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A&PI-Ch3
Cells-The Living Units
| Question | Answer |
|---|---|
| organisms arise spontaneously from garbage or other nonliving matter | theory of spontaneous generation |
| when define cell properties are defining | properties of life |
| activity of organism depends on both individual and collective | activities of its cells |
| biochemical activities of cells are dictated by relative number of their specific subcellular structures | principle of complementarity of structure and function |
| not highly differentiated biologically nor strictly adapted to a particular environment | generalized cells |
| specialized cells are considered | composite cells |
| fragile barrier; composed of phospholipids, cholesterol, & proteins; encloses cell contents; outer limiting cell membrane | plasma membrane |
| internal to plasma membrane; intracellular fluid packed with organelles, small structures that perform specific functions | cytoplasm |
| controls cellular activities & typically lies near cell's center | nucleus |
| depiction of membrane (7-10nm) structure of cell, as phospholipid bilayers in which proteins are dispersed | fluid mosaic model |
| many proteins, of plasma membrane, float in __ __ __, forming constantly changing mosaic patterns | fluid lipid bilayer |
| forms basic fabric of plasma membrane; constructed largely of phosolipids with smaller amount of cholesterol & glycolipids | lipid bilayer |
| refers to molecules, or portions of molecules, that interact with water and charged particles; lollipop-shaped phospholipid | hydrophilic |
| refers to molecules, or portions of molecules, that interact only with uncharged, nonpolar molecules; made of two fatty acid chains | hydrophobic |
| each lollipop-shaped __ has hydrophilic & __ that is hydrophobic | head; tail |
| hydrophilic polar heads are attracted to inner & outer surfaces of plasma membrane, because main constituent of both | intracellular & extracellular fluid |
| hydrophobic, nonpolar tails line up in __ of membrane | center |
| property of phospholipids encourages biological membranes to self-assemble into closed, generally spherical, structures and reseal themselves quickly when torn | self-orienting |
| plasma membrane is __ __ structure in constant flux | dynamic fluid |
| lipid molecules of bilayer move freely __ __ membrane surface, side to side | parallel |
| __ __ prevent lipid molecules from flip-flopping or moving from one phospholipid layer to other | nonpolar interactions |
| differ in kinds and amounts of lipids they contain; variations important in determining local membrane structure & function | inward- facing & outward-facing surfaces |
| majority of membrane phospholipids are __, condition which kins their tails (increasing space btwn them) & increases membrane fluidity | unsaturated |
| lipid with one or more covalently attached sugars | glycolipids |
| glycolipids are found only on __ plasma membrane surface, accounting for about 5% of total membrane lipid | outer |
| sugar groups of glycolipid make that end of the molecule __, whereas __ __ tails are nonpolar | polar; fatty acid |
| hydroxyl group of cholesterol is __ region and its fused ring system is __ region | polar; nonpolar |
| cholesterol wedges its platelike __ __ btwn phospholipid tails, __ membrane while increasing __ of phospholipid & fluidity of membrane | hydrocarbon rings; stabilizing; mobility |
| contained in outer membrane surface, 20%; dynamic assemblies of saturated phospholipids associated w/unique lipids called sphingolipids & lots of cholesterols | lipid rafts |
| lipid rafts are __ __ and orderly, less fluid than rest of membrane, & can include/exclude specific __ to various extents | more stable; proteins |
| lipid rafts are assumed to be __ __ for certain receptor molecules or for molecules needed for cell signaling | concentrating platforms |
| make up about 1/2 of plasma membrane by mass & are responsible for most of specialized membrane functions | proteins |
| firmly inserted into lipid bilayer have both hydrophobic & hydrophilic regions allowing them to interact both w/nonpolar lipid tails buried in membrane & w/water inside/outside cell | integral proteins |
| some integral proteins __ from one face only | protrude |
| most integral proteins, that span entire width of membrane & protrude on both sides | transmembrane proteins |
| most __ proteins are involved in transport, although some are __ | transmembrane; enzymes |
| some transmembrane proteins cluster together forming __/__, through which small, water-soluble molecules/ions can move | channels; pores |
| when transmembrane proteins form channels, allowing small, water-soluble molecules/ions to pass it bypasses the __ __ of membrane | lipid part |
| __ __ __ act as carriers that bind to substance & then move it through membrane | some transmembrane proteins |
| some transmembrane proteins are receptors for hormones or other chemical messengers & relay messages to cell interior; process is called | signal transduction |
| related to, located in, or constituting an outer boundary; attach rather loosely only to integral proteins & are easily removed w/out disrupting membrane | peripheral proteins |
| peripheral proteins include network of __ that help support membrane from cytoplasmic side | filaments |
| some __ proteins are enzymes | peripheral |
| some peripheral proteins are __ proteins involved in mechanical functions, i.e. changing cell shape during cell division & muscle cell contraction | motor |
| some proteins float freely, but in particular peripheral proteins are __ in their movements because they are tethered to intracellular structures that make up __ | restricted; cytoskeleton |
| many of proteins that abut extracellular fluid are __ w/branching sugar groups | glycoproteins |
| glycocalyx is layer of __ facing glycoproteins on cell's plasma membrane that determines __ __ | externally; blood type |
| glycocalyx involved in cellular interactions of fertilization, embryonic development, & immunity; acts as adhesive btwn cells | glycocalyx |
| term glycocalyx means | sugar covering |
| glycocalyx used to describe fuzzy, sticky, __ area at cell surface | carbohydrate-rich |
| glycocalyx that clings to each cell's surface is enriched by __ & __ secreted by cell | glycolipids; glycoproteins |
| glycocalyx provides highly specific __ __ by which approaching cells recognize each other | biological markers |
| cell of immune system identify __ by binding to certain membrane glycoproteins in __ glycocalyx | bacterium; bacterial |
| cancer cell's glycocalyx may change continuously, allowing it to keep ahead of immune system __ mechanism and avoid __; example of homeostatic imbalance | recognition; destruction |
| glycoproteins in glycocalyx, wavy contours of membranes adjacent cells (tongue-&-groove fashion), & special membrane junctions formed are three factors that | act to bind cell together |
| most important factor securing cells together are | junctions |
| area where plasma membranes of adjacent cells are fused; series of integral protein molecules in plasma membranes of adjacent cells | tight junctions |
| series of integral proteins molecules in tight junctions include | occludins & claudins |
| when series of integral proteins molecules, in tight junctions, fuse together they form __ junctions that encircle cell | impermeable |
| tight junctions help prevent molecules from from passing through __ __ btwn adjacent cell | extracellular space |
| although called impermeable junctions, some tight junctions __ & may allow certain types of ions to __ | leak; pass |
