Watch the following video on the Digestive System...
During the video, note down the following:
- The six main steps to digestion
- The components of the gastrointestinal tract
- The accessory digestive organs
Starter...
Start
Chew on a cracker for two minutes without swallowing.
After two minutes, answer the following questions:
- What can you conclude must be done to food before digestion begins?
- What changes occurred to the cracker?
- What caused the changes to the cracker?
- Did you notice a taste change in the cracker?
Group Investigation...
Introduction to Digestion
Questions...
Answer the questions in the booklet
Macronutrients & Micronutrients
Proteins
Fats
Calcium
Vitamin C
Carbohydrates
Fats – are used in making steroids and hormones and serve as solvents for hormones and fat soluble vitamins. Fats have the highest caloric content and provide the largest amount of energy when burnt. When measured by a calorimeter, fats provide about 9 calories per gram of fat, making them twice as energy-rich than carbohydrates. Extra fat is stored in adipose tissue, endurance athletes can store fat in muscles ready for use as a fuel.
Carbohydrates – are required for energy and provide body’s main source of energy (4 calories per gram); and exist in three form: sugar, starch and fibre. They are stored primarily as glycogen in the muscles and liver, with some glucosein the blood. The brain works entirely on glucose alone. Carbohydrates are also important for fat oxidation and can also be converted into protein.
Proteins – they provide amino acids and make up most of the cell structures including the cell membrane. They are the last to be used of all macronutrients for fuel. In cases of extreme starvation, the muscles in the body, that are made up of proteins, are used to provide energy. This is called muscle wasting. As for carbohydrates, proteins also provide 4 calories per gram.
Digestive System
End