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138 Cards in this Set
- Front
- Back
Basic living and structural unit of the body.
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Cell
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What are the 3 principal parts of a cell?
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Plasma membrane, cytoplasm (organelles + cytosol), and nucleus.
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Why is the plasma membrane best described using the fluid mosaic model?
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The membrane consists of proteins that float like icebergs in a sea of lipids. Many of the lipids and proteins are free to rotate and move sideways in their own half of the bilayer.
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What 3 lipid molecules make up the lipid bilayer? Give their ratio %.
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75% phospholipids, 20% cholesterol, 5% glycolipids
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How do hydrophobic and hydrophilic regions govern the arrangement of the lipid bilayer?
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The hydrophilic phosphate head faces the water and the hydrophobic fatty acid tails face eachother away from the water.
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How does cholesterol affect membrane fluidity?
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Because of the way it forms H bonds w/ phospholipid and glycolipid heads and fills space b/w bent fatty acid tails, cholesterol makes the lipid bilayer stronger but less fluid at normal body temperature. At low temps, cholesterol increases membrane fluidity.
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What substances can and cannot diffuse through the lipid bilayer?
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Permeable to nonpolar, uncharged molecules like oxygen, carbon dioxide, steroids. Slightly permeable to water and urea. Impermeable to ions and large, uncharged polar molecules like glucose.
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___ proteins extend into or through the lipid bilayer and are firmly embedded.
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Integral proteins
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Most integral proteins are ___ proteins that extend into or through the lipid bilayer.
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Transmembrane proteins
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___ proteins attach to the inner/outer surface of the membrane.
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Peripheral proteins
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A sugary coat made up of the carbohydrates of glycoproteins and glycolipids. Acts as a molecular signature.
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Glycocalyx
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Name the 6 types of membrane protein functions.
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Ion channel, carrier (transporter), receptor, enzyme, linker, cell ID marker.
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Membrane protein that allows specific ions to move through water-filled pore.
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Ion channel
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Membrane protein that transports specific substances across the membrane by changing shape.
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Carrier (transport)
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Membrane protein that recognizes specific ligand and alters cell's function in some way.
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Receptor
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Membrane protein that catalyzes reaction inside/outside cell.
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Enzyme
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Membrane protein that anchors filaments inside and outside the plasma membrane, providing stability and shape for the cell.
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Linker
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Membrane protein that distinguishes your cells from anyone else's.
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Cell identity marker
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The property of membranes allowing some substances to pass more readily than others is called ___. Supports the existence of concentration gradients.
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Selective permeability
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Difference in amount of solute from one place to another.
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Concentration gradient
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Difference in electrical charges in 2 regions is called ___. On the plasma membrane it is called ___.
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Electrical gradient. Membrane potential.
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Combined influence of concentration gradient + chemical gradient of ion is called ___.
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Electrochemical gradient
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What is the ratio of water volume in the body that makes up the cytosol (ICF)?
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2/3 ICF (1/3 ECF)
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How do substances move along their concentration gradient in a passive process vs. active process? Is energy required?
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Passive - substance moves down gradient using its own kinetic energy. Active - substance moves "uphill" against gradient using cellular energy (ATP).
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Passive process in which random mixing of particles in a solution occur because of the particles' kinetic energy.
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Diffusion
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5 factors that influence the rate of diffusion of substances across plasma membranes.
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Steepness of concentration gradient, temperature, mass of diffusing substance, surface area, diffusing distance
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The hormone insulin binding to a protein is best represented by which membrane protein function?
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Receptor
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How would a fever affect body processes that involve diffusion?
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Because fever increases body temperature, the rates of all diffusion processes would increase.
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What types of molecules move across the plasma membrane via simple diffusion?
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Oxygen, carbon dioxide, nitrogen gases, fatty acids, steroids, fat-soluble vitamins (ADEK). Water, urea, small alcohols.
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Passive process in which substances move freely through lipid bilayer without help of membrane transport proteins.
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Simple diffusion
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Passive process where solutes that are too polar or highly charged move through lipid bilayer with assistance of integral membrane protein.
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Facilitated diffusion
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The number of carriers available in a plasma membrane is called the ___, the rate at which facilitated diffusion can occur.
