Cell Structure & Function

1. Cell Structure & Function

2. Basic Structure of a Cell

3. Anton van Leeuwenhoek • In 1674, Leeuwenhoek (a Dutch microscope maker), was first to view organism (living things) • Leeuwenhoek used a simple, handheld microscope to view pond water & scrapings from his teeth

4. First to View Cells • In 1665, Robert Hooke used a microscope to examine a thin slice of cork (dead plant cells) • What he saw looked like small boxes

5. First to View Cells • Hooke is responsible for naming cells • Hooke called them “CELLS” because they looked like the small rooms that monks lived in called Cells

6. History of Cells & the Cell Theory Cell Specialization Virchow

7. Introduction to Cells Cells are the basic units of organisms Basic types of cells: Bacterial Cell Animal Cell Plant Cell

8. Number of Cells • Organisms may be: • Unicellular – composed of one cell • Multicellular- composed of many cells that may organize

9. Cells May be Prokaryotic or Eukaryotic • Prokaryotes include bacteria & lack a nucleus or membrane-bound structures called organelles • Eukaryotes include most other cells & have a nucleus and membrane-bound organelles (plants, fungi, & animals)

10. Prokaryotes • Nucleoid region contains the DNA • Cell membrane & cell wall • Contain ribosomes (no membrane) to make proteinsin their cytoplasm

11. Contain 3 basic cell structures: Nucleus Cell Membrane Cytoplasm with organelles Eukaryotic Cell

12. Two Main Types of Eukaryotic Cells Animal Cell Plant Cell

13. Organelles Very small size Can only be observed under a microscope Have specific functions Found throughout cytoplasm

14. Golgi Bodies • Stacks of flattened sacs • Have a shipping side & a receiving side • Receive & modify proteins made by ER • Transport vesicles with modified proteins pinch off the ends Transport vesicle

15. Lysosome • Contain digestive enzymes • Break down food and worn out cell parts for cells • Programmed for cell death (lyse & release enzymes to break down & recycle cell parts)

16. Nucleolus • Cell may have 1 to 3 nucleoli • Inside nucleus • Disappears when cell divides • Makes ribosomes that make proteins

17. Smooth & Rough Endoplasmic Reticulum Smooth ER lacks ribosomes & makes proteins USED In the cell Rough ER has ribosomes on its surface & makes proteins to EXPORT

18. Mitochondrion( mitochondria ) Cell Powerhouse • Rod shape • Site of Cellular respiration

19. In Animal Cells: Mitochondria • Active cells like muscles have more mitochondria • Burn sugars to produce energy ATP

20. Cell membrane Surrounding the Cell • Lies immediately against the cell wall in plant cells • Made of protein and phospholipids • Selectively permeable

21. Cell or Plasma Membrane Cell membrane • Living layer • Controls the movement of materials into and out of the cell • Selectively permeable

22. Cell Wall Cell wall • Nonliving layer • Gives structure and shape to plant and bacterial cells

23. Cytoplasm Cytoplasm of a Cell • Jelly-like substance enclosed by cell membrane • Provides a medium for chemical reactions to take place

24. More on Cytoplasm Cytoplasm • Contains organelles to carry out specific jobs • Examples: chloroplast & mitochondrion

25. Nucleus Control Organelle • Controls the normal activities of the cell • Contain the DNA • Bounded by a nuclear membrane • Contains chromosomes

26. More on the Nucleus Nucleus • Each cell has fixed number of chromosomes that carry genes • Genes control cell characteristics

27. Chloroplast Plant Cell Organelles • Contain the green pigment chlorophyll • Traps sunlight to make to make sugars (food) • Process called photosynthesis

28. Plant Cell Cell wall • Dead layer • Large empty spaces present between cellulose fibers • Freely permeable

29. Cell wall Plant Cell Made of cellulose which forms very thin fibers Strong and rigid Found in plant cells

30. Plant Cell Cell wall • Protect and support the enclosed substances (protoplasm) • Resist entry of excess water into the cell • Give shape to the cell

31. Vacuole Plant Cell Organelles • Have a large central vacuole • Surrounded by tonoplast • Contains cell sap • Sugars, proteins, minerals, wastes, & pigments

32. Onion Epidermal Cells Guard Cells root hair Root Hair Cell Different kinds of plant cells

33. Animal cell vacuole cytoplasm No cell wall or chloroplast Stores glycogen in the cytoplasm for food energy nucleus mitochondrion cell membrane glycogen granule

34. Near the nucleus Paired structures Help cell divide Animal Cell Organelles

35. white blood cell Amoeba red blood cell muscle cell sperm cheek cells nerve cell Paramecium Different kinds of animal cells

36. Similarities between plant cells and animal cells Both have a cell membrane surrounding the cytoplasm Both have a nucleus Both contain mitochondria

37. Differences between plant cells and animal cells Animal cells Plant cells Relatively smaller in size Relatively larger in size Irregular shape Regular shape No cell wall Cell wall present

38. Differences between Plant Cells and Animal Cells Animal cells Plant cells Vacuole small or absent Large central vacuole Glycogen as food storage Starch as food storage Nucleus at the center Nucleus near cell wall