Function Of Proteins Flashcards
Explain how hormones interact with organs
Synthesised by glands
Released into bloodstream
Can only cause a response in the target organ: hormone shape has to fit the organ’s receptor sites
Once hormone reaches target cell, a receptor molecule on the cells surface detects the hormone
Define: enzyme
A biological catalyst
Define: catalyst
A substance that speeds up chemical reactions inside organisms without getting used up in the reaction
How can you tell if a substance is an enzyme?
It name ends with “ase”
Explain why enzymes can only catalyse one reaction
Each substrate has to be complementary to the active site
Describe the two theories which describe how substrates bind with active sites
Lock and key: the substrate has to fit exactly into the enzyme
Induced fit:’the enzyme changes its shape to complement the substrate
Define: substrate
Reactant
Define: complementary
The substrate has to match (fit in) with the active site
Define: active site
Region of an enzyme that the substrate binds to, to form a chemical reaction
What 3 things is enzyme activity affected by?
Enzyme concentration (availability of enzyme) Substrate concentration (availability of the substrate) Changes in shape of the active site, caused by temperature and pH
Define: denaturalising
When the temperature of an enzyme is increased, so the atoms vibrate which causes hydrogen bonds to break
This changes the shape of the enzyme (in particular the shape of the active site), meaning it can no longer react with the substrate
This is irreversible
Define: deactivation
When there is not enough heat in an enzyme, and it moves around too slowly for the substrate to catalyse effectively
But the shape of the enzyme is not affected, so it can function normally
Define: hormones
Chemical messengers
