Cellular Biology

1. Cellular Biology Chapter 1

2. Prokaryotes vs. Eukaryotes • Prokaryotes • Nucleus (single, circular chromosome) • Cyanobacteria, bacteria, and rickettsiae • Eukaryotes • Complex cellular organization • Membrane-bound organelles • Well-defined nucleus • Higher animals, plants, fungi, and protozoa

3. Cellular Functions • Movement • Conductivity • Metabolic absorption • Secretion • Excretion • Respiration • Communication

4. Eukaryotic Cell • Nucleus • Nuclear envelope- Membrane around nucleus • Nucleolus- organelles involved in cell division • DNA- chemical blueprints of life • DNA replication- semi conservative method, repair with nuclear enzymes in some cancers sometime defective repair enzymes, and transcription – making mRNA and tRNA and r RNA from DNA gene templates • Histone proteins – bind to outside of DNA double helix and protect DNA as well as control what genes are expressed at what time. • Cell division – mitosis – Prophase – metaphase – anaphase – telophase – interphase. Cell cycle

5. Eukaryotic Cell • Nucleus

6. Eukaryotic Cell • Cytoplasm • Cytoplasmic matrix • Cytosol • Function • Cytoplasmic organelles

7. Eukaryotic Cell • Cytoplasm

8. Eukaryotic Organelles • Ribosomes - organelles • rRNA made from DNA and 2 protein subunits • Free ribosomes – independent from reticulum • Attached ribosomes associated with ER • Endoplasmic reticulum – ER membrane complex inside cell • Site of protein synthesis • Smooth vs. rough endoplasmic reticulum

9. Eukaryotic Organelles • Ribosomes involved with protein synthesis. Line up tRNA + aa, rRNA and mRNA with enzymes that attach aa’s into long polypetide strands • Endoplasmic reticulum –site where ribosomes produce proteins

10. Eukaryotic Organelles • Golgi complex – final processing site for proteins, especially those destined to be secreted from the cell. • Flattened, smooth membranes • Secretory vesicles • Proteins from the endoplasmic reticulum are packaged in the Golgi complex • Cisternae

11. Eukaryotic Organelles • Golgi complex

12. Eukaryotic Organelles • Golgi complex – usually associate with ER and outer cell membranes. Site of final processing of proteins to be secreted out of cell

13. Eukaryotic Organelles • Lysosomes membrane bounded structures • Originate from the Golgi and contain lytic enzymes • Catalyze and breakdown proteins, lipids, nucleic acids, and carbohydrates • Role in autodigestion • Some vitamins can destabilize lysosome membranes (retin A anti wrinkle cream) and cortisone stabilizes membranes preventing cellular breakdown (part of anti-inflamitory action • Peroxisomes • Contain oxidative enzymes • Break substances down into harmless products

14. Eukaryotic Organelles • Mitochondria • Surrounded by a double lipid–bilayer membrane • Participates in oxidative phosphorylation • Increased inner membrane surface area provided by cristae • Location where enzymes of the Krebs cycle are located and where ATP is produced in the Electro transport chain reactions

15. Eukaryotic Organelles • Mitochondria

16. Eukaryotic Organelles • Vaults • Cytoplasmic ribonucleoproteins, shaped like octagonal barrels • Cellular trucks

17. Eukaryotic Organelles • Cytoskeleton • “Bones and muscles” of the cell • Maintains the cell’s shape and internal organization • Permits movement of substances within the cell and movement of external projections • Microtubules • Centrioles • Microfilaments

18. Eukaryotic Organelles • Cytoskeleton

19. Plasma Membrane • Controls the composition of a space or compartment they enclose • Structure • Caveolae • Lipids • Amphipathic lipids • Hydrophilic and hydrophobic • Phospholipids, glycolipids, and cholesterol • Carbohydrates

20. Plasma Membrane

21. Plasma Membrane • Proteins • Integral, peripheral, transmembrane • Functions • Receptors • Transport • Enzymes • Surface markers • Adhesion molecules

22. Plasma Membrane • Plasma membrane protein functions

23. Proteolytic Cascades • Caspase-mediated apoptosis • Blood coagulation cascade • Matrix metalloproteinase cascade • Complement cascade

24. Membrane Fluidity

25. Cell-to-Cell Adhesions • Extracellular matrix • Production • Fibroblasts • Collagen • Elastin • Fibronectin

26. Cell-to-Cell Adhesions • Extracellular matrix

27. Cell-to-Cell Adhesions • Cell junctions • Desmosomes • Tight junctions • Gap junctions • Gating

28. Cell-to-Cell Adhesions • Junctional complex

29. Cellular Communication • Direct linkup • Gap junctions • Hormonal • Neurohormonal • Paracrine • Autocrine • Neurotransmitters

30. Cellular Communication

31. Signal Transduction • Extracellular messengers • Convey instructions to the cell’s interior • Transfer, amplify, distribute, and modulate • Channel regulation • Second messengers • Two pathways • Adenosine monophosphate (cAMP) • Ca++

32. Signal Transduction

33. Cellular Metabolism • Metabolism • Chemical tasks of maintaining essential cellular functions • Anabolism • Energy using • Catabolism • Energy releasing

34. Adenosine Triphosphate • Created from the chemical energy contained within organic molecules • Used in synthesis of organic molecules, muscle contraction, and active transport • Universal fuel for all cell functions • The Electron Transport Chain (cytochromes) are involved with the production of ATP

35. Cellular Energy • Digestion • Glycolysis - first step in the breakdown of glucose (6 Carbons) • Occurs in the cytoplasm results in Pyruvate (2x 3Carbons) • Anaerobic – no need for oxygen like mitochondria reactions. If no O2 present pyruvate converted to Lactate • Citric acid cycle • Also called Krebs cycle or the tricarboxylic acid cycle (TCA) in the mitochondria • Oxidative phosphorylation • Occurs in the mitochondria

36. Cellular Energy

37. Membrane Transport • Gradient • Passive transport • Diffusion – follows concentration gradients • Passive mediated transport – no energy needed • Filtration – just like making coffee • Osmosis – movement of water across membranes • Osmolarity vs. osmolality • Tonicity – describes hoe living cells react to solutions • Isotonic (same size), hypertonic (shrinks cell), and hypotonic (cells will swell when exposed to this kind of solution)

38. Membrane Transport

39. Membrane Transport

40. Membrane Transport • Active transport • Active transport pumps require ATP move charged ions and substances across membranes • Transport by vesicle formation • Endocytosis • Pinocytosis • Phagocytosis • Potocytosis

41. Active Transport Ions and charged molecules As well as large chemicals Like proteins need to be Transported across the Membrane barrier.

42. Membrane Transport

43. Electrical Impulses • Resting membrane potential – caused by the distribution of charged ions like Na & K • Action potential – the flow of ions when the membrane is disturbed • Depolarization • Threshold potential • Repolarization • Refractory period • Absolute and relative

44. Propagation of an Action Potential

45. The Cell Cycle • Mitosis vs. cytokinesis • Chromatin vs. chromosomes • Interphase • G1 phase • S phase • G2 phase

46. The Cell Cycle

47. The Cell Cycle • Prophase • Metaphase • Anaphase • Telophase

48. Influences on the Cell Cycle • Cellular division rates • Growth factors

49. Tissue Formation • Founder cells • Chemotaxis • Contact guidance • Cellular reproduction

50. Tissue Formation