Chapter 10: Cell Division

1. Chapter 10: Cell Division

2. Some things to think about: How big can a cell get? Why? Why aren’t organisms just one big cell instead of many smaller cells?

3. Why cells can’t get too big: • DNA overload • If a cell gets too big, there won’t be enough DNA to give out all of the necessary instructions. • Remember: DNA contains genes that code for proteinsthat give us our traits. • These proteins also include enzymes that regulate all of the reactions in our cells.

4. Why cells can’t get too big: • Surface area to volume ratio • The “surface area” of a cell is the cell membrane. • This is where materials must enter and exit the cell. • The “volume” of a cell is the cytoplasm and organelles. • This is where chemical reactions occur, such as breaking down glucose for energy (cell respiration!!).

5. Why cells can’t get too big:

6. Why cells can’t get too big: • If the surface area is too small compared to the volume, there won’t be enough area for materials to enter or exit. • Think about what would happen during passing time if there was only one way to get out of the commons! • How does this compare to there only being one door to a classroom?

7. Why cells can’t get too big: • Transporting materials • The nucleus contains the DNA and the instructions for cell processes. • If the cell gets too big, it would take too long for those instructions to reach their destination and the necessary processes wouldn’t be completed in time.

8. Why cells can’t get too big:

9. Tonight’s homework: Finish Cell Division Analogies Bring a calculator to class tomorrow if you have one!

10. Pg. 245 Copy the diagram from your textbook in your notebook.

11. Pg. 244 Copy the chromosome diagram from your textbook into your notebook. Sister chromatids