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Transport maximum
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List 2 types of facilitated diffusion processes in the cell membrane.
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Channel-mediated and carrier-mediated facilitated diffusion.
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Is the concentration of K+ in body cells higher in the cytosol or the ECF?
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K+ concentration is higher in the cytosol.
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How does insulin alter glucose transport by facilitated diffusion?
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Promotes copies of glucose carriers into the plasma membrane. Insulin elevates the transport maximum for glucose into cells. With more glucose carriers available, cells can pick up glucose more rapidly.
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Net movement of water through selectively permeable membrane from high water concentration (low solute) to low water concentration (high solute).
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Osmosis
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What 2 ways can water pass through the plasma membrane?
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Simple diffusion and aquaporins (integral membrane protein that functions as water channel)
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Pressure exerted by a liquid.
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Hydrostatic pressure
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Measure of solution's ability to change volume of cells by altering water content.
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Tonicity
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How does a cell's shape change in an isotonic solution? Give an example of an isotonic solution.
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Shape is maintained b/c there is no net water movement into or out of the cell. Ex. 0.9% NaCl
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What is a hypotonic solution and how do RBCs change shape? Give an example of a hypotonic solution.
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Solution that has a lower concentration of solutes outside of cell. Water enters cell and causes hemolysis (lysis). Ex. Pure water, sports drinks.
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What is a hypertonic solution and how do RBCs change shape? Give an example of a hypertonic solution.
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Solution that has a higher concentration of solutes outside of cell. Water leaves cell and causes crenation. Ex. 2% NaCl
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What is the main difference b/w primary active transport and secondary active transport?
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Primary - uses energy from hydrolysis of ATP. Secondary - uses stored energy from Na+/H+ concentration gradient.
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What solutes are transported across the plasma membrane using primary active transport?
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Na+, K+, H+, Ca2+, I-, Cl-
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Most prevalent primary active transport pump.
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Sodium-potassium pump (Na+/K+ATPase)
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Describe 2 reasons why the different concentrations of Na+ and K+ in cytosol and ECF are important.
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Crucial for maintaining cell volume and ability for some cells to generate electrical signals (action potentials).
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Transporter that moves substances in the same direction.
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Symporter
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Transporter that moves substances in different directions.
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Antiporter
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Process of materials moving into a cell in a vesicle formed from plasma membrane.
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Endocytosis
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Process of materials moving out of a cell by fusion w/ plasma membrane of vesicles formed inside cell.
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Exocytosis
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Process of cells taking up specific ligands which trigger infolding of clathrin-coated pit that forms vesicle.
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Receptor-mediated endocytosis
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What disease can be treated with a hypertonic solution?
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Cerebral edema b/c of excess interstitial fluid in brain.
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Why is digitalis given to patients with heart failure?
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It slows sodium-potassium pump which causes more Ca2+ to remain in heart muscle cells and strengthens heart contractions. P73
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What virus uses receptor-mediated endocytosis to enter and infect body cells?
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HIV which causes AIDS
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What ligands are transported with receptor-mediated endocytosis?
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Iron, vitamins, hormones, antibodies, low-density lipoproteins (LDLs)
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"Cell eating"; movement of solid particle into a cell after pseudopods engulf it to form a phagosome.
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Phagocytosis
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"Cell drinking"; movement of ECF into a cell by infolding of plasma membrane to form a vesicle. Largely found in intestines/kidneys.
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Bulk-phase endocytosis or Pinocytosis
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Phagocytosis helps protect body from disease. What 3 types of substances are engulfed?
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Bacteria, viruses, aged/dead cells
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2 important cells that carry out exocytosis.
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Secretory cells (enzymes, hormones, mucus) and nerve cells that release neurotransmitters.
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Process of vesicle transport to move substance into, across, and out of cell.
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Transcytosis
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What are some of the chemicals present in cytosol?
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Ions, glucose, amino acids, fatty acids, protein, lipids, ATP, waste products.
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What is the function of cytosol?
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Site of many chemical reactions needed for cell's survival.
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Fluid portion of cytoplasm that surrounds organelles and makes up 2/3 of water volume in body.
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Cytosol (ICF)
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Structures w/ characteristic shape and specialized function.
