Enzymes

Question 1

What is an anabolic enzyme?

Answer 1

Building up new substances and structures to form new cells and whole organisms

Question 2

What is a catabolic enzyme?

Answer 2

Breaking down substances such as the metabolic pathways in respiration or digestion

Question 3

What is an active site and what is it complementary to?

Answer 3

Specific to the substrate complementary to the substrate

Question 4

What is the name given to the enzyme and substrate combination?

Answer 4

Enzyme substrate complex

Question 5

What is the name given to the enzyme and product combination?

Answer 5

Enzyme product complex

Question 6

What is the activation energy of an enzyme and what does the energy prevent?

Answer 6

Enzymes lower activation energy and the energy prevents molecules from breaking down spontaneously

Question 7

What is activation energy?

Answer 7

The energy required to start the reaction

Question 8

What kind of protein is an enzyme?

Answer 8

globular

Question 9

What level of structure is important ?

Answer 9

Tertiary

Question 10

What does the lock and key hypothesis assume?

Answer 10

The substrate is exactly complementary to the active site

Question 11

What is the induced fit theory?

Answer 11

The substrate isn’t an exact fit. When it binds it caused the enzyme to bend around the substrate resulting in the close fit.

Question 12

What is an intracellular enzyme?

Answer 12

Act within the cell

Question 13

Why is catalase important?

Answer 13

Hydrogen peroxide is a toxic product of metabolic pathways, catalase breaks it down into water and oxygen

Question 14

What is the equation for the breakdown of hydrogen peroxide?

Answer 14

2H2O➡️ 2H2O+ O2

Question 15

Why do large molecules need to be broken down?

Answer 15

They cannot enter cells directly

Question 16

What is an extra cellular enzyme?

Answer 16

Enzymes can be secreted from the cell the break down large molecules so the products can be absorbed. Enzymes released from the cells in this way are extra cellular

Question 17

Give an example of an organism that digests it’s food outside of its body extracellularly

Answer 17

Saprophytic fungi

Question 18

What does amylase do?

Answer 18

Starch is broken down into maltose using the extracellular amylase

Question 19

Where is amylase released from in the human body?

Answer 19

Salivary glands and pancreas

Question 20

What does trypsin do? And where is it produced?

Answer 20

Breaks down proteins into smaller polypeptides. Produced in the pancreas secreted into the small intestine

Question 21

how does substrate concentration affect the rate of reaction?

Answer 21

higher concentration= faster reaction as more substrate means more likely to be collisions between the enzyme and substrate

Question 22

what is saturation point with the amount of substrate ?

Answer 22

after a certain point all of the active sites are full and this is all the enzymes can cope with so adding more substrate makes no difference

Question 23

what effect does enzyme concentration have on the rate of reaction?

Answer 23

more enzyme molecules results in more collisions to form enzyme substrate complexes so increases the rate of reaction

Question 24

what happens when the amount of substrate is limited with enzyme concentration?

Answer 24

there comes a point when there’s too many enzyme molecules to deal with the amount of substrate so adding more has no effect

Question 25

how does pH affect enzyme activity?

Answer 25

enzymes work best at the optimum pH value, for most human enzymes this pH is 7, however above and below the optimum pH the H+ and OH- ions found in acids and alkalis can mess up the ionic bonds and hydrogen bonds that hold the enzymes tertiary structure in place this results in a denatured enzyme

Question 26

what does the temperature coefficient (Q10) show?

Answer 26

this is a value that shows how much the rate of reaction changes when the temperature is raised by 10 degrees

Question 27

what effect does temperature have on the rate of reaction?

Answer 27

rise in temp makes the enzymes molecules vibrate more, if the temp goes above a certain level this vibration breaks some of the bonds that hold the enzyme in shape , the active site then changes so the enzyme and substrate no longer fit together at this point the enzyme is denatured

Question 28

what do enzyme inhbitors generally do?

Answer 28

prevent an enzyme from doing its job, it can be competitive or non competitive, reversible or non reversable

Question 29

how does a competitive inhibitor work?

Answer 29

the molecule or part of it has a similar shape so the substance can block the active site. The inhibitor and molecule therefor compete with the active site

Question 30

describe statins

Answer 30

used to reduce blood cholesterol, they're reversible and inhibit an enzyme used in cholesterol synthesis

Question 31

describe asprin

Answer 31

they are reversible, they inhibit the active site of a cox enzyme so prevent the synthesis of prostaglandins and thromboxane which are chemicals responsible for producing pain and fever

Question 32

in non competitive inhibition where does the inhibitor bind and why does this have an effect?

Answer 32

the allosteric site and causes the tertiary structure to change which changes the active site

Question 33

what is a cofactor and co enzyme and how tightly do they bind to the protein?

Answer 33

some enzymes need a non-protein component to carry put their function, they bind loosely

Question 34

which enzyme requires Cl- ions and why are they required?

Answer 34

amylase, to form the correctly shaped active site

Question 35

how can precursor enzymes be activated?

Answer 35

cofactors and a change in pH