vertebrates‚ which can be considered analogous to sensory cells of the antennae of invertebrates. In humans‚ olfaction occurs when odorant molecules bind to specific sites on the olfactory receptors. These receptors are used to detect the presence of smell. They come together at the glomerulus‚ a structure which transmits signals to the olfactory bulb (a brain structure directly above the nasal cavity and below the frontal lobe).[2] Many vertebrates‚ including most mammals and reptiles‚ have two distinct olfactory
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What kind of molecules can and cannot pass easily across a lipid bilayer? Structure of a lipid bilayer A lipid bilayer is a membrane mainly composed of lipid molecules‚ usually a phospholipids (See Figure 1). Phospholipids are formed from 3 components :- (1) 2 fatty acids tails – these are hydrophobic; (2) a negatively-charged hydrophilic phosphate group; and (3) a glycerol backbone. The bilayer structure is favourable energetically because the hydrophobic fatty acid tails cluster
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Chapter 11: Cell Communication Concept 11.1 External signals are converted to responses within the cell. I. Evolution of Cell Signaling 1. signal transduction pathway. a specific cellular response in a series of steps 2. signaling mechanisms first evolved in ancient prokaryotes and unicellular eukaryotes‚ then adopted for new uses 3. quorum sensing. allows bacterial populations to coordinate behaviors to carry out activities only productive when performed by a given number of cells
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tactile sensilla receptor is posted on figure 1. FIGURE 1: Mean action potential activity of tactile sensilla receptors in femural of cockroach. In this experiment‚ it was found that there exists a spontaneous resting activity within the cockroach tibia even though tactile sensilla receptors have not yet been stimulated. From figure 1 it can be observed that the mean spontaneous resting activity of the cockroach leg is (42+/-9.7) action potentials/sec. After the tactile sensilla receptors were stimulated
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(earthworm)‚ arthropods (crab)‚ and molluscs (squid) the nervous system shows further advances * Cephalization - concentration of ganglia and sensory receptors in a head region * Ganglion (pl. ganglia) - cluster of neurons Vertebrate Nervous Organization * Cephalization‚ and bilateral symmetry‚ results in paired sensory receptors to gather information about environment * Eyes‚ ears‚ and olfactory structures * Central nervous system (CNS) * Spinal cord and brain
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and Medicine College of Physicians and Surgeons Columbia University New York‚ NY 10032 Cytokines and STAT Signaling 1. Introduction First discovered as the major signal transducer in interferon-mediated gene activation‚ STATs (signal transducers and activators of transcription) are now known to play a significant role in signal transduction for most cytokines. STATs represent a family of conserved proteins‚ seven of which have been identified in mammals (i.e.‚ Statl‚ 2‚ 3 ‚ 4 ‚ Say5b‚ and 6;
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Cells come from pre-existing cells via division Cells of all organisms fundamentally similar in structure‚ function‚ and metabolic functions Contain hereditary information passed down during cell division A cell’s volume increases faster than it’s surface area Less surface area = less are for nutrient/waste diffusion Solves via: Dividing‚ getting thinner‚ form microvilli‚ store nutrients (Microvilli – within small intestine) Cells are highly organized‚ 3 basic parts Plasma membrane Selective
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Contents Oncogene An oncogene is a kind of abnormal gene that predisposes cells to develop into cancers. Unlike normal genes‚ which can be turned off after being turned on‚ oncogenes are altered in a way that keeps them stuck in a state of constant activity. That uninterrupted action helps drive the uncontrolled growth that underlies tumors. Oncogenes can be turned on by inherited changes - ones that are passed down from parent to child - or by cancer-promoting agents that
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signaling based on distance from source to reception. Section: 09.01 Overview of Cell Communication Topic: Cell Communication 4. In response to injury‚ cell fragments called platelets get activated to induce clotting. Activated platelets release factors that can in turn bind to specific membrane receptors on nearby cells. What type of signaling would this be considered? A. Direct contact B. Paracrine C. Endocrine D. Synaptic E. Autocrine Since the factors are acting
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BSCI422 Immunology January 26‚ 2010 Lecture 1 Introduction to the class Went over syllabus Student expectations BSCI422 Immunology January 27‚ 2010 Lecture 2 Innate Immunity‚ the signal transduction and cytokine production When you’re exposed to a microbe‚ your body has innate immune responses that can kill the microbe right away‚ there is no recovery or memory period. It is the very first response. If you amount an affective innate immune response‚ you don’t need to develop an adaptive
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