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Organelle
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Network of protein filaments that extend throughout cytoplasm, providing cellular shape, organization and movement.
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Cytoskeleton
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What protein filament is made of actin, is part of the framework of a cell and composes microvilli and cell junctions?
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Microfilament
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What protein filament is made of keratin, provides internal support for cells, and composes cell junctions, skin, keratinocytes?
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Intermediate filament
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What protein filament is made of tubulin, is found in the centrosome and aids in the mitotic spindle, cila and flagella?
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Microtubule
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Located near nucleus. Consists of pericentriolar material and pair of centrioles. Organizing center of growth for mitotic spindle.
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Centrosome
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What is the function of pericentriolar material in dividing vs. nondividing cells?
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Dividing - mitotic spindle. Nondividing - organizes microtubules
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Short, hair-like projections from cell surface that move fluids along cell surface.
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Cilia
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Hair-like projections on cell surface that are longer than cilia and move an entire cell.
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Flagella
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Consist of 2 subunits made in the nucleus. Site of protein synthesis
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Ribosome
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Where are subunits of ribosomes synthesized and assembled?
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Synthesized in nucleolus, assembled in cytoplasm.
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Functions in synthesizing fatty acids + steroids, helping liver cells release glucose into bloodstream and detoxification.
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Smooth ER
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Contain ribosomes that synthesize protein. Processes and sorts proteins that enter. Produces secretory proteins, membrane proteins, organelle proteins; forms glycoproteins; synthesizes phospholipids; attaches proteins to phospholipids.
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Rough ER
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Small flattened membranous sacs with bulging edges in Golgi Complex
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Cisternae
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Convex entry of Golgi complex that faces rough ER
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Cis face
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Concave exit of Golgi complex that faces plasma membrane
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Trans face
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Modifies, sorts, packages and transports molecules synthesized in rough ER in vesicles.
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Golgi complex
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Membrane enclosed vesicles formed in Golgi complex that contain strong hydrolytic and digestive enzymes. Carries out autophagy, autolysis, and extracellular digestion.
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Lysosomes
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Process where entire worn-out organelles are digested.
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Autophagy (self-eating)
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Process where lysosomal enzymes destroy entire cell containing them.
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Autolysis (self-break apart)
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Oxidizes amino acids, fatty acids, toxic substances (alcohol). Abundant in liver.
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Peroxisomes
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Organelle that destroys unneeded, damaged or faulty proteins into small peptides.
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Proteasomes
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Organelle that generates ATP. Consist of smooth outer membrane, inner membrane containing cristae, and cavity called matrix. Self replicating.
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Mitochondria
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How do the cristae of a mitochondrion contribute to its ATP producing function?
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Increase the surface area available for chemical reactions and contain enzymes needed for ATP production.
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In what cells would you find abundant mitochondria?
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Active cells like muscles, liver, kidneys
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Double membrane that separates nucleus from cytoplasm.
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Nuclear envelope
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Openings in nuclear envelope that control movement of substances b/w nucleus and cytoplasm.
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Nuclear pores
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Spherical body that produces ribosomes
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Nucleolus
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Cell's heredity units, control activities and structure of cell.
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Genes
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Long molecules of DNA combined w/ protein molecules
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Chromosomes
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Complex of DNA, proteins, some RNA called ___. Total genetic info carried in a cell is its ___.
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Chromatin. Genome.
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How many chromosomes do human somatic cells have and how many are inherited from each parent?
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46 chromosomes. 23 inherited from each parent.
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What are the components of a nucleosome?
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Double-stranded DNA wrapped twice around 8 proteins called histones.
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Describe 2 reasons proteins are important to the life of a cell.
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Determine physical and chemical characteristics of cells.
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All of an organism's proteins is called ___.
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Proteome
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A sequence of 3 nucleotides in DNA is called ___.
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Base triplet
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Set of rules that relates base triplet sequences of DNA to corresponding codons of RNA and amino acids they specify.
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Genetic code
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Where do transcription and translation occur?
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Transcription occurs in nucleus; translation occurs in cytoplasm.
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Regions within a gene that do not code for parts of protein are called ___. They are located b/w regions that do code for segments of a protein called ___.
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Introns. Exons.
