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

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

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?

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

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

Osmosis

The nucleus: Control center of the cell

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)

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

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

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

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

Issues in Genetic Biotechnology 23 and Me: https://www.youtube.com/watch?v=LrtPoke4X2g

Issues in Genetic Biotechnology