Respiration in cells (SQA National 5 Biology): Revision Note

Respiration is a series of enzyme-controlled reactions

It is a chemical process that involves the breakdown of nutrient molecules (specifically glucose) to release the energy stored within these molecules

• The energy released is used to generate ATP

Respiration can take place with oxygen (aerobically) or without oxygen (anaerobically)

• Much less energy is released for each glucose molecule broken down anaerobically compared to the energy released when it is broken down aerobically

Respiration occurs in all living cells; most of the chemical reactions in aerobic respiration take place in the mitochondria

Cells with a higher energy requirement e.g. muscle cells will be adapted to possess a higher number of mitochondria to support energy requirements

The energy released during respiration is used to carry out many processes

• Muscle cell contraction

• Protein synthesis

• Cell division

• Growth

• Active transport across cell membranes

• Generation of nerve impulses

• Maintaining a constant internal body temperature