Enzymes Flashcards
what are enzymes
biological catalysts that speed up chemical reactions in living organisms
what type of enzyme breaks down polysaccharides into monosaccharides
carbohydrase
what enzyme breaks down starch into glucose
amylase
what enzyme breaks down protein into polypeptides/amino acids
protease
what enzyme breaks down fats (lipids) into glycerol and fatty acids
lipase
4 points
what are properties of enzymes
most made up of proteins (one of the reasons why we need proteins in our diet)
speed up reactions without being used up (remains unchanged at the end of the reaction)
enzyme activity affected by pH and temperature
specific in their actions (maltase only for maltose, sucrase only for sucrose, etc.)
4 points
describe the lock-and-key hypothesis
active site of enzyme has a specific 3-D shape that only the substrate with a 3-D shape complementary to it can fit, just like a lock-and-key
the enzyme is the lock and the substrate is the key
substrate binds to enzyme, forming an enzyme-substrate complex
reaction takes place to convert substrate to products
5 points
what is the effect of temperature on enzyme activity
enzymes inactive at low temperatures as kinetic energy is low
increasing temperature increases kinetic energy of enzyme and substrate molecules so that they move faster and are more likely to collide
increasing the temperature increases the rate of reaction up to a certain temperature, the enzyme’s optimum temperature, at which it is the most active
if temperature increased beyond optimum temperature, bonds holding enzyme molecule together in shape eventually break and the active site loses its shape such that the substrate can no longer fit into it
^ enzyme is denatured (most denature at 60°C)
*activity past optimum temperature has steeper decline than increase in graph
2 points
what is the effect of pH on enzyme activity
enzymes have optimum pH (most 6-8)
at extreme pH, enzyme denatures and reaction will stop
*curve of graph is symmetrical