| cell junction composed of thickened plasma membranes joined by filaments; binding bodies; anchoring junctions | desmosomes |
| mechanical couplings scattered like rivets along sides of abutting cells that prevent their separation | anchoring junctions |
| button-like thickening on cytoplasmic face of each plasma membrane | plaque |
| thin linker protein filaments that extend from plaques & fit together with adjacent cells, like teeth of a zipper in intercellular space | cadherins |
| intermediate filaments forming past of cytoskeleton | keratin filaments |
| keratin filaments, of desmosomes, extend from __ side of plaque across width of cell to anchor plaque on cell's opposite side | cytoplasmic |
| desmosomes not only bind neighboring cells together, but also contribute to continuous __ __ of strong "guy-wires" | internal network |
| arrangement of desmosomes continuous internal network, distributes __ throughout cellular sheet & reduces chance of tearing when subject to pulling forces | tension |
| desmosomes are abundant in tissues subjected to great __ __, such as skin & heart muscle | mechanical stress |
| communicating junction/passageway between 2 adjacent cells; formed by transmembrane proteins called connexons | gap junction |
| hemichannel supplied by 1 protein cell, on 1 side of gap junction; | connexon |
| assembly of six protein hemichannels, supplied by cell on 1 side of gap junction | connexin |
| ions, simple sugars, & other small molecules pass through water-filled channels from 1 cell to next, acting as conduit btwn cytoplasm & extracellular space | connexon/connexin |
| gap junctions are present in __ __ tissues, where ion passage from cell to cell helps __ their electrical activity & contraction | electrically excitable; synchronize |
| fluid between the cells; derived from blood; contains amino acids, sugars, fatty acids, vitamins, regulatory hormones, neurotransmitters, salts & waste products | interstitial fluid (IF) |
| to stay healthy each cell must __ from the IF exact amounts of substance it needs at specific times | extract |
| allows some substance to pass while excluding others; keeps undesirable substance out while allowing nutrients in; keeps valuable cell proteins & other substance in cell, but allows waste out | selectively/differentially permeable membrane |
| substances cross membrane without any energy input from cell | passive process |
| membrane transport processes for which ATP is required, e.g., solute pumping and endocytosis | active process |
| characteristic of healthy, intact cells | selective permeability |
| when cell/plasma membrane severely dmgd, membrane becomes __ to virtually everything and substance flow into/out of cell freely; causes homeostatic imbalance | permeable |
| when someone is severely burned, precious fluids, proteins, and ions, "weep" from dead & dmgd cells; this is an example of a(n) __ __ membrane becoming a(n) __ membrane | selectively permeable; permeable |
| diffusion & filtration; two main types of __ transport | passive |
| spreading of particles in gas or solution w/movement toward uniform distribution of particles | diffusion |
| diffusion is tendency of molecules/ions to move from area where they are in __ concentration to area where they are in __ concentration | higher; lower |
| difference in the concentration of a particular substance between two different areas | concentration gradient |
| greater difference in concentration of diffusing molecules and ions btwn 2 areas, more collisions occur & faster __ __ of particles | net diffusion |
| driving force of diffusion is | kinetic energy |
| speed of diffusion is influenced by molecular __ & __ | size; temperature |
| in a closed container, diffusion eventually reaches equilibrium, with molecules moving equally in all directions causing a __ __ of molecules | uniform mixture |
| movement of ions across cell membranes & movement of neurotransmitters btwn two nerve cells | examples of diffusion |
| __ __ is almost impossible to see | pure diffusion |
| plasma membrane is physical barrier to free diffusion because of its | hydrophobic core |
| molecule will diffuse through membrane if molecule is __ __ | lipid soluble |
| molecule will diffuse through membrane if molecule is small enough to | pass through membrane channels |
| molecule will diffuse through membrane if molecule is assisted by a(n) __ __ | carrier molecule |
| unassisted diffusion of lipid-soluble molecules or very small particles | simple diffusion |
| unassisted diffusion of solvent (usually water) through a selectively permeable membrane | osmosis |
| assisted diffusion is known as | facilitated diffusion |
| in simple diffusion, these substances diffuse directly through the lipid bilayer; these incl oxygen, carbon dioxide, & fat-soluble vitamins | nonpolar & lipid-soluble substances |
| oxygen concentration is always higher in blood than in tissues, therefore oxygen always diffuses __ __ __ from blood to tissue | down concentration gradient |
| carbon dioxide is in higher concentration within tissues than blood, therefore it diffuses __ __ __ from tissue into blood | down concentration gradient |
| glucose/other sugars, some amino acids, & ions are unable to pass through lipid bilayer, therefore passive process of __ diffusion | facilitated |
| facilitated diffusion, allows substance unable to pass through lipid bilayer, to be transported by binding to __ __ in membrane that ferries them across | protein carriers |
| facilitated diffusion, allows substance unable to pass through lipid bilayer, to be transported by moving through water-filled __ __ | protein channels |
| transmembrane integral protein that shows specificity for molecules of certain polar substance/class of substances, too lrg to pass through membrane channels; i.e. sugars & amino acids | carriers |
| most popular model for action of carriers, indicates change in shape of carrier allowing it to envelop & then release substance, shielding it en route from | non polar regions of membrane |
| __ __, of carriers, is moved from one face of membrane to other by changes in conformation of carrier protein | binding site |
| one of spatial arrangements of atoms in molecule that can come about through free rotation of atoms about single chemical bond | conformation |
| glucose moves down its concentration gradient, just as in simple diffusion, when transported by __ __ diffusion | carrier-mediated facilitated |
| normally in higher concentration in blood than in cells, where its rapidly used for ATP synthesis | glucose |
| glucose transport within body is typically __, into the cells | unidirectional |
| limited by numbers of protein carrier present | carrier-mediated transport |
| when all glucose, carrier-mediated transport, carriers are __ they are said to be saturated & glucose transport is occurring at __ __ | engaged; maximum rate |
| transmembrane protein that forms aqueous pore, allowing substances to move from one side of membrane to other | channels |
| exist within channels, and channels are selective due to pore size and charges of amino acids lining channel | binding/association sites |
| channels always open & simply allow ion/water fluxes according to concentration gradients | leakage channels |
| some channels are gated & controlled, __ or __, by various chemical or electrical signals | open; closed |
| many channels can be inhibited by certain molecules, show __, and tend to be specific | saturation |
| substances moving through channels also follow the concentration gradient, always moving | down the gradient |
| when substance crosses membrane by simple diffusion, rate of diffusion is not controllable because __ __ of membrane is not immediately changeable | lipid solubility |
