Unit 3 AOS 2 Flashcards
ATP synthase
- enzyme used to convert ADP into ATP
- uses the concentration gradient of H+ to synthesise ATP from ADP
process of C3 photosynthesis
- captures energy in sunlight, storing it in a 6 carbon sugar (glucose)
6CO2+12H2O —> C6H12O6+6O2+6H2O
RuBisCo
- enzyme involved in carbon fixation (converting CO2) in the calvin cycle
- can use oxygen instead of carbon under high light & temps –> photorespiration (inefficient), waste of carbon as it produces no glucose or ATP (C3)
- uses CO2 which has been converted to malate in C4 to catalyse calvin cycle in bundle sheath cells –> preventing photorespiration
PEP carboxylase
catalyses carbon fixation
> converts CO2 into malate in C4 and CAM plants
factors affecting enzyme function
- temperature
> reactions are slower below optimal temp, above may cause denaturing - pH
> enzymes work fastest at optimal rate, higher or lower means slower rate. too far out of range = denature - concentration
> substrate conc below saturation point = slower reactions, past saturation = constant rate - enzyme inhibitors
> competitive: bind to active site and stop a substrate from binding
> non- competitive: bind to allosteric site & change shape of active site, stopping substrate from binding
light dependent stage
- occurs in the thylakoid membranes in grana
- uses light energy to split water molecules (hydrolysis) to produce…
inputs: - 12 H2O
- NADP+
- ADP + Pi
outputs: - ATP
- 6 O2
- NADPH
Light independent stage/ calvin cycle (location, inputs, outputs)
- occurs in the stroma
- doesn’t require light
inputs: - ATP
- NADPH
- 6 CO2
outputs: - H2O
- NADP+
- 1 glucose (C6H12O6)
- ADP + Pi
–> the purpose of photosynthesis is to produce glucose in plants
advantages of C3 photosynthesis
- more efficient than C4 and CAM under cool & moist conditions
- less enzymes & no specialised plant anatomy
- most plants are C3
process of C4 photosynthesis
- bundle sheath cells, where calvin cycle occurs
- mesophyll where LD occurs
- warm & high light condition environments
- ensures photorespiration doesn’t occur
> CO2 enters mesophyll, PEP carboxylase breaks it down into malate & sends it to the bundle sheath cells, where rubisco catalyses L.I stage to produce glucose
CAM photosynthesis
- light dependent occurs at night, calvin cycle day
- stomata open at night & absorb CO2 to reduce water loss by transpiration during the day.
- CO2 is stored as malate within the vacuoles, and the stored CO2 is used by rubisco during the day when light is available for photosynthesis
factors affecting photosynthesis
- light availability (amount/ intensity)
- water availability- humidity decreases transpiration
- temperature/pH- affect enzymes, photosynthesis is greatest when at optimal temp.
- CO2 conc. - rate of photosynthesis may be limited if there are low levels or stomata closed
how can CRISPR-Cas9 be used to increase crop yield
editing the genome to protect plants & crops
increase crop yield (amount) by:
- abiotic resistances (heat, drought, pests, etc)
> Increase water use efficiency; reduce water loss while maintaining photosynthesis
- Optimising light capture
> improving genes which collect light to allow more efficient photosynthesis
aerobic respiration
- uses oxygen to break produce ATP from glucose
- produces 30 or 32 ATP
equation:
C6H12O6 + 6O2 –> 6CO2 + 6H2O + 30 or 32 ATP
Mitochondrion anatomy
- intermembranous space
- crystal matrix
- cristae (folds)
glycolysis (inputs, outputs, location)
- in the cytosol
- splitting of glucose into 2 3-carbon molecules (pyruvate)
inputs: - glucose
- 2 ADP + Pi
- NAD+
outputs: - 2 pyruvate
- 2 ATP
- NADH
the krebs cycle (inputs, outputs, location)
- occurs in the mitochondrial matrix
- generates high energy electron & proton carriers, NADH & FADH2 (coenzymes)
inputs: - 2 pyruvate
- ADP+Pi
- NAD+
- FAD
outputs: - CO2
- 2 ATP
- NADH
- FADH2
ETC
- occurs in the cristae of the inter-membranous space
inputs: - NADH
- FADH2
- 6 O2
- ADP + Pi
outputs: - 26 or 28 ATP
- 6 H2O
- NAD+
- FAD
anaerobic fermentation
- ATP is produced without oxygen in the cytosol
- NADH recycles NAD+
- slows krebs cycle, no ETC
- occurs in animals & fungi
- more inefficient, but faster than aerobic
inputs & outputs of anaerobic fermentation in animals & yeast
inputs:
- glucose
outputs:
- lactic acid (animals)
- ethanol (yeast)
- CO2 (yeast)
> used for production of alcohol & baked goods
factors affecting rate of cellular respiration
- temperature: highest rate when at the enzymes optimal temp. above optimal denatures the enzyme
- glucose availability
- oxygen conc: increased conc.= increased aerobic, no oxygen=fermentation
biofuels/ bioethanol
- made from biomass- renewable matter from recently living plants and animals
- Biomass can be decomposed by yeasts via anaerobic fermentation, producing bioethanol, which can be used as a type of biofuel
- they are carbon neutral, an efficient use of waste & are essentially infinite
process of turning biomass into bioethanol
- deconstruction: increase SA:V to make fermentation more efficient
- enzymatic hydrolysis: biomass is broken down into glucose using enzymes and water, hydrolysis occurs
- ethanol fermentation: large amount of ethanol is produced, diffuses out of yeast cells & is collected for use
- purification & detoxification: water removed, biofuel purified, can be mixed in with a fossil fuel (eg. E10 fuel)
photosynthesis equation
carbon dioxide + water –> glucose + water + oxygen
6CO2 + 12H2O –> C6H12O6 + 6H2O + 6O2
- requires light and chlorophyll
aerobic respiration formula
glucose + oxygen –> carbon dioxide + water + energy
C6H12O6 + 6O2 –> 6CO2 + 6H2O + 30 or 32 ATP
