Enzymes

Question 1

Activation Energy

Answer 1

The minimum amount of energy needed for a reaction to happen

Question 2

Active Site

Answer 2

A specific region on an enzyme where the substrate binds and the reaction takes place

Question 3

Amylase

Answer 3

An enzyme that catalyses the extracellular breakdown of starch

Question 4

catalase

Answer 4

An enzyme that catalyses the intracellular breakdown of hydrogen peroxide into oxygen and water

Question 5

Coenzyme

Answer 5

A type of cofactor that is bound loosely o an enzyme with weak interactions

Question 6

Cofactors

Answer 6

A non-protein molecule that is needed for the effective functioning of an enzyme

Question 7

Competitive Inhibitor

Answer 7

A molecule which binds to the active site of an enzyme and prevents the substrate from binding

Question 8

End Product inhibition

Answer 8

A method of enzyme inhibition where the product f an enzyme controlled reaction can bind to the enzyme and prevent it from workin

Question 9

Enzyme

Answer 9

A biological catalyst used to speed up the rate of biochemical reactions without being used up or permanently altered

Question 10

Enzyme-Product Complex

Answer 10

The temporary complex formed after the enzyme has catalysed the reaction but before the products have left the active site of the enzyme

Question 11

Enzyme Substrate Complex

Answer 11

The temporary complex formed when th substrate binds to the active site of the enzyme

Question 12

Extracellular reaction

Answer 12

A reaction that occurs outside of cells

Question 13

Inactive Precursor

Answer 13

An inactive form of an enzyme that cannot carry out its function until it is activated

Question 14

Induced fit hypothesis

Answer 14

A model of enzyme action that describes how once a specific substrate binds to the active site; the enzyme undergoes subtle conformational changes to fit the substrate better

Question 15

Intracellular Reaction

Answer 15

A reaction that occurs inside the cells

Question 16

Lock and Key hypothesis

Answer 16

A model of enzyme action that describes how the enzyme will only fit a substrate that has the correct complimentary shape to the active site

Question 17

Metabolism

Answer 17

The sum of all the chemical reactions taking place in a cell

Question 18

Non-Competitive Inhibitor

Answer 18

An inhibitor which binds to a different part of an enzyme known as the allosteric site and prevents the enzyme from functioning

Question 19

Prosthetic group

Answer 19

A type of cofactor that is bound tightly to an enzyme with strong interactions

Question 20

Substrate Specificity

Answer 20

The ability of an enzyme to catalyse only a specific reaction or set of reactions which have substrates complementary to the active site of the enzyme

Question 21

Trypsin

Answer 21

An enzyme that catalyses the extracellular breakdown of proteins

Question 22

Enzymes Notes

Answer 22

• Biological catalysts
• Globular proteins
• have a specific tertiary structure
• Catalyses metabolic reactions
• Lowers the activation energy of reaction

Question 23

Effect of Temperature on Enzymes

Answer 23

As the temperature increases the kinetic energy does to. This means the substrate and the enzymes move around faster. The substrate and active site collide more often so Enzyme Substrate Complexes form which increases the rate of reaction.
Heat makes the molecules vibrate so the the weaker and ionic bonds break. The tertiary structure of the enzyme and active site changes shape so the substrate no longer first then the enzyme denatures

Question 24

Effect of PH on Enzymes

Answer 24

Enzymes have an optimum PH,where the rate of reaction is highest. The hydrogen and ionic bonds that hold the tertiary structure in place get broken. This alters the tertiary structure which denatures the enzyme since the substrate no longer fits the site and the enzyme substrate complex cannot form

Question 25

Effect of Enzyme Concentration on Enzymes

Answer 25

There are more active sites so it is easier for the substrate to collide with the active site so more name substrate complexes form increasing the rate of reaction.

Question 26

Effect of Substrate Concentration on Enzymes

Answer 26

There are more substrates to collide with the active site so more enzyme substrate complexes form which increases the rate of reaction

Question 27

Enzyme Regulation

Answer 27

- Enzymes can be activated by coenzymes - Enzymes can b inactivated by inhibitors - Inhibitors slow or stop enzyme activity - Inhibitors can be ir/rversible

Question 28

Competitive Inhibition

Answer 28

- have similar shape to the substrate so they fit in the active sites - The inhibitor blocks the active site - The activity of the enzyme is decreased

Question 29

Non-Competitive Inhibitors

Answer 29

- Binds at the allosteric site - a location other than the active site - The binding causes the tertiary structure to change shape - The substrate cannot bind to the active site

Question 30

Irreversible Non-Competitive Inhibitors

Answer 30

- Cannot be removed from the enzyme they are attached to

Question 31

End Product Inhibition

Answer 31

- The product of the reaction acts as an inhibitor for the enzyme that produces - Serves as negative feedback

Question 32

Cofactors

Answer 32

- A non protein compound required for the enzymes activity to occur - three types: activators, coenzymes and prosthetic groups - Coenzymes are organic factors which do not bind permanently, they facilitate the binding of the substrate - Activators are inorganic metal ions which temporarily binds to the inactive precursor enzyme and alters its active site - Prosthetic Groups are permanently attached to the enzyme