BIO MODE 5:Set 7 — Cellular Senescence & Apoptosis

How does the lecture define cellular senescence?

A controlled process of deterioration that leads to cell death.

Can cells divide indefinitely?

No, cells have limits on their ability to divide.

What are three possible contributors to cellular senescence listed in the lecture?

DNA damage, telomere shortening, and ethylene in plants.

How can DNA damage contribute to cellular senescence?

Accumulated DNA damage can interfere with normal cellular functioning.

How can telomere shortening contribute to cellular senescence?

Progressive shortening can limit a cell's ability to continue dividing.

What is ethylene?

A gas produced by plants that helps regulate ripening, senescence, and abscission.

Which plant structures can produce ethylene?

Fruits, flowers, seeds, leaves, and roots.

What are three processes promoted by ethylene in plants?

Fruit ripening, senescence, and abscission.

What is abscission?

The dropping of plant structures such as flowers, fruits, or leaves in response to signals.

What does plant senescence involve?

The aging and deterioration of plant cells or structures.

What is apoptosis?

Programmed cell death.

What types of signals can initiate apoptosis?

Internal or external signals.

In which organisms has apoptosis been observed according to the lecture?

All multicellular eukaryotes studied so far.

What cellular changes are shown in the apoptosis diagram?

Chromatin condensation, membrane blebbing, nuclear collapse, and apoptotic body formation.

What is the key distinction between senescence and apoptosis?

Senescence concerns cellular aging or deterioration, while apoptosis is programmed cell death.