Enzymes

Question 1

What is activation energy?

Answer 1

The energy that is provided for a reaction to take place

Question 2

Why have enzyme activity models changed over time?

Answer 2

Technology has developed and so scientists have realised that the enzyme action is actually different

Question 3

What are enzymes?

Answer 3

• Biological catalysts that speed up reactions without being used up
• generally soluble

Question 4

In living organisms virtually all ___________________ are catalysed by enzymes

Answer 4

Metabolic reactions

Question 5

What are intracellular enzymes?

Answer 5

Act inside cell
- hydrolyses (in lysosomes)
- ATPases (in mitochondria)
- catalyse to break down hydrogen peroxide

Question 6

What are extracellular enzymes?

Answer 6

• Act outside of cells
• supply cells with raw materials
  - digestion enzymes (amalase and trypsin)

Question 7

Enzymes reduce ____________?

Answer 7

Activation energy

Question 8

what are anabolic reactions?

Answer 8

building molecules uo

Question 9

what are catabolic reactions?

Answer 9

breaking molecules down

Question 10

what is metabolism?

Answer 10

all the chemical reactions that occur in an organism

Question 11

what is a catalyst?

Answer 11

an enzyme that speeds up the rate of reaction without being used up

Question 12

what is a metabolic pathway?

Answer 12

sequence of enzyme controlled reactions

Question 13

what is specificity in relation to the role of enzymes?

Answer 13

when you are only able to catalyse specific reactions

Question 14

what is a substrate?

Answer 14

a substance that binds to the active site of an enzyme

Question 15

what is a product?

Answer 15

a substance that is a result of a chemical reaction

Question 16

what is a cofactor?

Answer 16

non-protein components necessary for the effective functioning of an enzyme

Question 17

what are coenzymes?

Answer 17

an organic non-protein component

Question 18

what are many coenzymes derived from?

Answer 18

vitamins

Question 19

what are prosthetic groups?

Answer 19

non-protein component of a conjugated protein which are permanent

Question 20

what is the prosthetic group in haemoglobin?

Answer 20

iron (Fe)

Question 21

what is temperature coefficient (Q10)?

Answer 21

a measure of how much the rate of reaction increases with a 10 degree temperature increase

Question 22

what is vmax?

Answer 22

the maximum rate of an enzyme controlled reaction

Question 23

what is denaturation?

Answer 23

the change in the tertiary structure of a protein/enzyme, resulting in a loss of normal function

Question 24

what is the course of an enzyme reaction?

Answer 24

• initially the reaction that happens very quickly
  
  • a lot of substrate molecules, so every enzyme molecule has its active site filled
• as the reaction continues, the rate slows down
• the reaction gets slower and eventually stops

Question 25

what must happen for enzymes to catalyse a reaction?

Answer 25

enzymes must be at optimum temperature

Question 26

describe how temperature affects the rate of enzyme activity based on the provided information?

Answer 26

- low temps: prevent reaction/slows down - high temps: reaction to speed up

Question 27

explain what happens to enzymes at high temperatures and the term used to describe this process?

Answer 27

active site changes shape- denatures (bonds breaking)

Question 28

what are thermophiles and how do their enzymes differ from those of organisms that thrive in cold environments?

Answer 28

- They are organisms adapted to hot environments - depends on the environment they are in, but their enzymes would have a higher optimum temperature

Question 29

What is the relationship between substrate concentration and the rate of enzyme reaction?

Answer 29

The greater the substrate concentration, the higher the rate of reaction

Question 30

What is an extremophile?

Answer 30

An organism that thrives in harsh environments

Question 31

How do tardigrades survive extreme conditions?

Answer 31

By curling up into a dry ball

Question 32

What potential applications could studying extremophiles lead to?

Answer 32

Developing new medications and biofuels

Question 33

What might understanding extremophiles help scientists explore?

Answer 33

How life could exist elsewhere in the universe

Question 34

What happens with competitive inhibitors?

Answer 34

The inhibitor is the complimentary shape to the active site and so binds to the enzyme. This then directly blocks the active site and prevents the substrate from binding, meaning there is no reaction

Question 35

What happens with non-competitive inhibitors?

Answer 35

The inhibitor binds to the allosteric site and changes the tertiary structure of the enzyme, which changes the shape of the active site, so the substrate cannot bind

Question 36

What are the two types of enzyme-substrate models?

Answer 36

- lock and key model - induced fit model

Question 37

What are the factors that affect enzyme activity?

Answer 37

- pH - temperature - substrate concentration - enzyme concentration

Question 38

What bonds are in enzymes and what do they do?

Answer 38

Hydrogen and ionic bonds hold the tertiary structure of the enzyme (protein) together

Question 39

Why do low temperatures prevent or slow down reactions?

Answer 39

Molecules move slow as they have less kinetic energy which results in lower frequency of successful collisions between substrate molecules and enzymes

Question 40

Why do enzymes denature at high temperatures?

Answer 40

Increased kinetic energy and vibration of enzyme puts a strain on it, causing weaker hydrogen and ionic to break

Question 41

What is an example of a competitive inhibitor and what does it inhibit?

Answer 41

- statin - competitive inhibitor of enzyme used in synthesis of cholesterol- used to treat high cholesterol

Question 42

What are some examples of non-competitive inhibitors and what do they do?

Answer 42

- organophosphate -causes muscle cramp - blocks enzymes in nerve transmission - proton pump inhibitors -treat indigestion

Question 43

when is energy released and from what?

Answer 43

from large organic molecules, like glucose, in metabolic pathways consisting of many catabolic reactions

Question 44

what type of proteins are enzymes and how is this beneficial?

Answer 44

globular proteins that interact with substrate molecules causing them to react at much faster rates without the need of harsh environmental changes

Question 45

what is the process of digesting starch?

Answer 45

1) starch polymers are partially broken down into maltose by amylase which is produced in the salivary gland and pancreas 2) maltose is then broken down in to glucose by maltase, which is present in the small intestine

Question 46

what is trypsin?

Answer 46

a protease, which is a type of enzyme that catalyses digestion of proteins into smaller peptides

Question 47

where is trypsin produced?

Answer 47

in the pancreas and released with the pancreatic juice from the small intestine, where it acts on proteins

Question 48

why does substrate concentration effect rate of reaction?

Answer 48

when the concentration of substrate is increased the number of substrate molecules, atoms, or ions in a particular area or volume increases. the increased number of substrate leads to a higher collision rate so the RofR increases. The RofR reaches vmax, so all active sites are occupied

Question 49

what is end product inhibition?

Answer 49

the term used for enzyme inhibition that occurs when the product of a reaction acts as an inhibitor to the enzyme that produces it

Question 50

what are inactive precursor enzymes?

Answer 50

enzymes that are produced in an inactive form

Question 51

what type of enzymes are precursor enzymes?

Answer 51

enzymes that can cause damage within the cells producing them, to tissues where they are released or enzymes whose action needs to be controlled and only activated under certain conditions

Question 52

how are precursor enzymes activated?

Answer 52

they need to undergo a change in shape in their tertiary structure, particularly to their active site, which can be done by a cofactor

Question 53

what is another name for a precursor protein?

Answer 53

apoenzyme

Question 54

what does an apoenzyme change to when a cofactor is added?

Answer 54

a haloenzyme