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Biology-Enzymes > Factors Affecting Enzyme Activity > Flashcards

Factors Affecting Enzyme Activity Flashcards

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1
Q

What must happen for an enzyme to catalyse a reaction?

A

Must come into contact with the substrate, and the enzyme must have a complementary shape for the substrate.

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2
Q

What factors can affect an enzymes complex structure?

A

pH and temperature.

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3
Q

What can a change in pH and temperature cause for the enzyme?

A

A change in the shape of their active site. Enzymes are more likely to come into contact with the substrate if temperature and substrate concentration are increased.

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4
Q

How can factors affecting enzyme action be investigated?

A

By measuring the rate of reaction they catalyse.

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5
Q

How does temperature affect enzyme activity?

A

Increasing the temperature increases the KE of the particles. They they move faster and collide more frequently.

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6
Q

In an enzyme controlled reaction, what will an increase in temperature result in?

A

More frequent successful collisions between substrate and enzyme which lead to an increase in the ROR.

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7
Q

What is the temperature Coefficient (Q10) of a reaction?

A

A measure of how much the ROR increases with a 10 degree rise in temperature.

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8
Q

In enzyme controlled reaction, Q10 often takes 2. What does this mean?

A

The ROR doubles with a 10 degree temperature increase.

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9
Q

How does Denaturation occur from temperature?

A

-At higher temperatures, bonds vibrate more.
-As temperature increases, vibrations increase until bonds strain and break.
-Results in a change in the precise tertiary structure of the protein.

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10
Q

How does denaturation effect the enzyme?

A

-Active site changes shape, no longer complementary to substrate.
-Enzyme will no longer function as a catalyst.

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11
Q

What is the optimum temperature?

A

The temperature at which the enzyme has the highest rate of activity. It can vary significantly.

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12
Q

What is the optimum temperature for human body enzymes?

A

Around 40 degrees

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13
Q

What is the optimum temperature for Thermophilic Bacteria? (found in hot springs)

A

70 degrees

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14
Q

What is the optimum temperature for Psychrophilic Organisms? (live in cold regions)

A

Below 5 degrees

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15
Q

What happens once the enzyme has denatured above optimum temperature? And what type of change does it have to be?

A

The decrease in rate of reaction is rapid. Only needs to be a small change in active site to no longer be complementary.

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16
Q

Why is loss of activity pretty abrupt?

A

Happens to all enzyme molecules around the same temperature.

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17
Q

What happens with regards to the optimum temperature in an enzyme-controlled reaction?

A

Temperature coefficient (Q10) no longer applies as enzymes have denatured.

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18
Q

Why is the decrease in rate of reaction below optimum temperature less rapid?

A

Enzymes haven’t denatured, just less active.

19
Q

What happens in Extreme cold environments?

A

Enzymes controlling metabolic activities of organisms need to be adapted.

20
Q

What are some examples of Extreme Cold environments?

A

Deep Oceans, High altitudes, Polar regions

21
Q

What are some examples of the adaptations in Extreme Cold Environments?

A

-More flexible structures, less stable than enzymes that work at higher temperatures.
-Small temp changes will denature them.

22
Q

What are Thermophiles adapted for?

A

Extreme hot environments

23
Q

What are some examples of Thermophilic environments?

A

Hot springs, deep sea hydrothermal vents.

24
Q

What are some examples of adaptations for Thermophilic environments?

A

-Enzymes are more stable due to increased number of bonds in tertiary structures (hydrogen and sulphur bridges)
-The shape of these enzymes are more resistant to change as temperature rises.

25
Q

What does a change in pH refer to?

A

A change in hydrogen ion concentration.

26
Q

What hold proteins in their precise shapes?

A

Hydrogen bonds and ionic bonds between amino acid R-groups.

27
Q

What are these bonds a result of?

A

A change in interactions between polar and charged R-groups.

28
Q

What is the hydrogen ion concentration in a low pH?

A

More hydrogen ions.
(Acid)

29
Q

What is the hydrogen ion concentration in a high pH?

A

Less hydrogen ions.
(Alkaline)

30
Q

What is the optimum pH?

A

Active site will only be in the right shape at a certain ion concentration.

31
Q

What happens when there is a change from the optimum pH?

A

Active site is altered. If the pH then returns to optimum then the protein with resume its normal shape again and catalyse the reaction.

32
Q

What is this process called?

A

Renaturation.

33
Q

What happens when pH changed significantly?

A

Structure of the enzyme is irreversibly altered and active site will no longer be complementary.

34
Q

What has now happened to this enzyme?

A

-Denatured
-Substrates can no longer bind to active site
-Reduces ROR

35
Q

What happens in a Low pH?

A

R groups can’t interact as much with each other which leads to bonds breaking and enzyme shape changing.

36
Q

What happens in a High pH?

A

Reverse of low. Shape of enzyme will change as pH changes so will only function with a narrow pH range.

37
Q

What happens when the concentration of substrate is increased?

A

The number of substrate molecules, atoms or ions in a particular area or volume increases.

38
Q

What does this increase lead to?

A

A higher collision rate with the active sites of enzymes and the formation of more enzyme-substrate complexes.

39
Q

What happens to the number of active sites when the concentration of enzymes increase?

A

AS number increases in a particular area/volume which leads to the formation of enzyme-substrate complexes at a faster rate.

40
Q

What is it called when the rate of reaction is increased up to its maximum?

A

Vmax

41
Q

What happens the the Rate of Reaction increases up to its maximum ? (Vmax)

A

All the active sites are occupied by substrate particles and no more enzyme-substrate complexes can be formed until products are released from active site.

42
Q

How can this Rate of Reaction be increased?

A

By adding more enzyme or increasing the temperature.

43
Q

What happens if the concentration of the enzyme is increased?

A

More active sites are available so reaction rate can increase to a higher Vmax.

44
Q

In this scenario, what is the limiting factor? And what will increasing this allow?

A

Concentration of substrate and increasing this will allow reaction rate to rise until new Vmax is reached.

Biology-Enzymes (4 decks)

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