1. Cell Growth / Division / Reproduction (Ch 10.1)

2. Cell Size Cells will grow and divide because of the following:
the larger the cell, the more demands the cell places on the DNA
DNA contains all the information in a cell to build molecules for cell growth
Just because the cell increases, it does not mean the DNA increases in the cell
Library → If there is an increase in people and not books, there will not be enough books to lend out
the larger a cell, the less efficient in moving nutrients and waste across the cell membrane
Everything enters and leaves the cell through the membrane
surface area: the exchange of nutrients and waste depends on surface area
volume: the rate at which oxygen and food are used and waste is produced depends on volume
We need to look at the cell surface area to volume ratio to understand

3. Surface Area to Volume Ratio
By using a cube as a reference, we can see what happens to the surface area to volume ratio as it grows in size
Surface Area: length x width x number of sides
Volume: length x width x height
Results:

4. Cell Division
Cell division: the process of the cell dividing into two daughter cells
The DNA is copied before cell division so each daughter cell can each get the genetic code
Surface area to volume ratio increases making it efficient for the nutrients and waste materials to enter and leave the cell
Two Types:
Mitosis: making identical cells
Meiosis: dividing the chromosomes and creating genetic variation

5. Cell Reproduction Two Types: Asexual Reproduction Sexual Reproduction
the production of genetically identical offspring from a single parent
used in single-celled organisms (bacteria)
simple, efficient, effective, and quick
Can be used in multicellular organisms (Ex: hydra)
Sexual Reproduction
offspring inherits some of their genetic information from each parent
fusion of two parents’ genetic information combined in the offspring
Mostly in plants and animals (multicellular), but can occur in single- celled organisms

6. Cell Reproduction Asexual Reproduction Advantages
conditions are right → fast reproduction
Survival of the fittest → the most fit for the environment survive
Disadvantage
When conditions change, lack of genetic diversity will hinder survival
Sexual Reproduction
Disadvantage
requires more time → finding a mate / growth and development of offspring
Advantage
genetic diversity
more time to get optimal conditions for reproduction