4. proteins and enzymes Flashcards
what is the function of a structural protein?
offer support to the cell/organism
what is the function of an enzyme?
speed up cellular reactions and are unchanged in the process (biological catalysts)
what is the function of a hormone?
act as chemical messengers carrying information from one part of the organism to another
what is the function of an antibody?
combine with pathogens to destroy them and protect the body from disease
what is the function of a receptor?
are found on the surface of cells and allow signals to be transmitted across the membrane into the cell
what are the basic units of proteins?
amino acids
what links amino acids together?
peptide bonds
what is a degradation reaction?
large complex molecules are broken down into smaller simpler ones (e.g. starch being broken down into maltose and then glucose)
what is a synthesis reaction?
small, simple molecules are built up into large complex ones (e.g. glucose being built up into starch)
describe an enzyme controlled reaction
the molecule on which the enzyme works (substrate) joins temporarily at the active site on the surface of the enzyme
this facilitates the chemical reaction which can now take place quickly and forms product(s)
enzymes are specific to a particular substrate because…
the shape of the active site of an enzyme molecule is complementary to its specific substrate (key fitting into lock)
what can enzymes be affected by?
temperature and pH
what is the optimum temperature for enzymes and what happens to them at this temperature
37 degrees - the enzyme and substrate molecules more more quickly and collide more often therefore more reactions take place - most active
what happens to enzymes at temperatures above 37 degrees?
the chemical bonds break changing the shape of the enzymes active site - it becomes denatured and is permanently inactive
what pH do most enzymes work best at?
7 (neutral)
