1. (7th) Chapter 4-3 Cornell Notes
Cell Division

2. Chapter 4-3: Key Questions
What events take place during the three stages of the cell cycle?
Answer 1: ______________________________________________
How does the structure of DNA help account for the way in which DNA copies itself?

3. Chapter 4-3: Key Terms cell cycle- interphase- replication- mitosis-
chromosome-
cytokinesis-

4. Chapter 4-3 Part 1 cell cycle: cycle of growth and development;
3 stages.

5. Chapter 4-3 Part 2 Interphase: first phase, 3 parts;
Part 1: cells grows;
Part 2: copies its DNA (replication);
Part 3: prepares to divide into two;
now has 2 identical sets of DNA.

6. Chapter 4-3 Part 2
Problem: place the following events into the correct order:
Part __: copies its own DNA;
Part __: prepares to divide into 2;
Part __: cells grow;

7. Chapter 4-3 Part 3 mitosis 2nd phase, 4 parts;
DNA copied into two “daughter” cells;
Part 1 (prophase): chromatin in nucleus shrinks to form chromosomes;
Part 2 (metaphase): chromosomes line up, bound by centromere (“belt”);
Part 3 (anaphase): centromeres split, chromatids separate, new chromosome;
Part 4 (telophase): chromosomes stretch out, nuclear envelope forms; nuclear membrane forms/separates DNA;
now have 2 identical nuclei.

8. Chapter 4-3 Part 3 Summary: What is mitosis?
1. The chromosomes in the nucleus divide into two new chromosomes.
2. The cell divides into two new daughter cells.
3. The chromatin fibers in the nucleus divides into a new chromosome.

9. Chapter 4-3 Part 4 Cytokinesis: 3nd phase; cytoplasm divides;
organelles split up into the 2 new cells;
each daughter cell has same # chromosomes;
cytokinesis ends then interphase begins again.

10. Chapter Part 4
Participation: Please turn to your partner and share a fact about cytokinesis.

11. DNA replication makes sure daughter cells identical;
DNA ladder has 4 nitrogen bases, two on each rung;
4 types: adenine, guanine, thymine, cytosine;
adenine pairs w/ thymine and guanine w/ cytosine;
DNA replication begins when DNA ladder unwinds;
free nitrogen bases combines ladder attached bases;
nitrogen base order on both old and new strand same;
now 2 new and identical DNA molecules.
Chapter 4-3 Part 5

12. Question: Which nitrogen bases matches with what base?
1. adenine with guanine, cytosine with thymine.
2. adenine with cytosine, thymine with guanine.
3. adenine with thymine and guanine with cytosine.
Chapter 4-3 Part 5