MODULE 2
From the middle of Week 3
9A – Metabolism & Energy Currency
LO 1. Differentiate between anabolism and catabolism, and oxidation and
reduction
2. Explain how ATP can power cellular processes
3. Describe the major evolutionary events to maximize light capture by
plants
4. Describe, in overview, the conversion of radiant energy into chemical
energy
5. Explain the overall organization of the light reactions in photosystems
I and II
6. Describe ATP synthesis during photosynthesis
Fundamental - All organisms req constant input of energy
concept of - Cellular processes (e.g., building & breaking down complex
Energy & Life molecules) occur through stepwise chemical reactions
o Some chemical reactions are spontaneous & releases energy
whereas others req energy to proceed
o Living things must continually obtain more energy to
replenish what they have used
o i.e. life requires energy input; the energy input &
use/consumption involves chemistry
- Cell’s metabolism = chemical reactions that occur inside cells, incl.
Those that use & release Energy
Life’s
chemical
reactions
affect Earth’s
atmosphere
- Very small percentage of CO2 in the Earth with life; as plants are
using up CO2 during photosynthesis, only little amount of CO2 is left
at Earth w/ life
- Higher percentage of O2; as plants produce oxygen along with the
glucose as the product of photosynthesis, there’s a higher amount of
oxygen in Earth w/ life than the Earth w/o life
Metabolism: e.g. of metabolism (chemical reactions) involving glucose (a simple
Anabolism & carbohydrate)
Catabolism
, Anabolic reaction Catabolic reaction
- Small molecules assembled - Large molecules are broken
into larger ones down into smaller molecules
- Requires the input of energy - Energy is being released
(Energy being stored in the complex
molecule is being released => the
released E can be captured in the
form of ATP)
- Breaking down from
complex molecule to simpler
molecules
Metabolism: red/ox = reduction & oxidation reaction (in pairs)
redox
Two mnemonics:
- Leo Ger – Loss of electrons oxidation; Gain of electrons reductions
- Oil Rig – Oxidation involves loss, Reduction involves gain – of
electrons
e.g.
- Cells harvesting Energy from glucose
- Glu is oxidised (gradually) - controlled oxidation
o Carbon in the glu is oxidised -> to CO2
- End result: going from high Energy C-C bonds & C-H bonds in glu -> to
low Energy C-O bonds in CO2
, - Energy is being released in incremental fashion (controlled release of
Energy)
Metabolism: Redox involves the exchange of electrons by electron carriers
Electron
carriers (NAD+ will bind & carry those high Energy electrons from one molecule to
another)
NAD+ can accept electrons from an organic molecule according to the
general equation:
- RH = reducing agent
- NAD+ = oxidizing agent
o Can accept the electrons & H
- NADH = reduced
o NADH can carry electrons & hydrogen to another
- RO = oxidized
Different kinds of Electron carriers
- NAD+/NADH
, - FAD/FADH2
- NADP+/NADPH
Energy (All organisms require constant input of Energy)
Currency of Energy currency = ATP
cells
- ATP = adenosine triphosphate
o Energy is stored in a chemical form, as an ATP
- ADP = adenosine diphosphate
- Phosphate bonds = “high energy” bonds
- Cellular energy carrier
- In the ATP, there are 3 phosphoryl groups present
- the ‘high-energy’ phosphoanhydride bond = the energy is stored in
the bond between the 2nd & 3rd phosphoryl groups (of the ATP)
- If the bond between them (2nd & 3rd phosphoryl groups) is broken,
Energy is released. ATP -> ADP
- ATP – phosphate transfer --> ADP
- ADP – condensation reaction --> ATP
- Cutting off one bond – liberates 7.1 kcal/mol, which is the same
amount of energy as a single peanut
ATP is like a
rechargeable
battery
Exothermic: ATP -> ADP; free energy is released
e.g., ATP is out of charge as it releases its energy
Endothermic: ADP -> ATP; free energy is added to ADP to make ATP
e.g., ATP (rechargeable battery) has been recharged
From the middle of Week 3
9A – Metabolism & Energy Currency
LO 1. Differentiate between anabolism and catabolism, and oxidation and
reduction
2. Explain how ATP can power cellular processes
3. Describe the major evolutionary events to maximize light capture by
plants
4. Describe, in overview, the conversion of radiant energy into chemical
energy
5. Explain the overall organization of the light reactions in photosystems
I and II
6. Describe ATP synthesis during photosynthesis
Fundamental - All organisms req constant input of energy
concept of - Cellular processes (e.g., building & breaking down complex
Energy & Life molecules) occur through stepwise chemical reactions
o Some chemical reactions are spontaneous & releases energy
whereas others req energy to proceed
o Living things must continually obtain more energy to
replenish what they have used
o i.e. life requires energy input; the energy input &
use/consumption involves chemistry
- Cell’s metabolism = chemical reactions that occur inside cells, incl.
