Catalyst (12/3)

1. Catalyst (12/3) • Write 3 things you already know about cells. • Blood cells (red and white)* • Eukaryotes prokaryotes • Plants have cell wall • Cells make up every living things • Prokaryotes split • Mitosis/meiosis* • Organelles • Write 2 things you want to know about cells • What’s the function of different cells? • How are cells affected when damaged? • What a good way to remember difference between meiosis and mitosis?*

2. AP Biology-Chapter 6 A Tour of the Cell (Cell structure & Function)

3. Cell Function Regulates itself! All known living things are made of cells Structural and functional unit Produced by division of existing cells Contain hereditary information that is passed from cell to cell—DNA Smallest units that perform vital physiological functions Each cell maintains homeostasis at the cellular level Homeostasis at higher levels reflects combined coordinated action of many cells.

5. Common Features of All Cells • Plasma membrane • Cytoplasm • DNA • Nucleoid region/Nucleus • Ribosomes =prokaryotes =eukaryotes

6. Kary=seed Prokaryotes NO membrane bound organelles! • No membrane bound nucleus • “naked” circular DNA • No internal membrane-bound organelles • “naked” circular DNA • Small; <1.0-3.0 μm in diameter • Simple structure • Comprised of Domain Bacteria and Archaea Prokaryotes older than eukaryotes

7. Eukaryotes • Have a membrane bound nucleus—linear DNA • Internal membrane-bound organelles • Large; 10-100 μm in diameter • Complex structure • Comprised of Algae, Protozoa, Fungi, Animals, and Plants (Domain Eukarya)

8. Prokaryotic Structures and Functions • External Structures • Glycocalyces—capsule or slime layer • Flagella • Pili • Fimbriae

9. Glycocalyces Like “skin” • Gelatinous, sticky substance surrounding outside of cell • Composed mainly of polysaccharides • Some species make polypeptides • Two types: • Capsule • Slime layer • Capsule • Composed of organized repeating units of organic molecules • Firmly attached to cell surface • Protects cells from drying out • May prevent bacteria from being recognized and destroyed by host

10. Flagella • Responsible for movement • Long and whiplike • Composed of filament, hook, and basal body • Flagellin protein forms filament • Base of filament inserts into hook • Basal body anchors filament and hook to cell wall • Capable of rotating 360°. Eukaryotic flagella just move back and forth Basal Body (cell wall)

11. Pili • Long hollow tubules • Typically only 1 or 2 per cell • Join two bacterial cells to transfer DNA from one to the other (conjugation) • Also called: • Sex pili • Conjugation pili “reproduction”

13. Fimbriae “not moving” • Nonmotile extensions • Sticky and proteinaceous • Used to adhere to other bacteria, hosts, and other surfaces • May be hundreds per cell • Shorter than flagella “made from proteins” “stick”

14. Cell Wall • Provides structure and shape • Protects cell from osmotic pressure • Assists in attaching cells to other cells and surfaces • Made of peptidoglycan • Target bacterial cell wall with antibiotics because animal cells do not have them Penicillan inhibits bacteria’s ability to repair and make cell walls.

15. Catalyst (12/4) What does the word “prokaryote” mean? Pro=before kary=seed (before the nucleus) Who evolved first, eukaryotes or prokaryotes? Prokaryotes (less complex—endosymbiotic theory) How does not having membrane bound organelles affect prokaryotes? Naked DNA—more exposed to damage? Don’t go through mitosis/meiosis Can’t have sex—pili (conjunction) Make ATP not in mitochondria instead on plasma membrane (the two not crossed out are better answers)

16. Glycocalyces Carbohydrate side chain Glycolipid=lipid & carb Glycoprotein=protein & carb Formed from glycolipids and glycoproteins Never as organized as prokaryotic capsules Helps anchor animal cells to each other Strengthens cell surface Protects against drying out Function in cell-to-cell recognition and communication protein

17. Flagella Shaft composed of tubulin “9+2” arrangement of microtubules anchored to cell by basal body; no hook basal body has “9+0” arrangement of microtubules single or multiple; generally found at one pole of cell do not rotate, but undulate rhythmically

18. Cillia Can see 9+2 arrangement Can see 9+0 arrangement

19. Cilia Cilia found in…. Nasal cavity Trachea (throat) Ears Fallopian Tubes • Shorter and more numerous than flagella • Composed of tubulin in “9+2” arrangement • Coordinated beating propels cells through their environment • Also used to move substances past the surface of the cell

