chapter 4 - enzymes Flashcards

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1
Q

are enzymes globular or fibrous

A

globular

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2
Q

what are enzymes

A

biological catalysts

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3
Q

what is the lock and key hypothesis

A

the active site ( tertiary structure ) is fit with a specific substrate forming enzyme-substrate complex . substrates react to form enzyme-product complex

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4
Q

what is the induced fit hypothesis

A

initial interaction between enzyme and substrate changes tertiary structure of active site that strengthen binding which weakens bonds on substrate and lowers activation energy

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5
Q

what does amylase do

A

breaks down starch to maltose in saliva and pancreatic juice in small intestine

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6
Q

what does maltase do

A

breaks maltose down to glucose in small intestine

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7
Q

what does trypsin do

A

digests proteins into smaller peptides

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8
Q

factors affecting enzyme activity

A

temperature
pH
substrate concentration
enzyme concentration

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9
Q

what are inhibitors

A

molecules that prevent enzymes from carrying out their normal function

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10
Q

what is competitive inhibitor

A

a molecules with similar shape to substrate of an enzyme so fits in its active site preventing substrate from entering active site

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11
Q

what in non-competitive inhibitor

A

binds to allosteric site of enzyme causing tertiary shape of enzyme and active site to change therefore active site is no longer complementary to substrate so cannot carry out its function

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12
Q

what is end-product inhibition

A

when the product formed acts as an inhibitor for the enzyme used to produce it as negative feedback to prevent excess products

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13
Q

what are cofactors and coenzymes

A

non-proten components to help enzyme function. Co enzymes are organic molecule of cofactor

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14
Q

what are examples of cofactors

A

chloride ion used in amylase to form active site to breakdown starch
zinc
calcium
iron

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15
Q

what vitamins form coenzymes

A

vitamin b3 to synthesise coenzyme NAD
vitamin B5 to synthesise coenzyme A for breakdown of carbohydrates and fatty acids in respiration

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16
Q

what are precursor enzymes

A

inactive enzymes activated by cofactors

17
Q

how are inactive precursor enzymes activated

A

before cofactor is added , enzyme is called apoenzyme. When cofactor is added, enzyme is called holoenzyme