Aerobic respiration

• Your body needs energy for every activity it performs—from movement and growth to keeping warm, even while you’re asleep. 

• This energy comes from the food you eat. 

• Inside your cells, glucose from food reacts with oxygen in a process called aerobic respiration. 

• This reaction releases energy that powers cellular functions, producing carbon dioxide and water as waste products.

• The word equation for aerobic respiration is:

glucose + oxygen → carbon dioxide + water + energy

• Respiration takes place in mitochondria, which are structures inside cells. 

• Nearly all cells have mitochondria, but those with high energy demands, such as muscle cells, contain many more to provide the energy needed for their functions.

How does the body get glucose?

• Glucose is a carbohydrate obtained from food. 

• During digestion, food breaks down into smaller molecules, including glucose. 

• This glucose is absorbed through the walls of the small intestine and enters the bloodstream. 

• In the blood, glucose dissolves in plasma, the liquid component, which carries it to cells throughout the body. 

• From there, glucose diffuses into cells to be used in respiration.

How does the body get oxygen?

• When you inhale, oxygen fills the alveoli (air sacs) in your lungs. 

• Oxygen then diffuses into the bloodstream, where it binds to haemoglobin, a protein in red blood cells. 

• These cells transport oxygen throughout the body, delivering it to the cells that need it. 

• Once there, oxygen diffuses into the cells to be used in respiration.

How does the body get rid of carbon dioxide?