4 - Enzymes

Question 1

Active Site

Answer 1

Indented area on a surface of an enzyme with a complementary shape to the substrate.
The tertiary structure of the active site is crucial as its shape is complementary to the shape of the substrate molecule. So each enzyme is highly specific.

Question 2

Catalyst

Answer 2

Chemical that speeds up the rate of reaction and remains unchanged and unused by the end of the reaction.

Question 3

Extracellular

Intracellular

Answer 3

Inside the cell

Outside the cell

Question 4

Metabolic

Answer 4

The chemical reactions that take place within a living cell

Question 5

Product

Answer 5

Molecules produced from substrate molecules by an enzyme catalysed reaction

Question 6

Substrate

Answer 6

Molecules that are altered by enzyme-catalysed reactions

Question 7

Anabolic and Catabolic

Answer 7

The chemical reactions required for growth are anabolic reactions and they are catalysed by enzymes. Energy is released from large organic molecules or through metabolic pathways consisting of catabolic reactions

Question 8

Cofactor

Answer 8

A substance that has to be present to ensure the enzyme catalysed reaction takes place at the appropriate rate. SOME cofactors are part of the enzyme structure (prosthetic group) and others form temporary associates with the enzyme (coenzyme)

Question 9

Enzyme-substrate complex

Answer 9

A complex formed by temporary binding of the enzyme and substrate molecules during an enzyme catalysed reaction.

Question 10

The Lock and Key Hypothesis

Answer 10

This is where the active site and the substrate molecule fit because the tertiary structure of the enzymes active site is complementary to the substrate.

Question 11

The Induced Fit Hypothesis

Answer 11

The active site of the enzyme is not a fixed structure, but there’s substrate molecule that it induces changes shape giving a good fit.

Question 12

Enzymes lower the activation energy of a reaction AS THEY ….

Answer 12

Enzymes lower the activation energy of a reaction as they increase the kinetic energy of the molecule making a move model making the most successful collisions and then they react together.

Question 13

Enzyme product complex

Answer 13

Enzyme molecule with product molecules in its active site that I joined temporary together by non-covalent forces.

Question 14

Enzyme substrate complex

Answer 14

Enzyme molecule with substrate molecules in its active site that are joined together temporarily by non-covalent forces.

Question 15

The effect of temperature on enzyme activity

Answer 15

If a substance is heated, then there be more energy in the form of heat causing a molecules to move faster therefore there will be increased collisions.

Question 16

Denatured

Answer 16

When an enzyme becomes denatured its shape becomes reversibly changed and therefore the substrate can no longer be complimentary.

Question 17

pH

Answer 17

A buffer is something that research changes in pH. Enzymes work within a narrow range of pH

Question 18

Low pH

Answer 18

Enzymes that work extra cellular have an ultimate pH that is not seven. For example enzymes within the stomach have a low pH as hydrochloric acid is needed.

Question 19

Effect of changing substrate concentration

Answer 19

As a substrate is added and its concentration increases the rate of reaction increases. This is because more enzyme-substrate complexes can form meaning of product molecules are formed. Is the limiting factor as when it increases the rate of reaction increases.

Question 20

Competitive inhibition

Answer 20

Inhibition of an enzyme inhibitor molecule has a similar shape to the substrate molecule and competes with the substrate for the enzymes active site. It blocks the active site and prevents the formation of an enzyme substrate complex.

Question 21

Non competitive inhibition

Answer 21

Inhibition of an enzyme with a competitor molecules attached to the part of the enzyme, but not the active site this changes the shape of the active site which prevents the ES complex forming as the active site is no longer complementary in shape to the substrate molecule.

Question 22

Inhibitor

Answer 22

A substance that stops or reduces a reaction

Question 23

End product Inhibition

Answer 23

After the reaction has completed product molecules and missed a tightly bound to the enzyme so that it cannot produce more. More product than needed such radiation is known as negative feedback.

Question 24

Poisons and medical drugs

Answer 24

Snake venom contains a chemical that inhibits enzymes
Cyanide is highly toxic as it inhibits aerobic respiration. It also inhibits catalase
ACE inhibitors I used to lower blood pressure in patients with hypertension and treat heart failure.