proteins Flashcards

1
Q

How does the rate of an enzyme inhibitor decrease the rate of an enzyme-controlled reaction? (3)

A

-inhibitor has a similar shape to the substrate
-binds to active site
-prevents E.S complexes forming

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2
Q

if stale bread has changed starch which acts as a competitive inhibitor of amylase in the ileum, how does this reduce weight gain? (3)

A

-less hydrolysis of starch
-to maltose
-less absorption of glucose

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3
Q

describe the structure of a protein (5)

A

-1’=amino acid sequence
-2’=long chains of pp fold into alpha helix or beta pleated sheet held by H bonds
-3’=aa seq determines where H/I/D bonds are
-further folds into 3D shape
-4’=prosthetic group

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4
Q

why is there a higher concentration of fatty acids and a lower concentration of triglycerides an hour after eating comp to 45 mins? (3)

A

-fatty acids increase due to lipase
-triglycerides decrease due to hydrolysis
-of ester bonds

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5
Q

To see the concentration of triglycerides and fatty acids in a sample, why did the scientist immediately heat it to a high temp after? (2)

A

-denature enzyme
-prevent hydrolysis

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6
Q

describe the roles of micelles in the absorption of fats into cells lining the ileum (4)

A

-micelles include bile salts and fatty acids
-makes fatty acids more soluble in water
-carries fatty acids to ileum lining
-fatty acids absorbed by diffusion

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7
Q

how does E.S complexes increase the rate of reaction? (2)

A

-lowers activation energy
-by weakening bonds

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8
Q

when lyxose binds to an enzyme, why does it increases the rate of reaction? (3)

A

-binding to enzyme changes shape
-changes active site
-more E.S complexes form

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9
Q

describe the induced fit model and how an enzyme acts as a catalyst (3)

A

-substrate binds to active site
- active site changes shape SO it becomes complimentary to substrate
-lowers activation energy

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10
Q

explain this (2)

A

-as phosphate increases, more e.S complexes form
-at 40 all active sites are occupied

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11
Q

explain how the active site of an enzyme causes a high rate of reaction (3)

A

-lowers activation energy
-induced fit CAUSES active site to change shape
-E.S complexes form and CAUSES weakened bonds

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12
Q

how are dipeptides similar? (3)

A

-amine group
-carboxyl group
- two R groups

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13
Q

how are dipeptides different? (1)

A
  • ## different R groups
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14
Q

what does the position of the spots show about the three amino acids? (3)

A

-they moved to the negative electrode cuz they’re positively charged
-moved different distances cuz have diff charges
- shows two spots as two aa have same charge

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15
Q

describe how a non-competitive inhibitor reduces the rate of an enzyme-controlled reaction? (3)

A

-attaches to other binding site not active site
-changes shape of active site
-no longer complimentary SO substrate cant fit

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16
Q

how does a peptide bond form b/t two amino acids to form a dipeptide? (2)

A

-condensation reaction
-b/t amine and carboxyl group

17
Q

how is the 2’ of a pp produced by bonds b/t amino acids? (2)

A

-H bonds
-form b/t amine and carboxyl
-form alpha helix or beta pleated sheet

18
Q

why does two proteins have the same number and type of proteins but diff 3’? (2)

A

-different aa seq
-forms H/I/D bonds in diff places

19
Q

why does maltase only hydrolyse maltose?

A

-active site complimentary to substrate
-only maltose binds to it
-forms E.S complexes

20
Q

why is attaching lactase to beads more efficient than adding it directly to cow’s milk? (3)

A

-beads can be reused
-don’t need to remove lactase from milk
-allows continuous process

21
Q

why does lactose-free milk hydrolysed by lactase tastes sweeter than regular milk?

A

-galactose and glucose
-more sugars so sweeter

22
Q

why is it important to maintain a constant blood pH? (3)

A

-enzymes affected by changes in pH
-changes shape
-less O2 binds w/ haemoglobin

23
Q

Contrast competitive with non competitive inhibitor (4)

A
  • C binds w/ a.s|NC binds w/ allosteric
  • C doesn’t change a.s shape|NC changes shape of a.s
  • C enzymes still available|NC enzymes unavailable
  • C higher chance of collisions w/ high sub conc|NC not possible