Factors Affecting Enzyme Action

Question 1

What factors affect the rate of enzyme controlled reactions?

Answer 1

1. Temperature
2. pH levels
3. Substrate concentration
4. Enzyme concentration
5. Inhibitors (competitive and non - competitive)

Question 2

What a§ffect do temperature levels have on enzymes?

Answer 2

Enzymes are very sensitive to certain conditions. If temperatures are too low or too high, enzyme - substrate complexes will not form

Question 3

What happens to enzymes when the temperature is too low during enzyme controlled reactions?

Answer 3

If temperature is too low, there will be insufficient kinetic energy levels fo successful collisions between the enzyme and substrate

Question 4

What happens to enzymes when the temperature is too high during enzyme controlled reactions?

Answer 4

If temperatures are too high enzymes will denature. This makes the active site change shape and leads to enzyme - substrate complexes not forming

Question 4

Why do enzymes denature at higher temperatures?

Answer 4

The bonds that hold the amino acids in their fixed tertiary structure in the active site are broken as the enzyme molecules gain even more kinetic energy

Question 5

What affect do pH levels have on enzymes?

Answer 5

If pH levels are too low there will be too many -0H ions. If pH levels are too high there will be too many H+ ions. The increased levels in these ions will interfere with the charges in the amino acids in the active site

Question 6

Why are enzymes affected by different pH levels?

Answer 6

Enzymes that have pH levels that are too high or too low will have bonds that break which hold the tertiary structure in place, therefore changing the active site’s shape

Question 7

What happens to the enzyme when they are not at their optimum pH level?

Answer 7

When enzymes are not at their optimum pH level they denature, leading to fewer enzyme - substrate complexes forming

Question 8

Do all enzymes have the same optimal pH level?

Answer 8

Enzymes have different optimal pH levels. For example, amylase has a more alkaline level and proteases have a more acidic level

Question 9

What affect does the substrate concentration have on enzyme controlled reactions?

Answer 9

An insufficient substrate concentration, leads to slower rates of reactions. This is because of the fewer collisions occurring between the enzyme and substrate

Question 9

When you reach a higher rate of reaction, whilst adding substrate concentration, there is a plateau.
What becomes the limiting factor in the reaction?
Explain why

Answer 9

The limiting factor becomes the enzyme concentration. This is because when you add more and more amounts of substrate the enzyme active sites become saturated. The addition of more enzymes has been neglected, so without more enzymes to form enzyme - substrate complexes

Question 10

What affect does enzyme concentration have on the rate of enzyme controlled reactions?

Answer 10

Having insufficient enzymes will cause the enzyme active sites to become saturated with the substrate concentration and unable to work faster, leading to a slower rate of reaction.

Question 10

What does an insufficient enzyme concentration lead to in enzyme controlled reactions?

Answer 10

Insufficient enzyme concentrations will lead to slower rates of reactions, due to the active sites being unavailable

Question 11

When you reach a higher rate of reaction, whilst adding enzyme concentration, there is plateau
What becomes the limiting factor in the reaction, and explain why?

Answer 11

The limiting factor now becomes the substrate concentration. This is because there will be too many active sites without any substrates to form enzyme substrate complexes due to insufficient substrates

Question 12

What would the graph look like if there were equal parts of enzyme and substrate concentration?

Answer 12

If there was an equal supply of both enzyme and substrate concentration there would be a directionally proportional line on the graph. Showing a positive correlation indefinitely

Question 13

What are inhibitors?

Answer 13

Inhibitors are molecules which bind to the active site of an enzyme, preventing the enzyme from functioning

Question 14

How many types of inhibitors are there and what are they called?

Answer 14

There are two types: competitive inhibitors and non -competitive inhibitors

Question 15

What are competitive inhibitors?

Answer 15

Competitive inhibitors are molecules that are similar to the shape of the substrate, complementary in shape to the active site. This makes them capable of binding and forming an enzyme inhibitor complex

Question 16

What effect do competitive inhibitors have on enzyme controlled reactions?

Answer 16

Competitive inhibitors prevent the substrate from binding and enzyme controlled reactions occurring. As a result enzyme substrate complexes will not form

Question 16

How can you prevent competitive inhibitors from inhibiting enzymes?

Answer 16

By adding more substrate, the substrates will out compete the competitive inhibitor, knocking them out the active site. This will lead to a normal rate of reaction

Question 17

What are non - competitive inhibitors?

Answer 17

Non - competitive inhibitors are molecules that bind to the enzyme away from the active site, known as the allosteric site

Question 18

What is the site called where the non - competitive inhibitors bind to the enzyme?

Answer 18

The allosteric site

Question 19

What affect do non - competitive inhibitors have on enzyme controlled reactions?

Answer 19

Non - competitive inhibitors slightly change the structure and lead to the active site changing shape. The change in active site’s shapes results in the substrate being unable to bind, no matter how much substrate is added

Question 20

How do you identify the different reactions based on the presence or the lack of inhibitors?

Answer 20

If there are no inhibitors the rate of reaction will be at the highest

If there is a competitive inhibitor present, the rate of reaction will be in the middle, the rate of reaction will be lower than no inhibitors, but will increase toward the end due to increased substrate concentration