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Cell Biology 2

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Cell Biology 2 Syllabus Lectures: 1. differentiation of animal cells in respect to their function and morphology Cell biology 2. mechanisms of differentiation and dedifferentiation (regeneration) Laboratory courses: Iveta Herichová 1. how to use pipette in cell culturing techniques, types of cell culture and [email protected] their maintenance B2-422 2. cell culture viability, monitoring, growth curve Department of Animal Physiology and Ethology Faculty of Natural Sciences Comenius University in Bratislava web page: https://fns.uniba.sk/pracoviska/biologicka-sekcia/kzf/studenti/bakalarske-studium/ Differentiation - development and differentiation during embryogenesis - neurons - development and differentiation in mature individuals - blood cells - epithels What does happen during the cell cycle? 1. generation of new organelles and DNA replication Is the course of cells cycle the same during our lives? 2. delivery of synthesized compounds into newly formed cells the cell during division - all activities must be properly coordinated and timed - G1(gap) phase - synthesis of mRNA, proteins, organels, preparation for DNA replication - S (synthesis) phase - DNA replication - G2 (gap) fáza - syntéza mRNA, proteínov, organel, príprava na mitózu - M (mitosis) fáza - mitóza a cytokinéza Attention! cell cycle is not mitosis, mitosis in only one part of cell cycle 1 Cell cycle control in animal cells - during embryonic development: RNA, proteins mitosis, cytokinesis cell division is synchronous Lamin and the identical cells are arising H1 Abl Cyc B/(A) G2 M Cyc D’s G0 CDK1 3-4 h 1 h CDK4,6 resp. Cdc2 G1 S DNA, RNA, 6-12 h RNA, proteins proteins 6-8 h p53 Cyc A Cyc E pRb CDK2 CDK2 Cell cycle Does the cell cycle show inter-species differences? - regulatory systems of cell cycle has to activate enzymes and proteins necessary for the next step of the cell cycle and deactivate them after they are not needed -the regulatory system of cell cycle must be responsive to signals from another cells in - each step of cell cycle must be correctly finished before multicellular organisms mnohobunkových organizmov beginning of the next step e.g., stimuli informing that more cells of that particular e.g. new DNA replication can not be initiated before cell type is needed finis mitosis and acquire necessary size - number of cells of the tissue can be regulated by - regulatory systems has to be responsive to external programmed cell death conditions - if a regulatory system of the cell cycle does not work properly, after accumulation of several mistakes a cancer can develop - G1, S, G2, M phase http://outreach.mcb.harvard.edu/animations/preloaderStemCells.swf Is whole DNA (all genes) active? Is DNA (genes) in different tissues the same? 2 Is amount of used DNA still the same during the What is the difference between toti- a uni- potent cell? differentiation? What is relationship between active genes and physiological functions? Differentiation - principle - cells express different morphological, physiological na biochemical properties - it is caused by differently expressed genes (specific parts of DNA via corresponding mRNA and proteins exhibit different functions) What does cause gene expression differences? - factors influencing gene expression (physical, chemical) - coming from external environment - coming from other cells - cell signaling – in next lectures (prof. Tomaška) http://outreach.mcb.harvard.edu/animations/preloaderStemCells.swf Differentiation - principle in human body cells differentiate to be able to fulfill their specific physiologic functions - they can perform their role as single cells - or as a part of tissue or organ factor 1 - in both cases they has to cooperate with all other cells, factor 4 factor 2 tissues and organs in the body factor 3 factor 5 factor 6 3 Examples of differentiated cells and their physiological function What kind of cell is typical by high metabolism and lasts for decades? - cell with high metabolism that live during whole - the smallest unit of major regulatory and integrating system of the human life human body - it is able to quickly and precisely convey information from - short time living cells with low metabolism receptors to central neural system and mediate the response to effectors - short time living cells with high metabolism - they created complicated network neurons Neuron The central neural system is the main regulatory and integrative structure: cell body (soma), dendrites, axon (neurite), axon hillock, initial segment, myelin structure of the organism sheath - regulates or modulates functioning of all organs, coordinates their Nucleus (contain DNA, regulated cell development and activity) functioning and relationships in respect to organism needs