Fallis Flashcards

1
Q

Hard acids prefer what?

A

Hard bases

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2
Q

Soft acids prefer what?

A

Soft bases

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3
Q

8 examples of hard acids

A

+H+, Li+, Na+, K+, Mg2+, Ca2+, Cr3+ and Co3+

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4
Q

5 examples of hard bases

A

RNH2, NH3, O donors (H2O, OH-, RO-), F- and Cl-

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5
Q

6 examples of soft acids

A

Cu(I), Ag(I), Au(I), Hg(I), Hg(II) and Ti(I)

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6
Q

Rank the soft bases from softest to least

A

I- > Br- > CO > CN-

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7
Q

4 examples of borderline acids

A

Fe2+, Co2+, Cs+, Pb2+

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8
Q

7 examples of borderline bases

A

RCO2-, imidazole, N2, N3-, Br-, NO3- and SO42-

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9
Q

How are high reaction rates achieved by the entatic effect?

A

mimicking the transition state of the catalysed reaction, or the enzyme binds the TS more strongly than starting materials and products

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10
Q

What oxidation states are cycled by Rubredoxin?

A

Fe2+ and Fe3+

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11
Q

How does rubredoxin cycle between both oxidation states of Fe?

A

2+ longer bond length, so an intermediate bond length is used and metal is distorted towards the TS

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12
Q

Cu (I) prefers what kind of donors? Give an example

A

Soft donors - eg S

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13
Q

Cu (II) prefers what kind of donors? Give 2 examples

A

Hard donors - eg N & O

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14
Q

what’s the relationship between oxidation state and bond lengths generally?

A

Increasing ox state leads to ionic radius contracting and shorter bond lengths

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15
Q

What does the coordinated water molecule on a Zn enzyme act as?

A

A resting state, which can be replaced by a substrate

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16
Q

What catalyst would be needed for CO2 and why?

A

CO2 is both a LA and LB so requires a bifunctional LA/LB catalyst

17
Q

What re the uses of synthetic modelling?

A

To make models that look like a natural system and that have the natural system’s function

18
Q

what to SODs catalyse

A

the dismutation of superoxide radicals into molecular oxygen and hydrogen peroxide

19
Q

Describe the bovine erythrocyte SOD

A

Dinuclear Cu and Zn centres, bridging His residue with His residues, 1 Asp, 1 Arg and 1 Thr

20
Q

How can small anions (F- and N3-) affect Cu,Zn dinuclear/boving erythrocyte SODs?

A

Can compete with superoxide to act as inhibitors, binding to the active site

21
Q

Mn3+ SOD suggests what mechanism?

A

inner sphere

22
Q

Mn2+ SOD suggests what mechanism?

A

outer sphere

23
Q

If 2 reactions differ by ~0.4V or more, will the reaction go to completion?

24
Q

where does Cytc transfer electrons to?

A

from cytochrome c reductase to cytochrome c oxidase

25
Questions about mutations of enzymes
does charge at active site change? if it does, affects electrostatics and E HSAB arguments
26
What to look out for if a reaction is reversible or irreversible?
If E=0.4V or higher it's irreversible!
27
Why does pKa of water lower as oxidation state increases?
as ox state increases, metal pulls ED of the water molecules towards itself, tendency of water to release protons increases
28
examples of PCET
dismutation of superoxide and oxidation of water to molecular oxygen in photosynthesis
29
Role of tyrz in PSII
tyrz is oxidised by the energy of P680+, resetting the ability of P680 to absorb another photon and release another photo-dissociated electron
30
pH = .... (ratios!)
pH = pKa + log [A-]/[HA]