Chapter 3 Power Point

1. Chapter 3 Power Point Mrs. Wetzel Biology

2. Cell Theory • Early Discoveries: • Almost all cells are too small to be seen with the naked eye. • Prior to the discovery of the Microscope cells were unheard of. • The Dutch Eyeglass maker Zacharias Janssen and his father Hans. Get credit for making the first known Microscope.

3. Scientists who contributed to the Cell Theory • Robert Hooke (1665) Used a three lens microscope to examine thin slices of cork. He observed that cork is make of tiny hollow compartments. The compartments reminded Hooke of the rooms at the Monastery, so he gave them the same name, cells.

4. Cork Cells • What part of the cells was Robert Hooke seeing when he examined the cork?

5. Scientists who contributed to the Cell Theory • Anton Van Leeuwenhoek (1674)- Was studying new methods for using lenses to examine cloth. As a result of his studies he made a much more powerful microscope than Hooke had been using. • Leeuwenhoek was one of the first people the describe Living cells when he observed a drop of pond water. • He called these Organisms “Animalcules”

6. Scientists who contributed to the Cell Theory • Building On Hooke & Leeuwenhoek’s discoveries three more scientists added to the Cell Theory • Matthias Schleidon (1838) was the first to note that plants are made of cells • Theodore Schwann (1839) Concluded that ALL living things are made from cells • Rudolph Virchow (1855) proposed that cells only come from other living cells

7. Cell Theory • * All living things are made of cells • *All cells come from other living cells • *The cell is the most basic unit of life. There is nothing living that is smaller than a cell

8. Cell Theory • * All living things are made of cells • *All cells come from other living cells • *The cell is the most basic unit of life. There is nothing living that is smaller than a cell

9. Two types of Cells • Cells come in many different shapes and carry out many different jobs. However they all share some features. • 1. Cells are all SMALL • 2. Cells all have a membrane of some sort to keep materials in or out • 3. Cells have cytoplasm on the inside • 4. Cells have genetic material

10. Two types of Cells; Prokaryotic & Eukaryotic • Prokaryotic: • Prokaryotic Cells are VERY small. • Their DNA floats in the cytoplasm • They have no Nucleus • They have no distinct Membrane Bound Organelles

11. Two types of Cells • Eukaryotic: • Are larger than ProkaryoticCells • They have a nucleus • DNA (genetic material) Lives in the Nucleus • They have Membrane bound Organelles • Some are unicellular, some are multicellular

12. Two types of Cells

13. Two types of Cells

14. Two types of Cells

15. Relevancy Check • What Kingdoms have Eukaryotic Cells, Which ones have Prokaryotic? • Prokaryotic Eukaryotic

16. Cell Structures • Cytoskeleton: Your Skeleton is made of bones that help keep all of your body parts in place. • Eukaryotic Cells have a skeleton too. • The CYTOSKELETON is the framework for the cell

17. Cytoskeleton • Three Parts of the cytoskeleton are: • Microtubules-Movement • Microfilaments-Cell Division & movement • Intermediate filaments- Cell strength

18. Cell Structures • Nucleus: • Stores and Protects the DNA of the Cell • DNA contains genetic material and instructions for making proteins • It is often called the brain of the cell

19. Cell Structures • Endoplasmic Reticulum: • A network of folded membranes that helps in the production of proteins. • Looks like a maze

20. Cell Structures • Ribosomes: • Tiny organelles that link amino acids together to form proteins. • They are found on the ER, or floating in the cytoplasm

21. Ribosomes

22. Golgi Apparatus: Packages proteins for transport within the cell, or to destinations outside of the cell

23. Cell Structures • Vesicles: Are small sacs that carry different molecules to where they are needed.

24. Cell Structures • Mitochondrion: • Supplies Energy for the cell • Bean shaped • Inner Membranes with many folds and compartments • Converts food you eat into usable energy

25. Cell Structures • Vacuole: • A fluid Filled sac used for the storage of materials needed by the cell • Water, nutrients, etc. • ANIMAL CELLS- Small vacuoles • PLANT CELLS- LARGE Vacuole

