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148 Cards in this Set
- Front
- Back
Cell biology
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study of cellular structure
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Cell biology
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study of cellular structure
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plasma membrane
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cell membrane that encloses a cell and controls the traffic of molecules in and our of a cell
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transcription
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making RNA from DNA
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translation
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making protein from RNA
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mitosis
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nuclear division in which a cell divides once and produces two genetically identical daughter cells
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cells
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basic living, structural, and functional units of the body composed of characteristic parts, the coordinated function of which allows each cell type to fulfill a unique biochemical or structural role
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Cell structure and function are
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intimately related
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3 principle parts of a cell
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plasma membrane, cytoplasm, nucleus
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plasma membrane
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separates inside of cell from outside
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cytoplasm
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all cellular content between plasma membrane and nucleus
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nucleus
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large organelle that houses the cell's DNA
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2 components of cytoplasm
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cytosol and organelles
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cytosol
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clear, gelatinous colloid in which organelles are embedded
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organelles
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structures w/in a cell that have specific functions, where metabolism occurs, where things are stored
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plasma membrane
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surrounds and contains the cytoplasm, flexible barrier
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plasma membrane makeup
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50% lipid 50% protein
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protein channels
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gatekeepers, anything that isn't polar can't pass through, very selective about what comes in and out
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lipid bilayer
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basic framework of the plasma membrane
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3 types of lipids
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phospholipids, cholesterol, glycolipids
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phospholipids
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lipid w/ phospate attached
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cholesterol
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steroid with attached hydroxyl group
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glycolipids
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lipid w/ carbohyrate attached
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extracellular
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outside of cell
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are amphipathic molecules
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lipid bilayer
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lipid bilayer arrangement
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have both polar charged parts and nonpolar uncharged parts w/ the polar head pointing out and the nonpolar tail facing toward the center of the membrane
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cholesterol molecules in the lipid bilayer
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are weakly amphiphotic and are interspersed among other lipids
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where glycolipids appear in the membrane layer
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the part that faces the extracellular fluid
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phospholipid bilayer
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2 parallel layers of molecules(amphiphillic)
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integral membrane proteins
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are firmly embedded and extend into or across the entire lipid bilayer
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peripheral membrane proteins
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are more loosely associated with membrane, can be at inner or outer layer, and can be stripped away from the membrane w/out disturbing membrane integrity
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integral membrane protein functions
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ion channels, transporters, receptors, enzymes, linkers, cell identity markers
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peripheral membrane protein functions
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help support plasma membrane, anchor integral proteins, and participate in mechanical activities of cells
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microvilli
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extensions of plasma membrane that serve to increase cell's surface area
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where is the brushboarder of the microvilli located
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on the apical cell surface
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cilia
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hair-like projections of a cell that move using a powerstroke
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functions of cilia
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sensory(inner ear, retina), line respiratory and uterine tubes, some move mucus along surface layer
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flagella
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whip-like structure, much longer than cilia(sperm cell)
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membranes
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are fluid structures, rather like cooking oil, because most of the membrane lipids and membrane proteins easily move in the bilayer
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cholesterol in the membrane
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serves to stabilize the membrane and reduce membrane fluidity
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are selectively permeable
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plasma membranes
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is permeable to small, nonpolar, uncharged molecules, but impermeable to ions and charged or polar molecules, is also permeable to water
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lipid bilayer portion of the plasma membrane
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transmembrane proteins
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act as channels or transporters and increase the permeability of the membrane to molecules that cannot cross the lipid bilayer
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how macromolecules, unable to pass through the plasma membrane get through to the cytoplasm
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vesicular transport
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membrane potential
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an electrical gradient occurring because the inner surface of the membrane is more negatively charged and the outer surface is more positively charged
