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Biology > M2: Enzymes > Flashcards

M2: Enzymes Flashcards

1
Q

2.1.4 Enzymes: Action of Enzymes

What’s an Enzyme?

A

Biological Catalyst

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2
Q

2.1.4 Enzymes: Action of Enzymes

What’s a Catalyst?

A

Something that speeds up a chemical reaction without being used up

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3
Q

2.1.4 Enzymes: Action of Enzymes

What can Enzymes do?

A

Affect structures in an organism & its function

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4
Q

2.1.4 Enzymes: Heterotrophs & Autotrophs

What are Heterotrophs?

A

Organisms that obtain nutrients by consuming other organisms

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5
Q

2.1.4 Enzymes: Heterotrophs & Autotrophs

What are Autotrophs?

A

Organisms that produce their own food

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6
Q

2.1.4 Enzymes: Heterotrophs & Autotrophs

What are Endotherms?

A

Regulate body temp
↳ enzymes can work near optimum temp

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7
Q

2.1.4 Enzymes: Heterotrophs & Autotrophs

Why do Endotherms Regulate their body temp?

Birds & Mammals

A
  • Their enzymes function at near optimum temp
    ↳ helps them survive
  • Require greater food supply
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8
Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s an Extracellular Enzyme?

A

Released from outside the cell

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9
Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s an Example of an Extracellular Enzyme?

A
  • Amylase
  • Trypsin
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10
Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s the function of the Extracellular Enzymes Amylase & Trypsin?

A

Amylase: found in saliva & catalyses the hydrolosis of starch into maltose
↳ secreted in salivary glands
Trypsin: catalyses the hydrolosis of peptide bonds
↳ produced in pancrease & secreted in small intestine

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11
Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s an Intracellular Enzyme?

A

Found in cytoplasm

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12
Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s an Example of an Intracellular Enzyme?

A
  • Catalase
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13
Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s the function of the Intercellular Enzyme Catalase?

A

Catalase catalyses the breakdown of hydrogen peroxide to harmless oxygen & water

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14
Q

2.1.4 Enzymes:

What type of proteins are Enzymes?

A

Globular proteins

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15
Q

2.1.4 Enzymes:

Why are Enzymes specific?

A

They have an active site which has a specific shape
↳ where substrate mol bind to

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16
Q

2.1.4 Enzymes: Lock & Key Model

What’s the Lock & Key Model?

A
  • Only 1 Substrate (key) can fit into enzyme’s Active Site (lock)
  • Both structures have unique shapes
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17
Q

2.1.4 Enzymes: Induced Fit Model

What’s the Induced Fit Model?

A
  • Enzyme + Substrate = complex
    ↳ structural changes occur → Active Site fits precisely around substrate
    ↳ Substrate induces Active Site to change shape
  • Reaction takes place & product = different shape to substrate
    ↳ Active Site returns to its OG shape
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18
Q

2.1.4 Enzymes: Induced Fit Model

What are the Steps for an Induced Fit?

A

1) Shape of AS changes & moes to S closer to E
2) Amino acids = molded into precise form
3) Enzyme wraps around substrate → distorts it
↳ lowers AE
* Enzyme-substrate complex forms = fast reaction
E+S → ES→ P+E

Enzyme is not used up in reaction unlike substrate

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19
Q

2.1.4 Enzymes: Enzymes reduce Activation Energy

What is Activation Energy?

A

Energy required for particles to collide to cause a successful reaction

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20
Q

2.1.4 Enzymes: Enzymes reduce Activation Energy

More information on Activation Energy

Enzymes are catalysts → speed rate of reaction

A
  • Reduce AE required to start reaction between molecules
  • Substrate (reactants) are converted into products
  • Reaction may not take place w enzyme in absence
    ↳ each enzyme has a specific catalytic action
  • Enzymes catalyse a reaction at max rate of an optimum state
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21
Q

2.1.4 Enzymes: Enzymes reduce Activation Energy

What’s formed when a substance binds to an enzyme’s active site?

A

An enzyme substrate complex is formed which lowers AE

22
Q

2.1.4 Enzymes: Enzymes reduce Activation Energy

Why do Enzyme-Substrate Complex lower AE?

