“Apoptosis, Crossover, and Tumor-suppressor genes”

This week’s discussion is focused mechanisms that cells use to keep cell division under control, to prevent cancer, and to function well. For your primary post, respond toone of the following three topics. Also, please reply to at least one fellow student on any topic.

Topic 1 : Apoptosis. Watch the Khan Academy video about apoptosis (1)*, then answer the following questions in your own words:

• (a) What is the difference between apoptosis and necrosis?
• (b) What is the role of apoptosis in the normal, healthy development of animals?

Topic 2 [article]: Crossover. Read the article from the University of Rochester on a gene that influences crossover rates in fruit flies. Then address the following:

• (a) Explain the relationship between crossover, genetic diversity, and natural selection.
• (b) Summarize the findings regarding a gene that influences crossover.

Topic 3 [research]: Tumor-suppressor genes versus Proto-oncogenes. This is a library-research topic in which you are required to provide your sources. Mutations in tumor suppressor genes can contribute to or cause cancer, just as mutations in proto-oncogenes can also contribute to or cause cancer. However, tumor suppressor genes are very different from proto-oncogenes.

• (a) Explain why a gain-of-function mutation to a proto-oncogene (or its promoter) may be associated with increased risk of cancer.
• (b) Explain why a loss-of-function mutation to a tumor suppressor gene may be associated with increased risk of cancer.

References:

1. Khan Academy, No date given. Apoptosis , https://www.khanacademy.org/science/biology/cellular-molecular-biology/stem-cells-and-cancer/v/apoptosis
2. Lindsey Valich, April 19, 2018. Scientists discover gene controlling genetic recombination rates. http://www.rochester.edu/newscenter/genetic-recombination-selfish-dna-may-help-explain-differences-in-fruit-flies-312422/