Enzymes & Proteins Flashcards
what are enzymes
biological catalysts, globular proteins that interact with substrates and cause them to react much faster
anabolic and catabolic
ana= builiding up cata=breaking down
metabolism
sum of all the different reaction pathways in a cell or organism
mechanism of enzymes
molecules randomly collide but need right orientation and speed in order for it to be successful.
enzymes help the substrate molecules collide successfully to form products and therefore lower the activation energy
what is Vmax
maximum initial velocity or rate of an enzyme catalysed reaction(highest capacity of enzyme activity0
lock and key theory
active site is specific shaped area on enzymes in which only the right substrate bind
forms enzyme substrate complex , substrates react and form enzyme product complex then the products are released
substrate and R groups of enzyme can react forming temporary bonds holding it together and when products formed bonds break
induced fit hypothesis
Active site changes shape slightly as substrate enters, interaction between substrate & enzyme weak but interactions induce changes in enzymes tertiary structure that strengthen binding and put strain on the substrate. weakens bonds in substrate(lowers activation energy)
intercellular enzymes
enzymes that act inside the cell
extracellular enzymes
nutrients taken from our food cannot directly enter cell plasma membrane so need to be broken down by enzymes into smaller molecules for digestion
single cellular organisms like bacteria/ yeast release extracellular enzymes to their immediate environment to break down larger molecules that can be digested
digestion of starch
1starch broken down into disaccharide maltose by the enzyme amylase which is found in the salivary gland and pancreas
2maltose brown down into monosaccharide glucose by maltase found in the small intestine
glucose can be absorbed by cell lining of digestive system then is absorbed into the bloodstream
digestion of proteins
trypsin is a protease that breaks proteins into smaller peptides which can then be broken down into smaller amino acids. Made in the pancreas and released into the small intestine where it acts on proteins which is then absorbed into cell lining then the bloodstream
how does temperature affect proteins
increase particles Ke
particles move faster and more
collisions
in enzymes more enzyme substrate complex formed
temperature co-efficient q10
measure how much the Ror increases with a 10*c increase in temperature
for enzyme controlled reactions usually taken as 2
denaturing enzymes
at high temps the bonds holding the proteins together vibrate and break causing the tertiary structure to irreversibly change making it lose its complementary function(denatured)
active site changes shape and can no longer for ES complexes so no longer function as a catalyst
what is optimum temperature
the temperature in which enzymes have the highest rate of activity for humans its usually 40*c once enzymes have denatured above optimum temperature the rate of reaction decreases rapidly
q10 no longer efficent