Enzymes Flashcards
What is an enzyme?
A biological catalyst that speeds up the rate of chemical reactions
What is a substrate?
A molecule that binds to the enzymes active site
Can catalysts be re-used?
Yes
What are enzymes made up of?
Protein
Explain how enzymes work using the lock and key model
1) The active site of an enzyme is structured to fit a specifically-shaped substrate.
2) Once the substrate binds to the active site of the enzyme, the enzyme will facilitate the reaction to form an enzyme substrate complex.
3) The substrate is broken down into products and is released from the enzyme.
Enzymes and substrates are …………… to each other. Fill the gap.
complementary
Why are enzymes needed in digestion?
We need enzymes in digestion to break down food into smaller, soluble molecules which can be absorbed into our bodies.
What are the 3 types of enzymes in digestion and what do they break down?
- protease, breaks down protein
- amylase, breaks down starch into glucose
- lipase, breaks down lipids
Which factors affect the rate of enzyme-controlled reactions?
Temperature (°C) and pH
An increase in temperature or a change in pH can ………. in the active site causing it to ………. and the enzyme to ………. Fill in the gaps.
break bonds, change shape, denature
Describe an experiment to test how differing temperatures affect the rate of enzyme-controlled reactions.
1) Label 2 test tubes A & B and fill A with 10cm3 of milk and B with 10cm3 a protease enzyme e.g. Trypsin
2) Place both tubes in a water bath of 30°C for 3 minutes
3) Pour the contents of tube B into tube A and start a timer
4) Hold a white card with a black X on it against the test tube and observe at regular intervals.
5) Time how long its takes for X to become visible through the solution.
6) Repeat the experiment from 40°C until 80°C
