ENZYMES

Question 1

Enzymes

Answer 1

enzmes are tertiary structure of protein that acts as a biological catalyst

Question 2

all enzymes are?

Answer 2

globular proteins

Question 3

how does an enzyme work?

Answer 3

an enzyme works by lowering the activation energy

Question 4

activation energy

Answer 4

the minimum energy which is required to start a chemical reaction is called an activation energy.

Question 5

substrate

Answer 5

substrate is the substance in which the enzyme can react on.

Question 6

active site

Answer 6

active site is an area of the enzyme where the substrates bind.

Question 7

why is active site in enzyme unique

Answer 7

because of the specific folds and bonding in the tertiary structures of protein .

Question 8

co factors

Answer 8

non protein groups which are essential for the functioning of an enzyme.

Question 9

co factors?

Answer 9

prosthetic groups & co enzymes and activators

Question 10

prosthetic group

Answer 10

nom protein group which could be organic or inorganic. they form a permanent attatchment to the enzyme. iron in haem group. haem is also present in an enzyme called catalase.

Question 11

co enzymes

Answer 11

organic which are mostly derived from vitamins. eg NAD+ ( NICOTINAMIDE ADENINE DINUCLEOTIDE) is derived from vitamin B3.

Question 12

ACTIVATORS

Answer 12

inorganic ions. eg magnesium calcium zinc etc

Question 13

hypothesis in enzymes

Answer 13

1. lock and key hypothesis
2. induced fit hypothesis

Question 14

lock and key hypothesis

Answer 14

• suggests that the active site and enzyme substrate have complementary shapes so they fit together and form an enzyme substrate complex.
• because of the shape of the active site only one type of substrate can bind with the enzyme. enzymes are therefore said to be specific.
• once the esc are formed, within the active site are thought to distort the substance and lowers the activation energy. products are now released and active site is now empty and ready to be used.

Question 15

induced fit hypothesis

Answer 15

• modified form of lock and key hypothesis
• hands and glove
• suggests that the active site in an enzyme is slightly induced or changed to form an enzyme substrate complex. when the enzyme substrate complex is formed due to the molding of enzyme around the substrate, it puts strain on the bonds and lowers the activation energy.
• product is then removed and enzymes active site comes back to its original shape.

Question 16

factors affecting the enzyme

Answer 16

1. enzyme concentration
2. substrate concemtration
3. temperature
   4.pH

Question 17

ENZYME CONCENTRATION

Answer 17

there is a direct co relation between enzyme concentration and rate of reaction. as the enzyme conc increases, more activesites are available for the substrate to bind - more collisions - more product.

Question 18

substrate concentration

Answer 18

as the substrate conc is low, active sites are not fully utilised. as the substrate concentration increases, more active sites are utilised but there comes a point where all the active sites will be fully utilised and the enzyme wont work faster.

Question 19

temperature

Answer 19

increase intemperature - increase in kinetic energy - increased collisions between substrate and enzyme - more produts are formed - increases rate of rxn.

enzymes have an optimum temp of 40 c. if temp goes beyond , it causes denaturation of enzymes which means change in active site and shape which slows down the reaction as no substrates can bind.

high temp - additional kinetic energy - intramolecular vibrations betweeen weak hydrogen bonds holding polypeptide chains

Question 20

pH

Answer 20

• Too high or too low ph interferes with changes in amino acids in active sites which can break bonds holding tertiary structures in protein.

Question 21

inhibitors

Answer 21

certain substances that inhibits the activity of enzymes.

Question 22

types of inhibitors

Answer 22

competitive inhibitor and non competitive inhibitors

Question 23

competitive inhibitors

Answer 23

same shape as the substrate. substrate and inhibitor compete to bind to the active site. since inhibitors have similar characteristics to that of substrate, it binds to the active site preventing the substrate from binding.

Question 24

non competitive inhibitor

Answer 24

inhibitor doesnt bind to the active site, but binds to an allosteric site causing the active site to change shape and substrate can no longer bind.