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maintaining the concentration and electrical gradients are
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important to the life of the cell
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electrochemical gradient
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combined concentration and electrical gradients
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mediated transport
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moves materials w/ the help of a transporter protein
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nonmediated transport
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does not use a transporter protein
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active transport
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uses ATP to drive substances against their concentration gradients
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passive transport
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moves substances down their concentration gradient w/ only their kinetic energy
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vesicular transport
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moves materials across membranes in small vesicles, either by exocytosis or endocytosis
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exocytosis
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process in which a vesicle in the cytoplasm of a cell fuses w/ the plasma membrane and releases its contents from the cell, used in the elimination of cellular wastes and in the release of gland products and neurotransmitters
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endocytosis
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process in which a cell forms vesicles from its plasma membrane and takes in large particles, molecules, or droplets of extracellular fluid
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nonpolar, hydrophobic molecules move freely through the
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lipid bilayer
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diffusion through the lipid bilayer
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is important for life processes such as nutrients, waste, and gas exchange
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integral transmembrane proteins
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allow passage of small inorganic ions too hydrophillic to pass through lipid portion of bilayer
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passage through the integral transmembrane proteins
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is generally slower than diffusion across the lipid portion w/ less opportunity
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osmosis
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movement of water from an area of higher concentration to an area of lower concentration
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hydrostatic pressure
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force of pressure against membrane that opposes osmosis from forcing water back toward higher concentration of water
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osmotic pressure
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pressure of a solution proportional to concentration gradient of solute particles on side of membrane w/ more solutes
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tonicity
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measure of a solution's ability to change the volume of cells by altering their water concentration
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in an isotonic solution
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red blood cells maintain their normal shape
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in a hypotonic solution
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red blood cells undergo hemolysis(explode)
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in a hypertonic solution
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red blood cells undergo crenation(shrink)
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most prevalent primary active transport mechanism
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sodium ion/potassium ion pump
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requires 40% of cellular ATP, all cells have 1000's of them, maintains low concentration of K+ and high concentration of Na- in the cytosol
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sodium ion, potassium pump
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secondary active transport
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energy stored in the form of a sodium or hydrogen ion concentration gradient is used to drive other substances against their own concentration gradients
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bringing something into a cell
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endocytosis
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releasing something from a cell
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exocytosis
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phagocytosis
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cell eating by macrophages and WBCs, particle binds to receptor proteing and whole bacteria or viruss are engulfed and later digested
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pinocytosis
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cell drinking, no receptor proteins
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cytosol
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the intracellular fluid, is the semifluid portion of cytoplasm that contains inclusions and dissolved solutes
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composed mostly of water, plus proteins, carbs, lipids, and inorganic substances
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cytosol
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are either in a solution or in a colloidal(suspended) form
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chemicals in cytosol
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the medium in which many metabolic reactions occur
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cytosol
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specialized structures that have characteristic shapes and perform specific functions in cellular growth, maintenance, and reproduction
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organelles
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network of protein filaments throughout the cytosol
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cytoskeleton
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functions of cytoskeleton
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cell support and shape, organization of chemical reactions, cell and organelle movement
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some epithelial cells have______ projecting from surface
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cilia
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contain microtubules
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cilia
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some epithelial cells have_____ on surface to increase surface area for absorption
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microvilli
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tiny spheres consisting of ribosomal RNA and several ribosomal proteins
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ribosomes
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function of ribosomes
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protein synthesis
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ribosomes are made in the_____ and assembled in the_______.
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nucleolus, cytoplasm
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made up of a network of membranes
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endoplasmic reticulum
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studded w/ ribosomes
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rough E.R.
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does not contain ribosomes on its membrane surface
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smooth E.R.
