Respiration

Aerobic respiration uses oxygen to break down glucose and release energy. Some energy is released as heat, but most is trapped in a usable form of ATP.

In anaerobic respiration glucose is not completely broken down and so less ATP and therefore energy is released. It also produces toxic waste products, which must either be excreted or broken down (otherwise they will build up and so kill cells).

glucose + oxygen = carbon dioxide + water, c6h12o6 + 6O2 = 6co2 + 6h2o

Cell division, contraction of muscle cells, building large molecules e.g. protein, transporting molecules, maintaining body temperature

glucose -> lactic acid

glucose -> ethanol + carbon dioxide

We keep breathing heavily after exercise to supply the extra oxygen needed to dispose of the lactic acid in our bodies. The volume of oxygen needed to oxidise the lactic acid is called the oxygen debt.

Lactic acid builds up, causing cramps, and diffuses from muscles into the blood. In high concentrations lactic acid is toxic, so it is transported to the liver where it is oxidised.

As the peas start to grow they respire, releasing heat. The thermos flask is insulated, so heat is not transferred to the surroundings and we can measure the change in temperature. We only see a temperature rise in thermos A, as the peas in thermos B are dead. Soaked in Milton solution to kill off bacteria

Hydrogen carbonate indicator and insects: This indicator is red but turns yellow when carbon dioxide concentration increases. Carbon dioxide reacts with water to form a weak acid.

This equipment can be used to investigate the effect of changing a single variable on the rate of anaerobic respiration in yeast. Your dependent variable could be the time taken for the limewater to become cloudy. Alternatively, you could connect the delivery tube to a gas syringe, to measure the volume of carbon dioxide produced.

Change, Organism, Repeats, Measure, Same

Cell respiration is the process of breaking down food molecules to release ATP. It is a series of chemical reactions.

The advantage of anaerobic respiration is that it allows cells to obtain a small amount of usable energy even when oxygen supply is limited