Plant Cells

1. Plant Cells

2. Organism Organs Tissue Systems Tissues Cells Organelles The Body’s OrganizationEach level represents a different compartment

3. What is a Cell?

4. What is a Cell? • The smallest unit that conforms to the definition of life • Reproduction • Response to stimuli • Metabolism • Movement • Complexity of Organization • Adaptation to the environment

5. Major Evolutionary Events in the Origin of Life Multicellular Organisms 700-500 mya Eukaryotic Cells 1.7 bya First Cells Prokaryotes “the animation of matter” 3.5 bya Primordial Soup

6. Domains: Eubacteria Archaea Eukarya Kingdoms: Animal Fungi Plant Archaebacteria Protist Eubacteria Common ancestor Fig. 1.10

7. There are Two Groups of Cells • Bacterial Cells (Prokaryotic cells) • The first cell to have evolved • Relatively small and less complex than the… • Eukaryotic Cells • On average 100X larger than a bacterial cell • Contains organelles: internally more complex

8. The Bacterial Cell

9. Cyanobacteria The Cyanobacteria are capable of photosynthesis. It is believed that they are responsible for the first oxygen levels in the early atmosphere.

10. Cyanobacterium: Oscillatoria sp.

11. Anatomy of a Eukaryotic Plant Cell

12. Cell wall Cell membrane Cytoplasm Cytoskeleton Nucleus chromosomes Mitochondria Plastids Chloroplast Amyloplast Chromoplast Vacuole Organelles of the cell

13. Cell Walls • Made of carbohydrates (cellulose) • Protection and structure • All cells, except animal cells, have cell walls

14. The Cell Wall • Cell walls are: • Structural • Provide defense against invading pathogens • Provide pathways for communications between cells • Structural components: • cellulose • hemicellulose (glue that holds cellulose fibers together) • pectin (stiffens fruit jellies) • Proteins

16. Cell wall organization • Growing plant cells produce a primary cell wall, which stretches as the cell grows • A secondary cell wall may then be produced, inside the primary wall • Strong, thick • Secondary cell walls set limits to cell growth • Middle Lamella is the area between adjacent plant cells and is made of pectin

17. The cell membrane

18. The cell membrane • Semi-fluid cell boundary (thick oil) • controls passage in/out of cell • Made of 2 lipid layers with proteins on its surface and embedded within the layers

19. Cytoplasm • A rich “soup” of carbohydrates, proteins, fats and nucleic acids • Sometimes referred to as protoplasm • Watery or gelatin-like substance in which all organelles are suspended

20. “Control center” • Genetic information stored as chromosomes • The Genome: all the genetic material in a cell • Nuclear Pores allow passage between the nucleus and the cytoplasm Nucleus

21. Plant Chromosomes

22. The CYTOSKELETON • Extensive network of protein fibers • Functions in • internal support • provides internal structure to the cell • transport of organelles and protein vesicles • cell motility • cilia • flagella

23. View of Cytoskeleton • Network of protein fibers • Provides structure and shape to the cell • Movement of the cell • Internal movement of organelles and other molecules

24. Flagella

25. ATP= energy The MightyMitochondrion! Powerhouse of the Cell

26. Mitochondria • “powerhouse of the cell” • ATP production • Cell “breathing” is called cellular respiration • The mitochondrion has its own Genome Cellular respiration: converts sugars to energy (ATP)

27. Plastids • Contain pigments or storage products • Chloroplasts • Chromoplasts • Amyloplasts Cells of a red pepper

28. Chloroplast • Vary in size and shape • Thylakoids • where photosynthesis takes place • Stroma • Calvin cycle • sugar synthesis • The chloroplast has its own genome Photosynthesis converts light energy to chemical energy (sugars)

29. Chloroplasts of Elodeaand Spyrogyra

30. Amyloplasts store Starch

31. Vacuoles • stores water, ions, and nutrients • receptacles for waste products • regulates turgor pressure through osmosis

32. The Central Vacuole of Plant Cells

33. Domains: Eubacteria Archaea Eukarya Kingdoms: Animal Fungi Plant Archaebacteria Protist Eubacteria Common ancestor

34. The Algae • Many Algae live life as a single cell, but some are • Multicellular like the seaweeds • Members of Kingdom Protista • Primary producers of aquatic ecosystems

35. Spirogyra • Watersilk • Float in masses at the surface of quiet waters • Contain ribbon-shaped chloroplasts • Each chloroplast contains a pyrenoid • Pyrenoids contain enzymes for starch synthesis

36. Euglena • They live in fresh water streams and ponds, and are especially common in warm seasons when they may form a green scum on the surfaces of small ponds or drainage ditches. • Euglenas have spindle-shaped bodies, and range in size from 1/1000 to 1/100 of an inch (0.025 to 0.254 millimeter) long.

37. Volvox • Volvox is a colonial algae • It is a complete hollow ball of cells. • Note the smaller daughter colonies that are beginning to form within the parent body. • Each cell has 2 flagella which helps the entire colony swim.

38. Diatoms • Best known and economically most important algae • Cold and warm waters • Fresh and marine • Damp cliffs, sides of buildings, bark of trees, bare soil • The cell resides inside a glass box

39. Diatoms What often looks like an oil slick is a bio-film of diatoms

40. Diatoms: Melosera

41. Plant Tissues

42. Examples of the Different Types of Plant Cells • Parenchyma • Collenchyma • Sclerenchyma • fibers and sclerids • Vessels • Tracheids • Sieve tube members • Companion cells • Egg (ovum) • Sperm

43. The Parenchyma Cell • The generic plant cell • Most abundant and versatile • Function: • storage • flesh of fruit • storage in roots and seeds • basic metabolism • They can change and become other cells (differentiation) • Alive at maturity • Primary cell wall

44. The Collenchyma Cell • “glue” cells • Flexible support • Found in growing shoots, stems, & leaves • Differentiate from parenchyma cells • Alive at maturity • Primary and secondary cell walls • Ex: resilient strings found in celery

45. Thickened corner of cell wall Nucleus Cytoplasm Vacuole (b)

46. Rigid cells Function: support and strengthen non extending regions of a plant like mature stems Thick, non stretchable secondary cell walls Dead at maturity Two Types: Fibers long, slender, occur in strands Cotton Hemp Flax (Linen) Sclerids short, varying shape, occur in groups Gristle in pears Sclerenchyma

47. Plants Eggs and Sperm

48. CellsTissues • Like animal cells, plant cells are organized into tissues • Tissues are groups of cells that form a structural and functional unit • Simple tissues have one cell type • Complex tissues have two or more cell types

49. Tissues Tissue System • Tissues are organized into tissue systems • Vascular plants have three tissue systems • Ground tissue • Energy transformation, storage and support • Vascular tissue • Water and nutrient conduction system • Dermal tissue • Covering for the plant body

50. P r i m a r y M e r i s t e m T i s s u e S y s t e m T i s s u e s C e l l s e p i d e r m i s d e r m a l p a r e n c h y m a p e r i d e r m p r o t o d e r m v e s s e l s t r a c h e i d s p a r e n c h y m a x y l e m f i b e r s A p i c a l M e r i s t e m v a s c u l a r p r o c a m b i u m s i e v e t u b e m e m b e r s p h l o e m c o m p a n i o n c e l l s p a r e n c h y m a f i b e r s g r o u n d m e r i s t e m p a r e n c h y m a p a r e n c h y m a g r o u n d c o l l e n c h y m a c o l l e n c h y m a s c l e r e n c h y m a s c l e r e i d s C e l l D i f f e r e n t i a t i o n i n P l a n t s f i b e r s