Review Exam Final Cell Biology 2024 PDF

Review Exam Final 2024 Plasma Membrane, Golgi, cytoskeleton, extracellular matrix and Stem Cell/ Apoptosis. Biological Membrane Class I L.Spencer 1- Chemical Basics: - Hydrophobic (non-polar molecules → aggregation) Insoluble in water: Hydrophobic molecules. -...

Review Exam Final 2024 Plasma Membrane, Golgi, cytoskeleton, extracellular matrix and Stem Cell/ Apoptosis. Biological Membrane Class I L.Spencer 1- Chemical Basics: - Hydrophobic (non-polar molecules → aggregation) Insoluble in water: Hydrophobic molecules. - Hydrophobic Links: The force that produces the bond between non-polar molecules. These molecules are not able to form bonds with water. - Non-polar molecules can be bonded to each other, although in weak form through Van der Waals type interactions - Polar molecules: Dissolve in polar solvents as water and non-polar solvents such as Hexane. 2- Phospholipids are amphipathic molecules: Multiple non-covalent bonds are also essential for stabilizing the structure of bio-membranes. Main components: Phospholipids. Phospholipids: One or more chains of fatty acids. (Chain of hydrocarbons bound to a carboxyl group (-COOH). Fatty acids: Saturated (without double bond) Unsaturated (at least one double bond). Please, Who can explain this figure? This table present the most common lipids into the membrane TO ISOLATE THE ´PROTEIN FROM BIOLOGICAL MEMBRANE Form organized structure into the water micelle Sheet of the bilayer Liposome Two faces of the a cellular membrane as the Cytosolic face and the exoplasmic face Steroids: (cholesterol and its derivatives) → anphipatic Basic structure is a hydrocarbon and 4 rings (abundant in eukaryotic membrane) General structure of a steroid: Cholesterol Hydrophilic region Hydrophobic region  Table of lipid composition: Each type of membrane has characteristics of lipids and proteins. The relative proportion of them depends on the membrane. Other components of membranes Glucoproteins. Fig 3-32 (3) Glucolipids or Glycolipids. Carbohydrates attached to sugars increase the hydrophilic character of lipids and proteins and contribute to stabilize the conformations of many membrane proteins. Classification of proteins Surface or peripheral. Integral or Intrinsic. On the outside Function intervene in signals Protein domains Intracellular F. (pores or channels) Protein domains F. anchorage of the protein of the cytoskeleton in the cytosolic face F. Intracellular signaling. Schematic diagram of the typical membrane proteins of the biological membrane Plasma membrane defines the cell and separates the inside from the outside. Types of membrane proteins 2 Protein classes Peripheral of Membrane Integrals (Transmembrane proteins) Transmembrane or integral proteins: - Domains that cross the membrane (lipid bilayer) - Domains that are : α helix Multi stranded β outside inside What type the a.a are? Classification of amino acids Erythrocyte membrane  Fig. 3-34 Structure of Bacterodopsin, contains 2 or more alpha-helices that cross the membrane. - Prot. Multiple strands of Porins They form barrels (channels) that pass through the membrane. Porins: transmembrane proteins They provide channels for the passage of disaccharides and phosphates in E.coli. By X-Ray Porins are trimers RECEPTORS in the plasma membrane are proteins that allow the cell to recognize chemical signals present in its enviroment What is this figure? SDS Electrophoresis or SDS -PAGE Three liquid chromatography to separate proteins based on their mass, charge or affinity to a ligand  Result Western Blotting We will made in the Lab ELISA TEST Immunofluorescence to locate protein in the cell Microscopia confocal Experiment to demostrate the Evidents FRAP Trilaminar Fusion celular You must review the experiments Fracture membrane Secound Part Aparatus of Golgi Camilo Golgi (1898) “∆” Owl brain tissue + salts of Os+2 ↓ “Apparei reticulaire interne” -In the middle of the XX century, with the Electronic Microscope, the existence of the organelle was established. Polarization