BIOLOGY CHAPTER 7 SECTIONS 3-4

1. BIOLOGY CHAPTER 7SECTIONS 3-4 SECTION 3 CELL BOUNDARIES

2. Cell (Plasma) Membrane • All cells have a cell membrane • Functions: • Controls what enters and exits the cell to maintain an internal balance called homeostasis • Provides protection and support for the cell electron microscope picture of a cell membrane.

3. Structure of cell membrane: Lipid Bilayer -2 layers of phospholipids • Phosphate head is polar (water loving) • Fatty acid tails non-polar (water fearing) • Proteins are embedded in the membrane Phospholipid Lipid Bilayer

4. Fluid Mosaic Model of the cell membrane Polar heads love water & dissolve. Membrane movement animation Non-polar tails hide from water. Carbohydrate cell markers Proteins

5. MEMBRANE PROTEINS • May go completely across membrane or be on just one side • Functions: • Transport of ions and molecules across membrane • Provide shape • Allow cell to be recognized (such as by the immune system) • Signaling molecules (such as hormones) may attach and cause changes inside cell

7. Cell membranes have pores (holes) • Selectively permeable: Allow some molecules in and keeps others out • Small nonpolar molecules such as O2 and CO2 can go directly through the lipid bilayer • Carrier proteins transport other molecules and ions Pore

8. Structure of the Cell Membrane Outside of cell Carbohydrate chains Proteins Lipid Bilayer Transport Protein Phospholipids Inside of cell (cytoplasm) Animations of membrane structure

9. MEMBRANES INSIDE THE CELL As we have seen, many organelles have membranes: • Mitochondrion, chloroplast, nucleus (double membranes) • Endoplasmic reticulum, Golgi, lysosomes, vacuoles

10. Cell Walls • Found in plants, algae, fungi, and many prokaryotes • Surrounds plasma membrane • MAIN FUNCTION: provide support and protection for the cell • Animal cells DO NOT have cell walls!

11. What is the cell membrane made of? • What kind of cells have a cell wall? • What does it mean that the cell membrane is selectively permeable? • What is the theory that mitochondria and chloroplasts evolved from prokaryotic cells?

12. Which organelle modifies, sorts and packages proteins for storage or export? • What 2 things are found in the cytoplasm that construct the cytoskeleton? • Which organelle is used during cell division to pull chromosomes apart?

13. Animations of Active Transport & Passive Transport Weeee!!! high low This is gonna be hard work!! high low Types of Cellular Transport • Passive Transport cell doesn’t use energy • Active Transport cell uses energy

14. Passive Transport • cell uses no energy • molecules move randomly • Molecules spread out from an area of high concentration to an area of low concentration. • (High  Low) • This is referred to as a concentration gradient.

15. Simple Diffusion Animation Three types of passive transport:1. Diffusion – random movement of particles from of high concentration to low concentration. continues until all molecules are evenly spaced (equilibrium is reached) molecules will still move but stay spread out. http://bio.winona.edu/berg/Free.htm

16. Passive Transport: • 2. Facilitated Diffusion - • diffusion of specific particles through transport proteins found in the membrane • Transport proteins are specific – they “select” only certain molecules to cross the membrane • Transports larger or charged molecules A B Facilitated diffusion(Channel Protein) Diffusion (Lipid Bilayer) Carrier Protein • http://bio.winona.edu/berg/Free.htm

17. Two types of facilitated diffusion • Channel proteins - form a hole across membrane. Ex. - aquaporin lets water through • Carrier proteins - flip back and forth, allow something to bind on one side and then get released on the other. Ex. - glucose transporter

18. Aquaporin (water channel) • Although water can penetrate through the membrane, some cells need pores to make it go faster. • http://www.rsc.org/chemistryworld/Issues/2003/November/theflow.asp

19. Glucose transporter (carrier-type transport) cc.scu.edu.cn

22. Passive Transport: 2. Facilitated Diffusion Glucose molecules Cellular transport from a High high concentration • Channel Proteins animations Cell Membrane to a low concentration Low Transport Protein Through a

23. 3.Osmosis: diffusion of water through a selectively permeable membrane from high to low concentrations Osmosis animation • Water moves freely through pores. • Solute (green) too large to move across.

