Chapter 7 Cell Structure and Function

1. Chapter 7Cell Structure and Function Section 7.1- Life is Cellular Section 7.2- Eukaryotic Cell Structure Section 7.3- Cell Boundaries Section 7.4- Diversity of Cellular Life

2. Section 7.1- Life is Cellular Discovery of Cells Robert Hooke • Used light microscope to look at cork cells • Cells reminded him of monk cubicles • “many little boxes” • Called them CELLS

3. Section 7.1- Life is Cellular Discovery of Cells Anton van Leewenhoek • First to observe living cells • Invented simple, tiny microscopes

4. Section 7.1- Life is Cellular • The cell theory states that: • all living things are composed of one or more cells • cells are the basic units of structure and function in an organism • cells come only from the reproduction of existing cells

5. Section 7.1- Life is Cellular • Cellular Basis of Life • All living things • are made of organized parts • obtain energy from their surroundings • perform chemical reactions • change with time • respond to their environment • reproduce.

6. Section 7.1- Life is Cellular • Prokaryotes • Prokaryote cells lack a nucleus and membrane-bound organelles. • Have genetic material not contained in a nucleus

7. Section 7.1- Life is Cellular • Eukaryotes • Eukaryote cells have a nucleus and membrane-bound organelles

8. 7.4- The Diversity of Cellular Life

9. Unicellular Organisms • Single cell organism • Dominate life on Earth

10. Multicellular Organisms • Made up of many cells • MO depend on communication and cooperation among specialized cells • Cell Specialization • Cells develop differently to perform different tasks • A cell’s shape reflects its function.

11. Eukaryote Has a nucleus Has organelles Cytoplasm/cell membrane Prokaryote Lacks a nucleus Lacks organelles (ribosomes) Cytoplasm/cell membrane Two Basic Types of Cells Nucleolus

12. Cellular Organization • In multicellular eukaryotes, cells organize into tissues, organs, organ systems, and finally organisms.

13. Section 7.2- Eukaryotic Cell Structure

14. Basic Parts of a Cell

15. There are some differences between plant and animal cells There are some similarities Comparing Cells

16. Nucleus • “The Brain” • DNA, surrounded by nuclear envelope, nucleolus- where ribosomes are made

17. Ribosomes • “The Construction Company” • Builds proteins • Free floating in the cytoplasm or attached to the ER

18. Endoplasmic Reticulum • “The Highway” (tubes and sacs) • Rough • Produces phospholipids and proteins • Smooth • Produces cholesterols

19. Golgi Apparatus • “The Post Office” • Receives proteins from ER • Modifies, labels and directs proteins to locations in the cell

20. Lysosomes • Specialized organelles • Lysosome- “The Killer or Garbage Truck” • Breaks down molecules • Maintains cell’s health by getting rid of non-functioning parts

21. Vacuole • Specialized organelles • Vacuole- “The Storage Center” • Stores water, nutrients and waste

22. Mitochondria • “The Power House” • Where ATP is produced

23. Use light energy to make C6H12O6 and O2 Thylakoids Flattened membranous sacs that contain chlorophyll Chlorophyll Pigment that absorbs light and captures light energy for the cell Chloroplast

24. Cytoskeleton • “The Infrastructure” • Cell support • Microtubule • Hold organelles in place • Microfilaments • Cell movement • Intermediate Filaments • Maintain internal shape of cell

25. Section 7.3- Cell Boundaries

26. Cell Membrane • Cell membrane • Border • Phospholipid bilayer

27. Cell Membrane • Fluid Mosaic Model • Proteins embedded in lipid bilayer • Cell surface markers, pumps, channels, receptors

28. Cell Wall • rigid layer • made of cellulose

29. Passive Transport • What does passive mean? • What does transport mean? • Passive Transport • Movement of substances across a membrane “down” their concentration gradients without using energy

30. Diffusion • Net flow from high conc. to low conc. • Driven by kinetic energy (energy of motion)

31. Diffusion High [ ] Low [ ] • Semipermeable Membrane • Down Concentration Gradient • Equilibrium • “both sides are equal”

32. Diffusion of water across a membrane Direction of osmosis into or out of a cell depends on solute concentrations inside and outside the cell Osmosis Animation of Osmosis

33. Osmosis- Direction of Osmosis Isotonic Hypertonic Hypotonic • Salt is the solute • A solute is a substance that dissolves in a solvent

34. Facilitated Diffusion • Diffusion that requires the help of carrier proteins Animation of Facilitated Diffusion

35. Diffusion Through Ion Channels • Ion channels are membrane proteins that allow only specific ions to pass through. • Channels can be “open” or “gated” • If an ion channel is gated, it can be opened by stretching the cell membrane, a voltage, or a chemical

36. Active Transport • Cell Membrane Pumps • Movement in Vesicles

37. Active Transport • What does active mean? • What does transport mean? • Active Transport • Movement of substances across a membrane “up” their concentration gradients using energy

38. Cell Membrane Pumps • Carrier proteins that move substances from areas of low concentration to areas of high concentration. • Requires energy • What molecule furnishes the energy to power the pump? • ATP

39. Sodium-Potassium Pump • Transports Na+ and K+ • 3 Na+ out of cell / 2 K+ into cell

40. How Na+/K+ pump works: Animation of Sodium-Potassium Pump

41. Movement in Vesicles • What happens if substances are too large to pass through the cell membrane or carrier protein? • What does the prefix endo- mean? • What does the prefix exo- mean? • What does cyto- mean? • What does –osis mean?

42. Endocytosis Process by which cells ingest what they need. Requires energy Cell membrane folds and pinches off to form a vesicle Movement in Vesicles

43. Endocytosis • 2 Types • Pinocytosis • Endocytosis of solutes and fluids • Phagocytosis • Endocytosis of large particles and whole cells • Phagocytes

44. Exocytosis Process by which cells release unwanted substances. Requires energy Vesicles fuse to membrane to let substances out of cell Movement in Vesicles