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Cellular Biology Overview: Prokaryotes vs. Eukaryotes and Cellular Functions

Explore the differences between prokaryotic and eukaryotic cells, their structures, functions, and organelles. Learn about cellular functions like movement, respiration, and communication in eukaryotic cells, including the roles of the nucleus, cytoplasm, ribosomes, Golgi complex, mitochondria, lysosomes, and more. Delve into topics such as plasma membrane structure, cellular communication, signal transduction, and cellular metabolism. Enhance your knowledge of cellular biology with key information on cellular organization and functions.

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Cellular Biology Overview: Prokaryotes vs. Eukaryotes and Cellular Functions

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  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

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