Trilogy Biology Chapter 2Photosynthesis

Warming up
1-3 / Getting practice
4-5 / Stretching
6-8
Carbon dioxide + water  oxygen
+ glucose / 6CO2 + 6H2O  6O2 + C6H12O6 / Light provides the energy needed for the reaction.Chlorophyll absorbs the light energy for thereaction.
Reaction that takes in energy from its surroundings. / Plants respire all of the time to produce the energy they need for the chemical reactions in cells. / Plants use carbon dioxide to photosynthesise and produce oxygen. They use some of the oxygen for respiration and produce carbon dioxide (for photosynthesis).
Light
Carbon dioxide
Temperature / The temperature, carbon dioxide availability and the amount of chlorophyll / Benefits: can maximise photosynthesise
throughout the year to produce large yields
quickly.
Drawbacks: cost of heaters, extra lighting etc. andcomputer technology needs to be balancedagainst increased crop yield and income to ensureit is economically viable.
/ Surrounding each stoma are twoguard cells. Guard cells open and close to control the exchange of gases and water loss. The guard celled are attached to each other at both ends. When it is light the guard cells take in water and become turgid so the inner walls are thicken and rigid causing them to pull apart and open the pores. When it is dark the guard cells lose water so become flaccid causing the inner walls to move together and close the pore. / The cells are arranged end on so that more cellscan fit along the upper surface of the leaf and thechloroplasts are more concentrated towards theupper surface so that they can absorb themaximum amount of light energy possible.
The net movement of particle from an area of high concentration to an area of low concentration against a concentration gradient. / Increase SA
Increase distance particles have to travel.
Increase the conc. gradient. / Partially permeable membranes allow smallermolecules to diffuse through the gaps along aconcentration gradient, but block larger molecules.

It will increase the speed of diffusion. / a. temperature, carbon dioxide levels, amount of chlorophyll
b.correct labelling of equipment and correct setup. / It will appear to stop when an equilibrium is reached. The particles will always be moving randomly but there is no change in concentration
The movement of water through a plant / Phloem cells have end walls with sieve plates but xylem are hollow tubes. Phloem cells contain cytoplasm but xylem cells do not. / Stomata on the underside of leaves are protected from direct sunlight and wind to reduce water loss; the waxy cuticle is waterproof to prevent water loss from the leaf; spiny, needles or rolled leaves all have a reduced surface area to reduce water loss; rolled leaves and stomata in pits trap water vapour, to increase humidity and reduce water loss.
Set up two shoots in potometers. Put one in front of a fan (wind) and one in an area with no wind for a set period of time and measure the distance moved by the air bubble. /
  1. Light – stomata open wider to allow more CO2 into leaf for photosynthesis.
  2. Temperature – evaporation and diffusion increse at higher temperatures.
  3. Wind – water vaopur removed quickly by air movement , speeds up the rate of diffusion so more water vapour out of leaf.
  4. Humidity – diffusion of water vapour descreased as leaf is alrady surrounding by mosit air.
/ a. As temperature decreases, transpiration willnot change at first, but then it will decreaserapidly until at 0°C it almost zero too.
b. As the wind increases, the rate of transpiration increases.
c. As light intensity decreases, transpiration will not change at first, but then it will decreaserapidly until at 0°C it almost zero too.
d. As humidity increases, transpiration
decreases.
The movement of sugar around the plant / Glucose:
1. For respiration
2. To produce insoluble starch for storage
3. To produce cellulose for cell walls
4. combine glucose with nitrate ions and other minerals to produce amino acids for protein synthesis
5. To produce fats and oils for storage
Oxygen:
Used in repsiration
Released into air. /
  • 1. companion cells with a nucleus and many mitochondria, which provide the energy needed to move substances in the phloem
  • 2. limited amounts of cytoplasm and no nucleus, to allow efficient movement of substances
  • 3. perforated sieve plates to allow the movement of substances through the phloem
  • 4. two-way flow of substances so that they are transported all over the plant.