Unit 2 - Enzymes Flashcards
What does a substrate need to have in order to bind with an active site
Complementary shape
Opposite charges to the active site
How does change in pH alter the rate of the reaction
Electric charges of both the enzyme and substrate are neutralised by the presence of either positive or negative ions so no enzyme-substrate complex is formed
Properties of enzymes
Complementary active site to shape of substrate
High turnover no.
Ability to reduce activation energy
Left unchanged after reaction
What are enzymes affected by
Temperature
pH
Enzyme conc.
Substrate conc.
Lock and key hypothesis
Shape of active site caused by sequence of amino acids (specific tertiary structure - 3D)
Enzyme controlled reaction
Enzyme + substrate (E + S) —> enzyme substrate complex (ESC) —> enzyme product complex (EPC) —> Enzyme and product (E + P)
Effects of pH on enzymes
Enzymes fully denatures before pH 3 and after pH 11
Enzymes start to denature after pH 7
Hydrogen ions that cause acidity affect interaction between polar and charged R groups and alter tertiary structure
Measuring the rate of an enzyme-controlled reaction
Measure how fast the product appears and use this for comparison
Catalase catalyses H2O2 –> H2 + O2
Variables for reaction of breakdown of H2O2
IV -Temp (use water baths)
DV - vol of O2. produced
CV - pH (use same type of buffer), vol and conc of H2O2 and catalase (from celery)
Digestion of starch
Starch + amylose –> maltose
Occurs in mouth (saliva) and small intestine (pancreatic juice)
Maltose + maltase –> glucose (absorbed directly into bloodstream)
Occurs in small intestine
Digestion of proteins
Trypsin catalyses breakdown of proteins into smaller peptides in small intestine - release w/ pancreatic juices
AA absorbed by cells lining digestive system and then absorbed into the bloodstream
pH of enzymes in small intestine
8
Trypsin
Lipase
Amylase
Maltase
