Lecture 33: Genomic Organization of DNA (Textbook Chapter 17)
Note: Because of lack of time, material from chapter 17 has not been presented as a separate lecture. The questions that follow are mostly based on material that has been presented at other times during the semester. However, it should be possible to find answers to all of these questions in chapter 17,
1. What types of genes have been preferentially retained in mitochondrial genomes and why? (Hint: see lecture 16 notes and Figure 17.6)
2. List as many different examples of circular genomes as you can.
3. What is chromatin and what are its major structural components?
4. What is a nucleosome and what are its major components.
5. Describe the successive levels of compaction that must occur to compress an extended double helical DNA sufficiently to fit in a condensed mitotic chromosome (Hint: see figure 17.9).
6. What is heterochromatin and what is its significance?
7. Explain the relationship between heterochromatin and dosage compensation in female mammals, including humans.
8. Describe some of the ways in which chromosome banding patterns have been employed in research on human genetics.
9. What roles are played by centromeres and telomeres?
10. What features are shared by many (but not all) eukaryotic promoters (see lecture 23 notes and figure 17.17).
11. Distinguish between introns and exons in a manner that makes it clear you know what each is and how they differ (see lecture 23 notes and figure 17.17).
12. What is meant by a multigene family, and how is it believed to have originated during evolution?
13. Would you expect the diploid genome of a human male to contain the same amount of DNA as the diploid genome of a human female? Explain your answer. (Note that you can obtain some rather precise data from the web page whose link is included in the lecture 33 notes).
14. What is believed to be the evolutionary origin of the DNA genomes of mitochondria and chloroplasts?
15. The web page cited in the lecture 33 notes claims that human chromosome 1 contains 263 Mb of DNA. If you had a model of that DNA that was 20 cm in diameter, how long would it be? (Hint: use the dimensions of double helical DNA in figure 10.14 as a basis for your calculations). Convert your answer to miles (one kilometer = 0.621 miles).
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