Yeast+and+cellular+respiration

When glucose reacts with yeast, carbon dioxide is given off by the yeast - hence froth is produced. To speed up the reaction, the glucose can be warmed. Yeast is quite tolerant to heat.

If required to measure the height of the froth to determine amount of carbon dioxide, certain variables must be kept constant: -time -temperature -amount of water/glucose -amount of yeast

Oxidation - losing electrons, not presence of oxygen Reduction - gaining electrons

Methylene blue is an indicator to see if the chemical is reduced or oxidised. No reaction(neither oxidation nor reduction) takes place in the boiled(dead) yeast. - turns out blue However, reactions take place in the live yeast. - turns out colourless

Under a microscope: Methylene blue diffuses through all the yeast cells' membranes. If the yeast cell is alive, that means that reactions are taking place and therefore it will turn colourless. Those that remain dark blue are dead.

Aerobic respiration is one that involves oxygen. It occurs in three stages: 1) Glycosis -occurs in the cytoplasm -main process is to break down glucose -oxygen is not required -ATP is produced 2) The Krebs Cycle -occurs in the mitochondrial matrix 3) Electron Transport chain and oxidative phosphorylation (ETC) -occurs in the inner membranes of mitochondrion