of Dictiosomes Levels of organization: -Cisternae (staks): diameter 0.5- 1μm (tubules diameter of 30- 50μm). -Dictiosomes or bodies of Golgi: 5 to 8 cisternaes - Golgi complex: Levels of organization. Structure of A. Golgi Cis face Golgi presents a polarization Trans face Biochemical Activities of the Golgi Glycosylation of proteins (eg. glycosylase and glycosyltransferase enzymes in the Golgi membrane). Medial cisternaes → Mannose residuos are added N-acetylglucosamine (GlcNAc). TransGolgi → increase residuos of galactose, Sialic Ac. and Fucose Glycosylation of lipids. Residue of mannose-6-phosphate directs the enzymes to the lysosome. The conversion of proteins to the mature form, this is catalyzed by the Peptidase Ezyme in trans-cisterna and secretory vesicles. Glycosylation of proteins in ER and Golgi (cis; trans) ↓ Addition of carbohydrates to proteins Nitrogen amídic from aspargine Structural difference characteristic of N and O bonds of Oligosacharides. They differ in the residues of sugars. “O” → One to group Hidroxil of Ser o Thr, vía N-acetilglucosamine (GlcNAc) “N” → Its bind to Nitrogen of Asp vía (GlcNAc). Collagen: it binds an hidroxilisine vía galactose (Gal). hidroxilisin Acetil-glucosamina Nitrogeno amídico Summary of Antiport of the sugar nucleotides used in the synthesis of glycoproteins that come from the cytosol. N-acetylgalactosamine Cisternae of Golgi N-galactosyl transferase Types of blood groups ABO Blood Types are determined by two Glycosyltransferases. Ags of blood groups AgA ➔ Ez N – acetilgalactosamine Transferase. AgB ➔ Ez- Galactose Transferases. AgAB ➔ they have 2 Transferases. Ag O ➔ They do’n have Transferase Table of the immune response of blood groups Laboratory practice: Determination of blood group un slide and micro-place by precipitation with antibodies (Agglutination). Common precursor of N-oligosaccharide in ER proteins Precursor + Dolicol ➔ Sec: Asn – x – Ser / Thr. (lipid) Oligosaccharide Protein Transferase  Aspargine Enzimas Oligosaccharide protein transferase  Sialyltransferase galactosyl transferase Modifications of N-oligosaccharides are complemented in the Golgi complex. Location Galactosyl Transferase➔ Trans – Golgi Sialyltransferase ➔ Trans – Golgi and TNG Nextwork Oligosaccharides can promote folding and stabilize proteins: Exp. Antibiotic Tunicamycin. Prot HA of influenza blocks Glicosylation Acumulation + ==X==> in Dolicol ➔ Prot. HA in RER, Tunicamycin N - Oligosacharide bag folding Exp. with mutant in there is not Accumulation of Prot. Replacement Asn by ============> HA of virus of influenza bad glutamine of the prot. HA folding Glicosylation Some Proteins are secret in their final destination without being glycosylated. E.g: Fibronectin by fibroblasts. Fibronectin ➔ Non-glycosylated Rapidly degraded by tissue proteases of Extracellular matrix Conclusion: These results demonstrate that the oligosaccharide chains confer stability to many extra-cellular glycoproteins Peroxisome  Manosa-6-phosphate (M6P) is target for lysosomes Phosphorylation of the mannose residue in the lysosomal enzyme. GlcNAc Ez. Eliminates GlcNAc Phosphodiesterase Other Route of the M6P of Ez. Lysosomal (Trans-Golgi) M6P receptor. The segregation of M6P-bearing lysosomal enzymes from secreted and membrane proteins occurs in the trans-Golgi network. Here transmembrane mannose 6-phosphate receptors bind the M6P residues on lysosome-destined proteins very tightly and specifically. pH5,5 lysosomal storage disease pH6 or Cell Disease I Proteins that undergo proteolytic processes in maturation (Occurs in secretory vesicles) Cleavage Inective precursors = Pro – Protein ➔ Active Protein FURIN PROTEASE Endoproteases Carboxypeptidase Some Proteins transporting the Golgi complex to the Apical or Basolateral membrane. Fig. Plasma membrane in MDCK epithelial cells are polarized in 2 domains Virus Influenza: Prot. HA Apical Membrane Transcytosis MDCK Virus VSV: Prot. G Basolateral Membrane Part of final Exam Cytoskeleton Microvillus: Villin joining F-actin  