B4b: Photosynthesis Flashcards
Word equation for photosynthesis
carbon dioxide + water -(light energy) (chlorophyll)-> glucose + oxygen
What is the waste product in photosynthesis?
oxygen
Balanced symbol equation for photosynthesis
6CO2 + 6H2O -(light energy) (chlorophyll)-> C6H12O6 + 6O2
Describe the development of the understanding of the process of photosynthesis (3)
Greek scientists thought that plants gained mass only by taking in minerals from the soil
Van Helmont’s experimental conclusion from growing a willow tree that plant growth cannot be solely due to nutrients from the soil but also by absorbing water
Priestley’s experiment showed that oxygen is produced by plants and carbon dioxide is important for photosynthesis
Explain how experiments using isotopes have increased our understanding of photosynthesis
that oxygen produced by photosynthesis comes from the water and not the carbon dioxide (light energy is used to split water, not carbon dioxide)
Describe the 2 stages of photosynthesis(2)
during the day light energy is used to split water, releasing oxygen gas and hydrogen ions
during the day or night carbon dioxide gas combines with the hydrogen ions to make glucose
Describe the conversion of glucose and starch to other substances in plants and their use (4)
glucose is used in respiration to release energy
converted into cellulose for cell walls
converted into proteins for growth and repair
converted starch, fats and oils for storage (used when photosynthesis can’t happen (night))
Explain why insoluble substances such as starch are used for storage (3)
can be converted back into glucose for respiration in plant cells
insoluble so will not dissolve in water and flow away in solution from storage areas
does not affect water concentration inside cells
How can the rate of photosynthesis be increased? (3)
more CO2
more light
higher temperature
(increasing the limiting factor)
Effect of light on photosynthesis (2)
light provides energy to drive photosynthesis
+light, +rate of photosynthesis
Effect of carbon dioxide on photosynthesis (2)
raw material for photosynthesis
+CO2, +rate of photosynthesis
Effect of temperature on photosynthesis (4)
affects how quickly enzymes work
enzymes make reactions of photosynthesis happen
+temp, +rate of photosynthesis
if too hot, enzymes denature and photosynthesis stops
Why do plants carry out respiration all the time?
because respiration releases energy need by the plant to grow and survive
Gas movement in and out of leaf - Daytime(3)
photosynthesis rate > respiration rate
-take in more CO2 for photosynthesis than that is used up for respiration
extra oxygen produced in photosynthesis released
Gas movement in and out of leaf - Nighttime(3)
respiration occurs, no photosynthesis (no light)
more oxygen taken in for respiration
waste carbon dioxide from respiration released
