1. The Cell Membrane: Diffusion and Osmosis
Cellular Processes
The Cell Membrane:
Diffusion and Osmosis

2. Concentration
Concentration: the number of molecules of a substance in a given volume
Low Concentration High Concentration
- Think of Juice from concentrate : you have to add water. This is really concentrated fruit juice that needs to have water added to it to make it lower in concentration

3. Diffusion
Diffusion: the movement of particles from an area of high concentration to low concentration until all the particles are evenly distributed
DEMO: Food colouring in
HOT, COLD, ICE-COLD water
How does diffusion affect the size of a cell?

4. Why is diffusion important?
Diffusion is an essential cell process. It is responsible for moving things around in cells. It occurs:
Within a cell: movement of substances from one organelle to another
Across a cell membrane: oxygen diffuses through cell membranes into cells, carbon dioxide waste diffuses back out.
Outside a cell in body fluids: nerve cells communicate with each other by releasing chemicals which diffuse between the spaces between cells

5. Osmosis Osmosis is the movement of water molecules
across a semi-permeable membrane in response to concentration differences.
Semi-permeable membranei

6. Osmosis

8. The nucleus: Control center of the cell

9. What is DNA?
The nucleus contains the master set of instruction that determines what each cell will become, how it will function, how long it will live before being replaced, and other details about the organisms life
Each new cell needs to inherit a set of instructions from the original cell; these instructions are carried in chromosomes.
Chromosomes are made of deoxyribonucleic acid (DNA)

12. A small section of DNA is called a gene.
Genes provide instructions on how to build proteins
Proteins have many roles in the body
Proteins determines features: E.g. hair and eye colour

13. Critical Thinking… What caused this? 3 Legged frog…
Think-Pair-Share

15. Mutations Mutation: a change in the DNA of an organism
Changes the instructions
Changes the structure of the protein it produces; changes how well the protein does its job

16. What causes mutations? -Natural random mutation -Mutagens: a substance that physically damages DNA -Genetic engineering: the deliberate modification of the characteristics of an organism by manipulating its genetic material

17. Issues in Genetic Biotechnology
23 and Me:

18. Issues in Genetic Biotechnology