20. Microvilli FUNCTION: absorption, secretion, cellular adhesion, and mechanotransduction (mechanical stimulus to chemical—sense touch, balance, hearing) • Small (0.08 um in diameter, 1 um long) • Plasma membrane covered extensions with microfilaments • Actin cross links that allow limited motion • Increase the surface area by approx. 600 fold (humans) • Several thousand microvilli present on apical surface of a single cell in human small intestinal cells • Found in absorptive and secretory epithelial cells • Kidney cells • Intestinal cells • Also occur in sensory cells • Inner ear • Taste buds • Olfactory receptor cells • Also occur on sperm and egg. • Clustering of microvilli around the sperm holds it close and tight, enhancing fusion. More microvilli in…. Kidney Intestine Ear Tongue (taste buds) Nose (olfactory) (small intestine)

22. Cell Walls (not in animals!) Rigid! • Fungi, algae, and plants have cell walls but no glycocalyx • Composed of various polysaccharides • Plants—cellulose • Fungi—cellulose and chitin • Algae—cellulose and other polysaccharides *chitin makes fungi more closely related to animals than plants

23. Plasma Membrane (picture on back) Fluid mosaic of phospholipids and proteins Contains cholesterol Controls movement into and out of cell

24. Nonmembranous Organelles • Ribosomes • Cytoskeleton • Centrioles and centrosome

25. Ribosomes • Ribosomes • Larger than prokaryotic ribosomes • Site of protein synthesis • Assembled in the nucleolus • Made of RNA and protein • Exported into the cytoplasm • Free—unbound in the fluid cytoplasm • Produce proteins for use in the cell • Bound—attached to the endoplasmic reticulum (ER) • Produce proteins for export, or for plasma membrane Rough ER

26. Cytoskeleton “cell” Cytosol=liquid Cytoskeleton-proteins that make structural part • Extensive • Functions • Anchor organelles • Cytoplasmic streaming and movement of organelles • Critical in mitosis and meiosis • Cell contraction • Movement during endocytosis and amoeboid action • Provides basic shape • Composed of • Tubulin microtubules • Cylindrical tubes • In cilia and flagella • “superhighway” for organelles • Actin microfilaments • Fine, thread-like protein fibers • Work with myosin in muscle contraction • Intermediate filaments • Provide tensile strength STRUCTURE & MOTION thickest thinnest

27. Centrioles • Barrel shaped microtubule structure • Found in animal cells and algae; rarely in plants • Organize the mitotic spindle During mitosis

28. Nucleus • Largest organelle in the cell • Consists of • Nucleolus—site of ribosomal RNA synthesis • Chromatin—uncoiled DNA • Nuclear Envelope—separates nucleus from cytoplasm • Two main functions • Stores hereditary material • Coordinates cell’s activity CONTINUOUS!

29. Chromatin • Fibrous material consisting of DNA and proteins • DNA is never found “naked” • Always associated with histones—proteins • Also associated with RNA and other molecules (hormones and vitamins) • During mitosis chromatin condenses to become chromosomes Chromatinchromosomes (condensed)

30. Catalyst (12/5) What do you already know about the endomembrane system (Endoplasmic Reticulum, Golgi apparatus, microbodies, lysosomes)? TEST CORRECTIONS DUE TODAY!! TURN IN IN UPPER LEFT HAND CORNER OF DESK!

31. Nuclear Envelope Double membrane with a space in between called the perinuclear space Outer membrane is continuous with rough ER Nuclear pores regulate passage of material Selectively permeable

32. Endomembrane System “inside” “things that work together” • Series of continuous membrane enclosed vesicles, or • Discontinuous vesicles that communicate with one another through vesicles that are formed at one surface and move to another where they are incorporated • Endoplasmic reticulum • Rough ER • Smooth ER • Golgi apparatus • Vesicle—transport and storage • Microbody • Peroxisome in animal cells • Glyoxyomes in plant cells • Lysosomes Flow of materials Type of vessicle

34. Rough Endoplasmic Reticulum (RER)—ribosomes attached • Netlike arrangement of hollow tubules • Continuous with nuclear envelope • Transport network • Molecules that are targeted for certain modifications and/or • Specific final destinations • Produces and processes proteins for export or secretion • Produces transmembrane proteins—embedded in the membrane • Adds carbohydrates to some • Transports proteins to the golgi apparatus via vesicles • Transports proteins directly to nucleus due to close association of the ER lumen and the nucleus Na+/K+ pump, proteins in membrane Insulin, nonsteroid hormones More RER in…. Thyroid Pancreas Liver Adrenal Medulla (glycoproteins)

