Introduction to the Medical biology. Biology of cell

1. Introduction to the Medical biology. Biology of cell

2. Questions to answer • General and medical Biology as the sciences. • Characteristics of living things. • Levels of living organization. • The cell theory in its modern form. • Cellular level of life organization: -prokaryotic and eukaryotic cells -the differences between plant and animal cells. • The main components of eukaryotic cell.

3. Characteristics of living things. • use energy – have a metabolism- the building up and breaking down of chemicals • grow and developbecome larger and more complex • respond to their surrounding • reproduce- produce offspring that are similar to the parents   • have the chemicals of life, carbohydrates, proteins, lipids and nucleic acids (genetic material)   • have cells The fundamental characteristics of living things: • reproduction(self-reproduction), which is the process that gives rise to offspring; • genes(self-renewal) are the units of inheritance, passed prom parent to offspring, that control many daily functions. • Finally, populations of living organisms adjust to environment variations through evolution, a change in the traits of a species over time (self-regulation).

4. CELLS- are the basic units of structure and function in living things. • ROBERT HOOKE- first to look at cellslooked at a thin section of cork • ANTON VAN LEEUWENHOEK – made his own lenses made first compound microscope drew pictures that we can still identify today • Schleiden –concluded all plants are made of cells • Schwann – concluded all living things are made up of cells

5. Three main levels of living organization: • Microsystem - molecular, subcellalar, cellular levels; • Mesosystem – tissular, organellic, organismic; • Macrosystem of population and species, biocenotical, biosheric.

6. Cell theory • All organisms are composed of one or more cells, within which the life processes of metabolism and hereditary occur. • Cells are the smallest living things, the basic unit of organization of all organisms. • Cells arise only by division of a previously existing cell.

7. What are the cells? • Basic unit of life • Properties - biomembrane enclosed - four biomolecules: proteins, polysacharides, nucleic acids, lipids - metabolism and energy transformation Two major types: • Prokaryotic: lack defined nucleus • Eukaryotic: contain membrane bound nucleus

8. What are the differences between prokaryotic and eukaryotic cells? • Kindoms Kindoms 1. Monera (Fubacteria) 1. Protista 2. Archaea (Archaebacteria) 2. Fungi 3. Plantae 4. Animalia Characteristics Characteristics 1. Lack a nuclear membrane 1. Have a nuclear membrane 2. Have no membrane bound organels 2. Have membrane bound organels Current evidence indicates that eukaryotic evolved from prokaryotic between 1 and 1,5 billion years ago

9. What are the differences between plant and animal cells? • 1. Chloroplast 1. Centriole • 2. Vacuole 2. Lysosome • 3. Cell wall

10. Survey of organelle structure and function • Cytoplasm and cytosol • Plasma membrane • Mitochondria and plastids • Endoplasmic reticulum • Golgy apparatus( complex) • Lysosomes • Nucleus • Ribosomes • Vacuoles • Centrioles • Cytosceleton. Membranbound organelles Nonmembane organelles

11. Cytoplasm • Viscous contents of cell between the nuclear membrane and the plasma membrane. This include cell organelles • Cytosol- aqueous part. The semi-fluid medium found in the cytoplasm. This does not include the organelles • Cytoskeleton nightly organized network fibrous proteins that support the cell.

12. Mitochondria • A double membrane cellular organelle with its own circular DNA (prokaryote like genomes) and ribosomes found in both plants and animals. • Likely evolved from bacteria that were endocytosed (ingested). • It is the site of cellular respiration, a catabolic, exergonic, oxygen requiring process that uses energy extracted from organic macromolecules (like glucose) to produce ATP.

14. Endoplasmic reticulum • Extensive membranous networks of tubules and sacs called cisternae • Three distinct regions and maybe more • A .Rough Endoplasmic reticulum (RER) Studded with ribosome's. Site of protein synthesis. Carbohydrate Addition and modification B. Smooth Endoplasmic reticulum (SER) Synthesizes lipids, phospholipids and steroids. Detoxifies drugs, alcohol and poisons Carbohydrate Addition and modification C.Endoplasmic reticulum exit sites Accumulation of proteins (cargos ready for export)

15. Liver Cell, TEM

16. Ribosomes • Nuclear and cytoplasmic organells. Composed of 60 % protein and 40% ribosomal RNA rRNA • Site of protein synthesis • Can be found or as Polyribosomes

17. Golgy apparatus (complex) • Stacked, flattened membranous organelle with sacs called cisternae • Modifies, stores, and routes products from the ER to the Plasma membrane • Size 1 to 3 nm diameter by 4 to 7 membranous atacks high number up to 100 per cell.

18. Golgi Body & Lysosomes

19. Transport vesicles • A membrane organelle that transits materials from one part of the cell to another • ER-to Golgy apparatus • Golgy apparatus-to ER • Golgy apparatus-to PM • PM-to Golgy apparatus

20. Lysosomes endosomes • Membrane-enclosed bag of hydrolytic enzymes (digestive enzymes) • Degradation of old cell components or ingested materials • Low pH (membrane proteins pumps in H+ ) • Degradative enzymes (nucleases, proteases) • They vary in shape, size and number per cell • Mean size: 50-710 nm in diameter

21. Golgi body & Peroxisome which is a specialized form of lysosome.

22. Vacuoles • Large membrane-closed sac for cellular storage • Three types • Food vacuole (lysosomes attach) • Contractile vacuole (Protozoons) • Central vacuole (mature plant cell)

23. Plasma membrane • The boundary of every cell approximately 8nm thick • Separates the living cell from its nonliving surroundings. • Functions • Acts as selective barrier • Regulate movement of material into and out of the cell • Cellular recognition

24. Plasma membrane • envelops the cell and aids in maintaining its structural and functional integrity. • Composed of lipid bilayer and associated proteins. • -composed of an inner leaflet (facing the cytoplasm) and an outer leaflet (facing the extracellular environment). • Membrane proteins may be integral (are dissolved in the lipid bilayer) and peripheral proteins (don‘t extend into the lipid bilayer).

