1. Chapter 3: Cell Structure & Function 1

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3. First to View Cells 1665: Robert Hooke used a microscope to examine a thin slice of cork (dead plant cell walls) What he saw looked like small boxes 3

4. 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 4

5. Anton van Leeuwenhoek 1673: Leeuwenhoek was first to view organisms He used a simple, handheld microscope to view pond water & scrapings from his teeth 5

6. Beginning of the Cell Theory 1838: Matthias Schleiden concluded that all plants were made of cells Schleiden is a cofounder of the cell theory 6

7. Beginning of the Cell Theory 1839: Theodore Schwann concluded that all animals were made of cells Schwann also cofounded the cell theory 7

8. Beginning of the Cell Theory 1855: Rudolph Virchow observed, under the microscope, cells dividing He concluded that all cells come from other pre- existing cells by cell division 8

9. THE CELL THEORY 1.All living things are made of cells 2.Cells are the basic unit of life 3.Cells come from the multiplication of existing cells (cell division) 9

10. Simple and Complex Cells: Prokaryotic vs. Eukaryotic 10

11. Prokaryotes Nucleoid region (center) contains the DNA Surrounded by cell membrane & cell wall (peptidoglycan) Contain ribosomes (no membrane) in their cytoplasm to make proteins 11

12. ENDOSYMBIOTIC THEORY 1970: Lynn Margulis, provided evidence that some organelles within cells were at one time free living cells themselves Supporting evidence included that some organelles have their own DNA – Chloroplast and Mitochondria 12

13. Eukaryotes Cells that HAVE a nucleus and membrane-bound organelles Includes fungi, plants, and animals More complex type of cells 13

14. Two Main Types of Eukaryotic Cells 14 Plant Cell Animal Cell

15. CELL TYPE RECAP Prokaryotic: means “before” nucleus – Example: bacterial cells Eukaryotic: means “true” nucleus – Example: plant/animal/fungal cells 15 Organelles: The “Organs” of a Eukaryotic Cell Think of organelles as “little organs”

16. Cell Membrane Composed of a double layer of phospholipids (lipid bilayer) and proteins Surrounds outside of ALL cells Controls what enters or leaves the cell 16 Outside of cell Inside of cell (cytoplasm) Cell membrane Proteins Protein channel Lipid bilayer Carbohydrate chains

17. Phospholipids “Heads” are hydrophilic (attract water) “Tails” are hydrophobic (dislike water) Make up the lipid bilayer where tails point inward toward each other Can move to allow small molecules (O 2, CO 2, & H 2 O) to enter 17

18. Cell Membrane in Plants 18 Lies right inside the cell wall in plant cells Pushes out against to help the cell maintain shape Cell membrane

19. Cytoplasm of a Cell 19 Jelly-like that fills the inside of the cell Provides a place for chemical reactions to occur cytoplasm

20. Cytoskeleton Helps cell maintain cell shape Allows some organelles to move around within the cell Made of proteins Microfilaments: thread-like & made up of Actin Microtubules: tube-like & made of Tubulin 20

21. Nucleus – “The Brain of the Cell” 21 Controls the normal activities of the cell Contains the chromosomes that hold DNA Usually the largest organelle.

22. Nuclear Membrane (Nuclear Envelope) Surrounds the outside of the nucleus Made up of 2 layers Contains nuclear pores, which allows transport of materials in and out Connected to the rough Endoplasmic Reticulum 22 Nuclear pores

23. Nucleolus (Plural: Nuceloi) Inside nucleus Inside nucleus Cell may have 1 to 3 nucleoli at once Cell may have 1 to 3 nucleoli at once Disappears when cell divides Disappears when cell divides Makes ribosomes Makes ribosomes 23

24. Mitochondria – “The Powerhouse of the Cell” Singular = “mitochondrion” Make cellular energy called ATP Cells that do more movement or activity have more mitochondria This is where CELLULAR RESPIRATION (breaking down of glucose) takes place Interior called the matrix – Folded inner membrane increases surface area for more chemical reactions 24

25. MITOCHONDRIAL DNA 25 Have their own type of DNA Inherited only from your mother; links back to first female ancestor Supports the endosymbiosis theory

26. Endoplasmic Reticulum - ER Network of hollow membrane tubules Connects to nuclear envelope & cell membrane Functions in Synthesis of cell products & Transport 26

27. Rough ER Called rough because it has ribosomes on its surface Makes membrane proteins and other proteins for EXPORT out of cell 27

28. Smooth ER Called smooth because it lacks ribosomes on its surface Attached to the ends of rough ER Makes cell products that are USED INSIDE the cell 28 Makes membrane lipids such as steroids Also helps regulate calcium in muscle cells and destroy toxins in liver cells.

29. Ribosomes – “The Factory of the Cell” Made of PROTEINS and rRNA Can be attached to the Rough ER or free- floating in the cytoplasm Carry out Protein Synthesis: Joins amino acids to make proteins 29 

30. Golgi Apparatus – “The Post Office of the Cell” Modifies, sorts, & packages molecules from ER Prepares materials for storage OR transport out of cell Transport vesicles with modified proteins pinch off the ends to move materials Transport vesicles with modified proteins pinch off the ends to move materials Look like a stack of pancakes 30 Transport vesicle

31. Lysosomes – “The Wrecking Ball of the Cell” Contain digestive enzymes Contain digestive enzymes Break down food, bacteria, and worn out cell parts Break down food, bacteria, and worn out cell parts Programmed for cell death Programmed for cell death Lyse, or break open, & release enzymes to break down cell parts Lyse, or break open, & release enzymes to break down cell parts 31

32. 32 Phagocytosis: Lysosome Digestion Cells take in food by phagocytosis Lysosomes digest the food & get rid of waste

33. Vacuoles – “The Storage Facility of the Cell” Storage of sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes In plants: usually one very large and permanent structure In animals: usually several small structures 33

34. Centrioles Paired structures near nucleus Made of bundle of microtubules Appear during cell division to formmitotic spindle Help to pull chromosome pairs apart to opposite ends of the cell 34

35. Cell Wall Supports and protects cell Found outside of the cell membrane 35

36. Chloroplasts Outer membrane is smooth Inner membrane is modified into sacs called Thylakoids Thylakoids exist in stacks called Grana Stroma: gel like material surrounding the thylakoids Site of Photosynthesis: Allows plants to absorb energy from sunlight to make their own food in the form of glucose Has its own DNA (like Mitochondria); was also likely once a free-living organism 36

37. Cell Specialization Cells in a multi-cellular organism become specialized by turning different genes on and off This is also known as DIFFERENTIATION 37

38. Specialized Animal Cells Muscle cells 38 Red blood cells Cheek cells

39. Specialized Plant cells 39 Xylem cells Pollen Guard Cells

40. Factors Affecting Cell Size Surface area (plasma membrane surface) is determined by multiplying length times width (L x W) Volume of a cell is determined by multiplying length times width times height (L x W x H) Therefore, Volume increases FASTER than the surface area 40