Topic 3-L2 - Redox reactions Flashcards

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1
Q

Even phototrophic bacteria need a source of

A

electrons to carry out anabolic reactions in the cell

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2
Q

Electrons are at a lower energy state when they are associated with
more

A

electronegative atoms

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3
Q

Glucose is a great

A

source of high energy electrons.

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4
Q

Oxygen is a great

A

electron sink – leaves electrons at low energy state.

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5
Q

Energy released by electrons moving to lower energy state captured by the cell through

A

redox reactions

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6
Q

Oxygen is a great electron acceptor because it’s so ____________ - meaning?

A

electronegative – has a high affinity for electrons…accepts low energy electrons

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7
Q

The reduction potential (E0’ ) of a

redox couple indicates its

A

propensity to act as an electron donor or recipient

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8
Q

Redox couples with more negative
values (top of table) have a stronger
tendency to act as

A

electron donors (to be oxidized)

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9
Q

Redox couples with more positive
values (bottom of table) have a strong
tendency to act as

A

electron acceptors (to be reduced)

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10
Q

Glucose is a great electron _______, O2 is phenomenal electron ________

A

Donor. acceptor

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11
Q

Why is CO2/glucose a strong electron donor (-ve reduction potential – Eo’)?

A

Glucose has several C-H bonds – electrons in high energy state. In CO2 electrons have moved close to oxygen – lower energy state

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12
Q

Why is O2/H2O a strong electron acceptor (+ve Eo’) ?

A

Hydrogen wants to an donate electron, Oxygen is highly electronegative – in O2, electrons equally shared – in H2O, oxygen can “steal” electrons from hydrogen.

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13
Q

Redox reactions between couples that have bigger differences in redox potential

A

produce more energy

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14
Q

Soluble electron carriers like

A

(NAD+ / NADH) used to shuttle

electrons around the cell

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15
Q

NAD+ is

A
oxidizing agent (gets reduced
to NADH).
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16
Q

NADH is

A

reducing agent (Gets oxidized to NAD+)

17
Q

Electron carriers such as NAD+/NADH are

A

enzymatic cofactors

18
Q

Electron carriers allow

A

electrons donated in one reaction – stored in NADH – and accepted in a different reaction.

19
Q

Are electron carriers insoluble?

A

NO they are soluble

20
Q

Reactant that donates electrons

A
  • E.g. - Glucose 2
  • Gets oxidized
  • Loss of electrons “electron donor”
  • “reducing agent”
  • Often loses H atoms and/or gains O atoms