Tuesday, February 3, 2009

Lecture - DNA. chromosomes and gene expression

Ttoday we fineshed chapter 7, about the structure of DNA and chromosomes. We talked about how nucleosomes are organized to compact DNA into chromosomes. Then we talkes about the basics of DNA replication. Among other things we mentioned the "mini-dogma" that you must remember. DNA is always synthesized in the 5'-3' direction...!

We also started chapter 8, on gene expression. Specifically how the information strored in genes is transformed into proteins.

Reminder: We have exam 2 on Monday. Last topic to be included in the exam: Chapter 7.


QUIZ #8

1. What are the components of a nucleotide? (there are three)
Phosphate group, nucleotidic base, sugar

2. The DNA strands in the double helix are antiparallel. What does that mean?
One of the strands runs in the 5'-3' direction and the other runs in the 3'-5' direction

3. List three differences between DNA and RNA
DNA is double stranded, RNA is single stranded
The sugar in DNA is deoxyribose, in RNA is ribose
DNA has T in its sequence, RNA has U instead

4. What is the name for a core of histones and the DNA wrapped around it?
Nucleosome

5. What is DNA replication?
The process through which DNA is copied in a cell prior to cell division

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