| rate of facilitated diffusion is __ because permeability of membrane can be altered by __ activity/number of individual carriers or channels | controllable; regulating |
| vitally important to cellular homeostasis; passive transport by diffusion, either simple/facilitated, represents tremendous saving of cellular energy | oxygen, water, glucose, & various ions |
| if oxygen, water, glucose, & various ions had to be transported __, cell expenditures of ATP would __ exponentially | actively; increase |
| even though water is highly polar, it passes via osmosis through __ __ | lipid bilayer |
| transmembrane proteins that form water channels | aquaporins (AQPs) |
| water moves freely & reversibly through __ __ constructed by AQPs | water-specific channels |
| AQPs are particularly abundant in RBCs & cells involved in __ __, such as kidney tubules | water balance |
| osmosis occurs whenever __ __ differs on 2 sides of membrane | water concentration |
| if distilled water present on both side of selectively permeable membrane, no __ __ occurs, even though water molecules move in both direction through membrane | net osmosis |
| solute concentration on 2 sides of membrane differs, water concentration __ | differs |
| extent to which water's concentration is decreased by solutes depends on __ not on __ of solute particles | number; type |
| one molecule or one ion of solute | displaces one water molecule |
| number of solute particles present in 1 liter of a solution | osmolarity |
| when equal volumes of aqueous solutions of different osmolarity are separated by membrane that is permeable to all molecules in system, net diffusion of __ occurs; each moving __ its concentration gradient | both; down |
| pressure of fluid in a system | hydrostatic pressure |
| measure of tendency of water to move into more concentrated solution | osmotic pressure |
| higher amount of nondiffusible, non penetrating, solutes in cell higher the __ pressure & greater __ pressure that must be developed to resist further net water entry | osmotic; hydrostatic |
| major changes in hydrostatic/osmotic pressure do not occur in living animal cells because they lack | rigid cell walls |
| cause animal cells to swell or shrink, due to net water gain/loss, until wither solute concentration is same on both side of membrane, or membrane is stretched to breaking point | osmotic imbalances |
| ability of solution to change shape/tone of cells by altering their internal water volume | tonicity |
| of, relating to, or exhibiting equal osmotic pressure | isotonic |
| cells exposed to __ __ retain their normal shape, & exhibit not net loss/gain of water | isotonic solutions |
| body's __ fluids & most __ solutions are isotonic | extracellular; intravenous |
| solutions with higher concentration of nonpenetrating solutes than seen in cell | hypertonic |
| cells immersed in __ __ lose water and shrink | hypertonic solutions |
| having the margin or surface cut into rounded scallops; effect of immersion in hypertonic solutions | crenate |
| solutions more dilute than cells | hypotonic |
| cells placed in __ __ plump up rapidly, as water rushes into them | hypotonic solutions |
| represents most extreme example of hypotonicity, because contains no solutes, water continues to enter cells until they finally burst | distilled water |
| bursting of a cell | lyse |
| tonicity is based on how solute affects cell volume, which depends on solute __ & solute __ of plasma membrane | concentration; permeability |
| osmolarity is expressed as __ per liter | osmoles |
| 1 osmole = to 1 mole of __ molecules | nonioniziting |
| osmosis is extremely important in determining distribution of water in various __ __ of body | fluid-containing compartments |
| osmosis continues until osmotic & hydrostatic pressure acting at membrane are | equal |
| water is forced out of capillary blood by __ pressure of blood against capillary wall, but presence in blood on solutes that are too lrg to cross capillary membrane draws water back into __; resulting in very little net loss of __ __ | hydrostatic; blood-stream; plasma fluid |
| simple diffusion & osmosis occurring directly through plasma membrane are not __ processes | selective |
| simple diffusion & osmosis occurring directly through plasma membrane, whether molecule can pass through membrane depends chiefly on __ or __ in lipid, not on its unique structure | size; solubility |
| facilitated diffusion is often __ __ | highly selective |
| hypotonic solutions are sometimes infused in edematous patients, to draw excess water out of __ __ and move it into __ so it can be eliminated in kidneys | extracellular space; bloodstream |
| hypotonic solutions may be use to __ __ of extremely dehydrated patients | rehydrate tissues |
| requires carrier proteins that combine specifically & reversibly with transported substance | active transport |
| enzyme-like protein carrier that mediates active transport of solutes, such as amino acids & ions, uphill against concentration gradients | solute pumps |
| solutes moved by solute pumps, most importantly ions such as | Na+, K+, & Ca2+ |
| active transport processes are distinguished according to their | source of energy |
| energy to do work comes directly from hydrolysis of ATP | primary active transport |
| driven by indirectly by energy store in ionic gradients created by operation of primary active transport pumps | secondary active transport |
| secondary active transport systems are all __ __; that is, they move more than one substance at a time | coupled systems |
| if 2 transported substances, in 2ndary active transport system, are moved in same direction | symport system |
| in 2ndary active transport system, if transported substances wave to each other as they cross the membrane in opposite directions | antiport system |
| in primary active transport, hydrolysis of ATP results in __ of transport protein | phosphorylation |
| phosphorylation caused protein to change __ in such a manner that it __ bound solute across membrane | shape; pumps |
| incl calcium & hydrogen pumps, but most investigate example is operation of sodium-potassium pump | primary active transport systems |
| primary active transport system that simultaneously drives Na^+ out of cell against steep gradient & pumps K^+ back in | sodium-potassium pump |
| carrier enzyme in sodium-potassium pump | Na+-K+ ATPase |
| concentration in body cell is 10 times higher that outside | K+ |
| concentration in body cell is 10 lower higher that outside | Na+ |
| the __ __ __ of K+ vs Na+, are essential for excitable cells, like muscle & nerve cells, to function normally | ionic concentration difference |
| leak slowly but continuously through leakage channels in plasma membrane along their concentration gradient, & cross more rapidly in stimulated muscle & nerve cells | Na+ & K+ |
| operates more/less continuously as an antiporter | Na+ -K+ pump |
| maintained by Na+ -K+ pump, underlie most primary & secondary active transport of nutrients & ions; crucial for cardiac & skeletal muscle & neuron functions | electrochemical gradients |
| can indirectly drive secondary active transport of several other solutes | single ATP-powered pump |
| by Na+ -K+ pump, moving sodium across plasma membrane against concentration gradient, pump __ __ in ion gradient | store energy |
| substance pumped uphill/against concentration gradient across membrane can __ __ as it leaks back - propelled downhill along its concentration gradient | do work |
| in Na+ -K+ pump: as sodium moves back downhill, into cell w/help of carrier proteins, other substance are __ by common carrier, a symport system | cotransported |
