Resources from plants

• Describe the structure of a plant cell wall

  A rigid structure which is made of cellulose.
• what is the function of the cellulose cell wall? 


  provides structural support to the cell to maintain regular shape and rigidity of the cell
• describe the structure and function of the middle lamella 


  the outermost layer of the cell. It is made up of calcium pectate and acts as an adhesive to stick adjacent plant cells together. this provides stability.
• describe the structure and function of plasmodesmata 


  -narrow threads of cytoplasm which runs through neighboring cells, forming a continuous passage

  • they allow for transport of substances and communication between cells
• describe the structure and function of pits 


  pits are thin regions of the cell walls arranged in pairs. The pit in one cell wall aligns with the pit in the cell wall of the adjacent cell.

  they allow for the transport of substances between cells over a short distance.
• Describe the structure of a chloroplast

  1. Double membrane

  2. Contains membrane-bound compartments called thylakoid which are involved in photosynthesis. They contain chlorophyll to absorb light

  3. Thylakoids are stacked in structures called granum. granum are connected by lamellae

  4. Chloroplasts contain circular DNa

  
• what is the function of chloroplast

  They are the site of photosynthesis
• describe the structure and function of amyloplast 


  Amyloplast are membrane bound organelles which contain starch granules.

  They are involved in converting excess glucose into strach for storage. They have the Ability to convert starch into glucose for release
• Describe the structure of the vacuole 


  A large, permanent sac surrounded by a selectively permeable membrane called the tonoplast
• what does the vacuole contain 


  cell sap, which contains a mixture of water, enzymes, minerals and waste products.
• what is the function of the vacuole 


  1- maintain cell turgidity due to osmotic regulation by a precise balance of ions in the cell sap.

  2- isolate and break down toxic chemicals/ cell waste
• what is the function of the tonoplast 


  a selectively permeable membrane which maintains osmotic balance by regulating the movement of substances in and out of the vacuole
• what is the function of starch in plants 


  a polysaccharide which are involved in energy/ glucose storage in plants
• what are the two types of starch?


  Amylose and amylopectin
• describe the structure of amylose and why it is a good storage molecule 


  a long unbranched chain of alpha glucose containing 1,4 glycosidic bonds, with a coiled structure held together by hydrogen cross links. amylose is coiled in a helical structure, making it compact, so more can fit in a small space.
• how is amylopectin suitable for energy storage

  - a polymer of alpha glucose which is used to release energy

  • 1,4 and 1,6 glycosidic bonding allows for a branched structure. this allows for many terminals for the rapid hydrolysis of glycosidic bonds, allowing for rapid release.
  • insoluble, preventing osmotic effect on the cell.