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Describe the process of transcription (RNA/DNA).
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DNA unzips and uncoils. Enzyme RNA polymerase catalyzes transcription of DNA. Bases ATGC are paired but U replaced with T in RNA. Pre-mRNA strand is edited by enzyme snRNPs that remove introns and splice together exons. mRNA leaves nucleus.
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Describe the process of translation (RNA/DNA).
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mRNA binds to small ribosomal unit. tRNA anticodon + amino acid binds to mRNA start codon (AUG). Large ribo unit attaches to small ribo unit and initiator tRNA fits into P site. 2nd anticodon + amino acid fits into A site. Peptide bond forms b/w amino acids. tRNA in P site detaches, tRNA in A site w/ peptide chain shifts to P site. Repeats until stop codon reached at A site. Completed protein detaches from tRNA and ribosome splits into large/small units.
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Any cell of the body other than a germ cell.
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Somatic cell (soma=body)
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Gamete (sperm or oocyte) or precursor cell
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Germ cell
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___ cell division replaces or adds new ones and involves ___ and ___.
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Somatic. Mitosis. Cytokinesis.
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___ cell division results in gametes and consists of ___ and ___.
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Reproductive. Meiosis. Cytokinesis.
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2 chromosomes that make up each pair are called ___ ___.
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Homologous chromosomes (homologs)
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Somatic cells contain 2 sets of chromosomes and are called ___ cells.
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Diploid
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In chromatin's structure, each bead is called a ___ and consists of double-stranded DNA wrapped twice around a core of 8 proteins called ___.
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Nucleosome. Histones.
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A pair of ___ make up a chromosome.
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Chromatids
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Which type of RNA directs the synthesis of a protein?
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mRNA
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Which type of RNA joins with ribosomal proteins to make ribosomes?
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rRNA
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What enzyme catalyzes transcription of DNA?
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RNA polymerase
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What is the significance of a polyribosome?
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It is several ribosomes attached to the same mRNA which allows the translation of 1 mRNA into several identical proteins at the same time.
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Study of relationships b/w the genome and biological functions of an organism.
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Genomics
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In which phase of the cell cycle does the following occur: organelle/cytosolic components replication, centrosome replication.
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Growth 1 phase (G1)
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In which phase of the cell cycle does replication of DNA and centrosomes occur?
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Synthesis phase (S)
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In which phase of the cell cycle does replication of centrosomes complete, cell growth, enzyme/protein synthesis continue?
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Growth 2 phase (G2)
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Chromatin condenses into chromosomes; nuclear envelope disappears; centrosomes move to opposite ends as mitotic spindle lengthens
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Prophase
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Chromosomes line up at metaphase plate.
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Metaphase
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Chromosomes split and identical sets move to opposite sides of cell.
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Anaphase
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Nuclear envelope reappears. Chromosomes resume chromatin form. Mitotic spindle disappears.
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Telophase
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Cytoplasmic division; cleavage furrow forms and divides cell
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Cytokinesis
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What are the 5 steps of the cell cycle in somatic cell division?
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G1, S phase, G2, Mitosis, Cytokinesis
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Genetically programmed death of a cell
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Apoptosis
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Pathological cell death from tissue injury
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Necrosis
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What accounts for the genetic variation among organisms?
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Crossing-over results in genetic recombination
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How is anaphase 1 of meiosis different from anaphase of mitosis?
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During anaphase 1 of meiosis, the chromosome does not separate. In mitosis, the chromosome splits into chromatids.
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Why are sperm cells the only body cells that need to have a flagellum?
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They are the only cell that need to move a long distance.
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Branch of medecine that deals with medical problems and care of elderly.
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Geriatrics
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Study of process and problems associated w/ aging.
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Gerontology
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Out of the 4 types of tissues, which divide and which do not?
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Epithelial, connective DIVIDE. Nervous, skeletal muscle DO NOT.
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What is the one reason some tissues become stiffer as they age?
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Glucose forms irreversible cross links b/w adjacent protein molecules.
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Disease characterized by normal development in 1st year followed by rapid aging. Telomeres are short.
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Progeria
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Rapid acceleration of aging in 20's
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Werner syndrome
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Spread of cancerous cells to other parts of the body.
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Metastasis
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