| both cotransported substances (in Na+ -K+ pump: as sodium moves back downhill) move __ because energy for this type of transport is concentration gradient of the ion | passively |
| can be used in symport systems, or used to drive antiport systems | ion gradients |
| sugars, amino acids, and many ions are cotransported into cells lining small intestines; this is example of | symport system in secondary active transport |
| regulation of intracellulare pH by using sodium gradient to expel hydrogen ions, is an example of | antiport system in secondary active transport |
| whether energy is provided directly, in primary active transport, or indirectly, in secondary active transport, each membrane pump/cotransporter transports __ __ substances | only; specific |
| because membrane pump/cotransporter transports only specific substances, active transport systems provide way for cell to be very __ in cases where substances cannot pass by __ | selective; diffusion |
| pocket of embryonic tissue that is beginning of an organ; membranous sac | vesicles |
| movement of large particles & macromolecules across a plasma membrane | vesicular transport |
| mechanism by which substances are moved from cell interior to extracellular space as secretory vesicle fuses w/plasma membrane | exocytosis |
| means by which fairly large extracellular molecules or particles enter cells, e.g., phagocytosis, pinocytosis, receptor-mediated endocytosis | endocytosis |
| moving substances into, across, & then out of cells | transcytosis |
| moving substances from one are/organelle in cell to another | substance/vesicular trafficking |
| vesicular transport processes are energized by __, or in some cases another energy-rich compound, GTP - guanosine triphosphate | ATP |
| all forms of vesicular transport involve assortments of __ vesicles of 3 types, with some exceptions, all are __ by membrane receptors | protein-coated; mediated |
| protein-coated vesicles provide main route for __ & __ of bulk solids, most macromolecules, & fluids | endocytosis; transcytosis |
| often hijacked by pathogens seeking entry into a cell | protein-coated vesicles |
| in endocytosis stage1, substance to be taken into cell progressively enclosed by infolding portion of plasma membrane called | coated pit |
| protein coating that forms on cytoplasmic side of coated pit, in endocytosis | clathrin |
| clathrin & some accessory proteins; acts both in cargo selection & in deforming membrane to produce vesicle | clathrin coat |
| in endocytosis stage2, vescile __ | detaches |
| in endocytosis stage 3, __ __ are recycled back to plasma membrane | coat proteins |
| in endocytosis stage4, __ __ then typically fuse with endosome | uncoated vesicle |
| processing and sorting vesicle | endosome |
| in endocytosis stage5, some membrane components & receptors of fused vescile may be recycled back to plasma membrane in __ __ | transport vesicle |
| in endocytosis stage6, remaining contents of vesicle may, __ with lysosome, or be transported completely across cell & released by __ on opposite side | combine; exocytosis |
| specialized cell structure containing digestive enzymes where digested substance is degraded or released | lysosome |
| transcytosis is common in __ cells lining blood vessels because it provides quick means to get substance from blood to interstitial fluid | endothelial |
| based on nature & quantity of material taken up & means of uptake, 3 types of endocytosis that use clathrin-coated vesicles are recognized | phagocytosis, pinocytosis, & receptor-mediated endocytosis |
| type of endocytosis in which cell engulfs relatively lrg/solid material; e.g. bacteria, dead cell debris, foreign substances engulfed by cells | phagocytosis |
| in phagocytosis, when particle binds to receptors on cell's surface, __ __called pseudopods form & flow around particle & engulf it | cytoplasmic extensions |
| formed as a result of phagocytosis; vesicle containing engulfed material that fuses w/lysosome & its contents are digested | phagosome |
| in most cases phagosome fuses with __ & its contents are digested | lysosome |
| in human body, macrophages & certain WBCs are only cells that are experts at phagocytosis, called | phagocytes |
| flowing movement of the cytoplasm, into temporary pseudopods, of a phagocyte allowing them to creep along; "changing shape" | amoeboid motion |
| cells have the same __ parts | basic |
| plasma membrane, cytoplasm, nucleus, are all | basic parts of cells |
| cell membrane lipid bilayer w/proteins dispersed in it meaning it is a(n) | phospholipids bilayer |
| in cell membrane, __ float in the lipid bilayer | proteins |
| __ recognizes an ovum by its glycocalyx | sperm |
| glycocalyx forms cell __ molecules & __ | adhesion; receptors |
| transport, receptors, forming cell junctions are all functions of | membrane proteins |
| function of membrane proteins includes __ __ (glycocalyx) | cell-cell recognition |
| function of membrane proteins includes attaching to cytoskeleton & extracellular matrix to | help maintain cell shape |
| minute finger-like extensions of plasma membrane | microvilli |
| microvilli are example of __ of plasma membrane | specialization |
| microvilli increase __ __ | surface area |
| microvilli are found on __ __ i.e. kidney tubule cells & small intestinal cells | absorptive cells |
| example of desmosomes are | heart muscle cells |
| example of gap junctions are | heart muscle, smooth muscle |
| example of tight junctions are between epithelial lining of | digestive tract |
| lipids, CO2, O2 pass through plasma membrane via | simple diffusion |
| glucose, amino acids pass through plasma membrane via protein specific carrier in | carrier-mediated facilitated diffusion |
| vesicular transport requires | ATP |
| used for hormone, secretion, neurotransmitter release, mucous secretion | exocytosis |
| infolding plasma membrane pinches off droplet of extra cellular fluid & dissolved molecules- vesicle fuses w/endosome; occurs in most cells, esp. cells of intestines | pinocytosis |
| pinocytosis means | cell drinking |
| main mechanism for endocytosis & transcytosis of most macromolecules; substances bind to specific receptors on plasma membrane, vesicle formed; used for taking in some enzymes, hormones, cholesterol attaches to lipoproteins | receptor-mediated endocytosis |
| phagosome fuse with | lysosome |
| phagocytosis is process used by __ & __ to protect body | macrophages; neutrophils |
| exist across membranes of all cells of the body, resulting from separation of oppositely charged ions across membrane | electrical potential/voltage |
| in resting state cells have resting membrane __ ranging from 50-100 mV | potential |
| important in excitable tissues, such as nerve/muscle cells, where rapid changes are used to transmit impulses; typically ranges from -50 to -100 mV depending on cell type | resting membrane potential |
| resting membrane potential can also be considered | action potentials |
| the ionic concentration difference of K+ vs Na+, are essential for excitable cells, like muscle & nerve cells, for all body cells to maintain their normal __ __ | fluid volume |
| resting membrane potential is created by concentration of K+ more __ cells while that of Na+ is more __ cells | inside; outside |
| in __ membrane __, main factor is movement of K+ from inside to outside cell through leak channels (down concentration gradient) creating an electronegativity inside | resting; potential |
| in resting membrane potential, some diffusion of Na+ from outside-inside hardly makes difference to electronegativity because __ __ are 100x more permeable to K+ under resting conditions | leak channels |
