Factors affecting enzyme action

Question 1

How does increasing temp affect enzyme action?

Answer 1

Kinetic energy increases + makes more successful collisions, and more enzyme-substrate complexes are formed

Question 2

How is enzyme action affected when beyond optimum temp?

Answer 2

Strain placed on bonds, making them break. Causes enzyme to change tertiary structure

Question 3

What happens when a tertiary structure of enzyme is changed?

Answer 3

Active site not complimentary anymore to substrate + fewer enzyme-substrate complexes formed

Decreases rate of reaction

Question 4

What is the affect of low temps on enzyme action?

Answer 4

Rate slows due to lower kinetic energy between particles, causing less collisions

Question 5

What is the temperature coefficient (Q10)?

Answer 5

Measure of how much rate of reaction increases with 10 degree increases in temperature

Normally is 2, meaning it doubles with 10 degree increase

Question 6

Why does optimum temp of each enzyme differ?

Answer 6

Due to organism it comes from + its role

Question 7

What is the pH?

Answer 7

Measure of conc of hydrogen ions in solution

Higher conc of H ions, lower the pH and vice versa

Question 8

What happens to enzymes at their optimum pH?

Answer 8

Bonds that determine tertiary structure of enzyme all form to give active site its specific shape

Question 9

What are the bonds determining tertiary structure called?

Answer 9

Hydrogen, ionic, + disulfide bonds

Question 10

What happens to enzyme action when pH differs SLIGHTLY from optimum pH?

Answer 10

Shape of active site changes due to bonds breaking

If optimum pH restored, it returns to normal shape + reaction is catalysed again (renaturation)

Question 11

What happens to enzymes action when pH differs SIGNIFICANTLY from optimum pH?

Answer 11

Shape of active site changes irreversibly, + no substrates ab;e to bind with active site (denaturation)

Rate of reaction decreases

Question 12

What happens to enzymes action when substrate conc increases?

Answer 12

Theres more successful collisions + more enzyme-substrate complexes formed

Increases rate of reaction

Question 13

What happens at the point of saturation?

Answer 13

Increasing substrate conc has no further effect on rate of reaction (known as Vmax)

Question 14

Why doesnt rate of reaction increase after the saturation point?

Answer 14

All active sites are occupied by substrates + no more enzyme-substrate complexes can be formed until products released from active sites

Decreases rate of reaction

Question 15

What is the Vmax?

Answer 15

Max reaction rate/velocity of an enzymatically catalysed reaction when the enzyme is saturated with its substrate

Question 16

What effect does enzyme concentration have on enzyme action?

Answer 16

Vmax is limited by substrate conc

Can be i creased if enzyme conc increases - more enzyme active sites formed substrates to occupy + more enzyme-substrate complexes form

Rate increases until new Vmax is reached

Question 17

What is the Q10 equation?

Answer 17

Rate of reaction at (x + 10)C / Rate of reaction at xC

Question 18

What does it mean if Q10 is greater than 1? >

Answer 18

Rate is increasing

Question 19

What does it mean if Q10 is equal to 1?

Answer 19

Rate is constant, not increasing nor decreasing

Question 20

What does it mean if Q10 is less than 1? <

Answer 20

Rate is decreasing