1. Bellwork: Why are cells in the human body so small
Bellwork: Why are cells in the human body so small? What advantages and/or disadvantages does this provide?

2. Cell growth, division and reproduction
Section 10.1

3. Why do cells divide rather than continue growing?
The larger the cell the more demands on it’s DNA
DNA like a library of information
If too many users, not enough books to teach everyone

4. Why do cells divide rather than continue growing?
A large cell is inefficient at moving nutrients and waste across the cell membrane
It’s all about surface area to volume ratio

5. Large cells would be like congested towns/cities

6. How to cells overcome these issues?
As they get larger they divide
Two daughter cells are formed via cell division
DNA is replicated
Surface are to volume ratio is increased
Efficient exchange of materials

7. Asexual vs sexual reproduction
Common with single celled organisms
Genetically identical offspring are produced from one parent cell
Occurs in multicellular organisms

8. Asexual vs sexual reproduction
Two parent cells fuse together
Special reproductive cells fuse together, and offspring are produced
Genetic material comes from both parents
Most animals and plants undergo sexual reproduction

9. Asexual vs sexual reproduction
Asexual = survival strategy in single celled organisms
Fast reproduction = more likely to survive
This assumes conditions remain favourable, what happens if they change?
Sexual reproduction – take a lot longer
Can be useful if seasonal changes affect food availability
Increases genetic diversity
Increased resistance to disease, changes in condtions
Darwinism
Some organisms, like yeast can do both