addition unicellular organisms communicate with each other. Signals may use light‚ or touch but we will focus on chemical signals. 1. External signals are converted to responses within the cell a. Evolution of cell signaling i. In yeast a cells and αcells both secrete chemicals‚ which can only be received by the alternate type yeast. This signals the two cells to join via fusion 1. The process by which the signal on the surface of the cell is converted to a series of
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Chapter 33 notes: Intrinsic cellular defense against virus infection 1. Toll- like receptors sense virus infections a. Toll-like receptors (TRL) i. Located on the cell surface or in endosomal membranes = recognize conserved structures found in pathogens ii. Highly conserved receptors from flies humans iii. Most mammals have between 10-15 (humans = 10) iv. TLR – 2: lipoproteins/glycoproteins (mealsels‚ hepB‚ herpes) v. TLR– 3: dsRNA (west
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allowing acts on both AMPA and NMDA receptors. Sodium receptors are then able to flow through the AMPA. Next the depolarization of postsynaptic cells relieve the MG2 block to the NMDA. This allows sodium and calcium to flow to the dendritic spine. Thirdly the increase of calcium binds to calmodulin to activate calmodulin kinase which then undergoes autophosphorylation. Which means they become more sensitive to glutamate and promotes movement to the AMPA receptors. Lastly the entry of calcium activates
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noradrenaline‚ 5 HT transporters Receptors * Serve as recognition sites for specific endogenous compounds such as: 1. Neurotransmitters‚ e.g. noradrenaline 2. Hormones (thyroid hormones) 3. Local Hormones /Autacoids (released and act upon the same/nearby tissue‚ e.g. prostaglandins) Drug Receptors Most drugs exert their effects‚ by interacting with receptors present on the cell surface or intracellularly Action occurs when drug binds to receptor and this action may be: Ion channel
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The medulla oblongata then puts out an increase in sympathetic input to release adrenaline‚ a hormone of the endocrine system‚ which causes vasoconstriction. The vasoconstriction would then cause the blood pressure to rise back to normal. The body also regulates blood pressure by increasing or decreasing sympathetic and parasympathetic input of the nervous system. By increasing sympathetic input and decreasing the parasympathetic input‚ the body’s “fight or flight” response is triggered. The
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factor receptor (CNTF) also known as Akt contains three isoforms and regulates metabolism etc. Activation occurs down stream of P1-3K pathway. GSK is important and dysregulation of PK3 leads to Cancer‚ Diabetes and Schizophrenia. 2. Notch Signaling Pathway The Notch signaling pathway is a fundamental signaling system used by neighboring cells to communicate with each other in order to assume their proper developmental role. Notch proteins are cell surface transmembrane-spanning receptors which mediate
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1. Taxol its generic name being palitaxel stabilises cytoskeletal microtubes and thus spindles cannot be formed so cell division is prevented. During telophase taxol causes the reversal of prophase events such as the chromosomes decondense‚ spindle disassembly‚ nuclear envelope reformation‚ the Golgi apparatus and E.R. reform and the nucleus also reforms. Cytokinesis effects are that the cell still divides for animal cells a cleavage furrow made of actin and myosin II constricts the middle of the
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each lymphatic cell has receptors that enable them to recognize foreign substances. There are two major subtypes of T cells: the helper T cell and the killer T cell. Helper T cells are the major driving force and the main regulators of the immune defence. These cells do not kill infected cells or clear pathogens directly. Their primary task is to activate B cells and killer T cells. For helper T cells to activate any other cell‚ they themselves need to be activated. This happens through a process
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Platelets and clotting factors of the blood migrate to the injury site to heal the wound and confine infectious agents to the site. This hinders the spread of the pathogen throughout the body. Cells surrounding the injury site release chemical signals called chemokines. These will be in higher concentrations closer to the injury site. This allows a “route” for phagocytic cells to migrate to the area of infection. Symptoms of the immunological response include redness of the infected area (accounted
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identified by the two receptors involved in thermoregulation; the hypothalamus and the peripheral thermoreceptors. The peripheral thermo-receptor is located in the dermal layer of the skin and is able to detect a change in external temperatures - which is the stimulus. The hypothalamus is a portion of the brain that is the control centre for thermoregulation. Thermo-receptors on the anterior region of the hypothalamus are able to detect the change in blood temperature. As these receptors detect the change
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