| pumps out 3 Na+ for every 2 K+ pumped in; resulting in further loss of +charge from inside membrane, adding to electronegativity | Na+- K+ pump |
| have specificity for particular ligands; i.e., hormones, neurotransmitters | membrane receptor proteins |
| signaling chemicals that bind specifically to membrane receptors; most hormones, neurotransmitters, & paracrines | ligands |
| in membrane receptor, __ __ initiates specific/multiple cellular responses | ligand binding |
| common type of membrane receptors are G __ receptors | protein-linked |
| exert their effect indirectly through G proteins, which acts as middleman/relay to activate/inactivate membrane-bound enzyme/ion channel | G protein-linked receptors |
| cellular material surrounding the nucleus & enclosed by plasma membrane; contains the cytosol, organelles & inclusions | cytoplasm |
| largely water w/dissolved protein, salts, sugars, & other solutes | cytosol |
| mitochondria, peroxisomes, lysosomes, rough/smooth ER, & Golgi apparatus | membranous cytoplasmic organelles |
| cytoskeleton, centrioles, & ribosomes | nonmembranous cytoplasmic organelles |
| double membrane structure w/shelf-like cristae | mitochondria |
| mitochondria are __ __ in metabolically active cells like kidney/liver | more numerous |
| mitochondria contain __ __ DNA/RNA | their own |
| mitochondria provide majority of a cell's ATP via __ cellular respiration | aerobic |
| sites of protein synthesis; composed of proteins & rRNA; each has 2 subunits | ribosomes |
| __ __ synthesize soluble proteins | free ribosomes |
| located on RER; synthesize proteins to be incorporated into cells membranes/for export | membrane-bound ribosomes |
| system of interconnected tubes & parallel membranes enclosing cristae; is continuous w/nuclear membrane | endoplasmic reticulum |
| external surface studded w/ribosomes; manufacture all secreted proteins & proteins for cell membranes | Rough ER |
| RER __ __ in antibody producing plasma cells, secretory cells (pancreatic cells), liver cells which product plasma proteins | more abundant |
| enzymes of __ involved with lipid metabolism & cholesterol synthesis breakdown of glycogen (liver) | SER |
| enzymes of SER involved with synthesis of __ __, e.g. testosterone in testes | steroid-based hormones |
| enzymes of SER involved with __ reticulum in skeletal & cardiac muscle cells | sarcoplasmic |
| enzymes of SER involved with __ of drugs (liver & kidneys), | detoxification |
| role of calcium ion storage & release in muscle contraction, in skeletal & cardiac muscles | sarcoplasmic reticulum |
| stacked, flattened membranous sacs & tiny vesicles; functions in modification & packaging of proteins | Golgi apparatus |
| when transport vesicles from RER fuse w/Golgi apparatus, proteins are __ | modified |
| Golgi apparatus - proteins __ in vesicles, secretory vesicles move to plasma membrane, then are __ by exocytosis | packaged; discharged |
| spherical membranous bags of digestive enzymes (acid hydrolases); digest ingested bacteria, viruses, & toxins; degrade worn out organelles | lysosomes |
| lysosomes are __ in phagocytes | abundant |
| lysosomal rupture __ __ autolysis | results in |
| self digestion of the cell | autolysis |
| system includes nuclear envelope, SER, RER, transport vesicles, Golgi apparatus, lysosomes, & plasma membrane | endomembrane system |
| parts of endomembrane system work together to produce/export __ molecules & __ harmful substances | biological; degrade |
| membranous sacs containing oxidase & catalase; detoxify harmful/toxic substances; numerous in liver & kidney cells | peroxisome |
| peroxisomes __ dangerous free radicals | neutralize |
| highly reactive chemicals w/unpaired electrons (i.e. O2-) that can damaged cell components | free radicals |
| hollow tubes made of spherical protein tubulin; determine shape of cell & distribution of organelles; radiate from centrosome | microtubules |
| microtubules, microfilaments, & intermediate filaments __ __ the cytoskeleton | make up |
| strands of protein actin; involved in cell motility, muscle contraction, endocytosis, & exocytosis; 7nm | microfilaments |
| tough, protein fibers; resist pulling forces on cell & help form desmosomes; 10nm | intermediate filaments |
| paired, consisting of microtubules; located in centrosome near nucleus; form bases of cilia & flagella | centrioles |
| generated microtubules for mitotic spindle during cell division | centrosome |
| nucleus consists of | nuclear envelope, nucleolus, & chromatin |
| gene-containing control center of cell; contains instructions for building nearly all body's proteins | nucleus |
| most cells have __ nucleus | one |
| referring to nucleus, skeletal muscle cells & osteoclasts are __ | multinucleate |
| referring to nucleus, mature RBCs are | anulcleate |
| selectively permeable double membrane barrier containing nuclear pores; outer membrane continuous w/RER & studded w/ribosomes | nuclear envelope |
| nuclear envelope: through __ __ protein molecules are imported from cytoplasm | nuclear pores; |
| nuclear envelope: through nuclear pores RNA __ __ nucleus | exported from |
| nuclear envelope encloses jelly-like __ | nucleoplasm |
| dark-staining spherical bodies w/in nucleus; site of assembly of 2 types of ribosomal subunits | nucleoli |
| in nucleoli, 2 types of ribosomal subunits each consist of __ & __ | rRNA; proteins |
| in nucleoli, ribosomal subunits leave through nuclear pores, to form __ ribosomes | functional |
| nucleoli are __ in cells making a large amount of proteins | larger |
| make up is: 30% DNA, 60% histone proteins, 10% RNA; arranged in units called nucleosomes; 2 varieties consists of extended & condensed | chromatin |
| active chromatin that dictates protein synthesis | extended chromatin |
| inactive chromatin forms chromosomes when nucleus starts to divide | condensed chromatin |
| units within chromatin, made of arrangements of 8 histone proteins & 2 winds of the DNA | nucleosomes |
| series of changes cell goes through from time it is formed until it reproduces via interphase | cell cycle |
| stage of interphase when metabolic activity & growth, centrioles starts to replicate | G1 (gap 1) phase |
| interphase consists of subphases: | G1, S, G2 |
| stage of interphase when DNA replication takes places | S (synthetic) phase |
| stage of interphase when cell prepares for division; enzymes & proteins synthesize | G2 (gap 2) phase |
| 1 of 2 major periods in cell life cycle; includes period from cell formation to cell division | interphase |
| term interphase reflects idea of resting phase of cell through its meaning of stage __ cell divisions | between |
| during interphase cell is carrying out all its routine activities, only "resting" from __ | dividing |
| metabolic or growth phase would be __ __ name for interphase | more appropriate |
| consists of distinct events: mitosis and cytokinesis | M (mitotic) phase |
| process during which chromosomes are redistributed to 2 daughter nuclei; division of nucleus; continuous process w/one stage merging smoothly to next | mitosis |
| mitosis __ __ prophase, metaphase, anaphase, and telophase | consists of |
| division of cytoplasm that occurs after cell nucleus has divided; division of cytoplasm | cytokinesis |
| movement | -kines |
| thread | mit- |
| -osis | process |
| 1st stage mitosis | prophase |
| 2nd stage mitosis | metaphase |
| 3rd stage mitosis | anaphase |
| final phase mitosis | telophase |
| mitosis in human cells generally last about __ __, or less, from start to finish | an hour |
| in DNA replication, before a cell can __ DNA has to be replicated, which occurs in S phase | divide |
