Cell Terms (Prefixes):

1. Cell Terms (Prefixes): • Cyto – having to do with cells • Hypo – below or under • Hyper – above or beyond • Philic – loving • Phobic – fearing • Exo – exit or out • Photo – light • Endo – into • Phag – To eat • Pino – To drink • Glyco – having to do with sugar

2. Laminin

3. Diversity of cells – over 200 different kinds in the human body alone!

4. You can be 100% sure that this will be on the test! • The 3 postulates of the cell theory: • All living things are made up of 1 or more cells • Cells are the basic unit of life • All cells come from pre-existing cells

5. Cells: A quick review • Cells were discovered in the 17th century (late 1660’s) by Robert Hooke, who was observing cork cells (right)

6. Cells: A quick review Two different types of cells: • Prokaryotic • lacks a nucleus • Lacks any membrane-bound organelles • Eukaryotic • Contain a nucleus and membrane bound organelles. Two prominent members are plant cells & animal cells

7. Prokaryotic Cells • Smallest and simplest cells • A prokaryote is any single celled organism that lacks a nucleus and other membrane bound organelles. • Bacterium are the major example of prokaryotic cells

8. 3. Have a cell wall (like plants and fungi) that serves to support and protect the cell. 4. Cell wall made of peptidoglycan instead of cellulose 5. Many have a flagellum Prokaryotic Cells: 1. Have single-stranded, circular DNA 2. NO internal compartments (no membrane bound organelles.)

9. Eukaryotic Cells • Much more complex than prokaryotic cells. • Contain a nucleus and other membrane-bound organelles • Two major kinds of eukaryotic cells are:

10. Plant Cells • Have a cell wall composed of cellulose • Have a large central vacuole • Contain chloroplasts

11. 1. The Cell Wall -Made of a polysaccharide called cellulose. -Utilized for structural support; when the vacuole is full, turgor pressure is created and the plant can maintain its rigidity because of the sturdiness of the cell wall.

12. 2. Vacuole • Vacuoles can store metabolic wastes, some of which are economically important to us. (caffeine, nicotine, etc.) • Loss of water = loss of turgor pressure. What will happen then?

13. 3. Chloroplasts • Site of photosynthesis and energy production in plants • Utilize light energy, CO2, and H2O to make sugar. • Equation: 6 CO2 + 6 H2O = C6H12O6 + 6 O2 What are these compounds?

14. Lack a cell wall, have a cell membrane instead. Don’t have cellulose or chloroplasts Vacuole is much less prominent Animal Cells

15. CELL ORGANELLES • Cells contain smaller specialized structures called organelles.

16. Plasma Membrane • Plasma membrane is a phospholipid bilayer

17. Plasma Membrane • Made of a special kind of lipid called a “phospholipid” • Has a hydrophilic head & two hydrophobic fatty acid tails • In a double-layered configuration commonly called a “bi-layer”

19. Plasma Membrane • Plasma membrane is a phospholipid bilayer • Fluid-mosaic model containing: • Membrane proteins (channel proteins, trans-membrane proteins, receptor proteins etc.) • Glycoproteins (marker proteins) • Cholesterol

20. Membrane Proteins • Various proteins are located in the lipid bilayer of the cell membrane • Glycoproteins (marker proteins) have attached carbohydrate groups and can advertise the cell type. ( self/other) Also -hepatic, renal, cardiac, etc)

21. Membrane Proteins • Receptor Proteins recognize extra-cellular substances • Transport Proteins (also called channel proteins) assist in moving substances in or out of the cell; crossing cell membrane (ex.-sodium/potassium pump)

22. Membrane Protein Receptors • “Seeing eye dog” for the cell • Tells cell what molecules are in the extra-cellular environment • Identifies cells to each other (AIDS virus to the right) • NOTES

