B5 Plant nutrition Flashcards
What is photosynthesis?
Photosynthesis is the process by which plants manufacture carbohydrates from raw materials using energy from light.
What is the formula for photosynthesis?
formula for photosynthesis:
carbon dioxide + water=glucose + oxygen.
What is the chemical formulae for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2.
What type of reaction is photosynthesis?
Photosynthesis is an endothermic reaction where energy from the sun (surroundings) is transferred (absorbed) to the chloroplasts in given plants.
-energy is absorbed from to the sourroundings to the chloroplasts.
What is the process of photosynthesis?
process of photosynthesis:
-Light energy from sunlight is absorbed by chlorophyll.
-Green plants use this energy to produce carbohydrates (glucose).
-At the same time, oxygen is made and released.
What is the energy transfer (change) with chlorophyll/chloroplasts?
Chlorophyll traps light (energy) and transfers it to chemical energy in molecules, for the synthesis of carbohydrates.
What can carbohydrates (produced by plants -glucose) be used for?
Carbohydrates can be used for:
-Converted into starch molecules which act as an energy store.
-Converted into cellulose to build cell walls.
-Glucose can be used in respiration to provide energy.
-Converted to sucrose for transport in the phloem vessel.
-As nectar to attract insects for pollination.
what are the factors affecting the rate of photosynthesis?
Plants do not have unlimited supplies of their raw materials so their rate of photosynthesis is limited by whatever is slowest (limiting factors).
-Light intensity.
-Temperature
What is the relationship between varying light intensity and photosynthesis?
The rate of photosynthesis increases with increasing light intensity (close to plant).
-The more light a plant is given, the faster the rate of photosynthesis.
-At low light intensities, increasing the intensity will initially increase the rate of photosynthesis; But at a certain point, increasing light intensity stops increasing the rate of photosynthesis. The rate becomes constant and levels off regardless of how much light intensity increases. This is due to other factors limiting photosynthesis;
What is the relationship between varying temperature and photosynthesis?
The rate of photosynthesis increases with increasing temperatures.
-The temperature of the environment affects the amount of kinetic energy all particles have.
-Temperature affects the speed at which CO2 and water move through the plant.
-Increasing temperature will increase the kinetic energy of particles leading to more successful collisions between reactants and enzymes which results in the formation of products.
-However, at too high temperatures, the enzymes that control processes of photosynthesis can be denatured.
What is the significance of the xylem vessel?
The xylem vessel transports water into the leaf for mesophyll cells to use in photosynthesis and for transpiration from the stomata. They have woody material (lignin) deposited in their cell walls which acts as structural support.
What is the significance of the phloem vessel?
The phloem vessel transports sucrose and amino acids (glucose) around the plant.
What is the significance of the palisade mesophyll and distribution of chloroplasts?
It is mostly the mesophyll cells that contain chloroplasts. The palisade mesophyll contains the most so they perform photosynthesis. They are packed tightly together and close to the top to receive as much sunlight to maximise photosynthesis.
What is the significance of the stomata, spongy mesophyll and guard cells?
Guard cells control whether the stoma is open or closed. Stomata allows gases to diffuse into and out of the leaf. The spongy mesophyll contains internal air spaces that increase the surface area to volume ratio for the diffusion of gases. -Gas exchange.
-Happens in spongy mesophyll tissue of the leaf.
-To get to the spongy mesophyll, gases must diffuse through the stomata. The guard cells control when they open and close to control the loss of water from lead by transpiration.
What is the importance of nitrate ions?
Nitrate ions are a source of nitrogen needed to make amino acids to build proteins.