| in DNA replication, once DNA is replicated, DNA helices begin __ from nucleosomes | unwinding |
| in DNA replication, during the DNA unwinding process, helicases untwists __ __ & __ DNA into two strands | double helix; separates |
| in DNA replication, once DNA unwound, each nucleotide strand serves as __ for building new __ strand | template; complementary |
| in DNA replication, __ __used to begin DNA synthesis | RNA primers |
| in DNA replication, __ __ continues from RNA primer & adds complementary nucleotides to template | DNA polymerase |
| in DNA replication, DNA polymerase, only works in __ __ | once direction |
| __ __, of DNA polymerase, is synthesized continuously | leading stand |
| __ __, of DNA polymerase, is synthesized in segments in opposite direction, then joined w/leading strand | lagging strand |
| in DNA replication, 2 __ __ are formed, each having 1 old & new strand | DNA molecules |
| in DNA replication, histones are __ from cytoplasm, then __ w/DNA forming 2 chromatin strands | imported; associate |
| in DNA replication, chromatin untied by __; condensed to form __ | centromere; chromatids |
| in DNA replication, chromatids __ __ until cell enters anaphase | remain attached |
| dell division is essential for __ growth & __ repair | body; tissue |
| continuously dividing cells e.g. intestinal epithelium, skin; cells that can be stimulated to divide e.g. liver cells; cells that cannot divide e.g. neurons, cardiac muscle & skeletal muscle cells | 3 populations of cells according to their ability to replicate |
| in cytokinesis, __cytoplasm is pinched into 2 parts after mitosis ends- two __ cells | cytoplasm; daughter |
| chromatin condenses into chromosomes, each appears as sister chromatid held by centromere; nucleoli disappear; centriole pairs separate from each other; microtubules lengthen to form mitotic spindle | early prophase |
| nuclear fragments & membrane disappears; centrosomes at opposite poles; microtubules pull each chromosome from both poles | late prophase |
| in metaphase, chromosomes cluster at __ of cell w/their __ at equator of spindle | middle; centromeres |
| arrangement of chromosomes in plane midway between 2 poles is called | metaphase plate |
| in anaphase, centromeres of chromosomes __ | split |
| in anaphase, once chromosomes split, each chromosome __ __ a pole by microtubules | pulled toward |
| in anaphase, chromosomes look __ | V-shaped |
| in telophase, chromosomes have moved to __ __ | opposite poles |
| in telophase, chromosomes __ & become thread-like __ | uncoil; chromatin |
| in telophase, new nuclear membrane formed from __ __ | rough ER |
| in telophase, nucleoli that disappeared in early prophase, __ | reappear |
| in telophase, __ spindle appears | mitotic |
| in telophase, cytokinesis __ cell division into 2daughter cells | completes |
| in protein synthesis, 1 gene carries instruction for creating one __ chain | polypeptide |
| in protein synthesis, 1 DNA base triplet codes for one __ __ | amino acid |
| in protein synthesis, role of RNA includes: __, __, & __ | mRNA; rRNA; tRNA |
| in protein synthesis, carries genetic info from DNA to ribosomes | mRNA |
| in protein synthesis, is component of ribosomes | rRNA |
| in protein synthesis, loads up w/amino acids & base pairs w/the codons of mRNA at ribosome for synthesis | tRNA |
| in protein synthesis, involves transfer of info from DNAs gene base sequence to complimentary base sequence of mRNA | transcription |
| in protein synthesis during transcription, this binds to DNA & unwinds 16-18 base pairs at a time | RNA polymerase |
| in protein synthesis during transcription, RNA polymerase adds complementary __ __ on DNA template strand; other DNA strands is coding | RNA nucleotides |
| in protein synthesis when transcription stops, mRNA strand __ __ DNA | pulls off |
| 3 base sequence of mRNA corresponding to a DNA base triplet | codon |
| process in which DNA base sequence is translated into amino acid sequence for protein synthesis | translation |
| in protein synthesis during translation, once __ is made, it leaves nucleus through the nuclear pores, enters cytoplasm & attaches to __ small subunit | mRNA; ribosome |
| in protein synthesis during translation, __ __ initiator tRNA binds to start codon of mRNA (its anticodon base pairs) on ‘P’ site of ribosome | methionine carrying |
| in protein synthesis during translation, once methionine carrying initiator tRNA binds to start codon of mRNA on ‘P’ site of ribosome, large __ __ binds to this complex forming a(n) __ __ | ribosomal unit; functional ribosome |
| in protein synthesis during translation, 2nd tRNA binds to ‘A’ site on __, matching w/next 3bases on __ | ribosome; mRNA |
| in protein synthesis during translation, amino acid carried by 2nd tRNA binds to __, the latter separating from its __ which moves to ‘E ‘ site & exits | methionine; tRNA |
| in protein synthesis during translation, polypeptide chain __ till a stop codons is reached __ translation | elongates; ending |
| pinocytosis is also called | fluid-phase endocytosis |
| receptors for receptor-mediated endocytosis are __ __ __ that bind only certain substances | plasma membrane proteins |
| in receptor-mediated endocytosis, receptors & attached molecules are __ in clathrin-coated pit | internalized |
| enzymes, insulin & other hormones, low-density lipoproteins (i.e. cholesterol attached to transport protein), & iron are all | substances take up by receptor-mediated endocytosis |
| flu viruses, diphtheria, & cholera toxins use receptor-mediated endocytosis to | enter & attack our cells |
| tubular or flask-shaped inpocketings of plasma membrane seen in many cell types; capture specific molecules (folic acid, tetanus toxin) from extracellular fluid in coated vesicles & participate in from forms of transcytosis | caveolae |
| caveolae are involved in unique kind of receptor-mediated endocytosis called __ | potosis |
| caveolae are __ than most vesicles & their cage-like protein coat is __ & compose of caveolin | smaller; thinner |
| integral membrane proteins that are principal components of caveola membranes; believed to act as scaffolding for assembly of signaling complexes | caveolin |
| caveolae are closely associated w/lipid rafts that are platforms for __ proteins, receptors for hormones and enzymes involved in cell __ | G; regulation |
| caveolae vesicles appear to provide sites for cell __ & cross talk btwn __ pathways | signaling; signaling |
| 1 of macromolecular protein complexes, composed of 7subunits & present in cytosol, that are assembled to form coat of vesicles that transport proteins btwn cisternae of Golgi complex & btwn Golgi complex & ER | coatomer proteins |
| coatomer proteins used in most types of intracellular vesicular trafficking which transport substances btwn organelles | COP1 & COP2 |
| typically stimulated by cell-surface signal such as binding of hormone to membrane receptor or change in membrane voltage, accounts for hormone secretion, neurotransmitter release, mucus secretion, & in some cases ejection of wastes | process of exocytosis |
| in exocytosis, substance to be removed from cell is 1st enclosed in __ __ sac called vesicle | protein-coated membranous |
| in exocytosis, once substance to be removed is enclosed in vesicle, vesicle then migrates to plasma membrane, fuses with it, & then __, spilling sac contents, __ of cell | ruptures; out |
| exocytosis involves __ process in which transmembrane proteins on vesicles called __ recognize certain plasma membrane proteins, called __ & bind with them | v-SNAREs; t-SNAREs |
