INTRODUCTION AND CELLULAR LEVEL OF ORGANIZATION.pptx
- 1. Miss .P. G.Kamble Assistant Professor M. Pharm (Pharmaceutics) Gourishankar Institute of Pharmaceutical Education and Research Limb,Satara
- 2. CELL Cell is the living, structural and functional unit of the body enclosed membrane. There are about 200 different types of cells in our body . All cell arises from existing cell by the process of cell division. In which one cell divided into two cells. Cell biology is the study of cellular structure of and function,structure of cell intimately related to its function.
- 3. 1. Plasma membrane 2. Cytoplasm a. Cytosol b. Organelles 3. Nucleus
- 5. The plasma membrane, or the cell membrane, provides protection for a cell. It also provides a fixed environment inside the cell. And that membrane has several different functions. One is to transport nutrients into the cell and also to transport toxic substances out of the cell. The plasma membrane functions as a physical barrier between the external environment and the inner cell organelles
- 6. A Physical Barrier. ... Selective Permeability. ... Endocytosis and Exocytosis. ... Cell Signaling. ... Phospholipids. ... Proteins. ... Carbohydrates. ... Fluid Mosaic Model.
- 7. The cytoplasm has two components: a.Cytosol The cytosol, by definition, is the fluid in which organelles of the cell reside. This is often confused with cytoplasm, which is the space between the nucleus and the plasma membrane. The primary component of cytosol is water. Water makes up 70% of a cell and is primarily in the cytosol to dissolve other components. b.Organelles: Nucleus. Known as the cell's “command center,” the nucleus is a large organelle that stores the cell's DNA (deoxyribonucleic acid). ... Ribosomes. Ribosomes are the protein factories of the cell. ... Endoplasmic reticulum. ... Golgi apparatus. ... Chloroplasts. ... Mitochondria.
- 8. These are tiny granules composed of RNA &Protein. They synthesize protein from amino acids using RNA. When this is present in free units in the cytoplasm,the ribosomes make proteins for use within the cell. Ribosomes are also found on the outer surface of the nuclear envelope and rough endoplasmic recticulum where they manufacture proteins for export from the cell.
- 9. It is the series of interconecting membranous canals in the cytoplasm. There are two types of endoplasmic reticulum 1.Smooth endoplasmic reticulum Here is lack of ribosomes. 2. Rough endoplasmic reticulum This is studded with ribosomes that synthesize proteins.
- 11. It consist of stack of closely folded flattened membranous sac. It present in all cells but is larger in those cells that synthesize and export proteins. The proteins move from ER to golgi apparatus where they are packaged into membrane bound vesical called secretory granules. The vesicles are stored and when needed more to plasma membrane, through which the proteins are exported.
- 13. Every cell in the body has nucleus,with exception of mature RBC. Skeletal muscle and some other cell contain several nuclei. It is larger organelle of the cell and is contained within nuclear envelope. The nucleus containing body’s genetic material which directs all metabolic activities of the cell. This consist of 46 chromosomes, which are made from DNA.
- 14. This is also called as ‘power house of the cell’. They are involved in the aerobic respiration. The process by which chemical energy made available in the cell. This energy in the form of the ATP which releases energy when the cell break it down. Synthesis of ATP is most efficient in the final stage of aerobic respiration process requiring oxygen.
- 15. Motion of substances in and out of the cell. Cell membranes are selectively permeable. Two types of transport mechanism: 1. Passive transport 2. Active transport
- 16. Passive transport is movement of molecules through the membrane in which no energy is required from the cell. Active transport requires energy expenditure by the cell.
- 17. Passive transport is movement of molecules through the membrane in which no energy required from the cell. Molecules move in response to a concentration gradient. - A concentration gradient is difference between the concentration on one side of the membrane and that on the another side. - Passive transport mechanisms only movement substances along the concentration gradient.
- 18. Passive transport mechanisms only movement substance along the concentration gradient. Substances move from an area of high concentration to an area of low concentration. Mechanisms of passive transport: 1.Diffusion movement of solute molecules from high solute concentration to low solvent concentration. 2.Osmosis Movement of solvent water from high solvent concentration to low concentration.
- 19. Diffusion is movement of solute molecules from high concentration to low concentration.
- 20. There are two types of diffusion I. Simple Diffusion II. Facilitated Diffusion
- 21. Substance pass directly through the cell membrane. The cell membrane has limited permeability to small polar molecules, water and ions. The motion of water across the cell membrane is known as osmosis. The rate (molecules) of simple diffusion depends on the degree of concentration gradient . At equilibrium, substances pass in out of the membrane at equal rates.
- 22. Substances must pass through transported proteins to get through the cell membrane. The cell membrane is selectively permeable. Carrier proteins bind to the molecule that they transport across the membrane. Selective permeability : integral membrane proteins allow the cell to be selective about what passes through membrane. Channel proteins have a polar interior allowing polar molecules to pass through. Carrier proteins bind to specific molecule to facilitate its passage.
