1. Oxygen is needed by most living things for respiration. This is called aerobic respiration.
2. Glucose releases energy. This energy is changed into other forms – kinetic energy when you run, sound energy when you talk, or stored as chemical energy in the form of fat if a person consumes more energy than they need.
Learn more about forms of energy in Physical World 16.1 Factorising glucose The chemical formula for glucose, a six-carbon sugar, is C6H12O6.
1. Using your knowledge of algebra, factorise glucose so that it takes the following form: (CxHyOx)n where x, y and n are all natural numbers. The trick is to select the smallest possible values for x, y and n. This will give you the general form of all six-carbon sugars.
2. Research the term used to describe all six-carbon sugars. Products of Respiration
1. Carbon dioxide is a waste product of respiration. It passes out of the body through the lungs.
2. Water is also a waste product of respiration. Note that some of the energy produced by respiration will be ‘lost’ as heat.
Respiration in Cells Respiration takes place inside most plant and animal cells.
Mitochondria are tiny organelles in the cytoplasm. Respiration reactions take place in the mitochondria of cells. Enzymes carefully control these reactions.
Food Glucose Mitochondria Energy Cytoplasm Oxygen Carbon dioxide Water Fig. 3.3.3 Respiration in a cell
