Organisation

In this section we will learn about the human digestive system which provides the body with nutrients and the respiratory system that provides it with oxygen and removes carbon dioxide. In each case they provide dissolved materials that need to be moved quickly around the body in the blood by the circulatory system. Damage to any of these systems can be debilitating if not fatal. Although there has been huge progress in surgical techniques, especially with regard to coronary heart disease, many interventions would not be necessary if individuals reduced their risks through improved diet and lifestyle. We will also learn how the plant’s transport system is dependent on environmental conditions to ensure that leaf cells are provided with the water and carbon dioxide that they need for photosynthesis.

Tissues and Organs

The Human Digestive System

The Chemistry of Food

Catalysts and Enzymes

Factors Affecting Enzyme Action

How The Digestive System Works

Making Digestion Efficient

Breathing & gas exchange

Tissues & organs in plants

Transport systems in plants

Evaporation & transpiration

Factors affecting transpiration

Tissues and Organs

Objectives - After this topic you should know:

1. How specialised cells get organised into tissues.
2. How several different tissues work together to form an organ.

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The Human Digestive System

Objectives - After this topic you should know:

1. The position of the main organs of the human digestive system.

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The Chemistry of Food

Objectives - After this topic you should know:

1. The basic structure of carbohydrates, lipids and proteins.

Required Practical 4

- Use standard food tests to identify food groups - detect sugars, starch and protein in foods using Benedicts, iodine and Biuret solutions.

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Catalysts and Enzymes

Objectives - After this topic you should know:

1. What a catalyst is.
2. How enzymes work as biological catalysts.
3. What the metabolism of the body involves.

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Factors Affecting Enzyme Action

Objectives - After this topic you should know:

1. How temperature and pH affect enzyme action.
2. Different enzymes work fastest at different temperatures and pH values.

Required Practical 5

- Investigate the effect of pH on the rate of reaction of amylase enzyme - use a continuous sampling technique to determine the time taken to completely digest a starch solution at a range of pH.

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How The Digestive System Works

Objectives - After this topic you should know:

1. How the food you eat is digested in your body.
2. The roles played by different digestive enzymes.

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Making Digestion Efficient

Objectives - After this topic you should know:

1. The role of hydrochloric acid and bile in making digestion more efficient.

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The blood

Objectives - After this topic you should know:

1. How substances are transported to and from the cells.
2. That blood is made up of many different components.
3. The functions of each main component of blood.

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Blood vessels

Objectives - After this topic you should know:

1. How the blood flows round the body.
2. That there are different types of blood vessels.
3. Why valves are important.
4. The importance of a double circulatory system.

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