24. Movement in Vesicles • Movement into the cell is termed ENDOcytosis • Endo = “into” • Cyto = “cell”

25. Endocytosis • Phagocytosis is one kind of endocytosis; in which a cell engulfs a foreign body (Immune response) • Cells take in cholesterol through endocytosis • Notes

26. Movement in Vesicles • Movement out of the cell is termed EXOcytosis • Exo = “away from” or “out of” • Cyto = “cell”

27. Diffusion • Movement of a substance from an area of higher concentration to an area of lower concentration is called diffusion. • Will continue, if allowed to, until equilibrium is reached

28. Equilibrium • Equilibrium is a condition in which the concentration of a substance is evenly distributed throughout space. • Notes

29. Osmosis is the diffusion of water across a membrane. Water moves through special channels in the membrane known as “aquaporins”.

30. Osmotic Pressure Osmotic Pressure is the force exerted on the membrane as water moves across it in an attempt to reach equilibrium. The farther out of equilibrium, the greater the osmotic pressure, and the more water will move across the membrane.

31. Concentration Gradient • A difference in the concentration of a substance across a membrane is called a concentration gradient. • If the membrane is permeable to the substance, the concentration gradient will eventually reach equilibrium.

32. Passive Transport: • Movement across a cell membrane that does NOT require energy from the cell is called passive transport. • In many animal cells, water and most fat soluble (non-polar) compounds are able to passively cross the cell membrane.

33. Selective Permeability • The cell membrane is selectively permeable to extra-cellular substances • The cell membrane is “picky” about who it lets through the membrane! (NO polar ions!)

34. Crossing the Cell Membrane • Ions, because of their electrical charge, have to go to the gate! • The gate is called an “ion channel”. • Sodium (Na+) • Potassium (K+) • Calcium (Ca ++) • Chloride (Cl-)

35. Ion channels in a cell membrane

36. The 2 kinds of “gates” on ion channels • Chemical gates • Activated by a certain chemical (Acetylcholine for example) • Voltage gates • Activated by a change in polarity

37. -Notes

38. -Notes

39. Water movement across the cell membrane • Speed of water movement across the membrane depends on the concentraion gradient. The greater the difference in the amount of solutes (particles) in the solution, the more water will flow across the membrane.

40. Water movement across the cell membrane • Three possible conditions resulting from the osmotic pressure and concentration gradient. • Hypertonic • Hypotonic • Isotonic • Notes

41. Hypotonic (“Hypo” = less than)

42. Isotonic (“Iso” = same)

43. Hypertonic (“Hyper” = more than)

44. Tonicity • When a cell swells until it ruptures, we call it “cytolysis” or “plasmolysis”. • When a cell shrivels up from loss of water, we call it “crenation.”

45. Tonicity in plant cells

46. So, tell me why… Answer: Those “poles” are the cytoskeleton framework underneath; they protrude out much like a collapsed circus tent! • Why does a crenated erythrocyte (shriveled up red blood cell) have those little ridges and poles jutting out everywhere? • Anyone have a guess?

47. Ion transport • An ion’s charge affects its diffusion rate across the cell membrane. • Typically, the inside of a cell membrane is more negatively charged than the outside. (Remember, like charges repel, but opposites attract.)

48. Ion Transport + • A negatively charged ion INSIDE the cell will diffuse out easier. (Cl-) • A positively charged ion OUTSIDE the cell will diffuse into the cell easier (drawn in electromagnetically) • Na+ • K+ • Ca 2+ + + + _ _ + _ + _ Inside of cell membrane is NEGATIVELY charged! _ _ + _ _ + _ _ + _ + + + Outside of membrane is POSITIVELY charged!

49. Facilitated Diffusion • Cells have “carrier proteins” used to transport specific substances across the cell membrane. • Used for amino acids and glucose • Is a PASSIVE type of transport (weird, huh?)

50. Active Transport • Passive Transport can only move substances DOWN the concentration gradient • To transport substances AGAINST the concentration gradients requires ACTIVE transport!