Chapter
19 & 20
1. DNA isnÕt
just floating around in the nucleus like long pieces of string. In order to fit
into this small space it is intricately and carefully packaged. I would like
you to both discuss and illustrate
how this packing is accomplished. Use your book, pages 344-346,
especially figure 19.1. Be sure to include a discussion of the meaning of the
following words: histones, nucleosomes, chromatin, heterochromatin,
euchromatin.
2. Describe the
two different kinds of non-coding repetitive DNA (Tandemly Repetitive DNA and Interspersed Repetitive DNA) and their different characteristics. Be
sure to include a discussion of centromeres, telomeres, Alu elements, Fragile X syndrome,
HuntingtonÕs Disease.
3. Explain how gel
electrophoresis works.
Be sure to explain why it is used. Explain in a stepwise process how it is
done. Be sure to include a labeled illustration of the different steps. Include technical considerations since these are important. Use my
lecture notes, the book (p. 374 ÒMethodsÓ and text pages 372-373), or the animation at the DNAi website which is excellent
(http://www.dnai.org/b/index.html). Find the animation by following this path:
Technique->Sorting & Sequencing->Gel Electrophoresis
Another link to
demonstrate gel electrophoresis can be found at: http://learn.genetics.utah.edu/content/labs/gel/
4. Explain the polymerase
chain reaction (PCR).
Why is it so important? What is it used for? Be sure to explain what materials
are needed to make it happen. Explain in a step by step process what happens.
Be sure to include a labeled illustration of the different steps. The book does
a nice overview (page 371 “Methods” and the written text 371-372). To see a
great animation go to the DNA Learning Center and run the animation on “Amplification”
(http://www.dnalc.org/shockwave/pcranwhole.html). Check out the “Amplification
Graph” too. How long does it take to produce this many copies of a piece of
DNA?
Please note:
This free response (as well as #4) is critical to know well since you will
probably see these questions on the AP Bio exam.
5. Discuss gene
expression in eukaryotes.
You will need to read the book from page 353 beginning with the section entitled, "Transcription Initiation is Controlled By Proteins That Interact with DNA and Each Other," and ending on page 356, bottom of the first column. Be sure to mention the following items:
a. The typical eukaryotic gene and how it produces and modifies its mRNA (see figure 19.8) Diagram and discuss this process (this is a review from a previous lecture with a few new details).
b. Discuss and
illustrate the important points made in the CD ROM (Activity 19.1) slides 1 and 2. Relate this
back to the first slide of Chapter 19 Lecture 3.
c. How transcription factors work. Specifically describe the role of activators, enhancers, promoters,terminators (see figure 19.9). See slide 4 in the CD ROM (Activity 19.1) because it animates and explains this beautifully!. Diagram and discuss this process.
See CD ROM
(activity 20.1) for a great animated description of cloning.