As Profilin and Thymosin act in the assemblage of F. Actin Recruits actin ◼ F. Actin Cutters Protein P. Superfamily of GeIsolin: Requires ↑ [Ca+2] to Cut Actin´s filaments Microfilament Motor Proteins Myosin  Coupling of ATP hydrolysis to Myosin shift on the actin filament Steps: 1- Fixing ATP 2- Hydrolysis 3- Pi release 4- Release of ADP Pivot movement Model of Sliding Filaments Actin - Myosin in muscle contraction Actin and myosin in non-muscle cells Fluorescent antibodies reveal the localization of myosin I and myosin II during cytokinesis. Fluorescence micrograph of a Dictyostelium ameba during cytokinesis reveals that myosin II (red) is concentrated in the cleavage furrow, whereas myosin I (green) is localized at the poles of the cell. The cell was stained with antibodies specific for myosin I and myosin II, with each antibody preparation linked to a different fluorescent dye. [Courtesy of Y. Fukui.] Myosin VI is the only one that travels on F. From actin to negative end Electron micrograph (a) of a section of the apical domain of polarised Cartoon illustrating the possible involvement of myosin VI (arrows indicate human intestinal brush border cells (Caco-2 cells) after cytochalasin D direction of myosin VI movement) in sequential steps of endocytosis in treatment. Depolymerisation of actin ¢laments clearly increases the polarised cells containing microvilli at their apical domain: (1) spatial number of clathrin coated pits at the base of microvilli. Gold label organisation of the endocytic machinery at the base of microvilli; (2) indicates molecules of ricin binding to the microvillar surface. b^d: movement of receptors down to the base of a microvillus for sequestering Immuno EM localisation of myosin VI (5 nm gold) labelled with and coated pit formation; (3) invagination of the plasma membrane; (4) arrowheads and clathrin (15 nm gold) in NRK cells. In b myosin VI is vesicle scission with myosin VI attached to the plasma membrane moving associated with an early stage of clathrin coated pit formation, whereas in towards the minus end of actin ¢laments and thereby driving the filament to c it can be seen in a deeply invaginated pit and in d myosin VI is constrict the neck; (5) transport of clathrin coated vesicles away from the associated with a clathrin coated vesicle in the cytosol. plasma membrane into the cell. Cytoskeleton II Types of filaments : 2) F. Intermediate: Fibers resembling strands. Structural paper, are in multicellular organisms. D. 10nm (E.g.. Lamin) Give strength and resistance (hair, nails) Fig. 16-16 Structure of the intermediate filaments ( Protein Lamin) 8 Tetramer and 32 Colloidal helixes Keratin and cutaneous diseases The bunds of Keratin are united by cross-links of FILACRIN Deletion mutations of the terminal domains Cause: Epidermolysis bullosa simple Cytoskeleton II 3) Microtubules (Directs intra- cellular transport, cilia and flagella) Long, cylindrical and hollow Formed by tubulin protein Ø 25nm One end (-) → MTCO = Centrosome (MTCO) MT have polarity Cytoskeleton I Structure of a microtubule and its subunits interchanged Dynamic Instability Dynamic Instability Catastrophe ( - ) Rescue (+) Fig. 16-11 Dynamic Instability Permanent = Flagellar Axonema MT Form structures Transient Polymerization and depolymerization Acrosome spindle of mitosis Schematic of Dynamic Instability Cap of Tiubulin-GTP grows MT  Cytoskeleton I Polymerization of the nucleated tubulin to a ring complex  Cytoskeleton I Microtubules leave a centrosome(MTOC) Centrosome → Located next to the nucleus 2 Centrioles in the shape of "L" (right angle)  Microtubules -Similar to myosin II Kinesin -2 Heavy heads (globular) 2 types of motor prot. direction(+) -2 Light chains (Anterograde movement) -1 Coiled tail Dynein Towards the negative end of the MT(-) (Retrograde Movement) Fig. 16-55: Kinesin and related proteins. There are at least 10 families of related proteins or KRPs. They are involved in the formation of the achromatic spindle and separation of the chromosomes during cell