Term
| How does a cell organize itself? |
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Definition
| organelles isolate, organize, and segregate reactions |
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| Name the cell compartments |
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Definition
| Nucleus, endoplasmic reticulum, golgi apparatus, lysosomes, mitochondria, endosomes, peroxisomes, which are all surrounded by cytosol and enclosed in the plasma membrane |
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| the most prominent organelle, contains the genome |
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| in the middle of the nucleus, plays a role in rRNA synthesis |
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Definition
| the double membrane surrounding the nucleus. has nuclear pores that allow it to communicate with the cytosol. the outside of the membrane is continuous with the ER |
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Definition
| a system of interconnected sacs and tubes of membrane |
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| rough areas of the ER that have ribosomes attached |
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| smooth areas of the ER without ribosomes |
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| synthesis of lipids and membranes, distribution of newly synthesized proteins to other organelles and plasma membrane |
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| many protein molecules can be synthesized in a given time |
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| series of five to eight cup shaped membrane covered sacs called cisternae that look like a stack of deflated balloons |
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| Golgi apparatus functions |
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Definition
| receives proteins and lipids from the ER through cis-face, modifies them and dispatches them through trans-face to different destinations in the cell |
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Definition
| the site of intracellular digestion. small sac of digestive enzymes that degrades defectively synthesized macromolecules, worn out organelles, and foreign particles |
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| contain a set of enzymes that destroy toxic molecules by oxidation, rendering the potentially toxic substance safe for release back into the cell |
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| rod shaped organelles surrounded by a double membrane. considered the power generators of the cell, ATP synthesis by oxidative phosphorilation |
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| the liquid inside the cell; 70% water + a complex mixture of substances dissolved in water: small molecules such as ions, large complexes of enzymes that act together to carry out metabolic pathways |
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Definition
| the cytosol PLUS the organelles suspended within it except for the nucleus |
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Definition
| protein scaffold throughout the cytoplasm that maintains the cell shape, provides tracks for directing the traffic of vesicles between organelles, and is involved in cell movement |
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Term
| Where are proteins synthesized? |
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Definition
| all proteins are synthesized in the cytosol on the ribosomes located on the ER membrane. some are transported to various membrane enclosed compartments, others remain in the cytosol, and some are secreted outside of the cell. |
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Term
| How are proteins directed to their destination? |
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Definition
| they are directed to their specific compartments using "address labels" or signal sequences. |
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Term
| Signal sequences or sorting signals |
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Definition
| a sequence of amino acids that directs the proteins to the correct organelle; those destined to the cytosol lack any sort of sequence. |
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Term
| What happens when a sorting signal is experimentally moved from one protein to another? |
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Definition
| the proteins will switch destinations, the only way a cell knows where to send the protein is from that sequence |
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Term
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Definition
| proteins are translocated into organelles by 3 mechanisms. synthesis begins on ribosomes in the cytosol. it's location is completely dependent on the amino acid sequence that contains the sorting signal. |
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Term
| Protein translocation mechanism: Nuclear Pores |
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Definition
| selective gates. the signal sequence is recognized by the transport receptor and the receptor is recognized by the nuclear pores and allowed in. |
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Term
| Protein translocation mechanism: Translocators in Organelle Membranes |
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Definition
| seen in the mitochondria and other organelles. the signal sequence is recognized by a receptor in the membrane that will facilitate the protein transfer through membrane proteins that function as "translocators." once inside, the proteins remain there and the signal sequence is cleaved off. proteins synthesized on ribosomes attached to the ER enter the ER while being synthesized and then are often further transported to the Golgi apparatus. |
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Term
| Protein translocation mechanism: Vesicular Transport |
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Definition
| occurs betweens membrane enclosed compartments- highly organized. transport vesicles bud from one membrane and fuse with another, carrying membrane components and soluble proteins between cell compartments and to and from the extracellular space. |
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Definition
| inward vesicular pathway; receptor mediated. cells continuously take up fluid and small or large molecules from the extracellular space. the material to be taken in is enclosed by a small portion of the membrane, which buds inward and forms an intracellular vesicle called an endosome. this is delivered to the lysosome where it is degraded. |
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Definition
| outward vesicular pathway; secretory pathways. proteins destined to be secreted outside the cell are labeled in the golgi apparatus. transport vesicles bud from the golgi apparatus and take these proteins to the cell surface. |