25. Plasma membrane • Lipid bilayer is composed by phospholipids (hydrophilic and hydrоphobic), glycolipids and cholesterol. • Glycolipids are present in outer leaflet only. They have polar carbohydrate residues that extend from the outer leaflet into the extracellular space, forming part of glycocalix.

26. Plasma membrane • Cholesterol is located in both leaflets of the plasma membrane. It is constitutes approximately 2 % of the plasmalemma lipids and assists in maintaining the structural integrity of the plasma membrane. • Fluidity of the lipid bilayer is crucial to such activities as exocytosis, endocytosis, membrane trafficking and membrane biogenesis.

27. Glycocalyx • is a sugar coat commonly associated with the extracytoplasmic aspects of the outer leaflet of plasma membrane (in animal cells). • Functions • aiding in cellular attachment to extracellular matrix components • binding of cellular and enzymes to the cell

28. Plasma Membrane Transport Processes. • These processes include transport of a single molecule (uniport) or cotransport of two different molecules in the same (symport) or opposite (antiport) direction.

29. Passive transport includes simple and facilitated diffusion. • Neither of these processes requires energy because molecules move across the plasma membrane down a concentration or electrochemical gradient. • 1.Simple diffusion transports small nonpolar molecules (02 and N2) and small, uncharged, polar molecules (H20, C02, and glycerol). • 2.Facilitated diffusion occurs via ion channel and/or carrier proteins, structures that exhibit specificity for the transported molecules. It is faster than simple diffusion. • 3. Osmosis is the diffusion of water across a selectively permeable membrane in response to its concentration gradient.

30. Active transport • is an energy-requiring process which transports a molecule against an electrochemical gradient via carrier proteins. • Na+-K+pump.Mechanism. The Na+-K+ pump involves the antiport transport of Na+ and K+ ions mediated by the carrier protein, Na+-K+ ATPase. • Na+ ions are pumped out of the cell and two K+ ions are pumped into the cell. • The hydrolysis of a single ATP molecule by the Na+-K+ ATPase is required to transport five ions.

31. Comparison active and passive transport

32. Exocytosis • is way that substances can exit cells. • Part of the plasma membrane pinches off and forms a small membrane-bound sac, or vesicle, around some substance. • Vesicles even form around tiny cells (such as a bacterium) and fluids. • In exocytosis, vesicles form inside the cytoplasm and then move to the plasma membrane and fuse with it, so that their contents are moved to the outside.

33. Endocytosis • is way that substances can exit cells. • a patch of plasma membrane encloses material at the cell surface. • it sinks in and pinches off, forming a vesicle that either transports the material into the cytoplasm or stores it there.

34. Phagocytosis and Pinocytosis • Phagocytosis (cell eating) is transport process by which amoeboid-type cells engulf large material, forming an intracellular vacuole.

35. Pinocytosis • When macromolecules are taken in by endocytosis, the process is called Pinocytosis (cell drinking), and the result is formation of vesicle. • Both phagocytic vacuoles and pinocytic vesicles can fuse with lysosomes, whose enzymes digest their contents.

36. CYTOSKELETON • Network of fibers through out the cytoplasm. • Aids in cellular support and movement. • Composed of three components: 1. Microfilaments- globular protein (actin) - support and cellular contraction 2. Intermediate filaments - fibrous protein - support 3. Microtubles - globular protein (tubulin) - support and cell motility

37. In these cells, actin filaments appear light purple, microtubules yellow, and nuclei greenish blue. This image, which has been digitally colored, won first place in the 2003 Nikon Small World Competition.TORSTEN WITTMANN

38. Cytoskeleton

39. CENTRIOLES • found in animal cells only • Paired cylindrical organelles near nucleus • - Composed of nine tubes, each with three tubules • - Involved in cellular division • - Lie at right angles to each other

40. Nucleus • The cell nucleus is a conspicuous membrane-bound cellular organelle. • It functions to: • Store genes into chromosomes to allow cell division • Transport regulatory factors and gene products vie nuclear pores • Produce messages (messenger ribonucleic acid or mRNA) that code for proteins • Organise the incoiling of DNA to replicate key genes

42. Nucleolus • Spherical region in nucleus • Found in non-dividing cells • It is nuclear organizers and synthesize rRNA • Sometimes more than one nucleolus present

43. Nuclear envelope • Encloses the nucleus • A double membrane perforated wit pores through which materials enter and leave the nucleus. • The pores are octagonal orifices about 60nm in diameter forming the pore complex with the annulus

44. Heterochromatin -- tightly packed regions Euchromatin --- Regions where DNA is more openly packed, location of most functional genes Chromosome banding (requires special stains)

45. Types of chromosomes

46. Karyotype is a diploid number of chromosomes and it is a characteristics of the number and morphology of chromosomes, that is peculiarities of each species. • Male karyotype • 46=22A+XY • Female karyotype • 46=22A+XX

47. Thank you for attention!