Define an Enzyme:
- A biological catalyst that increases the rate of a specific reaction without being used up or changed.
- They can join or split particles, depending on their role.
- They are made from protein.
- They turn substrate molecules into product molecules.
The speed they work at depends on...
- Temperature: when it's warmer particles have more energy so move faster, resulting in more energetic and more frequent collisions with the substrate molecules. When it gets too hot, enzymes can become denatured.
- pH: this can interfere with bonds and denature the enzymes
They are used in different human processes:
- Digestion: breaking down complex molecules into simpler ones that can be absorbed into the bloodstream.
- Protein sythesis: joining amino acids together in a specific order.
- Respiration: enzymes in mitochodria increase the rate of respiration.
What is this energy used for?
- Building large molecules from smaller ones
- Muscle contractions for movement
- Maintaining a constant body temperature
- (PLANTS) Building amino acids from sugars and nitrates
Enzymes break down big molecules that can't diffuse through the cell membrane into smaller molecules that can:
- Starch -> Amylase -> Simple sugars
- Salivary gland
- Small intestine
- Protein -> Protease -> Amino acids
- Small intestine
- Lipids -> Lipase -> Glycerol and Fatty Acids
- Small Intestine
The role of bile
- Produced in the liver
- Stored in the gall bladder
- Released into the small intestine
Neutralises stomach acid to allow enzymes in the small intestine to work at an optimum, without becoming denatured
Emulsifies fats, breaking them into smaller particles which gives them a larger surface area. This increases the number of collisions and allows them to be broken down quicker by lipase.
Other Information about Digestion
- Hydrochloric acid kills bacteria in the stomach
- Rectum stores faeces
- Small intestine absorbs food
- Large intesting absorbs water
Enzymes in Industry
- Baby food: protease digests protein so it's easier for babies to digest.
- Sugar: carbohydrases break down starch into sugar, which is cheaper that sugar.
- Slimming food: Isomerase turns glucose into fructose which is sweeter so less needs to be used, resulting in fewer calories.
- Biological detergents: digest fats and proteins in stains on clothes
Advantages and Disadvantages of Enzymes in Industr
- Specific: only catalyse the reaction you want
- Lower temperature: lower costs, less energy used
- Long-lasting: not used up, spreads costs over a long time
- Biodegradable: less pollution
- People can be allergic to enzymes
- Easily denatured: expensive to control the conditions
- Enzymes can be contaminated, affecting the reaction