Plant Nutrition & Gas Exchange

• Fill in the blanks:

  A) light

  B) photosynthesis

  C) respiration

  
• Chlorophyll traps light energy and converts it into chemical energy for the formation of carbohydrates (glucose) and their subsequent storage (starch)
• Fill in the blanks for the balanced equation of photosynthesis

  A) 6

  B) 6

  C) 12

  D) 6

  
• Starch is used for storage, cellulose is used for plant cell walls, and glucose is otherwise used for respiration for energy production.
• Elodea or canadian pondweed is often used to investigate the speed of photosynthesis under different condiitons. You place it in a water & sodium hydrogen carbonaate solution with a funnel wherein, as it is a plant that grows underwater, you can see the oxygen bubbles rise and displace water in the top of the funnel wherein the water around rises.
• To test for starch, you first place a leaf in a beaker half full of water. You heat the water until it is boiling to kill the leaf. Then you turn the flame off. The next step is to transfer the leaf to a large test tube containing ethanol, which you boil in a water bath because ethanol is flammable. You leave it until all of the green colour (chlorophyll) is removed from the leaf. You then remove the leaf and rinse it in warm water where you then place it on a tile. Finally, you use iodine, the test for starch, and look for black areas.
• Starch molecules are comprised of 200 to 800 glucose molecules and are stored in a coiled shape so they take up less space.
• The long coiled chains of starch molecules end up becoming tangled up, and these large bundles build up forming a dense grain of starch.
• Starch is insoluble in water and is a concentrated energy store.
• Cellulose is made up of long, linear, parallel chains and is also insoluble. Comprised of 1000-1500 glucose molecules, with its tough fibres, criss-cross arrangement for added strength, and gaps that make it permeable, it makes for a good cell wall!
• To test for the effect of light you cover leaves in black bags and leave them for 48 hours, and then you use iodine to test for starch.
• To test for the need for carbon dioxide you place the plant in a darkened cupboard for at least 24 hours to destarch the plant, you then seal it for 24 hours in an environment that lacks CO2, and then you use iodine to test for starch.
• Fill in the blanks with the correct limiting factor:

  A) Light

  B) Concentration of Carbon Dioxide

  C) Temperature

  
• Fill in the blanks of this leaf structure:

  A) evaporation

  B) epidermis

  C) transparent

  D) protective

  E) palisade mesophyll

  F) waxy cuticle

  G) photosynthesis

  H) spongy mesophyll

  I) air

  J) diffuse

  K) vascular bundles

  L) phloem

  M) water

  N) sugar

  O) stomata

  
• Stomata are tiny pores present in great numbers on the lower epidermis. Guard cells control their opening and closing. They open in light to allow for carbon dioxide to enter.
• Fill in the blanks of this table

  A) nitrates

  B) ammonium

  C) magnesium

  D) proteins

  E) chlorophyll

  F) weak

  G) yellow

  H) yellowing

  I) veins