biology B8

• photosynthesis produces glucose which produces energy, happens in palisade cells and needs light energy in order to complete
• photosynthesis word equation: carbon dioxide + water - glucose + oxygen
• photosynthesis symbol equation: 6CO2 + 6H2 - 602 + C6H1206
• The waxy cuticle prevents water loss
• chloroplasts absorb light for photosynthesis
• palisade cells include many chloroplasts which increase the rate of photosynthesis
• airspaces allow gases to diffuse throughout the leaf
• guard cells open and close the stomata
• stomata are the small holes on the under surface of the leaf allowing diffusion of gases and transpiration ( water loss)
• xylem carries water and mineral ions
• phloem carries dissolves sugars
• water moves into the plant via the root hair cells by osmosis, its then carried up the leaf and into the xylem. Movement of water up the plant is transpiration.
• carbon dioxide diffuses into the leaf via the stomata. Moves from a high to a low concentration
• as the light intensity increases so does the rate of photosynthesis. Light intensity is the limiting factor.
• no sunlight means that the plant cant photosynthesise
• as the carbon dioxide concentration increases so does the rate of photosynthesis

  A) light/ temperature is the limiting factor

  B) carbon dioxide is the limiting factor

  
• as the light intensity increases so does the rate of photosynthesis

  A) temperature/co2 are limiting factors

  B) light intensity is the limiting factor

  
• as the temperature increases so does the rate of photosynthesis this is because molecules have more kinetic energy meaning they move faster and collide more.

  A) enzymes denature, slow down the rate

  B) active site changes shape

  
• plant and agal cells use some of the glucose produced during photosynthesis for respiration
• glucose is broken down by oxygen to provide energy for cells
• plants build up glucose into complex carbohydrates such as cellulose. strengthens cell walls.
• some glucose is converted into starch and is stored
• glucose is soluble in water whereas starch is insoluble so the effect on the water balance of the plant is none so the plants can store large amounts of starch in their cells
• respiration is the release of energy used in other processes. for example: active transport producing mineral ions.
• energy is needed in plants in order to build up small molecules into larger molecules
• in the cell walls some of the some of the glucose is built into more complex carbohydrates like cellulose for making cell walls
• proteins - energy is needed to combine sugars with other minerals from the soil to make amino acids. These are then built up to make proteins to be used in cells.
• seeds - energy is used to built up fats and oils to make a food store in the seeds.
• in the process of investigating photosynthesis:

  AIM: the affect of light intensity on photosynthesis

  INDEPENDENT: light intensity

  DEPENDENT: number of bubbles

  CONTROL: length of pond weed, volume of solution, same length increase each time
• the inverse square law means as one goes up the other goes down.
• inverse square law

  
• polytunnels are used to grow crops, internal conditions can be controlled, warmer atmosphere, grow fruit which cant usually be grown in the UK.
• yield is the amount of a product
• a paraffin lamp is a type of fuel you burn, releases carbon dioxide and heat
• hydroponics are plants grown in water with perfect balance of minerals such as nitrate ions and magnesium ions.