Unit 3 - Plant Nutrition

• What is the formula for photosynthesis?

  6CO2 + 6H2O + (light energy & clorophyll) -> C6H12O6 + 6O2
• Where does photosynthesis occur?

  Chloroplasts
• How do chloroplasts help with photosynthesis?

  Chloroplasts contain chlorophyll, which absorbs sunlight and converts it into chemical energy, and stored in glucose which is used through photosynthesis.
• What are the rates of photosynthesis?

  Carbon dioxide, light and temperature
• How does CO2 affect photosynthesis?

  As CO2 increases, photosynthesis increases
• How does sunlight affect photosynthesis ?

  As sunlight increases, photosynthesis increases
• How does temperature affect rate of photosynthesis?

  Temperature affects the rate of photosynthesis by increasing it up to an optimal point, after which it decreases. That is because of enzymes, they require optimal temp (25°C)
• How does a leaf structure look like?

  Broad, flat, and typically green with veins for transport and a waxy cuticle to prevent water loss.
• What does the palisade mesophyll layer do?

  Contains chloroplasts which help with photosynthesis.
• What does the spongy mesophyll layer do?

  Contains lots of air space, and allows gas diffusion in and out. As it increases surface area to volume ratio
• What does the stomata do?

  Gas exchange occurs and loss of water through evaporation
• What does the guard cell do?

  Regulate stomata's opening and closing by absorbing or releasing water
• What does the waxy cuticle do?

  Prevent water loss by evaporation
• What does the lower epidermis contain?

  Stomata and guard cells.
• Why is the upper epidermis transparent?

  To allow light to pass through and reach the photosynthetic cells in the lower layers of the leaf.
• What is the vascular bundle?

  A structure in plants (xylem and phloem) that transports water, nutrients, and sugars throughout the plant. They also support the leaf structure.
• What are the main minerals needed in a plant?

  Nitrogen, Phosphates , Potassium and Magnesium - NPPM
• What does nitrate do for a plant?

  Cell growth - Contain nitrogen which makes amino acids and protein.
• What happens if a plant does not get enough nitrate?

  Stunted, Old leave turn yellow
• Why do plants need phosphates?

  Respiration & Growth - Contain phosphorus which makes DNA and cell membranes
• What happens if a plant does not get enough phosphates?

  Poor root growth, old leaves turn PURPLE
• Why do plants need potassium?

  Help enzymes - needed for photosynthesis and respiration
• What happens if theres not enough potassium?


  poor flower and fruit growth, discoloured leaves
• Why do plants need magnesium?

  Make chlorophyll
• What happens if theres not enough magnesium?


  Leaves turn YELLOW
• What are the main transport systems?

  Xylem and Phloem
• What do xylem transport?

  Water and minerals - carried from roots up to the shoot to the leaves int he transpiration stream
• What do phloem transport?

  Sugars - amino acids and sucrose
• What is translocation?

  Movement of food substances around the plant
• Why do multicellular organisms need transport systems?

  To move substances to and from individual cells quickly
• What are the practicals to show what is needed for photosynthesis?

  Light, carbon dioxide, and chlorophyll.
• How do you show that photosynthesis has taken place within a plant?

  If the leaf turned from green to blue-black, showing if starch is present
• What is the experiment for starch?

  Iodine test

  1. Put the leaf in boiling water (stop chemical reaction within leaf)
  2. Put in boiling tube with ethanol and heat in electric bath till boils. (gets rid of any chlorophyll and makes the leaf a white-ish colour)
  3. Rinse in cold water and add IODINE.
  4. Leaf turn blue-black if starch is present
• What is the practical for light for plants?

  Store in place with no light access for 48 hours (use up all starch stores)

  Cut leaf to test for starch
• What is the practical for chlorophyll for plants?


  Take a variegated (green and white) leaf outside and test for starch
• What is the practical for CO2 for plants?

  1. Soda lime will absorb CO2
  2. Leave plant for a while, won't turn blue-black when testing for starch
  3. Shows no starch made - shows CO2 needed for phs.

  
• What is the experiment for rate of photosynthesis with oxygen?

  Sodium hydrogencarbonate may be added to make sure plant has enough CO2 by releasing CO2 into solution

  1. White light placed at specific distance from pondweed
  2. Leave pondweed to phs. for set amt of time
  3. As it phs, O2 releases and collected in capillary tube
  4. End - syringe draws gas bubble in the tube up alongside a ruler and the length of gas bubble is measured (proportional to vol. of O2 produced)

  
• What variables should be controlled for the experiment on the rate of photosynthesis with oxygen?

  Light intensity, temperature, carbon dioxide concentration, and water availability of the pondweed
• What should be repeated in the experiment for the rate of photosynthesis with oxygen?

  Light source placed at diff distances fromt he pondweed
• White light


  Placed at specific distance from pondweed to provide energy needed for photosynthesis to occur.