A
  1. If substrate mol need to be joined, attaching the enzyme holds them closer reducing repulsion between molecules
    ↳ they can bond more easily
  2. If enzyme is catalysng a hydrolysis reaction, fitting into the active site puts more strain on bonds in substrate
    ↳ substrate mol breaks up more easily
23
Q

2.1.4 Enzymes: Enzyme Functions

What are the Functions of an Enzyme?

A

1) Lowers AE
2) Speeds up reaction
3) Don’t take part in chemical reaction
4) Not used up

24
Q

2.1.4 Enzymes: Factors affecting Enzyme Activity

What’s the affect of Increasing Temps on enzymes?

A
  • Increasing temp, increses Ke of enzyme particles
  • But too much heat/wrong pH, denatures enzyme
    ↳ alters bonding & loses shape
25
Q

2.1.4 Enzymes: Factors affecting Enzyme Activity

What’s the affect of Decreasing Temps on enzymes?

A
  • Decreasing temp, enzyme becomes less active
    ↳ reduction in Ke of enzyme particles
  • Enzyme = Inactivated
    ↳ regain function when returned to normal temp
26
Q

2.1.4 Enzymes: Factors affecting Enzyme Activity

What’s Q10?

A
  • Over a range of 0 – 40°C, Q10 for an enzyme-controlled reaction is 2.
  • The rate of an enzyme-controlled reaction is doubled for every rise of
    10°C.
  • Heat increases molecular motion, thus thereactants move more quickly and chances of their bumping into each other are increased.
  • The temperature that promotes the maximum activity is referred to as the
    optimum temperature.
27
Q

2.1.4 Enzymes: Factors affecting Enzyme Activity

Enzyme-Substrate Complex

A

Increasing temp = Increasing Enzyme-substrate complex
* Increasing temp, increanses Ke of enzyme particles
↳ more frequence & successful collisions
* But too much heat energy/wrong pH alternates bonding within enzyme
↳ denatures → loses shape
* Lack of heat energy/pH
↳ disabled → can’t carry function anymore (slowly)
↳ enzyme can’t fit into substrate & lock into substrate

28
Q

2.1.4 Enzymes: Factors affectng Enzyme Activity

What’s the affect of pH on Enzymes?

A

Above or below optimum pH, the H+ & OH- ions found can mess up the ionic & hydrogen bonds that hold the enzyme’s tertiary structure in place
↳ changes active site shape : enzyme = denatured

29
Q

2.1.4 Enzymes: Factors affecting Enzyme Activity

What’s the affect of Concentration on enzymes?

A
  • Higher conc, higher speed
    ↳ more particles that are able to collide w each other → more frequent reactions
  • But if there’s a higher conc of substrate than AS, enzyme can’t work any faster
    ↳ working at its optimum or reached saturation point
30
Q

2.1.4 Enzymes:

Condensation Reaction w Enzymes

31
Q

2.1.4 Enzymes:

Hydrolysis Reaction w Enzymes

32
Q

2.1.4 Enzymes: Competitive Inhibitor

What’s meant by ‘Competitive Inhibitor’?

(Reversible)

A

Competes w SUBSTRATE to bind to AS but no reaction takes place
↳ block AS so no substrate can fit in it

33
Q

2.1.4 Enzymes: Competitive Inhibitor

Why are Competitive Inhibitors Irreversible?

A

They’re strong, covalent bonds
↳ inhibitor can’t be removed

34
Q

2.1.4 Enzymes: Competitive Inhibitor

What’s the shape of a Competitive Inhibitor?

A

Molecules have similar shape to that of the substrate mol

35
Q

2.1.4 Enzymes: Competitive Inhibitor

What factor affects how much the Enzyme is Inhibited?

A

Relative conc of the inhibitor & the substrate

36
Q

2.1.4 Enzymes: Competitive Inhibitor

How does High conc of Inhibitor affect how much enzyme is inhibited?

A

It’ll take up nearly all the AS & hardly any of the substrate will get to the enzyme

37
Q

2.1.4 Enzymes: Competitive Inhibitor

How do Higher conc of Substrate affect how much enzyme is inhibited?

