Chapter 4

List some general biological features observed in senescent cells near the end of their replicative life span.

The replicative life span of a cultured cell population has been widely accepted as "failure of the population to double within our weeks." Does this indicate that all cells have lost their nitotic capacity? Explain.

Explain why the age-related increase in entropy leads to an accumulation of damaged proteins in the cell.

The reduction of \(\mathrm{O}_{2}\) to water during aerobic metabolism is a vital process in the synthesis of ATP. Describe how oxygen-centered free radicals arise during the reduction of \(\mathrm{O}_{2}\).

Briefly explain how alterations in the structure-function relationship of proteins by ROS can lead to cellular aging.

The hydroxyl radical, ' \(\mathrm{OH}\), can cause considerable damage to the cell. Which cell structures are particularly susceptible to attack by the hydroxyl radical? How does damage to these structures lead to cellular dysfunction and aging? How does the cell protect itself from damage by the hydroxyl radical?

Reactive oxygen species have no known beneficial function. True or false? Explain.

What is the "end-replication problem" and how do telomeres solve this problem?

Describe the mitotic clock theory of cellular aging and how it supports the evolutionary theory of aging. What is the major argument against the mitotic clock theory of cellular aging as a model for whole-organism aging?