Final Countdown Flashcards
What is a catalyst?
A substance that speeds up a chemical reaction without being used up in the reaction itself.
What does catalase do?
What does amylase do?
What does trypsin do?
Works intracellularly to catalyse the breakdown of hydrogen peroxide, a toxic by-product of cellular reactions, into oxygen and water.
Secreted from salivary glands, it works extracellularly to catalyse the hydrolysis breakdown of starch into maltose in the mouth.
produced by cells in the pancreas, it works extracellularly to catalyse the hydrolysis of peptide bonds turning big polypeptides into small ones in the small intestine.
Chemicals require a certain amount of ______ ______ before a reaction starts.
______ reduce the amount of activation energy, often making reactions happen at a ______ ______. This ______ ______ the rate of reaction.
activation energy / Enzymes / lower temperature / speeds up
How does the ______ complex lower ______ ______ ?
(answer the question)
enzyme-substrate / activation energy
joining - the enzyme holds the molecules together reducing repulsion
breaking - active site puts strain on the bonds making them break more easily
Name 4 things that affect enzyme activity?
Temperature
pH
Enzyme Concentration
Substrate Concentration
More heat does what to enzymes?
What happens with too much heat?
Makes them move faster owing to more kinetic energy. This means they are more likely to collide.
The enzyme molecules vibrate more which can break the enzyme’s bonds. The active area changes shape and becomes denatured.
What does a pH above and below the optimum do?
Disrupts ionic and hydrogen bonds that hold the enzyme’s tertiary structure in place.
The higher the substrate concentration, the faster the reaction.
Until what?
Saturation.
If the enzymes are busy with what they have got, adding more substrate will have no effect.
Cofactors are ______ ______ or ______ . They help the enzyme and substrate to ______ ______.
Coenzymes ______ ______ ______ _______ and are changed.
They often act as ______ , moving ______ ______ between different enzymes.
inorganic molecules / ions / bind together
participate in the reaction
carriers / chemical groups
What is the difference between competitive and noncompetitive inhibition?
Competitive inhibitor molecules have a similar shape to the active area and block it right up.
Non-competitive inhibitors bind to an enzyme’s allosteric site which causes it to change shape.
What are the bonds associated with the following:
Reversible inhibitors
Nonreversible
Reversible inhibitors - weak hydrogen bonds and weak ionic bonds
Nonreversible - strong covalent bonds
How are metabolic pathways regulated?
By end-product inhibition.
E.g. Phosphofructokinase is an enzyme involved in the breakdown of glucose to make ATP. ATP inhibit the action of Phosphofructokinase to say, no more bruv! When the levels of inhibitor fall, the process can begin again.
