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- Digestion and enzymes
Digestion and enzymes
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Food has to be broken down into small molecules before your body can absorb it into the blood.
The digestive system
Oesophagus (gullet): muscles squeeze food down to the stomach.
Stomach: churns food with acid and enzymes. The acid also kills microorganisms.
Small intestine: more enzymes finish digestion, and small molecules are absorbed into the blood.
Large intestine: water is absorbed. Rectum stores faeces, which leave through the anus.
The liver makes bile and the pancreas makes enzymes; both pass into the small intestine.
Enzymes
Adaptations and bacteria
Your large intestine contains huge numbers of helpful bacteria. They break down some food that we cannot digest ourselves, and make some vitamins, such as vitamin K.
Describe what happens to a protein in a piece of chicken during digestion.
- Teeth break the chicken into small pieces.
- Protease enzymes in the stomach and small intestine break proteins down.
- The amino acids made are absorbed into the blood in the small intestine.
Answer: Protease breaks the protein into amino acids, which are absorbed in the small intestine.
Enzymes are biological catalysts. Amylase: starch to sugars. Protease: proteins to amino acids. Lipase: lipids to fatty acids and glycerol. Food is absorbed in the small intestine (villi) and water in the large intestine. Gut bacteria help digestion.
The interactive lesson includes the diagrams for this topic.
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