35. Smooth ER (SER)—no ribosomes Lipid production (fats) Detoxification of drugs and poisons Stores calcium (Skin, ovaries, testes) (liver) (bones, sarcoplasmic reticulum) Specialized SER in muscle cells

36. Golgi Apparatus (GA) • Series of cup-shaped, membrane-covered sacs called cisternae • Animal cells—10 to 20 stacks per cell • Usually located near the nucleus • Modifies proteins and lipids build in the ER • Molecules are added or removed off the ends • Identification and destination tags are added • Produces some polysaccharides (e.g. pectin) • Product is extruded from the GA vesicle • Secreted outside the cell • Incorporated into plasma membrane • Returned to rough ER • Vesicle may mature into a lysosome “post office” of the cell—packages and sends proteins

37. Closer to ER

38. Secretory Vesicle • Transport cell secretions from the GA to the plasma membrane for release • Hormones • Neurotransmitters Vesicle=small, membrane bound, holds something

39. Catalyst (12/6) If you were absent yesterdayWhat do you already know about the endomembrane system (Endoplasmic Reticulum, Golgi apparatus, microbodies, lysosomes)? If you were here yesterdaywhere in the body is there more RER? Why? TEST CORRECTIONS WERE DUE YESTERDAY (BUT SOME OF YOU WERE’NT HERE)!! TURN IN IN UPPER LEFT HAND CORNER OF DESK!

41. Peroxisome Lots of peroxisomes in liver cells—detox! • Roughly spherical and bound by a single membrane • Contain variety of enzymes • Primary function to destroy toxic substances • In particular, hydrogen peroxide (by product of cellular metabolism) • In liver cells—detoxify alcohol and other harmful compounds • Self-replicate • No DNA • Import the proteins they need to perform fission Break in 2

42. Lysosomes Perform hydrolysis (breakdown) • Roughly circular membranous sacs • Contain approx. 40 hydrolytic enzymes • Digest cellular materials that have exceeded their lifetime • Cellular waste products • Fats • Carbohydrates • Proteins • Worn out organelles (e.g. mitochondria) • Safety net • Internal environment has pH 4.8 • If lysosome ruptures the hydrolytic enzymes would denature in the neutral cytosol environment • Maintains low internal pH with the help of H+ ion pumps located in the membrane • Avoids self-digestion by glycosylation of membrane proteins. Many lysosomal disorders! acidic Enzymes won’t break down the cell!!

43. (the enzymes optimal pH is 4.8 but the cell’s pH is 7 denature)

44. Relatively large, oblong, double membrane bound organelles • Occur in numbers directly correlated to the cell’s level of metabolic activity • Convert oxygen and nutrients into ATP • Aerobic respiration • Elaborate structure very important to function • Aerobic respiration is a complex multi-step process • Reproduce independently—contain circular DNA Mitochondria CELLULAR RESPIRATION (exergonic/catabolic) Lots of mitochondria in muscles!! Mitochondria DNA is maternally inherited (you got it from your momma!)

45. Relatively large, oblong, double membrane bound organelles • Occur in all green parts of plants • Majority in leaves—one-half million per square millimeter • Convert solar energy and carbon dioxide into glucose • photosynthesis • Elaborate structure very important to function • Photosynthesis is a multi-step complex process • Reproduce independently—contain circular DNA PHOTOSYNTHESIS (endergonic/anabolic) Chloroplast

46. Central Vacuole (Plants only!) • Large, single membrane bound vacuole (can take up to 80% of cell) • Structural support • Storage • Waste disposal • Protection • Growth • Vacuoles (in animals) small and used for temporary storage or material transport (turgor pressure) (salts, nutrients, pigments) (can release molecules that are poisonous, odiferous, or unpalatable to predators) (aka vesicle) (endocytosis, exocytosis)

47. Groups of cells are organized into… Tissues Organs Organ systems More organized

48. These neighboring cells must be able to Adhere Interact Communicate “stick to each other”

49. Cell to Cell Junctions • Plasmodesmata—plants only • Cytosol passes through interacting with neighboring cells • Water and small solutes pass through • Sugars • Amino acids • Proteins and RNA • Larger molecules pass with aid of actin filaments

50. There are three types for animal cells “stop or obstruct” Occluding Junctions—Tight Junctions Adhesive Junctions—Adherens Junctions and Desmosomes Communicating Junctions—Gap Junctions All three common in epithelial tissue