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Enzymes Flashcards

1
Q

What is activation energy?

A

The energy that is provided for a reaction to take place

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2
Q

Why have enzyme activity models changed over time?

A

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

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3
Q

What are enzymes?

A
  • Biological catalysts that speed up reactions without being used up
  • generally soluble
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4
Q

In living organisms virtually all ___________________ are catalysed by enzymes

A

Metabolic reactions

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5
Q

What are intracellular enzymes?

A

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

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6
Q

What are extracellular enzymes?

A
  • Act outside of cells
  • supply cells with raw materials
    - digestion enzymes (amalase and trypsin)
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7
Q

Enzymes reduce ____________?

A

Activation energy

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8
Q

what are anabolic reactions?

A

building molecules uo

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9
Q

what are catabolic reactions?

A

breaking molecules down

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10
Q

what is metabolism?

A

all the chemical reactions that occur in an organism

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11
Q

what is a catalyst?

A

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

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12
Q

what is a metabolic pathway?

A

sequence of enzyme controlled reactions

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13
Q

what is specificity in relation to the role of enzymes?

A

when you are only able to catalyse specific reactions

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14
Q

what is a substrate?

A

a substance that binds to the active site of an enzyme

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15
Q

what is a product?

A

a substance that is a result of a chemical reaction

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16
Q

what is a cofactor?

A

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

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17
Q

what are coenzymes?

A

an organic non-protein component

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18
Q

what are many coenzymes derived from?

A

vitamins

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19
Q

what are prosthetic groups?

A

non-protein component of a conjugated protein

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20
Q

what is the prosthetic group in haemoglobin?

A

iron (Fe)

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21
Q

what is temperature coefficient (Q10)?

A

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

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22
Q

what is vmax?

A

the maximum rate of an enzyme controlled reaction

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23
Q

what is denaturation?

A

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

24
Q

what is the course of an enzyme reaction?

A
  • 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
25
what must happen for enzymes to catalyse a reaction?
enzymes must be at optimum temperature
26
describe how temperature affects the rate of enzyme activity based on the provided information?
- low temps: prevent reaction/slows down - high temps: reaction to speed up
27
what is the definition of the temperature coefficient, Q10, and its significance in enzyme reactions?
ratio between rates of that reaction at two different temperatures
28
explain what happens to enzymes at high temperatures and the term used to describe this process?
active site changes shape- denatures (bonds breaking)
29
what are thermophiles and how do their enzymes differ from those of organisms that thrive in cold environments?
- They are organisms adapted to hot environments - depends on the environment they are in, but their enzymes would have a higher optimum temperature
30
What is the relationship between substrate concentration and the rate of enzyme reaction?
The greater the substrate concentration, the higher the rate of reaction
31
What is an extremophile?
An organism that thrives in harsh environments
32
How do tardigrades survive extreme conditions?
By curdling up onto a dry ball
33
What potential applications could studying extremophiles lead to?
Developing new medications and biofuels
34
What might understanding extremophiles help scientists explore?
How life could exist elsewhere in the universe
35
What happens with competitive inhibitors?
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
36
What happens with non-competitive inhibitors?
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
37
What are the two types of enzyme-substrate models?
- lock and key model - induced fit model
38
What are the factors that affect enzyme activity?
- pH - temperature - substrate concentration - enzyme concentration
39
What bonds are in proteins and what do they do?
Hydrogen and ionic bonds hold the tertiary structure of the protein together
40
Why do low temperatures prevent or slow down reactions?
Molecules move slow as they have less kinetic energy which results in lower frequency of successful collisions between substrate molecules and enzymes
41
Why do enzymes denature at high temperatures?
Increased kinetic energy and vibration of enzyme puts a strain on it, causing weaker hydrogen and ionic to break
42
What is an example of a competitive inhibitor and what does it inhibit?
- statin - competitive inhibitor of enzyme used in synthesis of cholesterol- used to treat high cholesterol
43
What are some examples of non-competitive inhibitors and what do they do?
- organophosphate -causes muscle cramp - blocks enzymes in nerve transmission - proton pump inhibitors -treat indigestion
44
when is energy released and from what?
from large organic molecules, like glucose, in metabolic pathways consisting of many catabolic reactions
45
what type of proteins are enzymes and how is this beneficial?
globular proteins that interact with substrate molecules causing them to react at much faster rates without the need of harsh environmental changes
46
what is the process of digesting starch?
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
47
what is trypsin?
a protease, which is a type of enzyme that catalyses digestion of proteins into smaller peptides
48
where is trypsin produced?
in the pancreas and released with the pancreatic juice from the small intestine, where it acts on proteins
49
why does substrate concentration effect rate of reaction?
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
50
what is end product inhibition?
the term used for enzyme inhibition that occurs when the product of a reaction acts as an inhibitor to the enzyme that produces it
51
what are inactive precursor enzymes?
enzymes that are produced in an inactive form
52
what type of enzymes are precursor enzymes?
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
53
how are precursor enzymes activated?
they need to undergo a change in shape in their tertiary structure, particularly to their active site, which can be done by a cofactor
54
what is another name for a precursor protein?
apoenzyme
55
what does an apoenzyme change to when a cofactor is added?
a haloenzyme

Biology (12 decks)

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