Unit 5 Flashcards
What is a catalyst?
A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy, the catalyst is not changed by the chemical reaction.
What is an enzyme?
An enzyme is a protein which functions as a biological catalyst.
Where are enzymes made?
Enzymes are made in all living cells.
In what way are enzymes and their substrates complementary?
Enzymes and substrates have complementary shapes, this means that they fit together and that other substrate molecules could not fit in the enzyme.
Can enzymes work with more than one type of substrate?
Yes, but the substrates would have to be very similar.
What will a rise in temperature do to the rate of a chemical reaction?
It will speed it up.
What happens to enzymes when the temperature becomes very high?
At above around 50°C enzymes will permanently lose their shape and be unable to combine with substrates. In other words, they are denatured.
What is the temperature or pH that an enzyme works best at called?
It is called the optimum temperature or pH.
Are the effects of a change in pH for a cell reversible?
Yes, although a change in pH may affect the activity of an enzyme, these effects are typically reversible. The enzyme will usually resume it’s normal activity when it’s optimum pH is restored.
What are intracellular enzymes?
Intracellular enzymes are enzymes which are found in cells and speed up reactions in the nucleus and cytoplasm.
Where are all enzymes made?
All enzymes are made inside cells.
What are extracellular enzymes?
Extracellular enzymes are enzymes which work outside of cells.
How are extracellular enzymes used?
Fungi and bacteria release extracellular enzymes in order to digest their food. For example, mould growing on bread may release extracellular enzymes which will digest starch, the cell then absorbs the soluble sugar that the enzyme produces from the starch. In animals extracellular enzymes digest food in the stomach and intestines.
What is the substance on which an enzyme acts called?
The substrate.
What is an anabolic reaction?
An anabolic reaction is where large molecules are built up from smaller molecules.