plant structure + processes

• name the parts of a leaf

  A) blades

  B) midrib

  C) stalks (petioles)

  D) nodes

  
• name the parts of a cross section of a leaf

  A) guard cells

  B) palisade mesophyll layer

  C) spongy mesophyll

  D) upper epidermis

  E) waxy cuticle

  F) lower epidermis

  
• palisade mesophyll cells are specialised cells that contain chloroplasts and absorb sunlight
• stomata are found on the underside of the leaf and control what goes in and out of the leaf such as gases or transpiring water vapour. They consist of two guard cells.
• the spongy mesophyll layer in leaves control gas exchange
• vascular bundles are tube-like structures that transport substance around the plant. They contain the xylem and phloem
• Nitrogen and magnesium are major components of chlorophyll thus a defficiency of either would cause a shortage of chlorophyll. This would result in the plant not being able to perform photosynthesis properly as it cannot absorb enough sunlight.

  
• A nitrogen defficiency will cause the plant to turn yellow. A magnesium deficiency produces yellow areas between the veins of a plant.
• Plants have to types of vascular tissue: the xylem and phloem. The xylem transports water and mineral ions from the roots to the leaves. The phloem transports sugars and amino acids from the leaves to the rest of the plant. The xylem is made of dead plant cells and the phloem of alive cells.
• Cohesion is the intermolecular forces of attraction between water molecules

  A) osmosis
• Adhesion is the force of attraction between water molecules and the xylem walls
• What are the steps of Transpiration?

  1. water evaporates out of the stomata and into the atmosphere
  2. The water molecules pull water up the xylem because of this
  3. This then in turn pulls water up from the roots from the soil
  4. The water is then pulled up the xylem to the leaves and the process repeats
• translocation is the movement of products from the area of the plant they are produced or stored to other tissues in the plant. Nutrients are translocated from sources (regions of excess carbohydrates e.g mature leaves) to sinks (regions where the carbohydrate is needed)

  
  

  Examples of sinks are roots, flowers, fruits, stems, and developing leaves.
• name the process that happen at each step of transpiration

  A) evaporation

  B) diffusion

  C) transpiration pull

  D) osmosis