Photosynthesis Flashcards
substance X enters mitochondrion from cytoplasm.
each molecule of substance X has 3 carbon atoms.
name substance X?
pyruvate
in the link reaction, pyruvate is converted to a substance with molecules effectively containing only 2 carbon atoms.
describe what happens in this process?
- acetylcoA formed
- Co2 formed
- NADH formed
describe the role of coenzymes and carrier proteins in the synthesis of ATP?
- NAD reduced
- electrons transferred from co-enzyme to co-enzyme
- energy used to synthesise ATP from ADP and phosphate
you can measure the rate of dehydrogenase activity by measuring what?
rate at which DCPIP loses blue colour
if dehydrogenase activity is taking place, what will happen?
- abosrbance dec as DCPIP gets reduced
- loses blue colour
- faster absorbance dec
- faster rate of dehydrogenase activity
you should also check whether the absorbance changes at each distance in 2 negative control tubes.
how can you do this?
- first tube contains ONLY DCPIP and chilled isolation sol
- second contains DCPIP and chloroplast extract - wrapped in tin foil (no light reaches)
NO CHANGE IN ASBORBANCE SHOULD BE SEEN BETWEEN THESE TWO
the solution that the student used to produce the chloroplast suspension had the same water potential as the chloroplasts.
explain why it was important that these water potentials were the same?
- no osmosis
- prevents chloroplasts damaging / bursting
explain why the student set up tube 1?
- to show light doesnt affect DCPIP
- to show chloroplasts needed
explain the results in tube 3?
- DCPIP reduced by electrons
- in chlorophyll
allows comparison between weed killers
- less ATP produced
- less NADPH produced
explain why the scientists measured the rate of production of oxygen in this investigation?
- oxygen produced in LDR
- faster oxygen produced, faster LDR
the scientists suggested that mutant plants producing more chlorophyll b would grow faster than normal plants in all light intensities.
explain how these data support this suggestion?
- faster LDR
- more sugars produced
- more energy for respiration and growth
- faster production of ATP and NADPH
heat stress decreases LDR of photosynthesis.
explain why this leads to a decrease in LDR?
- less ATP produced
- less NADPH produced
the experiments were carried out at high carbon dioxide concentration.
why?
so CO2 not limiting factor
explain why it was important to grow the plants under the same conditions up to ten days before the experiment
to make sure ONLY iron-deficiency causing difference
the plants were left in the dark for 6 hours before the experiment
why?
so same amount of triose phosphate at start
iron deficiency reduced the electron transport.
use this info and your knowledge of photosynthesis to explain the decrease in production of TP from iron deficient plants?
- less NADPH produced
- less ATP produced
- less GP converted to TP
iron deficiency results in a decrease in uptake of CO2
explain why
- less TP converted to RuBP
- CO2 combines with RuBP
scientists investigated the effect of different concentrations of oxygen on rate of absorption of CO2 by leaves of soya bean plants
explain results in figure 2
- as oxygen conc inc, less RuBP combines with CO2
- there is comp inhibition between CO2 and O2 to bind to rubisco
- less RuBP formed
use your knowledge of LIDR to explain why yield from soya bean plants is decreased at higher concentrations of oxygen
- less GP produced
- less TP to form sugars
- less RuBP regenerated
why results in B similar to A
ATP and NADPH produced in grana
the conc of CO2 in air at different heights above ground in a forest changes over a period of 24 hours
use your knowledge of photosynthesis to describe these changes
- high conc of CO2 linked with night/darkness
- no photosynthesis in dark
- in dark, plants respire
- in light, net uptake of CO2 by plants greater than rate of resp
- dec in CO2 conc with height
- at ground level, fewer leaves photosynthesising
microorganisms make the carbon in polymers in a dead worm available to cells in a leaf
how?
- microorganisms = saprobionts
- secrete enzymes onto dead tissue
- absorb products of digestion
- respiration by microorganisms produces CO2
- CO2 taken into leaves
- through stomata
use the graph to explain the factors that limit the rate of photosynthesis
- inc in temp causes inc in rate of photosynthesis
- inc in light causes inc rate of photosynthesis
- growth will decrease at higher temp
- rate of respiration inc at higher temp
- photosynth dec as limited by light
volume of oxygen produced AND time
- pH increases
- as more CO2 removed for photosynthesis
a student who looked at the data in the table concluded that plants carry out more respiration than non-photosynthetic organisms in ecosystem
use info provided to suggest why these data may NOT support the students conc
- data only inc soil organisms
- doesnt inc organisms above grounf
- doesnt take into account anaerobic resp
crops use light energy to produce photosynthetic products
describe how crop plants use light energy during LDR
- excites electrons from chlorophyll
- electrons move along ETC, releasing energy
- energy used to join ADP and Pi = ATP
- photolysis of water produced protons, electrons and oxygen
- NADP reduced by hydrogen
- in light photosynthesis occurs
- in light CO2 from resp being used by photosynth
- photosynth prod sugars
- sugars used in resp
takes time to move sugars to root
- provides H+
- for reduction
- source of electrons for chlorophyll
the scientists suggested that mutant plants producing more chlorophyll b would grow faster than normal plants in all light intensities.
explain how these data support this suggestion
- mutant plants have faster production of ATP and NADP
- faster LDR
- produce more sugars –> resp
- more energy for growth
- faster synthesis of new organic mol
- no error bars
- to show overlap occurs so diff in means not sig
- reduced transfer of protons across thylakoid memb
- less ATP produced
- less NADP produced
- LIDR slows
energy released from high energy electrons
crops use light energy to produce photosynthetic products
describe how crop plants use light energy during LDR
- light energy excites electrons
- electrons move along ETC releasing energy
- energy used join ADP and Pi = ATP
- photolysis of water produces H+, electrons and oxygen
- NADP reduced by electrons = NADPH
after harvesting, the remains of crop plants are often ploughed into the soil.
explain how microorganisms in the soil produce a source of nitrates from these remains?
- proteins converted into ammonium compounds
- by saprobionts
- ammonia into nitrites
- nitrite into nitrate
- by nitrifying bacteria
what is the role of chlorophyll in photolysis?
- absorbs light energy
- accepts electrons from water to dissociate
how is the energy of light converted into chemical energy in LDR
- electrons raised to higher energy level
- use of electron carriers
- for production of ACT
why would the concentration of radioactive GP remain constant
- GP formed from RuBP and CO2
- GP converted to TP
- GP formed at same rate used
why would the concentration of radioactive RuBP increase
- not enough CO2 to combine with RuBP
- RuBP not changed to GP
