Notesale: Turn your study into money

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Energy
Role of energy
- light energy for photosynthesis
- ATP used for conversion of GP to TP
- ATP used to regenerate RuBP
- Energy needed for anabolic reactions: protein synthesis
- Activation energy to activate glucose in glycolysis
- Active transport: sodium potassium pump
- Movement: muscle contraction
- Endocytosis / exocytosis / pinocytosis / bulk transport
- Temperature regulation

ATP structure
- Nucleotide
- Three phosphate groups
- Nitrogenous base / adenine
- Pentose sugar / ribose
- Ester linkages / covalent bonds
ATP as universal energy currency
- Small
- Water soluble so can move around cell
- Immediate source of energy
- Intermediate between energy yielding and energy requiring reactions
- When hydrolysed, phosphate removed, releases energy
- 30
...
4 kJg^(-1)
Protein: 17
...
8 kJg^(-1)

Respiratory quotient (RQ)
Ratio of volume / moles of carbon dioxide given out divided by volume / moles of oxygen taken
in per unit time
...
Use respirometer
2
...
KOH to absorb carbon dioxide
4
...
Movement of fluid in capillary tube = uptake of oxygen
6
...
Measure oxygen uptake after certain time
8
...
Difference in manometer readings due to carbon dioxide given out

Respiration
Stages of aerobic respiration
1
...
Glucose phosphorylated by ATP
b
...
Forms hexose bisphosphate
d
...
Breaks down to two TP
f
...
Dehydrogenation
h
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4 ATP produced / net gain of 2 ATP
j
...
Reduced NAD enters oxidative phosphorylation
2
...
Krebs cycle
a
...
Acetyl CoA combines with oxaloacetate
c
...
4C to 6C
e
...
Dehydrogenation
g
...
Reduced NAD produced
i
...
ATP produced
k
...
Series of steps
m
...
Oxaloacetate regenerated
4
...
Reduced NAD / FAD passed to ETC
b
...
Hydrogens released from reduced NAD / FAD
d
...
H+ stays in the mitochondrial matrix
f
...
Energy released

h
...

j
...

l
...

n
...

p
...


Protons pumped into intermembrane space
Proton gradient
Protons pass through protein channels
ATP synthase / stalked particles
ATP produced
Chemiosmosis
Occurs three times for each reduced NAD
Oxygen acts as final e- carrier
Joins with H+
Forms water

*Role of oxygen
- Used in oxidative phosphorylation / ETC
- Final electron acceptor
- Proton acceptor
- Forms water
- Allows ETC to continue
- ATP produced
Synthesis of ATP in oxidative phosphorylation
1
...
At inner membrane
3
...
Split into electrons and protons
5
...
Energy released pumps protons into intermembrane space
7
...
Protons diffuse back through membrane / down gradient
9
...
ATP produced from ADP and phosphate
11
...
Addition of proton to oxygen to form water

Experiments to determine the effect of factors such as temperature and substrate
concentration on the rate of respiration of yeast using a redox indicator (DCPIP /
methylene blue)
1
...
Becomes colourless when reduced
3
...
Add named sugar solution and methylene blue / DCPIP
5
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Water bath at set temperature
7
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Use colorimeter
9
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Repeat experiment and calculate mean values
11
...
Plot graph of rate of respiration against temperature

Relationship between structure and function of mitochondria
- Double membrane
(inner membrane)
- Folded / cristae
- Large surface area
- Has ATP synthase / stalked particles
- Has carrier proteins / cytochromes
- Site of ETC / oxidative phosphorylation / chemiosmosis
(intermembrane space)
- Has high concentration of protons
- Accepts protons from ETC
- Proton gradient between intermembrane space to matrix
- ATP synthesis
(matrix)
- Contains enzymes
- Site of link reaction / Krebs cycle
(outer membrane)
- Presence of carriers for pyruvate / reduced NAD
- Ribosomes / DNA
Adaptation
Structure

Adaptation

Folded inner membrane / cristae

Increases surface area available

Intermembrane space

Allows accumulation of hydrogen ions

Impermeability of inner membrane to
hydrogen ions

Maintains proton gradient / protons only go
through channels

Channel protein / stalked particles / ATP
synthase

Channel for protons / ATP synthesis

Linear arrangement of ETC on inner
membrane

Greater efficiency

cDNA

Synthesis of ATP synthase

70S ribosomes

Synthesis of protein / enzyme / ATP synthase

Respiration in aerobic vs anaerobic conditions in mammalian tissue and yeast cells
Yeast
-

Mammalian tissue
- Reduced NAD used
NAD regenerated / glycolysis can continue

Decarboxylation
Irreversible
Two steps
Ethanal accepts H
Ethanol dehydrogenase

-

No decarboxylation
Reversible
One step
Pyruvate accepts H
Lactate dehydrogenase

Anaerobic respiration
Yeast
1
...
Decarboxylation
3
...
Ethanol formed
Mammalian tissue
1
...
Process uses reduced NAD from glycolysis
3
...
Catalysed by lactate dehydrogenase
5
...
Small energy

Adaptation of rice to grow with its roots submerged in water
- ethene in plant stimulates production of gibberellin
- Gibberellin stimulates cell division / cell elongation / increase in stem length
- Leaves / flowers above water so photosynthesis can occur / so sexual reproduction /
pollination can occur
- Aerenchyma present - air space in stem and roots
- Help oxygen to move / diffuse to roots

-

Shallow roots
Allow oxygen to diffuse from water surface
Air can be trapped by specialised underwater leaves / corrugated leave surface
Submerged parts of plant carry out anaerobic respiration
Produce ethanol
Can tolerate high concentrations of ethanol
Produce a lot of ethanol dehydrogenase for anaerobic respiration

Investigations using simple respirometers to measure effect of temperature on the
respiration rate of germinating seeds or small invertebrates
1
...
Use KOH to absorb carbon dioxide
3
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Choose 4 different temperatures
5
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Leave for set time
7
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Use tap to reset respirometer
9
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Calculate rate as distance + time
11

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