Enzymes

Question 1

enzymes

Answer 1

• biological catalysts
• speed up chemical reactions
• catalyse metabolic reaction (both at cellular level, form the organism as a whole)
• can affect structures in an organism as well as functions
• action can be intercellular within cells
• proteins
• active site has a specific shape for a substrate molecule to fit
• specific due to their tertiary structure

Question 2

How enzymes speed up reactions

Answer 2

• activation energy is provided as heat
• ae us the certain amount of energy needed to be supplied to the chemicals before the reaction start
• enzymes lower the amount of activation energy that’s needed often making reactions happen at a lower temp than they could without an enzyme
• speeds up rate of reaction

Question 3

enzyme - substrate complex when joining substrates

Answer 3

• lowers activation energy
• 2 substrate molecules need to be joined
• attached to enzyme holds them closer together
• reduces repulsion between molecules
• bond more easily

Question 4

ES complex when catalysing a breakdown reaction

Answer 4

• fitting into active site puts strain on bonds in the substrate
• breaks them up more easily

Question 5

lock and key mdel

Answer 5

-active site and substrate have a complementary shape

Question 6

induced fit model

Answer 6

-substrate makes the active site change shape so its complementary to substrate

Question 7

enzyme properties

Answer 7

• specific so usually on catalyse one reaction because only one complementary substrate will fit into the active site
• active site shape determined by tertiary structure
• substrate shape doesn’t match active site an enzyme substrate complex won’t be formed and the reaction won’t be catalysed