Those that use & release Energy
Life’s
chemical
reactions
affect Earth’s
atmosphere
- Very small percentage of CO2 in the Earth with life; as plants are
using up CO2 during photosynthesis, only little amount of CO2 is left
at Earth w/ life
- Higher percentage of O2; as plants produce oxygen along with the
glucose as the product of photosynthesis, there’s a higher amount of
oxygen in Earth w/ life than the Earth w/o life
Metabolism: e.g. of metabolism (chemical reactions) involving glucose (a simple
Anabolism & carbohydrate)
Catabolism
, Anabolic reaction Catabolic reaction
- Small molecules assembled - Large molecules are broken
into larger ones down into smaller molecules
- Requires the input of energy - Energy is being released
(Energy being stored in the complex
molecule is being released => the
released E can be captured in the
form of ATP)
- Breaking down from
complex molecule to simpler
molecules
Metabolism: red/ox = reduction & oxidation reaction (in pairs)
redox
Two mnemonics:
- Leo Ger – Loss of electrons oxidation; Gain of electrons reductions
- Oil Rig – Oxidation involves loss, Reduction involves gain – of
electrons
e.g.
- Cells harvesting Energy from glucose
- Glu is oxidised (gradually) - controlled oxidation
o Carbon in the glu is oxidised -> to CO2
- End result: going from high Energy C-C bonds & C-H bonds in glu -> to
low Energy C-O bonds in CO2
, - Energy is being released in incremental fashion (controlled release of
Energy)
Metabolism: Redox involves the exchange of electrons by electron carriers
Electron
carriers (NAD+ will bind & carry those high Energy electrons from one molecule to
another)
NAD+ can accept electrons from an organic molecule according to the
general equation:
- RH = reducing agent
- NAD+ = oxidizing agent
o Can accept the electrons & H
- NADH = reduced
o NADH can carry electrons & hydrogen to another
- RO = oxidized
Different kinds of Electron carriers
- NAD+/NADH
, - FAD/FADH2
- NADP+/NADPH
Energy (All organisms require constant input of Energy)
Currency of Energy currency = ATP
cells
- ATP = adenosine triphosphate
o Energy is stored in a chemical form, as an ATP
- ADP = adenosine diphosphate
- Phosphate bonds = “high energy” bonds
- Cellular energy carrier
- In the ATP, there are 3 phosphoryl groups present
- the ‘high-energy’ phosphoanhydride bond = the energy is stored in
the bond between the 2nd & 3rd phosphoryl groups (of the ATP)
- If the bond between them (2nd & 3rd phosphoryl groups) is broken,
Energy is released. ATP -> ADP
- ATP – phosphate transfer --> ADP
- ADP – condensation reaction --> ATP
- Cutting off one bond – liberates 7.1 kcal/mol, which is the same
amount of energy as a single peanut
ATP is like a
rechargeable
battery
Exothermic: ATP -> ADP; free energy is released
e.g., ATP is out of charge as it releases its energy
Endothermic: ADP -> ATP; free energy is added to ADP to make ATP
e.g., ATP (rechargeable battery) has been recharged
