Some unit 2 bio notes

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The founder effect: New population established by a small number of individuals only some genetic variation

Genetic bottleneck: large proportion of population is killed or otherwise prevented from reproducing

Replication of DNA:

1) Helicase enzymes unwind two strands of DNA, breaking hydrogen bonds seperating the two strands

2) add primers signal where to being copying

3) DNA polyermerase attach to primers more along exposed strands

Tissue group of specfic cells

Organs tissues performing specfic physiological functions

Basic adaptions gas exchange

- Large surface area

- Thin membranes, distance for diffusion is as short as possible

-Effficeient transport system

Gas exchange in fill:

- Gill lamellae and gill filaments have a large surface area

- Countercurrent system faciliatates gas exchange

Gas exchange plants:

Mesphyll cell air spaces between cells providing large surface area. Stomata open to allow gases to diffuse in and out the movement of large volumes of fluid and dissolved substances within a transport system is known as mass flow

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