B4b: Photosynthesis Flashcards Preview

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Flashcards in B4b: Photosynthesis Deck (15):

Word equation for photosynthesis

carbon dioxide + water -(light energy) (chlorophyll)-> glucose + oxygen


What is the waste product in photosynthesis?



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