Enzymes

Question 1

how do enzymes increase the rate of a chemical reaction?

Answer 1

Lower the amount of activation energy needed to i make the reaction proceed.

Question 2

What is a intracellular and extra cellular enzyme?

Answer 2

Intracellular-inside cells
Extracellular-outside cells.

Question 3

What does the lock and key model suggest?

Answer 3

The active site is always the exact complementary shape at the optimum temp, so reactions are fastest in these conditions.

Question 4

The enzyme combines reversible with the substrate to form a what…?

Answer 4

Enzyme-substrate complex.

Question 5

What does the induced fit model suggest?

Answer 5

The active site changes shape to become complementary
(This ‘strained’ fit between the active site and substrate distorts a particular bond and so reduces the activation energy needed to break the bond.)

Question 6

What is want by metabolism?

Answer 6

All reactions in the body

Question 7

When would the rate of reaction increase in an enzyme?

Answer 7

-The temp increased
-The concentration of a dissolved reactant is increased
-Solid reactants are broken into smaller pieces
-A catalyst is used.

Question 8

WhY is the substrate later released in the lock and key model?

Answer 8

Because when the reactions occur they no longer fit as well so are released to allow for more reactions.

Question 9

Draw a graph of the effect of temperature on enzyme activity

Answer 9

.

Question 10

Why do enzyme reactions produce a curve; why is it the fastest at the start and slower as it progresses?

Answer 10

More substance as the start=more ES complexes. As substrate used up fewer successful collisions.

Question 11

What happens to an enzyme when temperature increases?

Answer 11

Enzyme and substrate molecules gain more kinetic energy so move about quicker. As a result they collide more frequent lymph so a greater number of enzyme-substrate complexes are formed.

Question 12

What happens to enzymes at low temperatures?

Answer 12

Molecules are inactive but undamaged move around slowly so rarely collide.

Question 13

What happens to enzymes at temp above 40 degrees?

Answer 13

-hydrogen bonds break
-tertiary structure changes
-active site changes shape and substrate no longer fits
-enzyme substrate complexes cannot form
-enzymes are denatured

Question 14

What is an inhibitor?

Answer 14

A substance which decreases the rate of enzyme controlled reaction and may bring it to a halt.

Question 15

How does a competitive inhibitor compete with a substrate?

Answer 15

Inhibitors are a similar shape to the enzyme. substrate it binds to the active site and blocks the substrate from binding.

Question 16

What is the bond formed in the reversible inhibitors?

Answer 16

Weak hydrogen bonds or non-covalent bonds.

Question 17

What are the bonds formed in irreversible inhibitors?

Answer 17

Strong covalent bonds

Question 18

Draw a graph of the effect of PH on enzyme activity

Answer 18

.

Question 19

Draw a graph off the effect of increasing concentrations of substrate on enzyme activity

Answer 19

.

Question 20

Why does increasing concentration of a substance make the graph level out at a certain period of time?

Answer 20

All the active sites are occupied/saturates. the concentration of enzyme is a limiting factor.

Question 21

What does the graph look like when you increase enzyme concentration but there isn’t enough substrate molecules to occupy all the sites at one time?

Answer 21

.

Question 22

What alters if there is a change in PH?

Answer 22

It alters the charges on the amino acids which make up the active site of the enzyme. this causes some of the hydrogen and ionic bonds to break these alter the shape of the active site.

Question 23

Why do enzymes work best at the optimum PH?

Answer 23

The active site is exactly complementary to teh substrate, so the max number of ES complexes are formed.

Question 24

How does a non-competitive inhibitor decrease the rate of reaction?

Answer 24

Bind to the allosteric site which changes the tertiary structure of the enzyme, so changes the active site so the substrate cannot bind.

Question 25

What does the rate of reaction look like when the substrate reaction increases with and without a competitive inhibitor?

Answer 25

.

Question 26

What are enzymes?

Answer 26

Biological catalysts

Question 27

What is collision theory?

Answer 27

When molecules collide bonds between their atoms can break, and then new bonds can form to make new molecules.

Question 28

Sketch a graph to show the effect of increasing substrate concentration on the rate of reaction, with and without a non-competitive inhibitor.

Answer 28

.

Question 29

Enzymes catalyse both anabolic and catabolic what does this mean?

Answer 29

Anabolic= to build up
Catabolic=to break down

Question 30

What is the equation for calculating rate?

Answer 30

Amount of product/time taken.