Question

You are studying aging in budding yeast. With each division, mother yeast cells bud and divide, forming a daughter that has renewed replicative potential (in other words, it is rejuvenated). The mother, however, does not show a renewed replicative potential. You find that the mother cell dies after a few more divisions, but the daughter cell dies after it divides 30 or more times. What would you expect to see at a cellular level?

1. Vacuoles (‘yeast lysosomes’) are more active in the mother cell than in the daughter.
2. There are more aggregated proteins in the mother cell than in the daughter.
3. Fragmented mitochondria with low membrane potential are more abundant in the daughter cell than in the mother.
4. Both A and B
5. All of the above

Answer 1

The right option is Option (B)

Explanation :-

Lysosomes have proteases which cleans the cell by degrading harmful substances and these lysosome becomes less efficient and less active in old cells. This leads to cell death as harmful substances accumulate inside the cell. So lysosome will be less active in mother cells.

Protein aggregate is one of the sign of cell death as proper functioning of cell organelles is impacted and protein sorting may not work which result in aggregation of Proteins. It can be seen as human equivalent of Alzheimer in which amyloid aggregate cause neuro degeneration and its chances increases with old age.

Fragmented mitochondria is the prime sign of cell apoptosis and so that it will not be found in high amount in daughter cells. In fact old and dying cells will have fragmented mitochondria.