Enzymes Flashcards
What is an enzyme? ( definition )
- a biological catalyst
- responsible for speeding up the reaction
Why are enzymes important?
- Biological reactions would not take place fast enough without them
- Effective at low concentrations
- Reusable ( can use until they are not able to )
What is activation energy?
The energy needed to get started on a chemical reaction.
How do enzymes affect activation energy?
Enzymes reduce the activation energy needed to start reactions.
By how much can enzymes speed up reactions?
Reactions with enzymes can happen as much as 10 billion times faster than without them.
What is the active site of an enzyme?
A space between the folds of an enzyme where substrate fits.
What is a substrate in relation to enzymes?
- a molecule that fits into the active site of an enzyme, making it easier for the enzyme to break or form bonds during a chemical reaction.
What are the two types of reactions involving substrates?
- Catabolic reactions: 1 substrate is split into 2 products
- Anabolic reactions: two substrates are bonded into a product
What is enzyme specificity?
- The concept that the active site has a very specific shape and will only catalyse one reaction.
- Each enzyme only works with a specific substrate (molecules) to produce a specific reaction.
What is the lock and key hypothesis?
- The idea that each enzyme action is due to a unique molecular shape.
- The enzyme is the lock, and the substrate is the key. Only the correct “key” (substrate) fits into the “lock” (enzyme) to make the reaction happen.
What factors affect enzyme activity?
- pH
- Temperature
- Concentration of the substrate
- whether or not there are any metals blocks on the way
What can inhibit enzyme activity?
Certain toxins (e.g., heavy metals) that block the active site.
How are enzymes typically named?
They are usually named after the substrate acted upon and always end in the suffix ‘-ase’.
- lipase -> breaks down lipids
- sucrase -> breaks down sucrose
True or False: Enzymes can be used up in a reaction.
False
What is the structure of enzymes?
- made from a highly folded protein chain
What happen if enzymes are out of their ideal conditions
- they can become denatured ( lose their shape and function )
What is pH?
- how acidic something is
How is temperature affects enzymes
- temperature change the shapes of enzymes
- after being heated to the maximum temperature, the enzymes stop working
Why is it important to keep the same shape of enzymes?
- When enzymes are heated up, their shape changes so they are no longer working anymore as enzymes only work if the substrate fit exactly in the active site (they are no longer fit into the “lock and key” structure)