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Definition
| exocytosis where the proteins are continually secreted from the cell, i.e. collagen. |
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| exocytosis where the proteins are concentrated and stored in vesicles that wait for a signal that stimulates them to fuse with the plasma membrane and release their content to the cell exterior, i.e. insulin secreted due to increased glucose concentration |
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| endocytosis that transports fluids and small molecules |
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| endocytosis in specialized cells that transports large particles |
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| macrophages and neutrophils are specialized cells that ingest large particles though phagocytosis and defend against infection |
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Term
| Where do materials to be degraded in the lysosomes come from? |
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Definition
| phagocytosis, R-mediated endocytosis, autophagy |
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Term
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Definition
| degradation of obsolete parts of the cell itself |
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Term
| **First General Step of Cell Signaling** |
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Definition
| Information comes as the signal (primary messenger) and stimulates a target cell by binding to and activating a specific receptor. |
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Term
| **Second General Step of Cell Signaling** |
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Definition
| Signal transduction: the receptor converts the primary messenger into a secondary messenger. |
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Term
| **Third General Step of Cell Signaling** |
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Definition
| The second messenger activates a metabolic pathway (intracellular signaling) by changing the cytoskeleton configuration or by switching a gene on or off. |
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Term
| general idea of cell signaling |
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Definition
| after the ligand binds to the extracellular signal molecule, the receptor converts it into an intracellular signal. the message is then transmitted downstream until it reaches the effector protein involved in the cell response |
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Definition
| hormones are distributed throughout the body. the hormone leaves the endocrine cell, and travels through the bloodstream to it's target cell. ex: insulin regulates glucose uptake by all cells. |
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Definition
| the electrical signals are converted into chemical signals by realeasing the neurotransmitter molecules into the gap between the two cells. involves a neuron right up against a target cell with a synapse in between and the neurotransmitters traveling between the two cells. |
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Definition
| signal molecules diffuse locally. all the cells are close together and the signals travel freely between them. |
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Term
| contact dependent cell signaling |
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Definition
| a cell surface signal molecule binds to a receptor on an adjacent cell. cells must be touching. |
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Term
| ion channel coupled receptors |
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Definition
| an ion channel that, in response to binding to signal molecules, opens its legs and allows ions to flow across the plasma membrane |
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Term
| g-protein coupled receptors |
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Definition
| the receptor activates protein G, which then activates and enzyme or an ion channel. G-protien is a membrane bound protein that is able to bind to GTP as an energy source. this receptor has three parts, the receptor, the moving g protein, and the enzyme. |
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Definition
| the receptor in and enzyme or is associated with a membrane bound enzyme. usually looks like two puzzle pieces that are brought together by the signal molecule, sometimes involves a third enzyme. |
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Definition
| adrenaline enters g protein receptors, which activates adenylyl cyclase. this can cause both glycogen breakdown and transcription of a target gene. the breakdown of glycogen increases your glucose concentration and makes you more ready for action. |
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Definition
| enzyme coupled receptors bind growth factors. they regulate the growth, proliferation, differentiation, and survival of cells. through a phosphorylation cascade effector proteins are activated and they control gene transcription. |
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Definition
| mitosis (nuclear division) + cytokinesis (cell division). requires less than an hour. |
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Term
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Definition
| time to grow and double all cell components. takes about 23 hours for a typical human cell. |
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Term
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Definition
| cells grow continuously in interphase and divide in M phase. s phase is when DNA is replicated and all of the proteins and organelles are synthesized. |
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Definition
| your brain grows very fast very early. your body height grows fast at first, then levels out, then spikes again. your reproductive organs start slow and then later spike |
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Definition
| survival signals. cells in multicellular organisms require signals to stay alive. |
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Definition
| physiological event. balances mitosis in all tissues. intervenes in normal processes. the cell shrinks and condenses. the cytoskeleton collapses and the chromatin becomes dense. the cell dies neatly and doesn't affect other cells. it is not an inflammatory response. |
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| pathological event. usually the result of acute injury. in necrosis the cell swells and bursts, spilling all over the neighboring cells. it is a damaging inflammatory response. |
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Term
| Proteins that build the Cytoskeleton |
