Respiration is a chemical reaction that is fundamental to all living things. It happens in every cell of every plant and animal.
Respiration is the reaction between glucose (from food) and oxygen in the air you breathe. It produces carbon dioxide and water (waste products) and ENERGY! Energy is needed for movement, growth and repair and generally staying alive.
Glucose + Oxygen –> Carbon Dioxide + Water + ENERGY
Glucose and oxygen are transported to cells in blood and the waste products removed.
The process can also occur anaerobically if there is a shortage of oxygen. This can happen if you exercise really hard!
Anaerobic Respiration in Animals
glucose –> lactic acid
It’s lactic acid that makes your muscles hurt when you’ve done a lot of exercise. Lactic acid isn’t broken down until you start to respire aerobically again.
In plant cells respiration also occurs in the mitochondria of the cell.
Comparison of Photosynthesis and Respiration
You can see from the diagram above that the reactants and products of photosynthesis and respiration are opposites.
Respiration converts nutrients from the soil into energy and happens all the time, but as photosynthesis needs light it only happens in the daytime.
Photosynthesis converts light energy to glucose which can then be used for respiration. This process allows plants to make their own food!
On a sunny day photosynthesis occurs faster than respiration so more oxygen is given off by the plant than is used. This is great for us as we need oxygen to breathe!
More Respiration Experiments
The gas produced by yeast can be used to blow up a balloon.
Children can see respiration in action by baking bread or pizza dough.
Edventures has a super simple activity allowing kids to see bubbles of gas appearing on the leaf of a plant as it photosynthesises.
A hands on way to learn about plant structure is by dissecting the a flower or plant.