1. Aim # 49: Why do cells need to divide?
Date: February 14th, 2017-
Happy Valentine’s Day!!
Aim # 49: Why do cells need to divide?
HW:
Daily Review of Class Notes
All Labs due Friday
Do Now: Quick Write (1 minute)
Write down ANYTHING that comes to mind when you hear the terms “Cell Division” Go!

2. Aim #49: Why do cells need to divide?

3. Compare the size of these organisms
Vs.
Vs.

4. 1) Do these organisms have different size cells?
No, the cells of a large organism are
the same size of a small organism.
2) How do organisms get so big?
Cell
Division

5. 3) Why do cells divide rather than grow in size?XX XX XX XX XX +

6. DNA “Overload” Small Town DNA Library
The larger the cell, the greater the
demands on the DNA library. Eventually,
the cell’s DNA would no longer be able
to serve the increasing needs of the
growing cell.
City

7. 4) Exchange of Materials
What part of the cell is responsible for the
exchange of materials in and out of the cell?
Cell Membrane
The rate at which particles are able to move across the cell
membrane depends on the surface area of the cell
(the amount of the cell surface exposed to the environment). SA
Rate of Exchange

8. 5) Surface Area
Small particles have a relatively larger surface area than
large particles.
Why?
What will melt first?
The smaller chips
have more surface
area.
Vs.
Ice Chips
Ice Cube
Smaller cells have more surface area
and can exchange materials across
membrane more efficiently.

9. 6) What is Cell Division? The process by which a cell divides into
2 new daughter cells.

10. 7) What happens to chromosomes before a cell divides?
The chromosomes are replicated before a cell divides.

11. 8) What does replicate mean?
Replication is the process by which DNA makes a copy of itself

12. 9) Why is it beneficial for daughter cells to be smaller?
Smaller size of daughter cells increases the surface area and increases rate of exchange of materials across the membrane.

13. Chromosomes What are chromosomes made up of? DNA and Protein
The chromosomes are replicated
before a cell divides.
Centromere
Chromatids
Chromosome
Replication
2 Chromatids
+ Centromere
Chromosome

14. When do cells divide? Organism Growth
Cells at the root tips divide very rapidly

15. When do cells divide?
Repair

16. 12) What tissues in our body need to undergo a lot of cell division?
Skin
Stomach
Why?
The cells of these tissues are
constantly growing or repairing
themselves.
Bone

17. Let’s Review… What is cell division? When do cells divide?
When does DNA replication occur?
Draw a duplicated chromosome and label the CENTROMERE and SISTER CHROMATIDS.
Why is it important that cells are small?
To increase the ________ of _______________ of
materials through the ________ _________ _.
Process by which a cell divides into 2 new daughter cells
GROWTH & REPAIR
BEFORE cell division
RATE
EXCHANGE
CELL
MEMBRANE

18. Mitosis Images Chromosomes Spindle Fibers
Mitosis is the process that divides the cell’s nucleus into two,
each with a complete set of genetic material from the parent cell.