Unit 2.1 Topic 1

Biochemistry and Metabolism

You are - literally - what you eat. The nutrients any organism takes in build and maintain a healthy body because:

• they become part of your body - often after being broken down into smaller pieces (digested), then rebuilt to form the different parts of the organism.
• they are used to provide the energy needed to drive metabolism, (living processes).

If substances taken into the body cannot be digested or take part in metabolic processes, they are removed from the body.

Organisms are adapted to remove these substances in a variety of ways. For example;

• The human intestine is adapted to work best when indigestible fibre is present in food.
• The fibre does not provide nutrients for building the body.
• It does not provide energy, but it is essential component of the diet. This is because it eases the flow of materials through the guts by giving gut muscles a bulk to push against.
• Fibre also helps to remove some waste products such as, bile salts, which can be toxic.
• A low diet in fibre is a risk factor for a number of disease including intestinal cancer and some other cancers.

All organisms are made up of many thousands of different molecules. In order to survive, an organism must be able to either make of take in all the molecules required. These molecules fall into a small…