Photosynthesis Flashcards
Photosynthesis word eq
Carbon dioxide + water = glucose and oxygen
Photosynthesis symbol eq
6CO2+6H2O = C6H12O6+6O2
Endothermic reaction
Chemical reactions where reactants absorb energy from surroundings to form products. Light energy is absorbed in the process of photosynthesis
What do leaves need to photosynthesise
- Large surface to absorb light
- Chloroplasts containing chlorophyll
- A supply of water and carbon dioxide
- A system for carrying away the products of photosynthesis
Why are stomata on the lower epidermis
Less water will be lost through evaporation as the lower epidermis is shaded
Upper Epidermis
Protective layer of cells that produces the waxy cuticle
Palisade Layer
Main photosynthetic layer with many chloroplasts
Spongy Mesophyll Layer
Have air spaces to allow CO2 to diffuse through
Veins
Made of xylem and phloem - xylem carrying water and phloem carrying sugars
Guard cell
Opens and closes to let CO2 in but not out. Opens when there is lots of water, closes when there isn’t
Stoma(ta)
Main photosynthetic layer with many chloroplasts
Air space
Space for gases to travel through the leaf
Many chloroplasts
Absorbing as much sunlight as possible for photosynthesis
Waxy cuticle
Reduces the water loss from the leaf surface
Limiting factors of photosynthesis
Temperature, Carbon dioxide concentration, Light intensity and wavelength, Chlorphyll levels in the plant
Temperature graph
Particles gain more kinetic energy leading to more frequent collisions between substrate and active site. Therefore the rat increases until optimum temperature for enzymes is reached. After this enzymes begin to denature so the active site changes shape and can no longer fit the substrate
Carbon Dioxide Concentration graph
Increased rate - as co2 conc rises so does photosythesis rate - means co2 is limiting factor
after a certain point, rise in co2 has no effect meaning light or temp must be the limiting factor
Light Intenisty graph
same as co2
wavelength effect on plants
Plants reflect green light and absorb red and blue light. If the plant does not recieve enough blue and red, photosynthesis will be affected
Chloropyll effect
If chlorophyll is limited, less photosynthesis will take place
w/o enough minerals e.g. magnesium, it cannot make chlorophyll - rate drops
Greenhouses (photosynthesismaxxing)
Commercial growers use greenhouses to take control of limiting factors.
Hydroponics
Practice of growing plants in a bath or a flow of highly oxygenated, nutrient enriched water without any soil
Water is kept flowing to circulate minerals to the roots
Water is well oxygenated so roots can respire, producing the energy needed to take up the minerals by active transport
Pros of hydroponics
Crops are clean and soil free, can be grown where land is poor, no need to prepare land, requires less labour, can adapt mineral content, space max, faster growing
How plants use glucose - respiration
Glucose is broken down using oxygen to provide energy for plant and algal cells to respire. Co2 and water are waste products
How plants use glucose - cellulose
Plants build up glucose into complex carbs e.g. cellulose used to strengthen cell walls
How plants use glucose - starch
Plants convert some glucose into starch to be stored as starch is insolube and wont affect osmosis. Found in cells all over plant as an energy store in leaves, bulbs, tubers
How plants use glucose - lipids
Glucose and energy is used to build up fats and oils - may be used in cells as an energy store, oftne in seeds providing food for the new plant to respire as it germinates
How plants use glucose - nitrates, proteins, carnivorous
Plants use glucose to make amino acids by combning sugars with nitrate ions and other mineral ions, these can then be built up into proteins to be used in many ways e.g. enzymes, this uses energy from respiration. Very few plants can survive in low mineral soil. Some obain nutrients from animals/insects that are trapped