Mitochondrion (oxidative metabolism, ATP production) - it closely cooperates with endocrine system Ribosomes (usually associated with endoplasmatic reticulum, protein synthesis) - the primary role of NS in respect to ES is given by these features: Golgiho system (protein modification, sorting and traffiking, membrane renewal) Lyzosomes (enzymatic degradation) accuracy, speed and capacity of information registration Vezicules (endocytosis or exocytosis) prompt new data processing and analysis in context with data in Endoplasmatic reticulum – ER (protein and lipid synthesis) memory storage synthesis and output information to maintain homeostasis - specific features of neuron organeles Principles of neural system development: - very robust rough endoplasmic reticulum called Nissl bodies (they absorb Nissl 1. functional differentiation of neural cells stain very well) 2. concentration of neural cells into ganglia - many vesicles containing neurotransmitters 3. centralization, development of brain ganglia, bilateral symmetry 4. increase in number of neural cells Differentiation of neuron - morphology – cell structures - synthesis of specific neurotransmitters - cell membrane differs in its features even within single cell 4 link Microtubular structure Microtubules - in eukaryotic cells grow from - tubulin diemer binding GTP, after centrosomes localized close to GTP hydrolysis tubulin nucleus dimers dissocite - globular proteins: α- - they position organelles inside tubulin and β-tubulín the cell - tubulin dimers create - they create pathway for protfilament, 13 protofilaments create vesicular trafficking tubilin czlinder 25nm in diameter α-tubulin end = minus end β-tubulin end = plus end (growing) 5 Prepojený obrázok sa nedá zobraziť. Súbor bol pravdepodobné presunutý, premenovaný alebo odstránený. Skontrolujte, či prepojenie smeruje k správnemu súboru a umiestneniu. Axonal transport Anterograde transport – from cell body to synapse 0.5 mm/days - 400 mm/day quick transport – up to 410 mm/day, molecules including complex proteins packed into vesicles intermediate transport - cca 200 mm/day slow transport – less than 6 mm/day, transport of proteins (not packed in vesicles) Retrograde transport – transport from periphery to cell body – only material packed into vesicles - 200 mm/days Motor proteins: kinesin discovered first kinesin (anterograde transport): - two ATP-binding heads and a tail. Energy derives from continuous ATP hydrolysis by ATPases present in the heads. The head domains interact with microtubules, and the tail binds to specific receptor binding sites on the surface of vesicles and organelles. •hydrolysis of one ATP mol. – conformation change = 1 step •1 step = 8nm = 1 tubulin dimer dynein - retrograde transport Neurotransmitter definition: Neurotransmitters 1. It is synthesized in the neuron. 2. It is released in amount sufficient to cause a specific effect. • Neurotransmitter is chemical 3.If an exogenous chemical is administered it cause the same effect like endogenous neurotransmitter compound released from presynaptic 4. There is a specific mechanism of neurotransmitter elimination from synaptic membrane. It is diffusing through cleft synaptic cleft and allow action potential Acetycholine Acetycholine: Biogenic aminey: • autonomous NS (all preganglionic and propagation. dopamine parasymphatetic postganglionic connections) noradrenaline • CNS: spinal cord, medulla oblongata adrenaline • neuromuscular connections serotonin receptory: • There are excitatory and inhibitory histamin •muscarinic type: v srdci, inhibítor atropín, agonist Aminoacids: muscarine neurotransmitters. γ-aminobutyric acid (GABA) •nicotinic type: nervovosvalová platnička, inhibítor glutamate kurare, agonist nicotine glycine it is hydrolyzed by enzyme acetylcholinesterase on postsynaptic membrane Noradrenalin: membrane • most of sympathetic postganglionic features differ within connections one cell in •CNS: hypothalamus, medulla such a way that only in oblongata, cerebellum axon can receptors: produce action •α usually excitatory potential •β usually inhibitory some NA is taken up by glial cells, some is taken up by presynaptic membrane and some is oxidized by MAO or carboxylated by katechol-O- metyltransferase Action potential: - is basic physiological capacity of neuron Neuromodulators: - it is caused by selective change in membrane permeability for ions, which is cause of small local modulate sensitivity of postsynaptic membrane current generation and its propagation and activation of next neuron endorphíns, enkephalins, P substance, prostaglandins - it is generated always in the same way and it is propagated without decrement - myelinated axons can propagated action potential more quickly 6 Differentiation - cell with high metabolism that live during whole human life - short
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