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functions of ER
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transports, synthesizes, packages, and stores proteins, also detoxifies chemicals, and releases calcium ions involved in muscle contraction
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processes, sorts, and delivers proteins and lipids to the plasma membrane, lysosomes, and secretory vesicles
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Golgi Complex
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membrane-enclosed vesicles that contain powerful digestive enzymes and have and internal pH that reaches 5.0,
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Lysosomes
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functions include digesting substances and recycling organelles
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lysosomes
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is bound by a double membrane
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mitochondria
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the outer membrane is smooth; the inner membrane is arranged in folds called cristae
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mitochondria
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site of ATP production in the cell by the catabolism of nutrient molecules
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mitochondria
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self-replicate using their own DNA
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mitochondria
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has circular DNA w/ 37 genes
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mitochondria
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usually the most prominent feature of a cell
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nucleus
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these cells don't have a nucleus
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red blood cells
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these muscle fibers have several nucleus
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skeletal muscle fibers
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parts of the nucleus
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nuclear envelope, nuclear pores, nucleoli, DNA
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located w/in the nucleus, cell's hereditary units, are arranged in single file along chromosomes
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genes
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# of human DNA molecules or chromosomes
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46
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non-dividing cells contain nuclear_____, which are loosely packed DNA
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chromatin
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dividing cells contain_______, which are tightly packed DNA that copied itself before condensing
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chromosomes
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long molecule of DNA that is coiled together w/ several proteins
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chromosomes
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have 46 chromosomes arranged in 23 pairs
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human somatic cells
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various levels of DNA packing represented by
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nucleosomes, chromatin, fibers, loops, chromatids, and chromosomes
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determine the physical and chemical characteristics of cells
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proteins
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where the instructions for protein synthesis are found
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in DNA, in cell's nucleus
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involves transcription and translation
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protein synthesis
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process by which genetic information encoded in DNA is copied onto a strand of RNA called messenger RNA(mRNA), which directs protein synthesis
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transcription
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process of reading the mRNA nucleotide sequence to determine the amino acid sequence of the protein
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translation
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process by which cells reproduce themselves
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cell division
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cell division that results in an increase in body cells and involves a nuclear division called mitosis, plus cytokinesis
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somatic cell division
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cell division that results in the production of sperm and eggs and consists of a nuclear division called meisosis, plus cytokinesis
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reproductive cell division
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an orderly sequence of events by which a cell duplicates its contents and divides in two; consists of interphase and the mitotic phase
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cell cycle
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contain 46 chromosomes or 23 pairs of chromosomes
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human somatic cells
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two chromosomes that make up a chromosome pair
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homologous chromosome or homologs
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cell w/ a full set of chromosomes
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diploid cell
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a cell w/ only one chromosome from each pair
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haploid
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during this stage of the cell cycle, the cell carries on every life process except cell division
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interphase
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the doubling of DNA and centrosome occur in this stage
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interphase
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phases of interphase
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G1, S, G2
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what happens in G1
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cytoplasmic increase
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what happens in S phase
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replication of chromosomes
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what happens in G2 phase
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cytoplasmic growth
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doubling of genetic material happens during this part of interphase
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S phase
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the distribution of tow sets of chromosomes, one set into each of two separate nuclei
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mitosis
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stages of mitosis
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prophase, metaphase, anaphase, telophase
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during this phase of mitosis, the chromatin condenses and shortens into chromosomes
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prophase
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during this phase of mitosis, the centromeres line up at the exact center of the mitotic plate or equatorial plane region
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metaphase
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this phase of mitosis is characterized by the splitting and separation of centromeres and the movement of the two sister chromatids of each pair toward opposite poles of the cell
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anaphase
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this phase of mitosis begins as soon as chromatid movement stops; the identical sets of chromosomes at opposite poles of the cell uncoil and revert to their threadlike chromatin form, microtubules disappear or change form, a new nuclear envelope forms, new nucleoli appear, and the new mitotic spindle eventually breaks
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telophase
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the division of a parent cell's cytoplasm and organelles;
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cytokinesis
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this process begins in late anaphase or early telophase w/ the formation of a cleavage furrow
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cytokinesis
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what happens after cytokinesis is complete
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interphase begins
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uncontrolled cell division
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cancer
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3 possible destinies of a cell
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remain alive and functioning w/out dividing, to grow and divide, or to die
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induces cell division
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Maturation promoting factor(MPF)
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cell death, is triggered from outside the cell or from inside the cell due to a "cell-suicide" gene
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apoptosis
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pathological cell death due to injury
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necrosis
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results in the production of haploid cells that contain only 23 chromosomes
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meiosis
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Four phases of meiosis 1
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prophase1, metaphase1, anaphase1, telophase1
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during this phase of meisosis1, the chromosomes become arranged in homologous pairs through a process called synapsis
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prophase1
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during this phase of meiosis1, the homologous pairs of chromosomes line up along the metaphase plate of the cell, w/ the homologous chromosomes side by side
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metaphase1
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during this phase of meiosis1, the members of each homologous pair separate, w/ one member of each pair moving to an opposite pole of the cell
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anaphase1
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in meiosis2, the phases are similar to those in mitosis, but result in ______
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four haploid cells
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