division. Dyneins: -It moves towards the negative end of the MT. -Involved in vesicular traffic and ciliary beat. -2 or 3 heavy chains (motor domains). -1 or more associated light chains. Ej. cytoplasmic dynein 2 heads ciliary dynein 3 heads Kinesin has a movement directed towards the + end (anterograde) Kinesin and Kinesin-related proteins Another representation of the model of binding of a vesicle to the Microtubule Structure of axonemes of cilia and flagella Fig. 16-78: Dynein ciliary Extreme arms of axonema dynein Fig. 16- 79: Flexion of an axoneme. (Prot. Union = nexin) The displacement of the microtubules causes flexion. Nexin Make a table of the differents filaments of Cytoskeleton And What is the difference between cilia and flagella? Extravasion: Inward displacement of tissues ↓ It requires the successive formation and rupture of the intercellular contacts between leukocytes and Endothelial cell ↓ Mediated by Selectin P Fig. 22-4: Interaction between the cell adhesion molecule (CAM-Selectin) and an active endothelial cell Adhesion and Extracellular Matrix Cell-Cell and Cell-Extracellular matrix interactions Different types of cells in tissues are arranged in complex patterns. ↓ The coordinated functioning of cells in tissues = Move, metabolize, reproduce, etc. The key to the Evolution of Multicellularity has been the ability to establish contact and interaction with other cells. CAM: Different integral membrane proteins called "Cell- Adhesion Molecules" Function: To facilitate the adhesion between itself and other cells, or with others of the same type → giving firmness and specificity Fig. 22-1: General Scheme of the Molecules that bind the cells together and with. ECM Types of adhesion: - Homophilic - Heterophilic Classes of CAM (Adhesion Molecules) Cadherins Homophilic Igs Super Family Selectin Heterophilic Mucins Integrins Cell-Matrix interaction Intercellular adhesion: Cadherin Depends on Ca+2 Selectin Integrins (C-ME) It does not depend on Super Family Igs Ca+2 Fig. 6.2 CAM classes (Adhesion Molecules)  Genetic defect of β 2 Integrin synthesis Leukocyte adhesion deficiencies→ Bacterial infections Connections containing cadherins connect cells to each other → Desmosomes (clusters of adhesion molecules) Fig. 22.5: Adhesion molecules at the junctions involved in intercellular adhesion  Fig 22-5: Desmosomes: -Adhesion Plate Cadherina E + Prot. - Prot. Trans-membrane → desmoglein Adaptadora → desmocollin Catenina + F. actina - Prot. Plate : Placoglobin -F. Intermediate: keratin +Desmoplaquin GAP Unions → cilindric particles (prot. Conexin) → H2O channels→ Bind cytosols → Displaces small molecules and ions , a.a, fosfonucleotides, cAMP(secund menssenger) + hormone Metabolic Cooperation of Cells Fig 22-7: Micrograph E. of the fine cut of the GAP junction → Allows the passage of small molecules between cells Fig. 22-8: GAP Unions Structure.  GAP or Cleft Model - Sub-units of conexin (prot 25.000-50.000 kDa) ↓ 6 molec. (Cell) Hexagonal Particle : 2 conexina molecules 6 molec. (Cell) → Semichannel - 12 genes have been cloned → Family of Conexin ↓ Different peptides ↓ Heterodynamic Channels Difference in the permeability of the channels Adhesion between cells and the ECM In the functions of the CAMs are the unions directly involve ECM and the cytoskeleton Tabla 6.6 Some vertebrate integrins and their ligands (relatively low affinity) ↓ Modulates the adhesion to the MEC  Platelets: they are small cellular fragments of the blood and they act in the coagulation E.g.: Cell-ECM por integrins Platelet membrane (Integrinas αIIb β3) ↓ Formation of clot ↓ Binding integrins to collagen + Fibrinogen after activating platelets Patient with defect in the Integrin cytosolic domain β subunit ↓ Hemorrhage Collagen: Fibrous Protein of ME and connective T. Most abundant Individual Protein There are at least 16 types(80% → collagen types I,II,III) Molecules are grouped into thin fibers Collgen triple helix : Abundant glycine, proline and hydroxyproline motif Gli-Pro-X - Large protein (300 nm) - Ø 1.5 nm - 3 Coiled subunits Table 6-1: Types of Collagen Fig. 22-17: Assembly F. Collagen begins RE and is completed outside the cell. Steps of Collagen Biosynthesis Fig. 22-17: Collagen type IV. Basal lamin  Component NO Collagen of Extracellular Matrix ECM: - Collagen (insoluble) 1) Prot. Multiadhesives: - Function: Join Molecule tail to ME - They bind Fibronectin receptors 2) Proteoglycans: Molecule Protein center and multi-chains polysaccharide 3) Hyaluronano (Hyaluronic Ac.) Function: Give ECM volume, diffusion of molecules between cells and tissues Prot. Laminin + Collagen IV Form the two-dimensional reticulum of the basal lamina Fig 22-19: Structure of laminin → Protein in the shape of a cross. Heterodimer multiadhesive product. It is on all the basal lamina Fig. 6-13: Model of the basal lamin Entactin Fibronectins: Dimer of 2 polypeptides attached at the carboxyl termini by Disulfide bonds, c/u → 60-70 mm de largo. Ø → 3nm Fig 22-22: Structure of the fibronectin chain (6 adhesion domains) Proteoglycans: It consists of multiple glycosaminoglycans linked by a central protein Function: They act as anchors of cells. Fibronectins bind + Collagen in ECM Fig. 6-22: Proteoglycan aggregate structure of a cartilage What is Mechanotransduction? Interaction between endothelial cells Also, this molecule is called as ……….. CELL BIRTH or Stem Cell, LINEAGE, AND DEATH Prof. Lilian Spencer The mode of reproduction also changed, with some cells becoming specialized as germ cells (e.g., eggs, sperm), which give rise to new organisms, as distinct from all other body cells, called somatic cells. - The mode of reproduction also changed, with some cells becoming specialized as germ cells (e.g., eggs, sperm), which give rise to new organisms, as distinct from all other body cells, called somatic cells. Cell lineages are controlled by intrinsic (internal) factors—cells acting according to their history and internal regulators—as well as by extrinsic (external) factors such as cell-cell signals and environmental inputs (FIGURE) A cell lineage begins with stem cells, unspecialized cells that can potentially reproduce themselves and generate more-specialized cells indefinitely. What is a Stem Cell? Stem cells are defined functionally as cells that have the capacity to self-renew as well as the ability to generate differentiated cells. A cell lineage ultimately culminates in formation of terminally differentiated cells such as skin cells, neurons, or muscle cells. Terminal differentiation generally is irreversible, and the resulting highly specialized cells often cannot divide; they survive, carry out their functions for varying lengths of time, and then die. - Many cell lineages contain intermediate cells, referred to as precursor cells or progenitor cells¸ whose potential to form different kinds of differentiated cells is more limited than that of the stem cells from which they arise. - Typically we think of cell fates in terms of the differentiated cell types that are formed. A quite different cell fate, programmed cell death, also is absolutely crucial in the formation and maintenance of many tissues Stem Cells Give Rise to Stem Cells and to Differentiating Cells: A pluripotent (or multipotent) stem cell has the capability of generating a number of different cell types, but not all. A pluripotent blood stem cell will form more of itself plus multiple types of blood cells, but never a skin cell. In contrast, a unipotent stem cell divides to form a copy of itself plus a cell that can form only one cell type. In contrast to apoptosis, cells that die in response to tissue damage exhibit very different morphological changes, referred to as necrosis. Typically, cells that undergo this process swell and burst, releasing their intracellular contents, which can damage surrounding cells and frequently cause inflammation. Process of Apoptosis What are the genes that regulate the apoptosis process? Final Examen Martes 26 de Noviembre Hora: 8: 30 AM Aula: aula A-17 del segundo piso del Senecyt (SE-PA2-A17) Por confirmar