Revision:Digestion and Nutrition

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Explain why digestion of large food molecules is essential

Large food molecules must be digested as they are crucial to our bodies. We would die if we could not digest them.

Explain the needs for enzymes in digestion

Enzymes are 3D globular proteins. They increase the rate of reaction though they are not part of the reaction. They lower the activation energy i.e. the amount of energy needed for reaction to occur.

State the source, substrate and optimum pH for one of each type of enzyme

Draw a diagram of the digestive system

Draw a diagram of the digestive system including mouth, oesophagus, stomach, small intestine, large intestine, anus, liver, pancreas and gall bladder

Draw a villus in vertical section

Define absorption

Absorption is the movement of a molecule(s) across a membrane; usually by active transport in humans.

Explain the concept of a balanced diet

A balanced diet is one that supplies all the necessary nutritional foodstuffs. Age may determine which foodstuffs are prioritised. Health is also a determining factor.

Explain the general importance of vitamins and minerals

Vitamins and Minerals are health enhancers but it is their absence in the body that signifies a problem. They are involved in many small ways to maintain normal growth and metabolism.

• Vitamins are organic compounds
• Minerals are organic elements

Outline the problems associated with Obesity

Where body weight is 20% greater than the maximum body weight desirable for a person's height.

Probably the oldest metabolic disorder.

Occurs when excess food stored in body.

Risk of Coronary Heart disease, strokes, diabetes, Gall Bladder disease.

Caused by:

• lack of exercise
• smoking and drinking
• bad diet
• over eating

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