Chapter 5

Cells often require protein synthesis to occur quickly in response to a changing intracellular environment. Briefly list and describe the factors that contribute to the rapid pace of protein synthesis.

You have performed experiments to show that inhibition of gene expression is the mechanism by which a particular cellular event occurs. You also know that this inhibition occurs in the presence of a repressor protein. However, the repressor is not associated with preventing binding of an activator to an enhancer site. Speculate on what gene expression inhibition process is most likely taking place. Briefly explain the process.

As a specialist in geriatric medicine, you have noticed that patients with short stature seem to show signs and symptoms of premature aging. Since this fast rate of aging occurs simultaneously in several organs, you hypothesize that the relationship between stature and rate of aging may be under genetic regulation. Describe the steps you might take to determine whether a gene that codes for stature also affects longevity.

Yeast (S. cerevisiae) has developed two strategies for increasing its reproductive life span. Briefly describe the two strategies. What is the evolutionary rationale as to why these two strategies make yeast a powerful model for studying the genetics of longevity?

Explain briefly why the experiments using weak daf-2 mutations (as opposed to knockout mutations) demonstrated the importance of this pathway to overall biogerontology.

The Methuselah \((\mathrm{mth})\) gene extends life span in Drosophila by protecting the animal from environmental stress. For what other species has it been suggested that a similar mechanism extends life span? Discuss briefly the significance of this finding.