Enzymes Flashcards
(46 cards)
What are enzymes?
They’re proteins which are biological catalysts that speed up chemical reactions.
What reactions do enzymes catalyse?
Metabolic reactions.
At what level to enzymes catalyse metabolic reactions?
- At cellular level (respiration).
* And for the organism as a whole (digestion in mammals).
What can enzymes affect in organisms?
- Structures
* Functions
What structures can enzymes affect?
e.g. Enzymes are involved in the production of collagen, which is an important protein in the connective tissues of animals.
What functions can enzymes affect?
e.g. Respiration
What can enzymes action be regarding cells?
- Intracellular (within cells).
* Extracellular (outside cells).
What gives an enzyme their shape?
An active site.
What shape is each type enzyme’s active site?
A different specific shape.
What happens at the active site of enzymes?
This is where the substrate molecules bind to.
Why are enzymes highly specific?
Due to their tertiary structure.
What do chemical reactions need to begin?
Activation energy.
What is activation energy?
A certain amount of energy needed to be supplied to the chemicals before the reaction will start (usually heat).
What do enzymes do to the activation energy of a chemical reaction?
They lower the amount of activation energy that is needed.
When enzymes lower the amount of activation energy what does this cause?
The reactions often happen and lower temperatures.
What do enzymes do to the rate of reaction?
They speed it up.
What does a graph comparing activation energies with and without enzymes look like?
Picture
What happens when a substrate reacts with an enzyme?
It fits into the enzymes active site forming an enzyme-substrate complex.
What does the enzyme-substrate complex cause?
The lower activation energy.
Why does the enzyme-substrate complex cause the lower activation energy?
- The molecules can bond more easily.
* The substrate molecule can break up more easily.
Why does the enzyme-substrate complex cause the molecules to bond more easily?
Because if two substrates need to be joined, being attached to the enzyme holds them close together, thus reducing any repulsion between the molecules so they can bond more easily.
Why does the enzyme-substrate complex cause the substrate molecules to break up more easily?
Because if the enzyme is catalysing a breakdown reaction, fitting into the active site puts strain on bonds in the substrate, so the molecule breaks up more easily.
What is the ‘lock and key model’?
Where the enzyme’s active site and the substrate have a complementary shape.
What is the complementary shape of the enzyme ‘lock and key’ model?
Where the substrate fits into the enzyme the same way that a key fits into a lock.
