Photosynthesis (2) ✅ Flashcards
(46 cards)
where plants use, sugars from water and CD
definition of photosynthesis
Where plants use light energy to make sugars from water and carbon dioxide.
word equation for photosynthesis
CWOG
Water + carbon dioxide –> Glucose + Oxygen
Carbon dioxide + Water –>C6H12O6 + oxygen
balanced symbol equation for photosynthesis
6CO2 + 6H2O –> C6H12O6 + 6O2
water, carbon dioxide
Where does the plant get the raw materials for photosynthesis
Water = through the roots
Carbon Dioxide = diffuses into the leaf in stomata
G = STORED AS S then –> as SUCROSE THEN USED IN R + FOR G
O = diffuses out
What happens to the products in photosynthesis
Glucose - Stored as starch, Transported as sucrose, Used in respiration, Used for growth
Oxygen - Diffuses out of leaf, Used in respiration
If a plant has photosynthesised it should make starch. How do we test for starch
Test with iodine – check if starch present.
Starch present: changes from yellow brown - blue black
Starch absent = stays yellow brown.
Label:
What is the trend + what is limiting
As light intensity increases, rate of PS increases until it levels off
- light is limiting : when light increases further, the Rate of PS increases
- Something else is limiting at 2: it doesn’t matter how much the light increases, Rate of PS doesn’t increase further. Could be carbon dioxide or water or temperature.
what 2 things are limiting here
Light is limiting at start
Cold temp is limiting
what is the word equation for respiration
Glucose + oxygen –> water + carbon dioxide
what is released in respiration and what is taken in during photosynthesis
in respiration CO2 is released, in photosynthesis CO2 is taken in.
for questions about Respiration and Photosynthesis in different conditions what 3 important things you need to talk about
Light intensity, temperature, Co2 levels
H C i
what indicator can we use to test the amount of CO2 released
hydrogen carbonate indicator
what colour will the hydrogen carbonate indicator turn if there is:
more CO2:
normal levels of CO2:
less CO2:
more - yellow
normal - red
less - purple
what is an endothermic reaction
(en - in)
reactions that take in energy
what test can we use to see if starch is present
the starch test
how do we carry out the starch test
- put leaf in boiling water
- boil leaf in ethanol
- dip in boiling water again
- put on white tile
- add iodine
why do we boil the leaf to carry out the starch test
kills the leaf
why do we boil the leaf in ethanol to carry out the starch test
removes chlorophyll
why do we dip the leaf in boiling water AGAIN to carry out the starch test
makes leaf soft and less brittle
what will the colour change be if starch is present
yellow brown - blue black
what do we need to do before carrying out the starch test
destarch the plant in a dark place for 48 hours
why do we need to destarch the plant before carrying out the starch test
ensure any starch produced is only produced during the experiment
how do we show light is needed for photosynthesis
- destarch
- partially cover with tin foil
- put plant in bright light
- test for starch
