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OCR A BIOLOGY > 2.4 enzymes > Flashcards

2.4 enzymes Flashcards

1
Q

what is the effect of aspirin?

A

inhibits the enzyme that makes nerve cells more sensitive to pain and swelling

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2
Q

what is the effect of ATPase inhibitors?

A

allow more calcium ions to enter the cell, increasing mucles contraction, strengthening heeart beat

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3
Q

what is the effect of ACE inhibitors?

A

lower blood pressure

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4
Q

what is the effect of protease inhibitors?

A

prevent the replication of virus particles in host cells.

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5
Q

what is the effect of nucleoside reverse transcriptase inhibitors?

A

inhibit the enzyme involved in making DNA with viral RNA as a templeate. Used to treat patients with HIV

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6
Q

What is the effect of snake venom?

A

paralysis and suffocation

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7
Q

what is the effect of cyanide?

A

produces a very toxic gas that inhibits the final stages of aerobic respiration

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8
Q

what is end-product inhibition?

A

yhe product molecule stays bound to the enzyme are the reaction is completed, to prevent more product forming

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9
Q

what is an inactivator?

A

a competive inhibitor that binds irreversibly to the emzymes active site

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10
Q

what is the allosteric site?

A

the region of the enzyme that the non-competitive inhibitor binds to.

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11
Q

what is a competivive inhibitor

A

a substance that has a similiar shape to the substrate, it bind/blocks to the active site so the substrate cant fit

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12
Q

what is an inhibitor?

A

a substance that reduces or stops a reaction

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13
Q

what effect does increasing enzyme concentrstion have on enzyme activity?

A

as enzyme concentration increases, more active sites become available so more ES complexes can form, increasing rate of reaction.

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14
Q

what is enzyme degredation?

A

breaking down enzymes into amino acids and synthesising new enzymes from the amino aicds.

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15
Q

what is enzyme synthesis?

A

the making of enzymes

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16
Q

what effect does increasing substrate concentration have on enzyme activity?

A

more ES complexes form so rate of reaction increases.

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17
Q

how can an excess of hydrogen ions affect enzymes?

A

too many hydrogen ions can interfere with hydrogen bonds and ionic forces, causing the active site to change shape.

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18
Q

what happens to the enzyme if there is a small change in pH?

A

rate of reaction is reduced as the shape of the active site is disrupted. If the normal pH is restored the active site can be fixed, so small changes are reversible

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19
Q

what is a buffer?

A

something that resists a change in pH

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20
Q

what is a thermophile?

A

an organism that is adapted to living in very hot environments

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21
Q

what is Q10?

A

the temperature coefficient

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22
Q

what is the Q10 equation?

A

Q10= rate at higher temperature / rate at lower temperature

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23
Q

what factors affect enzyme activity?

A

temperature
pH
enzyme concentration
substrate concentration
inhibitors

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24
Q

how do you calculate initial rate of reaction?

A

draw a tangent at 0, then calculate the gradient

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25
what is a metabolic pathway?
a series of consecutive reactions
26
what are metabolites?
reactants products intermediates
27
what is a catabolic pathway?
metabolites are BROKEN DOWN into smaller molecules, releasing emergy
28
what is an anabolic pathway?
energy is use to MAKE larger molecules from smaller ones
29
what coenzyme is derived from vitamin B3?
NAD and NADP
30
What is a vitamin B3 deficiency called, and its symptoms?
PELLAGRA - diarrhoea - dermatitis - dementia
31
what coenzyme is derived from vitamin B6?
coenzyme A
32
what aare the symptoms of a vitamin B6 deficiency?
elevated blood plasma triglyceride levels
33
what coenzyme is derived from vitamin B12?
cobalamin coenzymes
34
what is a vitamin B12 deficiency called?
PERNICIOUS ANAEMIA
35
what are coenzymes?
small organic non-protein molecules that bind temporarily to the enzymes active site.
36
Why must coenzymes be recycled back to their original state?
they are chemically changed during the reaction
37
what do enzymes do to the activation energy of a chemical reaction?
they lower activation energy by bringing the subsstrate molecules close enough to the active site to react
38
what is the 'induced fit' hypothesis?
when the substrate molecule fits into the active site, the active site changes shape slightly to mould around the substrate molecule
39
what is the 'lock and key' hypothesis?
the idea that an enzymes active site represents a 'lock' and the 'key' is the substrate molecule. The shape of the active site is complementary to the specific substrate
40
what is the enzyme-substrate complex?
an enzyme moleucle with substrate moleucles in its active site
41
what is the enzyme-product complex?
an enzyme moleulce with product molecules in its active site
42
what are 2 examples of complex metabolic pathways?
- respiration - photosynthesis
43
what is a cofactor?
a substance that has to be present to ensure that an enzyme- catalysed reaction takes place at an appropriate rate
44
what are examples of cofactors?
- prosthetic group - mineral ion - organic coenzymes
45
what is an example of an enzyme with a cofactor?
CARBONIC ANHYDRASE has the cofactor ZINC. it enables carbon dioxide ton be carried from respiring tissues to the lungs.
46
what coenzyme is derived from folic acid?
tetrahydrofolate
47
what is folic acid deficiency called, and what are its symptoms?
MEGALOBLASTIC ANAEMIA - large and irregularly shaped erythrocytes
48
what coenzyme is derived from vitamin B1?
thiamine pyrophosphate
49
what is a vitamin B1 defieciency called, and what are its symptoms?
BERI BERI - mental confusion - irregular heartbeat - muscular weakness - paralysis - heart failure
50
what is an active site?
the indented area on the surface of an enzyme molecule, with a shape that is complementary to the substrate molecule
51
what is a catalyst?
a chemical that speeds up the rate of reacttion and remains unchanged and reusable at the end of the reaction
52
what is a product?
a molecule produced from substrate molecules by an enzyme-catalysed reaction
53
what is a substrate?
a molecule that is altered by an enzyme-catalysed reaction
54
what is metabolism?
the chemical reactions that take place inside living cells or organisms
55
what is turnover number?
the number of reactions that an enzyme molecule can catalyse per second
56
what might prevent an enzyme from functioning?
a mutation or change to a codon- this changes the tertiary structure so the active site also changes
57
what affects an enzymes ability to catalyse reactions?
- pH - temperature they change the shape of the active site by breaking the bonds holding the tertiary structure
58
what are the extracellular enzymes?
- amylase - trypsin
59
where is amylase made?
the pancrease and salivary glands
60
what reaction does amylase catalyse?
starch --> maltose
61
what reaction does trypsin catalyse?
proteins --> peptides
62
where is trypsin made?
the pancreas
63
what is an example of an intracellular enzyme?
catalase
64
where reaction does catalase catalyse?
hydrogen peroxide --> water + oxygen
65
where is catalase found?
in peroxisomes in eukaryotes
66

OCR A BIOLOGY (26 decks)

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