- 24. Carrier proteins bind to specific molecule to facilitate its passage
- 25. Osmotic concentration is determined by the concentration of all solutes in solution.
- 26. Active transport Requires energy – ATP used directly or indirectly to fuel active transport. Able to moves substances against the concentration gradient-from low to high concentration. -allows cells to store concentrated substances. Requires the use of carrier proteins.
- 28. Bulk transport of substances is accomplished by 1.Endocytosis –movement of the substances into the cell. 2.Exocytosis –movement of the substances out of the cell. Endocytosis: occurs when the plasma membrane envelops food particles liquids. 1.phagocytosis: the cell takes in particulate matter. 2.pinocytosis:the cell takes in only fluid. 3.receptor-mediated endocytosis-specific molecules are taken in after they bind to a receptor.
- 29. Interacellular space in closely packaged tissue is about 20 nm .the cells are bound together by the specific adhesive glycoprotein. Epithelial cells are adhere to each other through glycoproteins called cadherins. Modified cell membrane contributing in cohesion and communication are called cell junctions.
- 30. There are three types of cell junctions 1.Tight junctions or occluding junctions 2. Adhering junctions 3.Communicating junctions
- 31. Found in epithelial tissues. Also known as “tight junctions” Do not allow passage of small molecules form impermiable membrane Types : 1.Zonula Occludens 2.Fascia Occludens
- 32. Encircles the entire cell perimeter. Occludes the interacellular space Series of local fusions The adjacent cell membranes approach each other, outer leaflets fuse ,diverge again and then fuse again. At fusions sites specific trans membranous proteins named (occludins and claudins) perform the binding function Less in PCT and more in the intestinal mucosa.
- 33. A strip like tight junction of limited extent . Found between the endothelial cells of the blood vessels.
- 34. Anchoring junctions Provide cell-cell or cell to basal lamina adherence Types 1.Zonula adherens 2.Fascia adherens 3.Macula adherence (Desmosomes) 4.Hemidesmosomes
- 35. A belt like junction . No fusion of cell membrane. Trans membraneous glycoprotein “ E-cadherin” occupies intracellular gap. E-cadherin links to adherent proteins in cytoplasm which are : 1.Cadherin 2.Vinculin
- 36. Structurally it is similar to zonula adherence. But its cell junction is strip–like (not ring-like or belt – like). i.e cardiac muscle cells.
- 37. Macula adherins are commonly known as desmosomes. “spot-weld” like junctions. Randomly distributed along lateral plasma membranes of the cell in simple epithelium In stratified epithelium it is distributed throughout the plasma membrane It is also found in cardiac muscle cells Cell membrane in the region of junctions are seen further apart (30mm) than the usual gap .
- 38. Electron dense attachment plaques are loacated opposite to each other on the cytoplasmic aspects. Intermediate filaments of the cytoskeleton are anchored to the attachment plaques Two types of transmembranes glycoproteins named desmogleins provide adherence
- 39. These junction serve to anchor the epithelial cells to the basal lamina. A hemidesmosomes is a spot like adhering junctionjwhich gives appearance of half desmosome. In hemidesmosome transmembrrane linker proteins are integrins The cytoplasmic intermediate filaments of keratin are inserted in to the attachment plaque.
- 40. Characterized by presence of minute tubular passageways. Provide direct cell to cell communication. Tubular passages allow movement of ions and other small molecules between adjacent cells.
- 41. Gap junction are also called “nexus” which are communicating junctions,occur frequently between the epithelial cells. Also found in cardiac muscle cells,smooth muscles,nurons ,astrocytes and osteocytes Plasma membrane of the adjoining cells are closely opposed with a gap of only 2 nm. The gap junction contains closely packed numerous tubular intercommunicating channels.
- 42. The lumens of the channels of gap junction have an average diameter of 1.5 nm. These channels permit free passage of ions, sugar and amino acids. In cardiac and smooth muscles the gap junction provides electrical coupling of the adjacent cells. Gap junction are frequently found in embryonic cells.
- 44. Mitosis The process of cell division which results in the production of two daughter cells from a single parent cell. The doughter cells are identical to one another and to the original parent cell.
- 45. 1. Interphase 2. Prophase 3. Metaphase 4. Anaphase 5. Telophase
- 46. DNA replicated Organelles replicated Cell increases in size
- 47. The cell prepare for nuclear division. Chromosomes become visible under light microscope. Threads become shorter and thicker consist of two chromatids joined by centromere. Nucleoli disappears. Centrioles seprates and migrate to each pole and starts giving out mitotic spindle.
