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PLANT NUTRITION - Coggle Diagram
PLANT NUTRITION
Leaf structures
Waxy cuticle: Waterproof layer on the top of the leaf, used for preventing the escape of water in photosynthesis and protection against sunlight on the leaf and dust.
Upper epidermis: Top layers of cell with no nucleus that is thin and transparent to allow sunlight to to reach the palisade mesophyll cells for photosynthesis. And Prevents water from escaping
Palisade mesophyll: Packed with chloroplasts(arranged broadside on) , Tall and thin, tightly packed together, top of leaf to maximize the exposure of sunlight and absorption of light energy. (photosynthesis rate)
Spongy mesophyll: air spaces to allow gas exchange and surface area to volume ratio. This also creates a cooling effect.
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Guard cells- Lower epidermis cells that control the opening and closings of the stomata using turgor pressure as an indicator(regulates water loss)
Stomata: Pores formed from the surrounding guard cells. For Gas exchange, Opens at day and closes night and more concentrated on downside of leaf to prevent uneccesary water loss
Vascular Bundles: network of veins to transport substances, thin cell walls and shorted distance to mesophyll cells - faster diffusion rate. , supports stem and leaf. (xylem-transport water from roots to mesophyll cells for photosynthesis) (phloem, transport of glucose and amino acids around the plant)
Chlorophyll-for photosynthesis. Arranged on the membranes of the chloroplasts to have a higher exposure to sunlight for more light energy absorbed to increase the amount of reactions.
The leaf thin for a larger surface area and more cells exposed to sunlight and also decreases the distance of diffusion for an effective gas exchange
Uses of glucose
1) Convert to starch molecules for energy store, As starch is insoluble in water, it doesn’t have an effect of water potential on the cells so it won’t affect osmosis in cells and increase the turgor pressure.
2) Converts into cellulose to build cell walls.:Cellulose is a polysaccharide of glucose. Cell walls in plants helps protection, structual support and growth. It also allows turgor pressure on the cell in, preventing the cell to burst.
3) Glucose used in respiration for photosynthesis: This occurs in the mitochondria of cells where glucose reacts with oxygen to form carbon dioxide and water while releasing energy.
4) Converted to sucrose to be transported in phloem:This is mainly used in fruits to deliberately attract animals and spread seeds
5) Nectar to attract insects for pollination-Plants use nectar for insects to help them cross pollinate with other plants and spread thier seeds.
6) Converted into fats and oils for storage in seeds: Glucose can also be stored in the form of lipids as seeds and oils(such as sunflower oil and margarine)
7) Protein synthesis-Nitrogen and other minerals absorbed in the roots are combined with carbon, hydrogen and oxygen to make amino acids which join to form proteins.(the building blocks of life) Proteins are structual parts of many organelles within cells and sustain life in plants
Photosynthesis- the synthesis of carbohydrates from the raw materials(water and CO2) using light energy from the sun obtained by chlorophyll
Raw materials of photosynthesis: Carbon dioxide( diffuses from atmosphere outside leaf through stomata to air spaces between mesophyll cells and into chloroplasts) And Water (absorbed from the soil by root hair cells and transported through xylem in the leaves)
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Products of photosynthesis-Glucose(transported from the phloem, converted into other substances in the plant and used for respiration)
And Oxygen (used for respiration or diffuses out of the leaf through stomata.)
Sunlight and chlorophyll is also necessary for photosynthesis: Green pigment found in chloroplasts, converts light energy in the leaf into the chemical potential energy in glucose that is used to break the bonds of reactants for carbohydrate synthesis.
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Experiments!
Testing a leaf for starch:1)Boil water in a beaker and drop the leaf into the boiling water to break the cell membranes and allow iodine to be more permeable into the cell. 2)Place leaf into a boiling tube with alcohol inside placed in a beaker of hot water, as chlorophyll is soluble in ethanol, it will dissolve from the leaf into the ethanol.
3)Remove the leaf and drop it back in hot water so it is not brittle.
4)spread out the leaf on a white tile and cover it up with iodine solution, the blue/black parts consists of starch.
Investigate light intensity on photosynthesis: An aquatic plant is used as it is easier to measure the rate through counting oxygen bubbles produced per minute.
1) Collect the aquatic piece and attach a paperclip to the top
2)Place the aquatic plant into a beaker filled with water and a test tube over the plant
light intensity: Move the distance of the lamp and record the rate for different equally increasing/decreasing distances
Temperature: increase the heat of the water and record the results for different equally increasing/decreasing temperatures
CO2 concetration: Dissolving different amounts of sodium hydrogen carbonate and recording the rate to the amount dissolved.
When measuring the rate of each factor, the other factors should be kept constant.
Gas exchange: Use a PH indicator such as Hydrogen carbonate indicator 1) Place the indicator on top of an aquatic plant and note down thesurroundings and colour change.
If the rate of photosynthesis is lower than the rate of respiration, the carbon dioxide concentration will be high in the surroundings near the plant. As carbon dioxide is acidic, the color of the indicator will turn yellow
If the rate of photosynthesis is higher than the rate of respiration, the carbon dioxide concentration will be low as they are converted to oxygen. therefore, the indicator will turn purple
If the rate of photosynthesis is the same as the rate of respiration, the atmosphere will be normal and the indicator color will be red
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