Biochemistry- Thermodynamics and Enzymes

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  • Created by: KayshaN
  • Created on: 23-10-19 14:53
What is Thermodynamics?
study of energy and its distribution
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What is Energy?
Capacity to do work
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What is the First Law Of Thermodynamics?
the amount of energy within the universe is constant, energy cannot be created or destroyed
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What is the Second Law Of Thermodynamics?
energy moves from an area of high concentration to one of lower concetration
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What are the rules of the Second Law?
heat flow from material higher temp to one lower temp, some heat energy lost when energy converted, in isolated system the process can only occur if it increases the total entropy of the system.
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What does high Entropy mean?
Disordered
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What does low Entropy mean?
Ordered
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What are the implications of the Second Law in Life?
1) universe tends towards diorder (high entropy) 2) need to use energy to get order 3) life very ordered
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What is Enthalpy?
the energy required to form a system (delta H)
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What do different changes in Enthalpy tell us about a reaction?
Positve change means endothermic, neagtive change means exothermic
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Why do endothermic reactions proceed?
delta G must still be negative for reaction to proceed, biology does this with coupled reactions.
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What do enzymes do?
decrease activation energy, increase RoR, doesnt chage equilibrium
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How do enzymes decrease the activation energy?
Bind to substartes and bring them into favoruable postition
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What is an example of an enzyme that brings substartes in to close proximity?
Hexokinase, begins glucose metabolism, Gucose and ATP
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Write the Gibbs Free Energy Equation. (with words)
G=H-TS (Gibbs=Enthalpy - (TempConstant x Entropy))
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How does Gibbs free energy determine the direction of a reaction?
G<0 run forward, G>0 run backwards
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Eqution for the Equilibrium Constant of A-->B
Keq= [B]/[A]
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Gibs Free Energy in realtion to Keq
G=RxTxlnKeq (Gibbs=gasxtempxnat log Keq)
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Define Enzyme Promiscuity.
Catalyse different reaction
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Outline the role of LDH
Lactate Dehydrogenase catalyses Pyruvate+NADH+H-->Lactate+NAD+, AS--> Arginie 171 positve charge attracts pyruvate, bind causes conformational change, small neg charge pyruvate attracts Arginine 109, chnage shape shut lid no water, pull on double
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Outline role LDH (2)
Stretch O=, weakens, H+ from NADH donated to C Pyruvate, Double bond breaks, donate H+ to Histidine, Pyruvtae --> Lactate
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Outline two diseases that is related to malfunction of enzymes.
Gout--> build up of uric acid, xanthin oxidase, Type 1 Albinism--> lack melatin, white hair etc, tyrosinase pathway
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Outline some drugs that alter enzyme activity.
1)DNA Topoisomerase inhibitors (anticancer) 2) Angiotensin converting enzyme inhibitors (blood pressure) 3)Xanthine Oxidase inhibitors (Gout)
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How do we measure concentration of enzymes?
1) S+E->ES->EP 2) Colour, Chromophore 3)Size
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Describe how colour/chromophore can be used to measure concentration of enzymes?
substrates and products can have colour or we can add, e.g. Blactomase degrades Penicillin, can use modified version which is coloured, yellow to red.
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Describe how size can be used to measure concentration of enzymes
some enzymes change size substrates, e.g. DNA restriction endonucelases, big fragments can be seperated from small in electrophoresis
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Write the Michaelis Menton Equation
V= Vmax[S]/Km + [S]
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How does Km relate to enzyme infinity for substrate?
the lower the Km, the higher the infinity
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What is the Km?
the substarte concentration that gives you half maximum rate
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What are the pros and cons of the Michaelis Menton Equation?
Pros= tells you Km, tells you Vmax Cons=very hard to plot by hand- Solution Create Linear Plot
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How do you do a Linear Plot of enzyme rate?
1/V=Km/Vmax (Slope) 1/[S] + 1/Vmax
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How does a compeitive inhibitor effect the rate of reaction?
increase time it takes to get to Vmax
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Ki= Inhibitory Constant, usefullness?
how active a drug will be, lower Ki the better inhibitory effect.
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What is the Second Law Of Thermodynamics?

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Card 5

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What are the rules of the Second Law?

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