| binding of v-SNAREs & t-SNAREs causes membranes to __ together & fuse, rearranging lipid monolayers w/out mixing them | corkscrew |
| membrane material added by __ is removed by __, the reverse process | exocytosis; endocytosis |
| voltage across plasma membrane | membrane potential |
| electrical potential energy resulting from separation of oppositely charged particles | voltage |
| in cells, oppositely charged particles are __, & barrier that keeps them apart is __ __ | ions; plasma membrane |
| because of resting membrane potential all cells are said to be __ | polarized |
| a minus side before voltage, of a cell, indicates that the __ of cell is negative compared to its __ | inside; outside |
| resting membrane potential voltage, or charge separation, exists __ __ the membrane | only at |
| if all the - & + charged in cytoplasm were add up, would find cell interior is __ __ | electrically neutral |
| + & - charges in extracellular fluid __ each other out __ | balance; exactly |
| resting membrane potential comes about because, diffusion causes ionic imbalances that __ membrane, & active transport processes __ that membrane potential | polarize; maintain |
| resting membrane potential is determined mainly by __ __ of K+ & by __ permeability of plasma membrane to K+ & other ions | concentration gradient; differential |
| K+ & protein anions __ inside body cells | predominate |
| extracellular fluid contains relatively more __, largely balanced by __ | Na+; Cl- |
| unstimulated plasma membrane is somewhat permeable to K+ because of __ __, but impermeable to protein __ | leakage channels; anions |
| combined difference in concentration & charge; influences distribution & direction of diffusion of ions | electrochemical gradients |
| ions diffuse according to __ gradients, thereby recognizing effect of both electrical & __ (chemical) forces | electrochemical; concentration |
| although diffusion of K+ across plasma membrane is aided by membrane's greater __ to it & by ion's concentration gradient, its diffusion is resisted somewhat by __ __ on cell exterior | permeability; positive charge |
| Na+ is drawn into cell by __ __ gradient, & limiting factor is membrane's relative __ to it | steep electrochemical; impermeability |
| upsetting resting membrane potential by __ opening of Na+ & K+ channels in plasma membrane is normal means of __ neurons & muscle cells | transient; activating |
| whether cells interact directly/indirectly the glycocalyx is __ __ | always involved |
| best understood of participating glycocalyx molecules fall into 2 large families | cell adhesion molecules & plasma membrane receptors |
| another group of membrane proteins, which are important in cells that respond to electrical signals | voltage-sensitive channel proteins |
| cell surface glycoproteins that mediate intercell adhesion in body; cadherins, integrins | cell adhesion molecules (CAMs) |
| sticky glycoproteins (cadherins, integrins) act as molecular "Velcro" that cells use to anchor themselves to molecules in extracellular space & to each other | CAMs |
| sticky glycoproteins (cadherins, integrins) act as "arms" that __ cells use to haul themselves past one another | migrating |
| sticky glycoproteins (cadherins, integrins) act as SOS signals, sticking out from blood vessel lining that rally __ __ to nearby infected or injured area | protective WBCs |
| sticky glycoproteins (cadherins, integrins) act as __ __ that respond to local tension at cell surface by stimulating synthesis or degradation of adhesive membrane junctions | mechanical sensors |
| sticky glycoproteins (cadherins, integrins) act as __ of intracellular signals that direct cell migration, proliferation, & specialization | transmitters |
| large, diverse group of integral proteins & glycoproteins that serve as binding sites for signaling molecules | membrane receptors definition |
| actual coming together & touching of cells, & is means by which cells recognize one another | contact signaling |
| contact signaling is particularly important for normal __ & __ | development; immunity |
| some bacteria & other infectious agents use contact signaling to identify their "preferred" __ tissues/organs | target |
| most plasma membranes receptors are involved in __ signaling | chemical |
| different cells respond in different ways to the __ ligand | same |
| ligand that stimulates skeletal muscle cells to contract, but inhibits heart muscle | acetylcholine |
| target cell's response to chemical signaling depends on __ __ that receptor is linked to, not specific ligand that binds to it | internal machinery |
| when ligand binds to membrane receptor, receptor's __ changed, & cell proteins are __ in some way | structure; altered |
| example of ligand changing membrane receptor's structure muscle proteins change to __ __ | generate force |
| some membrane receptor proteins are __ proteins that function as enzymes | catalytic |
| common in muscle/nerve cells; respond to ligands by transiently opening/closing ion gates, which in turn changes excitability of cell | chemically gated channel-linked receptors |
| some lipid rafts group together many receptor-mediated elements, thus __ cell signaling | facilitating |
| protein that relays signals btwn extracellular 1st messengers, such as hormones or neurotransmitters, & intracellular 2nd messengers, such as cyclic AMP, via an effector enzyme | G protein |
| intracellular molecule generated by binding of chemical to plasma membrane receptor; mediates intracellular responses to chemical messenger | 2nd messengers |
| intracellular 2nd messenger that mediates effects of 1st (extracellular) messenger (hormone or neurotransmitter); formed from ATP, by plasma membrane enzyme (adenylate cyclase) | cyclic AMP |
| 2 important 2nd messengers; both typically activate protein kinase enzymes, which transfer phosphate groups from ATP to other proteins | cyclic AMP & ionic calcium |
| when protein kinase is activated by 2nd messenger, it can activate a(n) __ __ of enzymes that bring about desired cellular activity; because single enzyme can catalyze hundred of reactions, this __ __ of such a chain of events is tremendous | whole series; amplification effect |
| key signaling pathway involved in neurotransmission, smell, vision, & hormone action | G protein signaling system |
| one of simplest molecules; 1nitrogen & 1oxygen; environmental pollutant & 1st gas known to act as biological messenger; slips in/out of cells easily; unpaired electrons make highly reactive | NO |
| certain plasma membrane proteins are channel proteins that respond to changes in membrane potential by opening or closing channel | electrical signaling |
| cytoplasm is site where most cellular activities are __ | accomplished |
| cytosol is complex mixture with properties of both a(n) __ & a(n) __ __ | colloid; true solution |
| cytoplasmic organelles are __ __ of cell | metabolic machinery |
| chemical substances that may/may not be present, depending on cell type | inclusions |
| stored nutrients, suck as glycogen granules abundant in liver/muscle cells; lipid droplets common in fat cells; melanin granules seen in certain cells of skin/hair; water-containing vacuoles; & crystals of various types are all | examples of inclusions |
| membrane enabling membranous organelles to maintain internal environment different from that of surrounding cytosol, called __, is crucial to cell functioning | compartmentalization |
| without compartmentalization, thousands of enzymes would be randomly __ & biochemical __ would be chaotic | mixed; activity |
| organelle's membrane often unites it w/rest of interactive intracellular system called __ system | endomembrane |