- 48. The cell prepares chromosomes for division Chromosomes line up at the center of the cell. Spindle fibers attached from doughter cells to chromosomes at the centromere. Equatorial plate is formed. Microtubules of mitotic spindle are attached at centromere. Microtubules exert pull on the chromosomes.
- 50. The chromosomes divide Spindle fibres pull chromosomes apart. Half of each chromosome (called chromatid ) moves to each doughter cell. Chromatids seprate and move to respective poles as an independent chromosomes . In human cell two identical sets of 46 chromosomes move to the opposite poles.
- 52. The cytoplasm divides A constriction called clevages forrow appears in the middle of elongated cell. Nuclear envelop is formed enclosing chromosomes 2 nuclei form. Cell wall pinches in to form the 2 new doughter cells.
- 54. Meiosis is the type of cell division by which germ cells (eggs and sperm) are produced. One parent cell produces four doughter cells. Doughter cells have half the number of chromosomes found in original parent cell. During meiosis , DNA replicates once but the nucleus divides twice. Four stages can be described for each division of the nucleus.
- 55. Prophase is much longer consisting of five stages. 1. Leptotene : chromosomes becomes visible in the nucleus. 2. Zygotene:homologus chromosomes come together along their entire length and synapses are formed. 3. Pachytene: chromosomes become thicker and shorter. Each chromosome pair is bivalent.
- 56. 4.Diplotene :chromosomes began to nseprate along their entire length.Each bivalent consists of four chromatids. 5.Diakinesis:sepration of chromosomes continue.Nucleolus and the nuclear envelop disappeares.
- 57. A spindle of microtubules is produced by centrioles. Equatorial plate is formed. The bivalent chromosome pairs align in the centre of spindle.
- 58. Chromosomes of homologus pairs completely seprates and move to opposite poles. No division of centromere occurs and the whole chromosomes move to opposite poles.
- 59. Nuclei are reconstructed The parent cell is divided into two daughter cells. Each daughter cell contains haploid (23) chromosomes. Each chromosome is double structured consisting of two sister chromatids.
- 60. Mitosis Meiosis Cell divides once Cell divides twice Two daughter cells Four haploid daughter cells Genetic information is identical Genetic information is different
- 61. Cell signaling is part of complex system of communication that governs basic activities and coordinates cell actions. The ability of cells to perceive and correctly resspond to their microenvironment is the basis of development, tissue repair,and immunity as well as normal tissue homeostasis. Classification: The signals can be categorized based on the distance between signaling and responder cells,signaling within , between and among the cells subdivided into the
- 63. 1. Intracrine signals are produced by the target cell that stays within target cell. 2. Autoacrine signals are produced by target cell, are secreated and affect the target cell itself via receptors,sometimes autocrine cells can target cells close by if they are tha same type of cell as the emitting cell. An example of this is immune cells. 3. Juxtacrine signals target adjacent (touching) cells.these signals are transmitted along the cell membranes via protein or lipid components integral to the membrane and capable of affecting either the emitting cell or cells immediately adjacent. 4. Paracrine signals target cells in the vicinity of the emitting cell. Eg. Nutotanmitters.
- 64. 5. Endocrine signals distant cells.Endocrine cells produce hormones that travel through the blood to reach all parts of the body. 6. Some cell-cell communication requires direct cell- cell contact. Some cells can form gap junctions that connect their cytoplasm to the cytoplasm of adjacent cells.
- 65. In which two adjacent cells must make physical contact in order to communicate.This requirement for direct contact allows for very precise control of cell differentiation during embryonic development.In the worm caenorhabditis eleagans,Two cells of the developing gonad each have an equal chance of terminally differentiating or becoming a uterine precursor cell that continues to divide.The choice of which cell continues to provide is controlled by competition of cell surface signals.One cell will happen to produce more of cell surface protein that activates the notch receptor on the adjacent cell.
- 66. Paracrine signals such as retinoic acid target only cells in the vicinity of the emitting cell.Nurotransmitters represent another example of a paracrinr ignal.Some signaling molecules can function as both a hormone and a nurotransmitter.For example,epinephrine and norepiephrine can funtion as hormones when released from the adrenal gland and are transported to the heart by way of the blood stream.
- 67. Synaptic signaling is the special case of paracrine signaling (for chemical synapses) or juxtacrine signaling (for electrical synapses) between the nurons and atrget cells.Signaling milcecules interact with target cell as a ligand to cell surface receptors,and/or by entering into the cell through its membrane or endocytosis for intracrine signaling. This generally results in the activation of second messengers,leading to various physiological effects.
- 68. Many cells signals are carried by molecules that are released by one cell and move to make contact with another cell. Endocrine signals are called hormones.Hormones are produced by endocrine cells and they travel through the blood to reach all parts of the body. Specificity of signaling can controlled if only some cells can respond to a particular hormone.