Plant cell structure and organelles

• 1. Plasmodesma
  2. Cell Sap
  3. Tonoplast
  4. Vacuole
  5. Cell surface membrane
  6. Smooth endoplasmic reticulum
  7. Nuclear pore
  8. Nucleolus
  9. Chromatin
  10. Nuclear envelope
  11. Nucleus

  
• 12. rough endoplasmic reticulum

  13. Microtubule

  14. Ribosome

  15. grana

  16. Envelope

  17. Mitochondrion

  18. Cytoplasm

  19. Golgi vesicle

  20. Golgi body

  21. Chloroplast

  22. Middle lamella

  
• Plant cells are eukaryotes
• A vacuole is a fluid filled space inside the cytoplasm which is surrounded by a membrane. In non-woody plants, the vacuole is a permanent structure, and can occupy up to 80% of the volume of the plant cell. It is surrounded by a specialised membrane called the tonoplast.
• The tonoplast contains many specialised protein channels and carrier systems. It controls the movement of different substances into and out of the vacuole and controls the water potential of the cell
• The vacuole is filled with cell sap, a solution of various substances in the cell. This solution causss water to move into the cell by osmosis, ans this means the cytoplasm is kept pressed against the cell wall. This means the cell is kept turgid and the whole plant stays upright.
• Vacuoles are used to store several different substances. Many vacuole store pigment. If the tissue is heated, the characteristics of the membrane around the vacuole will change and pigment will leak out.
• Vacuoles can store proteins in the cells of seeds and fruits, and in some plant cells, they contain lytic enzymes that are similar to lysosomes in plant cells. Vacuoles often store waste products and other chemicals
• Not all plants contain chloroplasts - only cells from the green parts of the plant. However all plant cells contain genetic information to make chloroplasts
• Chloroplasts are the site of photosynthesis and enable plants to make their own food
• Chloroplasts and mitochondria have a lot of similarities:

  • are large organelles - biconvex shape
  • contain their own DNA
  • are surrounded by an outer membrane
  • have an enormously folded membrane - increased surface area where enzyme-controlled reactions take place
  • are thought to have been free-living prokaryotic organisms that were engulfed by and became part of other cells
• Differences between mitochondria and chloroplasts:

  • chloroplasts are the site of photosynthesis
  • chloroplasts contain chlorophyll, the green pigment that is largely responsible for trapping light
• Amyloplasts are another specialised organelle. They are colourless and they store starch. The starch can be converted to glucose and used to provide energy when the cell needs it
• 1. Outer membrane
  2. inner membrane
  3. Ribosomes
  4. starch grain
  5. Granum
  6. Grana
  7. Thylakoid
  8. stroma