Telomeres- Science Of Aging

Question 1

Problem w DNA replication

Answer 1

Some DNA lost

- final RNA primer put down on lagging strand not replaced with DNA nucleotides

Question 2

Telomeres

Answer 2

Prevent loss of critical info

Definition: Zones of repetitive, non-coding sequences found at ends of chromosomes

Question 3

Role/Function

Answer 3

Prevent chromosomes from fusing to other chromosome

Prevent damage from other enzymes

Play role in determining how many times cell can divide; therefore playing critical role in determining lifespan of organism

Question 4

Cell Senescence

Answer 4

Period in cell’s lifespan when it loses ability to divide and grow; referred to as cell aging

• telomere completely lost, no protection for chromosomes
• essential parts of DNA lost leading to new cells potentially losing their ability to function

Question 5

Hayflick Limit

Answer 5

Total number of times normal cell cans divide

• in humans, cell can divide 50 times before telomeres too short

Question 6

Telomerase

Answer 6

Enzyme that adds new telomere sequences to ends of chromosomes

• restore length to shortening telomeres
• stem cells and WBCs show presence of telomerase