Plant Cells

1. Plant Cells

2. FLASHBACK Are plants eukaryotic or prokaryotic? What does eukaryotic mean?

3. Parts of a Plant Cell cell wall cell membrane Golgi vesicles Golgi apparatus ribosome chloroplast smooth ER nucleolus vacuole membrane nucleus rough ER raphide crystal druse crystal Large central vacuole mitochondrion amyloplast cytoplasm

4. Cell Wall • Surrounds the plasma membrane • 3 layers • Middle Lamella • Primary Wall • Secondary Wall

5. Middle Lamella • 1st layer formed • Outer wall of the cell • Shared by adjacent cells and cements them together

6. Primary Cell Wall • INDSIDE middle lamella • Rigid skeleton of cellulose microfibrils in a gel-like matrix of pectic and cellulose compounds. • Contains everything that is located between plasma membrane and the cuticle

7. Primary Cell Wall Functions • Structural & mechanical support • Maintain cell shape • Resist turgor pressure • Control rate and direction of growth • Carbohydrate storage • Cell-cell interactions

8. Secondary Wall • Formed after cell enlargement is completed. • Extremely rigid • Contains lignin- brown phenolic polymer • Present in trees and shrubs

9. Plasmodesmata • Small passages that penetrate all layers of the cell wall • Pathways for transporting cytoplasmic molecules

10. Plasma (cell) Membrane • Phospholipid bilayer • Sandwich model- phospholipid layers sandwiched between protein layers • Embedded glycoproteins • Water permeable • Not permeable to molecules and ions by simple diffusion • Gatekeeper for the cell.

11. Golgi Apparatus • Stack of flattened membrane-bound sacs • Storage, modification, and secretion of proteins and lipids • Lipids and proteins can be used within the cell or destined to leave the cell

12. Calcium Oxalate Crystals • Located in the central vacuole • Potentially toxic • Raphide crystals-pointy and needle like • Druse crystals-faceted

13. Mitochondrion • Membrane-bound organelle • “power house” of the cell • Respiration takes place here.

14. Golgi vesicle • Membrane bound • Buds from Golgi apparatus • Contain proteins • Fuse with membrane and discharge contents in a process called exocytosis

15. Ribosome • Site of protein synthesis • Composed of small sub unit, large sub unit, and central groove.

16. ER • Smooth ER • Membrane bound system of folded sacs • Provides a membrane surface where a variety of complex carbohydrates and lipids, including phospholipids are synthesized • Detoxifies toxic substances • Rough ER • Attached ribosomes

17. Nucleolus • Where rna is synthesized

18. Nucleus • Membrane bound • Where chromatin is stored

19. Large Central Vacuole • Large membrane bound sac • Stores water, salts, pigments, and potentially toxic molecules. • Helps maintain rigidity

20. Others • Amyloplast- a membrane-bound organelle made of layers of starch • Lysosome- membrane-bound organelle containing hydrolytic (digestive) enzymes • Peroxisome- a membrane-bound organelle that contains specific enzymes imported from cytosol (e.g. catalase)

21. Chloroplast Intro • Membrane bound organelle • Site of photosynthesis

22. GROUPS OF FOUR Take 15 CELL CITY

23. Endosymbiont Theory • Chloroplasts and mitochondria house their own DNA. • It is possible to track lineage through chloroplasts and mitochondria. • Chloroplasts and mitochondria have their own phospholipid membrane.

24. Endosymbiont Theory • Scientists believe that plant and animal cells acquired chloroplasts and mitochondria through the process of symbiogenesis • Symbiogenesis is acquiring cells or dna from other organisms. • In other words: