M2: Enzymes Flashcards by Etin <3

Q

2.1.4 Enzymes: Action of Enzymes

What’s an Enzyme?

A

Biological Catalyst

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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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Q

2.1.4 Enzymes: Action of Enzymes

What can Enzymes do?

A

Affect structures in an organism & its function

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Q

2.1.4 Enzymes: Heterotrophs & Autotrophs

What are Heterotrophs?

A

Organisms that obtain nutrients by consuming other organisms

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Q

2.1.4 Enzymes: Heterotrophs & Autotrophs

What are Autotrophs?

A

Organisms that produce their own food

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Q

2.1.4 Enzymes: Heterotrophs & Autotrophs

What are Endotherms?

A

Regulate body temp
↳ enzymes can work near optimum temp

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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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Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s an Extracellular Enzyme?

A

Released from outside the cell

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Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s an Example of an Extracellular Enzyme?

A

Amylase
Trypsin

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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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Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s an Intracellular Enzyme?

A

Found in cytoplasm

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Q

2.1.4 Enzymes: Extracellular & Intercellular Enzymes

What’s an Example of an Intracellular Enzyme?

A

Catalase

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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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Q

2.1.4 Enzymes:

What type of proteins are Enzymes?

A

Globular proteins

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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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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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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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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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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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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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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

Q

2.1.4 Enzymes: Enzymes reduce Activation Energy

Why do Enzyme-Substrate Complex lower AE?

A

If substrate mol need to be joined, attaching the enzyme holds them closer reducing repulsion between molecules
↳ they can bond more easily
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

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

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

# **2.1.4 Enzymes:** Factors affecting Enzyme Activity What's the affect of Decreasing Temps on enzymes?

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

# **2.1.4 Enzymes:** Factors affecting Enzyme Activity What's Q10?

* 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.

# **2.1.4 Enzymes:** Factors affecting Enzyme Activity Enzyme-Substrate Complex

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

# **2.1.4 Enzymes:** Factors affectng Enzyme Activity What's the affect of pH on Enzymes?

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

# **2.1.4 Enzymes:** Factors affecting Enzyme Activity What's the affect of Concentration on enzymes?

* 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

# **2.1.4 Enzymes:** Condensation Reaction w Enzymes

# **2.1.4 Enzymes:** Hydrolysis Reaction w Enzymes

# **2.1.4 Enzymes:** Competitive Inhibitor What's meant by 'Competitive Inhibitor'? | (Reversible)

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

# **2.1.4 Enzymes:** Competitive Inhibitor Why are Competitive Inhibitors Irreversible?

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

# **2.1.4 Enzymes:** Competitive Inhibitor What's the shape of a Competitive Inhibitor?

Molecules have similar shape to that of the substrate mol

# **2.1.4 Enzymes:** Competitive Inhibitor What factor affects how much the Enzyme is Inhibited?

Relative conc of the inhibitor & the substrate

# **2.1.4 Enzymes:** Competitive Inhibitor How does High conc of Inhibitor affect how much enzyme is inhibited?

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

# **2.1.4 Enzymes:** Competitive Inhibitor How do Higher conc of Substrate affect how much enzyme is inhibited?

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

# **2.1.4 Enzymes:** Non-Competitive Inhibitor What's meant by 'Non-Competitive Inhibitor'? | (Reversible)

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

# **2.1.4 Enzymes:** Non-Competitive Inhibitor Why are Non-Competitive Inhibitors Reversible?

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

# **2.1.4 Enzymes:** Non-Competitive Inhibitor Why don't they compete w substrate?

They are a different shape to the substrate mol

# **2.1.4 Enzymes:** Non-Competitive Inhibitor How does increasing conc of Substrate affect RoR?

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

# **2.1.4 Enzymes:** Non-Competitive Inhibitor What's the Allosteric Site?

**Anywhere** in an **enzyme** **except** the **active site**

# **2.1.4 Enzymes:** What are Irreversible Inhibitators?

* Binds to enzyme ↳ form covalent bonds at AS ↳ enzyme denaturs **:** there's no enzyme substrate complex

# **2.1.4 Enzymes:** | (5 marks)

**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

# **2.1.4 Enzymes:** What are Cofactors? | Molecule/ion that helps enzyme work

* Inorganic (minerals) * Temporarily Bound i.e Cl- in amylase

# **2.1.4 Enzymes:** What are Coenzymes? | Organic non-protein mol. binds temporarily w substrate to enzyme AS

* Organic (vitamins) * Temporarily Bound i.e NAD (respiration), NADP (photosynthesis)

# **2.1.4 Enzymes:** What are Prosthetic Groups? | Non-protein organic mol. that forms permanent part of protein mol.

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

# **2.1.4 Enzymes:** What's a Colorimeter? | Equipment that gives us a quantitative reading of colour

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

# **2.1.4 Enzymes:** What's the affect of Deadly Poisons on Enzymes? | 100-200 mg Cyanide kills adult in 2 hrs

* Inhibit or Over-activate enzymes * Cyanide = Non-Competitive Inhibitator ↳ for respiratory enzyme

# **2.1.4 Enzymes:** What's Ethylene Glycol Poisoning? | Found in Anti-freeze

* 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

# **2.1.4 Enzymes:** What's the affect of Snake Venom on enzymes? | Contains Phosphodiesterases

* 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

# **2.1.4 Enzymes:** What's the function of Antibiotics? | Kill / Inhibit growth of micro-organisms

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