24. Active Transport (Low  High) • Cell uses energy (ATP) to do this • Actively moves molecules or ions to where they are needed • Movement from an area of low concentration to an area of high concentration • Three Types:

25. Sodium Potassium Pumps (Active Transport using proteins) Types of Active Transport • 1. Ion pumps and molecular pumps-transport proteins that require energy to do work • Example 1: sodium/potassium pumps – move Na+ out and K+in. Uses chemical energy of ATP hyperphysics.phy-astr.gsu.edu

26. Example 2: sodium-linked glucose transport in intestine and kidney. Sodium moves from high concentration outside to low inside (releasing energy); this is coupled to glucose going from low to high (requiring energy). classes.midlandstech.edu

27. Types of Active Transport 2. Endocytosis: taking bulky material into a cell • Uses energy (ATP) • Cell membrane folds around food particle to form a vesicle • “cell eating” • may form food vacuole and digest food

28. PHAGOCYTOSIS EXTRACELLULAR FLUID 1 µm CYTOPLASM Pseudopodium Pseudopodium of amoeba “Food” or other particle Bacterium Food vacuole Food vacuole An amoeba engulfing a bacterium via phagocytosis (TEM). PINOCYTOSIS 0.5 µm Plasma membrane Pinocytosis vesicles forming (arrows) in a cell lining a small blood vessel (TEM). Vesicle • Two Types of Endocytosis: • Pinocytosis: Liquids • Phagocytosis: Solids

29. Types of Active Transport Endocytosis & Exocytosis animations 3. Exocytosis: Forces material out of cell in bulk • Membrane surrounding the material (vesicle) fuses with cell membrane • Requires energy (ATP) • Ex.: Hormones or wastes released from cell

30. Which type of cellular transport requires energy? • Which type of cellular transport always goes from high to low concentration? • What is the diffusion of water from high to low concentration?

31. Effects of Osmosis on Life • Water is so small and there is so much of it the cell can’t control its movement through the cell membrane.

32. Osmosis Animations for isotonic, hypertonic, and hypotonic solutions Hypotonic Solution Hypotonic: The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (low solute; high water) Result: Water moves from the solution to inside the cell): cell swells and bursts open (cytolysis)

33. Osmosis Animations for isotonic, hypertonic, and hypotonic solutions Hypertonic Solution Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (high solute; low water) shrinks Result: Water moves from inside the cell into the solution: Cell shrinks (plasmolysis)

34. Osmosis Animations for isotonic, hypertonic, and hypotonic solutions Isotonic Solution Isotonic: The concentration of solutes in the solution is equal to the concentration of solutes inside the cell. Result: Water moves equally in both directions and the cell remains same size (dynamic equilibrium)

35. What type of solution are these cells in? B C A Hypertonic Isotonic Hypotonic

36. How Organisms Deal with Osmotic Pressure • Bacteria and plants have cell walls that prevent them from over-expanding. In plants the pressure exerted on the cell wall is called turgorpressure. • A protist like paramecium has contractile vacuoles that collect water flowing in and pump it out to prevent them from over-expanding. • Paramecium (protist) removing excess water video

37. How Organisms Deal with Osmotic Pressure • Paramecium (protist) removing excess water video • Salt water fish pump salt out of their specialized gills so they do not dehydrate. • Animal cells are bathed in blood. Kidneys keep the blood isotonic by remove excess salt and water.

38. SECTION 4. THE DIVERSITY OF CELLULAR LIFE Organisms are either unicellular or multicellular. Unicellular organisms include: • All prokaryotes. These are Bacteria and another domain, Archaea (originally grouped with bacteria) • Some eukaryotes. Include most of the organisms referred to as protists (such as protozoa and some algae), and some fungi (such as yeast).

39. Some unicellular eukaryotes biology.tutorvista.com

40. Multicellular organisms include: • All plants • All animals • Some protists • Some fungi

41. Multicellular Organisms • Cell specialization – cells throughout an organism develop in different ways to do different tasks. • Specialized animal cells: Ex: red blood cells – transport oxygen muscle cells – movement • Specialized plant cells Ex.: guard cells – monitor internal conditions

42. Tissues Tissue = group of similar cells that share a structure and function Examples: • muscle tissue • epithelial tissue - sheets that enclose or line body parts. Ex. - outer layer of skin • connective tissue - holds organs in place • nervous tissue

45. Organs • Groups of tissues work together to form an organ • Examples: • Stomach has • Muscles to mix food and digestive juices • Epithelial tissue to produce acids for digestion • Blood to provides oxygen • Others: lungs, liver, kidney, thyroid, muscles, brain

46. Tissues of the Stomach bioserv.fiu.edu

47. Human Organs www.sciencekids.co.nz

48. Organ Systems • A group of organs that work together to perform a specific function • General functions of organ systems: • Exchanging materials with environment • Transporting materials to and from cells • Allowing movement • Storing nutrients for later use • Responding to stimuli

49. Some Human Organ Systems • Cardiovascular or circulatory system: heart, blood vessels. Distributes blood (with nutrients, gases, immune cells) to all parts of the body. • Respiratory system: nose, mouth, trachea, lungs. Takes in oxygen, removes carbon dioxide.

50. www.lung.ca www.bupa.co.uk