26. Cell Structures • Lysosome: • Organelles that contain enzymes • Protect a cell by attacking incoming bacteria and viruses • Breaks down old cell parts

27. Cell Structures • Centriole: • Shaped like tiny tubes in a circle • Help animal cells divide

28. Plant Cells Vs. Animal Cells Plant Cell Animal Cell Cell Wall Large Vacuole Chloroplasts Centrioles Lysosomes

29. Plant Cells Vs. Animal Cells Plant Cell Animal Cell

30. Plant Cells Vs. Animal Cells Plant Cell Wall Animal Cell Membrane Cell Wall; Strong, rigid, layer that protects, supports, and shapes the cell. Some cell walls are very thick Cell Membrane; a thin layer that separates the inside of the cell from the outside. It is selectively permeable.

31. Cell Wall vs. Cell Membrane Cell Wall Cell Membrane

32. Cell Membrane • PhospholipidBilayer- • Provides a selectively permeable protective covering for cells • Allows some materials to pass through, some can not • The cell membrane is referred to as a fluid mosaic model because the phospholipids are not rigid, they can move and slide

33. Cell Membrane • Phospholipid • Charged Phosphate group • Glycerol • 2 Fatty acid chains

34. Cell Membrane • A variety of Molecules are embedded among the phospholipids. • Cholesterol: Molecules strengthen the cell membrane • Proteins: Channels that extend through the membrane helping materials to cross over • Carbohydrates: act as identification. Allowing the cell to communicate with each other

35. Selective Permeability • A selectively permeable membrane allows some, but not all molecules to cross.

36. Relevancy Check: • What can you think of that has a selectively permeable membrane?

37. #14 • A ________________ detects a signal molecule and carries out an action in response?

38. #14 • A ________________ detects a signal molecule and carries out an action in response? • Answer: Receptor

39. #15 • A ________________ is a molecule that acts as a signal when it binds to a receptor.

40. #15 • A ________________ is a molecule that acts as a signal when it binds to a receptor. • Answer: Ligand

41. #16. • A ligand that can cross a cell membrane can bind to an _____________ receptor.

42. #16. • A ligand that can cross a cell membrane can bind to an _____________ receptor. • Answer: intracellular

43. #17. • A ligand that can not cross a cell membrane can send a message to a cell by binding to a _______________receptor which then _____________shape.

44. #17. • A ligand that can not cross a cell membrane can send a message to a cell by binding to a _______________receptor which then _____________shape. • Answer: Membrane, Changes

45. Concentration Gradient • Concentration is the amount molecules of one type in an area. • Few Molecules= Low concentration • Lots of Molecules= High concentration. • Concentration of molecules can vary from one area to another. • A Concentration Gradient is the difference in the concentration of a substance from one location to another.

46. Relevancy Check • What in your daily life reminds you of a concentration gradient?

47. Movement across the Cell Membrane • Ways molecules can move across the cell membrane (enter or leave a cell) • 1. Passive Transport • A. Diffusion: The movement of molecules from an area of High concentration to an area of Low concentration (no energy needed) • B. Osmosis: The movement of WATER molecules from an area of high concentration to low concentration • C. Facilitated diffusion: gets help from protein channels embedded in cell membrane

48. Movement across the Cell Membrane • Ways molecules can move across the cell membrane (enter or leave a cell) • 1. Active Transport: Requires energy from the cell. Molecules move across the concentration gradient. From an area of low concentration to High concentration. • A. Endocytosis- takes in large molecules of • Phagocytosis is a type of endocytosis that “Eats” large molecules B. Exocytosis – opposite of endocytosis- large molecules exit the cell

49. Facilitated Diffusion vs. Simple Diffusion • Facilitated diffusion relies on Protein Channels to transfer larger ions across the cell membrane. It requires no energy from the cell because the molecule go from an area of high concentration to an area of low concentration.

50. Osmosis • Osmosis The movement of water across a semi permeable membrane. Osmosis is the movement of water (red dots) through a semipermeable membrane to a higher concentration of solutes (blue dots).