stop dividing and age.

Fetuses

Early developmental stage with high telomerase activity.

Somatic Cells

Body cells with negligible telomerase as aging occurs.

Nobel Prize

Award shared by Blackburn and Greider for telomerase discovery.

Chromosome Shortening

Progressive loss of DNA at chromosome ends.

Cloning Challenges

Issues related to telomere length in cloned animals.

Dolly the Sheep

First cloned mammal with short telomeres.

Cancer Cells

Cells with high telomerase, leading to uncontrolled growth.

RNA Primer

Short RNA sequence used to initiate DNA replication.

Eukaryotic Chromosome

Chromosome structure in organisms with complex cells.

Repetitive Sequences

DNA sequences that repeat, found in telomeres.

Telomere Length

Measured in nucleotides, varies with age.

Cell Division Limit

Skin cells divide approximately 80 times before senescence.

Elizabeth Blackburn

Co-discoverer of telomerase, Nobel laureate.

Carol Greider

Co-discoverer of telomerase, Nobel laureate.

Telomere Function

Protects chromosome ends from degradation.

Human Health Relevance

Short telomeres linked to aging and disease.

Telomere Animation

Visual representation of telomere and telomerase function.