Topic 5 Flashcards
1
Q
Thylakoids Membrane
A
-folded membrane
- contains photosynthetic proteins (chlorophyll)
- electron carrier proteins embedded in membranes
- both proteins involved in LDR
2
Q
Stroma
A
- fluid centre
- contains enzymes involved in LDR
3
Q
Inner and outer membrane of chloroplast
A
Control what can enter and leave the organelle
4
Q
Where do LDRs and LIRs take place and what are they part of
A
- LDR = thylakoids membrane or grana
- LIR = stroma
- photosynthesis two stage reaction - LDR and LIR
5
Q
LDR
A
- first stage
- requires light
- light energy and water used to create ATP and reduced NADP needed for LIR
6
Q
Stages of LDR
A
- Photolysis
- Photoionisation of chlorophyll
- Chemiosmosis
- Production of ATP and reduced NADP
7
Q
Photolysis of Water
A
-photolysis = light splitting
- light energy absorbed by chlorophyll and splits water into oxygen, H+ and e- (H2O - 1/2O2+2e-+2H+)
- H+ picked up by NADP to form NADPH - used in LIR
- passed along chain of electron carrier proteins
- oxygen used for either respiration or diffuses out of leave via the stomata
8
Q
Photoionisation of chlorophyll
A
- light energy absorbed by chlorophyll
- electrons become excited and leaves the chlorophyll
- so chlorophyll has been ionised by light
- some energy released used to form ATP and reduced NADP in chemiosmosis
9
Q
Chemiosmosis
A
- Electrons that left chlorophyll go along series of proteins embedded in thylakoid membrane
- As they move along they release energy and pump protons across the chloroplast membranes
- Electrochemical gradient created and protons pass through ATP synthase - produces ATP
- Protons combine with NADP (coenzyme) to become reduced NADP. Protons move from high to low concentration gradient - Chemiosmosis
10
Q
LIR
A
- Calvin Cycle
- Stroma - contains enzyme called RuBisCo which catalyses the reaction
- temp sensitive as it involves enzymes
- uses CO2, reduced NADP and ATP to form a hexose sugar
11
Q
Calvin Cycle
A
- ATP hydrolysed - energy
- reduced NADP donates hydrogen to reduce molecules GP
- CO2 reacts with ribulose phosphate - forms two molecules of glycerate 3-phosphate (3 carbon compound)
- GP reduced to triode phosphate using energy from ATP and accepting reduced NADP
- some carbon leaves from TP to turn into useful organic substances
- Rest of molecule used to regenerate RuBP
12
Q
Limiting Factors
A
- reduces rate of photosynthesis
- temp, CO2 concentration and light intensity
13
Q
Aerobic Respiration
A
- Glycolysis (cytoplasm)
- Link Reaction (mitochondrial matrix)
- Krebs Cycle (mitochondrial matrix)
- Oxidative Phosphorylation (mitochondrial inner membrane - cristae)
- produces ATP
14
Q
Glycolysis
A
-1st stage aerobic and anaerobic
1. Phosphorylation glucose to glucose phosphate, using ATP
2. Production of TP
3. Oxidation of TP to produce pyruvate with a net gain of ATP and reduced NAD
15
Q
A
- Glycolysis (cytoplasm)
- Link Reaction (mitochondrial matrix)
- Krebs Cycle (mitochondrial matrix)
- Oxidative Phosphorylation (mitochondrial inner membrane - cristae)
- produces ATP
16
Q
Link Reaction
A
- pyruvate and NADH actively transported to mitochondrial matrix
- pyruvate oxidised to acetate
- NAD picks up hydrogen and becomes reduced NAD
- acetate combines with coenzyme A - Acetylcoenzyme A
17
Q
Krebs Cycle
A
- AcetylCoA reacts with 4C molecule releasing CoA and producing a 6C molecule
- series of redox reactions - generates reduced coenzymes and ATP by substrate level phosphorylation and CO2 is lost
- 3x reduced NAD, 1x reduced FAD, 1x ATP, 2xCO2
18
Q
Oxidative Phosphorylation
A
- most ATP made during this stage
- electron transfer chain
- movement of protons across cristae
- catalysed by ATP synthase
19
Q
Anaerobic Respiration
A
- absence of oxygen, occurs in cytoplasm only
- pyruvate produced in glycolysis reduced to form ethanol and CO2 (in plants and microbes) or lactate (in animals) by gaining hydrogen from reduced NAD
- NAD can be reused in glycolysis and ensures more ATP is produced
20
Q
Energy Transfer
A
- in any ecosystem, plants are producers - able to produce own food (carbs) using CO2 and water
- majority of energy lost between each tropic level via respiration and excretion. Remaining used to form biomass.
- amount of biomass remaining in organism measured in mass of carbon or dry mass of tissue per given area
21
Q
Net Primary Production and Gross Primary Production
A
- GPP - chemical energy store in plant biomass in given area. Total energy resulting from photosynthesis.
- NPP - chemical energy store in plant biomass taking into account energy lost from respiration (R)
- NPP = GPP-R
22
Q
Net Production of Consumers (animals)
A
- N=I-(F+R)
- I = chemical energy store in ingested food
- F = chemical energy lost to environment in faeces and urine
- R = respiratory losses
23
Q
Nitrogen Cycle
A
- Saprobiotic nutrition and microbes
- Ammonification
- Nitrification
- Nitrogen Fixation
- Denitrification
24
Q
Importance of Nitrogen Cycle
A
- Plants and animals cannot obtain nitrogen through gas exchange
- Nitrogen gas (N2) contains a triple bond
- Microorganims needed to convert N2 into nitrogen containing substances that plants and animals can absorb - proteins, ATP and nucleic acids all contain nitrogen
25
Q
Phosphorus Cycle
A
- phosphorus used for DNA/RNA,ATP,Phospholipid bilayer - essential element for life
- different to carbon and nitrogen cycle as it is not found in gas (atmosphere)
- mainly found as phosphate ion, in mineral form in sedimentary rocks
26
Q
Mycorrhizae
A
- fungal associations between plant roots and beneficial fungi
- beneficial for plant growth:
1. Increases SA for water and mineral absorption
2. Acts like sponge - holds water and minerals around the roots
3. Makes plants more drought resistant and able to take up more inorganic ions. - role in nutrient cycles - improving uptake if relatively scarce ions (phosphate ions) - mutualistic relationship
27
Q
Fertilisers
A
- added to soil to replace nitrate and phosphate ions lost when plants are harvested and removed from nutrients cycles as crops
- either natural (manure) - cheaper, but minerals and proportions can’t be controlled
-artificial (inorganic chemicals) - exact proportions of minerals, more water soluble so more ions dissolve in water surrounding the soil
28
Q
Leaching
A
- water soluble compounds washed away, often into rivers/ponds
- causes eutrophication
29
Q
Eutrophication
A
- nitrate leached from fertilised fields stimulates growth of algae in ponds (algal bloom)
