enzymes and metabolism Flashcards
(17 cards)
what is catabolic metabolism
larger molecules are broken down into smaller molecules
- releases energy
e.g. digestion
what is anabolic metabolism
small molecules are built up to larger ones
- requires energy
e..g protein synthesis
what are enzymes
catalysts/proteins that speed up chemical reactions by lowering the activation energy.
they are not consumed or altered during a reaction
what is an enzyme substrate complex
the enzyme and substrate combined.
what is activation energy
energy needed to start a chemical reaction
why do enzymes and substrates only combine with a particular type
they have characteristics that are complementary to one another.
shape/structure
what is the active site
the part of the enzyme that the substrate combines with
what are the models used to describe how enzymes function
lock and key- the enzyme is complementary to the substrate and will fit like a lock and key.
induced fit model- when the substrate/enzyme join, there is a weak bond that changes the shape of the enzyme to make them complementary.
factors effecting enzyme activity
- concentration of an enzyme
- concentration of substrate
- removal of products
- temperature
- pH
- cofactors
- enzyme inhibitors
how does the concentration of an enzyme effect enzyme activity?
higher concentration = faster chemical reaction
how does the concentration of a substrate effect enzyme activity?
higher concentration= increased rate of reaction.
- BUT if all enzymes are occupied then there will be no effect.
how does the removal of products affect enzyme activity?
if too many products are present while other reactions are taking place, reactions will be slowed
how does pH affect enzyme activity?
enzymes are sensitive to pH and enzymes all have a optimum pH at which they work the most effectively.
how does temperature influence an enzymes activity
the rate of chemical reactions will increase to a point but past that point their structure can change making them denatured.
explain what a denatured enzyme is
an enzyme that has lost its normal three-dimensional structure making it no longer able to function.
how do cofactors effect enzyme activity
they change the shape of an active site so the enzyme can combine with a substrate.
- e.g. coenzymes (vitamins)
how do enzyme inhibitors effect enzyme activity
they slow or stop the activity of an enzyme.
e.g. penicillin
