Biology B2: Respiration

Respiration is the process that the body uses to release energy from digested food (glucose).

The word equation for aerobic respiration is:

glucose + oxygen ------> carbon dioxide + water + energy

The reaction between glucose and oxygen (the one above) releases lots of energy.

This type of respiration is called aerobic respiration because the reaction happens with oxygen 

When you exercise you respire more. This is because the muscles need more enery to contract.

When the body cannot supply the cells with the oxygen needed to break down glucose, then it has to carry out anaerobic respiration. this means the energy is released without oxygen. This forms lactic acid and energy:

glucose --------> lactic acid + energy

This doesn't produce as much energy as aerobic respiration but it is useful in emergenicies. The lactic acid produced soaks the muscle cells and prevents muscles from doing their job. This causes fatigue and sometimes cramps.

After exercise, you breath heavily. This happens because your body need lots of oxygen to get rid of lactic acid that has built up in the body. The amount of oxygen required to get rid of the lactic acid is called excess post-exercise oxygen consumption (EPOC).

Lactic acid + oxygen -------> carbon dioxide + water

-----------------------------------------------------------------------------------------------------------------Cardiac output = Heart rate x sroke volumecardiac output is the volume of blood the heart pumps in one minute - it increases as heart rate increases.

- Diffusion in scientific terms, is the movement of particles from an area of higher concentration to an area of lower concentration. 

 -When cells respire they use up oxygen and glucose, so the concentration of these inside the cells is low. The concentrations of these substances in the blood is higher, so they diffuse from the capillaries into the cells 

 -It's the gradual movement of particles to where there are lots of them to where there are fewer