A

Substrate’s chances of getting to AS before inhibitor increases
↳ increases RoR

38
Q

2.1.4 Enzymes: Non-Competitive Inhibitor

What’s meant by ‘Non-Competitive Inhibitor’?

(Reversible)

A

Binds enzyme away from AS
↳ binds to enzyme’s allosteric site
↳ AS changes shape : substrate mol can no longer bind to it

39
Q

2.1.4 Enzymes: Non-Competitive Inhibitor

Why are Non-Competitive Inhibitors Reversible?

A

They’re weaker Hydrogen or Ionic bonds
↳ inhibitor can be removed

40
Q

2.1.4 Enzymes: Non-Competitive Inhibitor

Why don’t they compete w substrate?

A

They are a different shape to the substrate mol

41
Q

2.1.4 Enzymes: Non-Competitive Inhibitor

How does increasing conc of Substrate affect RoR?

A

Doesn’t affect RoR
↳ enzyme activity will still be inhibited

42
Q

2.1.4 Enzymes: Non-Competitive Inhibitor

What’s the Allosteric Site?

A

Anywhere in an enzyme except the active site

43
Q

2.1.4 Enzymes:

What are Irreversible Inhibitators?

A
  • Binds to enzyme
    ↳ form covalent bonds at AS
    ↳ enzyme denaturs : there’s no enzyme substrate complex
44
Q

2.1.4 Enzymes:

(5 marks)

A

A: As temp increases, enzyme & substrate gain more energy, increases AE causing more frequent & successful collision
B: Enzyme rate of reaction reached its optimum
C: Lots of heat energy, causing enzyme to denature decreasing the rate of reaction → AS changes shape

45
Q

2.1.4 Enzymes:

What are Cofactors?

Molecule/ion that helps enzyme work

A
  • Inorganic (minerals)
  • Temporarily Bound

i.e Cl- in amylase

46
Q

2.1.4 Enzymes:

What are Coenzymes?

Organic non-protein mol. binds temporarily w substrate to enzyme AS

A
  • Organic (vitamins)
  • Temporarily Bound

i.e NAD (respiration), NADP (photosynthesis)

47
Q

2.1.4 Enzymes:

What are Prosthetic Groups?

Non-protein organic mol. that forms permanent part of protein mol.

A
  • Permanently Bound

i.e Fe2+ in haem group (haemoglobin)
Zn2+ in Carbonic Amhydrase

48
Q

2.1.4 Enzymes:

What’s a Colorimeter?

Equipment that gives us a quantitative reading of colour

A

Measures light absorbance when it passes through a cuvette of a coloured liquid

49
Q

2.1.4 Enzymes:

What’s the affect of Deadly Poisons on Enzymes?

100-200 mg Cyanide kills adult in 2 hrs

A
  • Inhibit or Over-activate enzymes
  • Cyanide = Non-Competitive Inhibitator
    ↳ for respiratory enzyme
50
Q

2.1.4 Enzymes:

What’s Ethylene Glycol Poisoning?

Found in Anti-freeze

A
  • Broken down by liver (alcohol dehydrogenase)
    ↳ producing oxalic acid (very toxic)
  • Alchohol = Competitive Inhibitor

Treatment
* Large dose of ethanol
↳ reduced RoR → allows ethylene to be excreted harmlessly

51
Q

2.1.4 Enzymes:

What’s the affect of Snake Venom on enzymes?

Contains Phosphodiesterases

A
  • Interferes w workings of prey’s heart
    ↳ fall in blood pressure
  • Contains Inhibitator for Acetylcholineesterase
    ↳ enzyme involved in nerve transmission
  • Contains Hyaluronidase
    ↳ digestive enzyme that breaks down connective tissue
    ↳ helps toxins penetrate tissue quickly
52
Q

2.1.4 Enzymes:

What’s the function of Antibiotics?

Kill / Inhibit growth of micro-organisms

A
  • Penicillin = Inhibitor of Bacterial Enzyme
    ↳ forms cross bridges in cell wall
  • Cell walls = not made
    ↳ bacterial reproduction = halted

Biology (14 decks)

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