1. Warm-Up (12/03)
Answer the following questions, and explain in a complete sentence why each answer is correct.
Name
Date
Period
What are the main functions of DNA polymerase?
A. breaks hydrogen bonds and exposes bases
B. holds DNA strands apart and adds new bases
C. zips and unzips the double-stranded DNA
D. binds nucleotides and corrects base pair errors D A
Draw the structure to the right and label A, B, C and D. C B

2. DNA History Watson and Crick: found the structure of DNA
Edwin Chargaff: found that A complements T and G complements C.

3. Guided Practice Chargaff found that some DNA was 10% adenine (A).
What percentage was thymine (T)?
What percentage was guanine (G) and cytosine (C)?

4. Your Turn – on your closure!
Fleengaff found that some DNA was 35% adenine (A).
What percentage was thymine (T)?
What percentage was guanine (G) and cytosine (C)?

5. Cell Cycle
Purpose #1 – to grow
10,000

6. Cell Cycle Purpose #2 – to replace dead cells
What’s this cell going to do?

7. Cell Cycle 4 Steps: G1: normal life S: replicate DNA G2: grow
M: divide
Draw this!

8. Cell Cycle
Draw this!
The length of each phase depends on how badly it wants to divide!

9. Cell Cycle 3 Checkpoints G1: ready to copy DNA?
G2: Replicated DNA all okay?
M: Ready to divide?

10. Your Objective On the plate,
Show the four stages of the cell cycle and state the function.
Show the three checkpoints and state the function.
State the two enzymes that work in S phase (yesterday).

11. Closure Answer the following question in a complete sentence:
Name
Date
Period
Do you think a skin cell would have a long or short G1 stage and why?
Scale from 1-10