2. CHAPTER 2 cells P. 38 - 44

3. EARLY DISCOVERIES Anton Van Leeuwenhoek - made microscopes. - made microscopes. - saw “critters” in a drop of water never seen before.

4. Robert Hooke - first to see cells in slices of cork - ‘named’ cells. Led to others studying cells.

5. Matthias Schleiden - studied every part of plants. - concluded all plant parts were made of cells. Theodor Schwann - studied animals. - concluded that all animals were made of cells.

6. Rudolph Virchow - new cells come from other living cells. These scientists’ work led to the Cell Theory.

7. Cell theory 1. All organisms are made of cells. 2. Cells are the basic unit of structure and function in all organisms. 3. All cells come from other cells. Read p. 38 - middle p. 42.

8. STRUCTURE OF CELLS (p. 38) Scientists discovered there were parts inside the cell.

9. A) Cell Membrane Like the protective skin of the cell Like the protective skin of the cell - the outer covering. - controls what goes in and out. Food, water, oxygen enter - Wastes leave. Food, water, oxygen enter - Wastes leave. Selectively permeable: controls what enters and leaves Selectively permeable: controls what enters and leaves

10. CELL MEMBRANE

11. B) Nucleus - the ‘control center’. B1) nuclear membrane -controls what goes in and out of the nucleus.

13. Contains chromosomes: - structures that hold hereditary material to determines what you look like. - made of DNA.

14. C) Cytoplasm Found inside the cell membrane outside the nucleus. Found inside the cell membrane outside the nucleus. Gel - like substance: mostly water. Gel - like substance: mostly water. Contains small structures called organelles Contains small structures called organelles -all have a “job” inside the cell.

15. CYTOPLASM

16. Cell Organelles Cells work 24 hours a day, 7 days a week Cells work 24 hours a day, 7 days a week Cell Organelle: working parts of the cell. Cell Organelle: working parts of the cell.

17. Cell Organelles 1. Mitochondria Powerhouse of cell Powerhouse of cell Food broken down and energy is released. Food broken down and energy is released. Which cells might have lots of mitochondria? Which cells might have lots of mitochondria?

19. 2. Endoplasmic Reticulum (E.R.) Folded membrane Folded membrane Like conveyer belts in the factory. Like conveyer belts in the factory. (or a highway) Transports materials throughout the cell. Transports materials throughout the cell.

21. 3. Ribosomes Most numerous organelle in the cell Most numerous organelle in the cell Some attached to E.R. Some attached to E.R. Produces protein (food) for the cell Produces protein (food) for the cell - releases energy from food. Which cells might have the most ribosomes? Which cells might have the most ribosomes?

23. 4. Lysosomes - contains chemicals (enzymes) to digest wastes and ‘worn out’ parts of the cell. - called ‘suicide sacs’ - break open and digest the cell when it dies.

25. 5. Vacuole Storage sacs Storage sacs Hold food, water, and wastes Hold food, water, and wastes Larger in plant cells Larger in plant cells

27. 6. Golgi Bodies -packages and secretes substances to the outer parts of the cell -packages and secretes substances to the outer parts of the cell

28. ASSIGNMENT: WORKSHEET “CELL STRUCTURE”. COLORED PENCILS NEEDED TOMORROW!

29. PLANT CELLS - have two different parts than animal cells. 1. Cell Wall - found outside the cell membrane. - found outside the cell membrane. - for support and protection. - non-living

30. 2. Chloroplasts - where photosynthesis takes place (turns sunlight into food). - contains chlorophyll. (green)

32. Two basic types of cells  Prokaryotic cells - oldest on Earth - oldest on Earth - no membranes around internal - no membranes around internal structures - (no nucleus) structures - (no nucleus)

33. - very small - simplest type of cell ex. Bacteria ‘pond scum’

34. 2) Eukaryotic cells - organelles surrounded by a membrane. - has a nucleus

35. - most complex type of cell - all plants and animals … - all plants and animals … - much larger than prokaryotic cells