30.3- ENZYMES

Question 1

What are enzymes?

Answer 1

protein-based catalysts found in living things

Question 2

What type of proteins are enzymes usually?

Answer 2

globular proteins

Question 3

What does the shape of enzymes have?

Answer 3

has a cleft or crevice

Question 4

What is the shape of the cleft or crevice in the shape of the enzyme?

Answer 4

it’s active site

Question 5

Where does the reactions happen on an enzyme?

Answer 5

active site

Question 6

How does the reacting molecule fit in the active site of the molecule?

Answer 6

reacting molecule fit precisely in active sit + held in just the right orientation to react

Question 7

Which molecules only can react?

Answer 7

molecules whose shape fits active site can react

Question 8

What is the hypothesis of only molecules of whose shape fits can react?

Answer 8

lock and key hypothesis

Question 9

What else must the substrate do other than fitting the shape of the active site?

Answer 9

must bond to active site temporarily by intermolecular forces

Question 10

Whilst the substrate is bonded to the enzyme, what do the forces promote?

Answer 10

promote movement of electrons within substrate that lower activation energy for reaction

Question 11

Why do many enzymes only catalyse reactions of one or other of a pair of enantiomers?

Answer 11

active site of enzyme can be so selective of shape of substrate

Question 12

What are the enzymes that only catalyse reactions of one or other of a pair of enantiomers called?

Answer 12

stereospecific

Question 13

If you can block an enzyme that catalyses a harmful reaction, what can you effectively do?

Answer 13

stop reaction

Question 14

How can enzymes be denatured (have their shapes changed)?

Answer 14

by changes in temp. and pH

Question 15

What is a different way of destroying an enzyme’s ability to catalyse a reaction?

Answer 15

devise molecule of similar shape to its substrate

Question 16

What will devising a molecule of a similar shape to an enzymes substrate do?

Answer 16

will bind to active site + block active site of enzyme to substrate

Question 17

What is it called when a molecule of similar shape to a substrate binds to the active site + block active site of enzyme to substrate?

Answer 17

enzyme inhibition

Question 18

What is enzyme inhibition the mode of?

Answer 18

mode of action of some drugs

Question 19

What are chemists able to use computer modelling techniques to do?

Answer 19

predict shape of proteins even before they’ve been synthesised, and so predict their properties

Question 20

What does chemists being able to use computer modelling techniques to predict the shape of proteins even before they’ve been synthesised, and so predict their properties, help them do?

Answer 20

helps them to design drugs that may be used to treat a range of medical conditions