B8- Photosynthesis Flashcards
(22 cards)
what is photosynthesis
Photosynthesis
Photo = light
synthesis = making
Photosynthesis = chemical reaction where the plant makes glucose using light
The glucose made is the plant’s ‘food’
why can photosynthesis only happen in the green parts of the plant
Photosynthesis happens in the green parts of the plant - mainly the leaves
Photosynthesis can only happen in the green parts of the plant because the green colour is given to the plant by the pigment chlorophyll
what id chlorophyll
Chlorophyll is a green pigment found in chloroplasts, which absorbs light energy for it to be used in photosynthesis
what type of reaction is photosynthesis
Photosynthesis = an endothermic reaction - it absorbs/requires energy for the reaction to take place
what is the equation for photosynthesis
CO2 + H2O ⟶ C6H12O6 + O2
what is respiration
Photosynthesis is the opposite of respiration - they are the same equation in opposite directions
Photosynthesis requires energy, respiration releases energy
Photosynthesis makes glucose, respiration uses up glucose
Some of the glucose made in photosynthesis is used by the plant in respiration
how is glucose stored as?
Most of the glucose is stored as starch
Starch is the storage molecule for glucose as it is large and insoluble
what are adaptations of leaves for photosynthesis
Leaves adaptations for photosynthesis:
Broad ⟶ big surface for a lot of light to fall on at the same time
Thin ⟶ short diffusion distance for CO2
Chlorophyll ⟶ to absorb light
have veins ⟶ xylem - brings water, and phloem - takes away the glucose
air spaces ⟶ allows CO2 to diffuse in and O2 to diffuse out
Guard cells ⟶ opens and closes stomata to regulate gas exchange
6 points
what are limiting factors
Limiting factor = factors that are short in supply, that restrict the amount of the reaction that can happen
what is the effect of temperature on all chemical reactions
Temperature affects all chemical reactions - the higher the temperature, the higher the rate of reaction up until a certain temperature - after the optimal temperature, the rate of reaction decreases because the enzymes start to denature
draw and describe the graph for Photosynthesis and light intensity
Drawing- Search on Google
Description- The graph starts off with a rapid increase as the higher the light intensity the higher the rate of photosynthesis however the graph starts to plateau as eventually something other than light intensity becomes the limiting factor for example CO2 or water.
draw and describe the graph for Photosynthesis and CO2
Drawing- Search Google
Description- the graph starts off with a rapid increase of co2 levels as the higher the CO2 levels the higher the rate of photosynthesis where CO2 is the limiting factor until the graph starts to plateau where likely another factor becomes the limiting factor for example light intensity
draw and describe the graph for Photosynthesis and temperature
Drawing- Search Google
Description- As the temperature increases the rate of photosynthesis also increases as the higher the temperature the faster the reaction as the enzymes have reaches an optimum temperature. when the graph starts to plateau the enzymes have been denatured which causes the plateau in the graph
what do plants react glucose with to make amino acids
Plants react glucose with nitrate ions to make amino acids
what do amino acids become?
the amino acids become proteins which the plants use for growth
why cant glucose be stored as glucose
If glucose was just stored as glucose, it would affect the plant’s water levels, SO it is stored as the INSOLUBLE molecule starch
why is starch stored in leaves?
Starch is stored in the leaves ⟶ energy source for when light levels are low
what is used to test for starch
Starch is tested with iodine solution ⟶ treat the leaves by boil them in ethanol (removes the waxy cuticle and removes the colour) and rinse in warm water (soften the leaf)
