6.1 Why we need plants

• What is the importance of photosynthesis to plants and life on earth?

  Plants use the process of photosynthesis to transform water, sunlight, and carbon dioxide into oxygen, and simple sugars that the plant uses as fuel. Without photosynthesis life on earth would not be possible.
• What are the functions of these leaf parts:

  Palisade cells: have most chloroplasts and absorb most of the light energy plants need for photosynthesis.

  Stoma: lets gas molecules in and out

  Guard cells: surround the stomata and make them open and close

  Epidermis: are transparent to let light through and covered in a waxy layer to make the leaf waterproof.

  Mesophyll: are surrounded by air spaces which let gases diffuse through the leaf.
• How do plants store excess glucose produced by photosynthesis?

  If plants want to keep glucose they need to convert it into something insoluble like starch.

  Starch is a macromolecule because it is made up of 100’s of glucose all joined together.
• What is Biomass?

  Biomass is renewable organic material that comes from plants and animals.
• Photosynthesis equation:

  carbon dioxide + water = glucose + oxygen
• Where does photosynthesis takes place?

  Photosynthesis takes place in the tall thin palisade cells. They have chloroplasts to absorb light energy.
• Respiration equation:

  glucose + oxygen = carbon dioxide + water
• Conversion of light to chemical energy?

  This is called photosynthesis.
• What are the raw materials for photosynthesis?

  carbon dioxide, water, and sunlight.
• Basic function of cells in a leaf

  Palisade cells: most photosynthesis takes place here. They have chloroplasts to absorb light energy.

  Xylem vessels: transport water and minerals from their roots to the leaf.

  Stomata: diffuses carbon dioxide into the leaf

  Mesophyll layer: makes it easy for gases to circulate
• What is starch?

  Starch is a macro molecule made up off glucose. It is made when soluble glucose molecules can't be stored in cells, so they join together to make starch.
• Why is pond weed used to show oxygen production.

  Pond weed is put in water, and during photosynthesis while it is releasing oxygen it forms bubbles in the water. This is useful when you want to measure oxygen production.
• How iodine is used to show starch presence in leaves

  If starch is present the iodine will turn black, If its not it will stay orange/brown