B8- Photosynthesis Flashcards
(46 cards)
What do plants use as there source of energy ?
Light from the sun .
What is the reaction plants use to trap this light energy ?
Photosynthesis .
-Photosynthesis takes in energy , so it is an exmple of a n endothermic reaction .
Where does photosynthesis tke place ?
Photosynthesis takes place in the leaves of a plant . (palisade mesophyl)
-Leaves contain the green chemical chloropyll , chlorophyll can baosrb light energy .
What is the firsts tage of photosynthesis .
Carbondixoide is taken up by the plant into the leaf .
- Light energy is then absorbed by the chlorophyll .
- Ther energy is then used to convert co2 and water into the sgar glucose , this reaction also producs oxygen .
Write the symbol and word equation for photosynthesis .
Check sheet.
Check photosyntheis sheet, first graph , what does the first star show ?
When the light intensity is zero , the rate of photosyntheis sis zero . Plants need light to carry out photosynthesis
Check photosyntheis sheet, first graph , what does the second star show ?
- As we increase the light intensity , the rate of photosynthesis increases
- As the plnat has more light energy to carry out photosyntheisis reaction , so the reaction geets faster .
If we increase the liggt intensity and the rat eof photosynteiss increases , what does that show ?
It shows that light intensity is the LIMTING FACTOR ,. (pHontosytheiss was not as fast because there was not enough light ) .
Check photosyntheis sheet, first graph , what does the third star show .
- If we keep increasung the light intesnity , there come sup a point where he rate of phtoosyntehsis no longer increases .
- At this point light intensity is no longer the limiting factor . Something else is in short supply - co2 in the air .
Check photosynthesis sheet second graph , what does this show .
- As we increase the carbondixoide leve , the rate of photosyntheiss increases .
- This tells us co2 is the limtiing factor.
Check phtosynthesis sheet second graph . what does the first star show .
At a certain point , the rateof photosyntehsis no longer increases . Co2 is no longer a limtiing factor .
What is another think that affects the rate of photosyntheis s.
The amount of chlorphyll in the leaf , the less chlorophyl a leaf has (less green) , it can trapp less liht energy than leaves with more chorphyll , lowering the rate of photosyntheis .
Check last graph on photosynthesis shseet , what does the first star show .
Temperature also affectsthe rate of photosyntehsis .
As we increase the temperature , the enzymes involved in phtoosyntehsis work faster so rtae increases .
Check last graph on photosynthesis sheet , what does tthe second star show ?
-If we keep icnreasing the temperature , the enzymes will denature and the rate of photosyntheis falls .
What does th limting factors start one graph oone show ?
- Initially the rtae of photosyntheies increases as we increase lihgt intensity .
- This tells us light intensity is the ilmint factor at this point .
What odes limting factors graph 2 show ?
At a certain point , the rate of photosyntheiss stops increasing . Now light intensity is no longer the limtign facvtor something rlse is limiting factor .
What three other thins affect the rat eof phtosynthesi s.
-Co2 conc
-temperature
-amout of chlorphyll in leaves .
(can chanhe temp and con2 conc but not chlorphyll in leaves .
Limitng factor co2 graph , what does the graph sho .
- The grpah shows the same experiment as graph 2 but with a higher cocnentraiton of co2 .
- The normal co2 conc shows that at the levels of co2 increases , the rate of photosyntehis sncreases , telling us the conc oof co2 was a limiitn g factor .
What about the higher conc of co2 on the grapgh .
- In the increased co2 conc , rate of photosyntesis hasn’t changes , co2 was no longer limiitng factor ..
- As the high levels of co2 meant there was plenty of co2 available .
Limiting factor , temp graph , what does the higher temperatrue show ?
- At the higher temperature , the rate of photosyntheis has increased .
- Telling us the that temp was the limting factor .
What if we increase he temperature toomuch ?
-The enzymes in the lead start to denature and the rate of photosynthesis will fall .
Why do farmers want to increase the rate of photosyntehsis ?
- As this increases the yield of crop sthey produce .
- To do this , the farmed add light and heat to their greenhosues , as well as extra co2 (they exploit the limiting factors of photosyntheis s).
Problem with exploiting limiting actor in photosyhteis .
extra costs has to be justified by the increase in yield .
-So gardnerres use oil burners as there rlease heat and CO2 at the same time .
What is the first stage for the Photosynthesis RQP ?
1.Start by taking a boiling tube and placing it ten cm away from an LED light source .