| organelle membrane's lipid makeup allows it to __ & __ w/other organelles | recognize; interact |
| glycolipid | plasma-membrane lipid possessing a sugar chain that functions in cell recognition |
| phospholipid | most abundant molecule found within lipid bilayer of plasma membrane |
| cholesterol | plasma-membrane lipid that improves rigidity of plasma membrane & increases membrane's impermeability to water |
| protein | component of plasma membrane that can act as doorway for charged particles |
| endocytosis | method by which large particles & macromolecules enter cell by infolding of plasma membrane |
| osmosis | movement of water across a selectively permeable plasma membrane from region of high concentration to region of low concentration |
| exocytosis | mechanism by which substances are moved from cell cytoplasm to outside of cell by fusion of a vesicle w/plasma membrane |
| diffusion | tendency of molecules to move along their concentration gradient from region of high-low concentration |
| transport mechanisms | methods carry molecules, pump molecules, or form channels through which specific molecules pass across plasma membrane |
| phagocytosis | endocytosis of large items, such as bacteria or cellular debris |
| pinocytosis | endocytosis of a tiny quantity of extracellular fluid containing solute molecules |
| receptor-mediated endocytosis | endocytosis that utilizes selective plasma membrane receptor proteins |
| hormones such as insulin, low-density lipoproteins move into cell by | receptor-mediated endocytosis |
| water movement across membrane into cell by | osmosis |
| movement of oxygen, carbon dioxide, and other small uncharged molecules across membrane into cell | diffusion |
| movement of large particles, bacteria, or cellular debris by endocytotic vesicle into cell | phagocytosis |
| molecules moving against the concentration gradient into cell by | active transport mechanisms |
| mitochondrion characteristics | cristae; matrix |
| ribosome characteristics | composed of two subunits; can be "free" in the cytosol or attached to rough ER |
| rough ER characteristics | produces protein transport vesicles |
| Golgi apparatus characteristics | possesses a cis and trans side; composed of cisternae |
| centrioles characteristics | composed of microtubules arranged in nine groups of three |
| microfilaments characteristics | thinnest members of the cytoskeleton are composed of strands of actin protein |
| intermediate filaments characteristics | cytoskeleton members are tough, insoluble protein fibers that possess a high tensile strength |
| microtubules characteristics | hollow tubular members of cytoskeleton composed of spherical protein subunits & can be quickly assembled & disassembled by cell |
| chromatin | strands of DNA and associated histones in the nucleus of a non-dividing cell |
| nuclear envelope, or nuclear membrane | membrane that surrounds the nucleus of a cell |
| nuclear pore | tiny passageway that allows large molecules to freely pass in and out of the nucleus |
| nucleolus | dark-staining body found in the nucleus of a cell that functions in producing ribosomes |
| nucleoplasm | jelly-like fluid found within the nucleus of a cell |
| chromosomes | dark-staining, rod-shaped structures composed of highly coiled chromatin, found in cells undergoing cell division |
| histones | spherical protein molecules around which DNA wraps |
| extended chromatin | fine, uncoiled strands of DNA in the nucleus of a non-dividing cell |
| condensed chromatin | dark-staining regions in the nucleus of a non-dividing cell composed of tightly coiled strands of DNA |
| nucleosome | section of DNA and its eight associated histone proteins |
| G1 | cell is metabolically active, synthesizing proteins, and growing rapidly |
| G2 | cell division enzymes are synthesized, and the centrioles complete replication |
| S | DNA replicates itself |
| metaphase | chromosomes line up along cell equator |
| prophase | chromatin condenses into chromosomes; centrioles move toward opposite poles of the cell |
| anaphase | identical sets of chromosomes moved to opposite sides of cell |
| telophase | chromosomes uncoil and revert to chromatin; nuclear membranes form around the sets of chromosomes |
| protein synthesis is function of | ribosomes |
| lipid synthesis is function of | smooth ER |
| intracellular digestion is function of | lysosomes |
| organize spindle during mitosis | centrioles |
| support cell & give it shape; involved in cell movements | microtubules |
| product produced by mitochondrion | ATP |
| product produced by rough ER | transport vesicles |
| product produced by Golgi apparatus | lysosomes & secretory vesicles |
| product produced by nucleolus | ribosomes |
| product produced by centrioles | cilia & flagella (microtubules) |
| events occurring in cytokinesis | division of the parent cell cytoplasm into two daughter cells |
| events occurring in mitosis | separation of two identical sets of chromosomes to opposite sides of the parent cell |
| events occurring in interphase | non-dividing stage involving rapid growth, DNA replication, and preparation for division |
| random motion of a substance resulting in movement from area of high to lower concentration | characteristics of diffusion |
| passive process utilizing a protein carrier or channel | characteristics of facilitated diffusion |
| movement of a substance that utilizes a carrier; energy comes directly from hydrolysis of ATP | characteristics of primary active transport |
| movement of a substance that utilizes a carrier, and has a concentration gradient as the source of energy | characteristics of secondary active transport |
| carries genetic instructions from nucleus to the site of protein synthesis | function of mRNA |
| uses an anticodon to guide its attached amino acid to the complementary codon on the mRNA at the ribosome | function of tRNA |
| combines in a complex with proteins to make the large and small subunits of a ribosome | function of rRNA |
| can control, or inhibit, certain genes | function of microRNA |
| adjacent cells joined by a line of membrane proteins that form an impermeable junction | tight junction |
| button-like junctions that use linker proteins to hold adjacent cells together | desmosomes |
| adjacent cells held together by connexon proteins that form cylinders allowing ion flow between the cells' cytoplasm | gap junctions |
| tiny finger-like projections of the plasma membrane; increase surface area for absorption | microvilli |
| motile cellular extensions found in large numbers in some epithelial cells | cilia |
| long, cellular projections that are tail-like and aid in propulsion | flagella |
| cytoskeleton is an elaborate network of rods running throughout the cytosol, functioning in | supporting cellular structures & generating cell movements |
| DNA | nucleic-acid molecules are involved in transcription but not translation in the synthesis of a particular polypeptide |
| DNA is copied into mRNA in transcription within the nucleus in the synthesis of a(n) | particular polypeptide |
| mRNA start codon, AUG, matches up with a tRNA anticodon | GAC |
| definite changes in the __ of the cell membrane can be seen in a cell that is becoming cancerous | glycocalyx |
| simple diffusion is best described as substances | moving down a concentration gradient passively |
| crenation takes place when a cell is placed in a(n) | hypertonic solution |
| type of RNA contains regions that act as a switch to turn protein synthesis on & off for the protein it codes for | Riboswitches |
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lfrancois
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