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Biology - 2.4 Enzymes > Inhibitors > Flashcards

Flashcards in Inhibitors Deck (16)
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1

what are competitive inhibitors

>competetive inhibitors molecules have a similar shape to the of substrate molecules
> They compete with the substrate molecules to bind to the active site, but no reaction takes place
> Instead they block the active site, so no substrate molecules can fit in it

2

How does higher conc of substrate affect an competitive inhibitor?

> The chances of substrate getting to an active site before an inhibitor increase
> so increasing conc of substrate will increase the rate of reaction

3

How does higher conc of an competitive inhibitor affect an enzyme?

it will take up nearly all of the active sites and hardly any of the substrate will get to the enzyme

4

What are non competitive inhibitors?

> Non competitive inhibitors molecules bind to the enzyme away from its active site
> the site they bind to is known as the enzyme's allosteric site
> This causes the active site to change shape so the substrate molecules can no longer bind to it.

5

Why do non competitive inhibitors don't compete with the substrate molecules to bind?

Because they are a different shape

6

How does increasing conc affect a non competitive inhibitors?

increasing conc will make no differnce because they don't bind to the active site as they have a different shape

7

how do irreversible inhibitor bind?

they bind permanently to an enzyme as they have strong covalent bonds

8

how do reversible inhibitor bind?

they don't bind permanently to an enzyme as they have weak hydrogen bombs or weak ionic bonds

9

How does an antiviral drug inhibitor work?

e.g. reverse transcriptase inhibition treat HIV. They work by inhibiting the enzyme reverse transcriptase, which catalyse the replication of viral DNA. This prevents the virus from replicating.

10

How does antibiotic inhibitor work?

e.g. pencilin inhibits the enzyme transeptidase, which catalyses the formation of protein in cell walls. This weakens the cell wall and prevent the bacterium from regulating its osmotic pressure. As a results the cell bursts and the bacterium is killed.

11

What is cyanide (metabolic poisons)

> its a non competitive, irreversible inhibitor of cytochrome
C oxidase
> it catalyses respiration reactions

12

What is Maltonate (metabolic poisons)

> its a competitive inhibitor of succinate dehydrogenase
> catalyses respiration reactions

13

What is Arsenic (metabolic poisons)

> its a non competitive inhibitor of peruse dehydrogenase
> catalyses respiration reactions

14

What is product inhibition?

its when a product inhibits the enzyme that has catalysed its formation

15

what is end product inhibition?

its when the final product in a metabolic pathway inhibits an enzyme that acts earlier in the pathway

16

describe enzyme as inactive precursors

Enzymes are sometimes synthesised as inactive precursors in metabolic pathway to prevent them causing damage to cells. Part of the precursors molecule inhibits its action as an enzyme. Once this part is removed the enzyme becomes active