Overview of Digestion
Biology: AQA A Level, topic 3.3.1
Hydrolysis
Digestion involves the break down of large, biological molecules into smaller molecules. The smaller molecules can then be taken up by the cells and used for a number of functions.
Break down
- When an organism eats, it ingests large, biological molecules (e.g. carbohydrates).
- These biological molecules are important to allow the organism to survive.
- The molecules could be used in the cells for important reactions (e.g respiration) but they are too large to be transported into the cells.
- The large molecules must first be broken down.
Hydrolysis
- Hydrolysis is the reaction that breaks down large, biological molecules.
- The reaction requires water and splits larger molecules into their smaller components.
- These smaller molecules (e.g. glucose) can easily diffuse into cells or be transported using protein channels.
Products of hydrolysis
- Hydrolysis of protein produces amino acids.
- Hydrolysis of carbohydrate produces disaccharides and monosaccharides.
- Disaccharides are two monosaccharides joined together.
- Hydrolysation of lipids produces fatty acids and monoglycerides.
E.g. Hydrolysis of protein
- A human eats a ham and cheese sandwich.
- The sandwich is made up of carbohydrate (in the bread), protein (in the ham) and fat (in the cheese).
- In the stomach, the protein is broken down into amino acids in a hydrolysation reaction.
- The amino acids are taken up by the cells and used to make new proteins for other uses.
Test yourself on Overview of Digestion
Which of these are NOT a product of hydrolysis of carbohydrate?
Which of the following statements about hydrolysis are true?