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Definition
| actin/microfilaments, microtubules, intermediate filaments |
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Term
| Roles of the Cytoskeleton |
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Definition
| allows the cell to adopt a variety of shapes, organize many processes inside the cell, interact mechanically with the environment, and carry out coordinated movements |
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Term
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Definition
| one of the proteins that build the cytoskeleton. ropelike fibers with great strength. their function is to withstand mechanical stress that occurs when cells are stretched. built from keratin in the epithelial cells, vimentin in fibroblasts and muscle cells, neurofilaments in nerve cells, and nuclear lamins in the nucleus |
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Definition
| one of the proteins that makes up the cytoskeleton. stiff hollow tubes formed by the polymerization of tubulin. they can rapidly disassemble in one location and reassemble in another,growing out from the centrosome (a small structure near the center of the cell.) during cell division, microtubules form the mitotic spindle, the machinery that will segregate the chromosomes equally between the two daughter cells. paired with motor proteins, they help organelle traffic in the cell. |
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Definition
| motor proteins that use the energy from ATP hydrolysis to move along the microtubules in the cytoskeleton and carry specific membrane vesicles and other cargoes |
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Definition
| one of the proteins that makes up the cytoskeleton. two strand helical polymers of actin. dispersed throughout the cell, and highly concentrated in the cortex ( the region beneath the plasma membrane.) assemble and disassemble in cell locomotion |
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Definition
| the first step in cell crawling. actin polymerization at the leading edge of the cell pushes the plasma membrane forward. |
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Definition
| the second step in cell crawling. new points of anchorage are made between actin filament and the surface. |
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Definition
| the third and final step in cell crawling. contraction of the rear of the cell draws the body of the cell forward. |
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Definition
| motor protein that uses the energy of ATP hydrolysis to move along actin filaments: they can carry organelles along actin filament tracks or cause adjacent actin filaments to slide past each other in contractile bundles. have a tear drop shaped head with a wavy tail that grab on to what it is moving. |
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Term
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Definition
| has two ATP-ase heads and a coiled-coil tail. molecules bind to each other forming a bipolar myosin filament in which the heads projects from the sides. one set of heads binds to actin filaments in one orientation and moves them one way while the other set of heads bind to other actin filaments in the opposite orientation and moves them in the opposite direction. |
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Definition
| extracellular matrix. an intricate network of macromolecules filling the extracellular space. composed of polysaccharide chains and proteins. |
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Term
| polysaccharide chains in the ECM |
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Definition
| glycosaminoglycans (GAGs), usually found covalently linked to protein in the form of proteoglycans. |
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Definition
| proteins with structural and adhesive functions such as collagen, elastin, fibronectin, laminin. |
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Term
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Definition
calcified- in rock hard structures like bones and teeth
transparent- cornea
ropelike- organization that gives tendons their enormous tensile strength
flexible- thin tough mats around or under the cells, basal lamina (basement membrane) |
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Term
| Role of Polysaccharides in ECM |
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Definition
| polysaccharide gel resists compressive forces on the matrix while permitting the rapid diffusion of nutrients, metabolites, and hormones between the blood and the cells. |
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Term
| Role of Collagen protein fibers in ECM |
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Definition
| strengthen and help organize the matrix. |
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Term
| Role of Elastin protein in ECM |
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Definition
| rubberlike elastin fibers give resilience |
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Term
| Role of Adhesive proteins in ECM |
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Definition
| help cells attach to the matrix |
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Term
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Definition
| collagen is usually in the form of tropocollagen, which is a triple helix. they are then cross linked together to form collagen fibrils. fibrils group together to form fibers. |
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Definition
| elastin molecules are joined together by covalent bonds to create a cross linked network of elastic fibers. extensibility is due to the hydrophobic elastin molecule sequences. the elasticity is crucial for large arteries, skin, and lungs. |
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Definition
| composed of cells and ECM. |
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Definition
| binds structures and fill spaces. contains cells such as fibroblasts, macrophages, and mast cells. provides support and protection. |
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Definition
| covers organs and the body. lines body cavities. cells are tightly packed. it's functions are protection, secretion, and absorption. |
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Definition
| three types: skeletal, smooth, and cardiac. skeletal is attached to bones. smooth muscle makes up the walls of organs and blood vessels. cardiac muscle is in your heart. |
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Term
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Definition
| found in the brain, spinal cord, and peripheral nerves. found in neurons and neuroglial cells |
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