AP Bio Test 2
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251 terms
Terms | Definitions |
|---|---|
 light microscope | visible light is passed through the specimen and then through glass lenses which refract the light in such a way that the image of the specimen is magnified as it is projected, cannot resolve detail finer than 0.2 micrometers or 200 nanometers, magnifies up to 1000x actual size, shows contrast but organelles are too small to see |
| electron microscope | focuses a beam of electrons through the specimen or onto its surface, can theoretically achieve a resolution of about 0.002 nanometers, measures the cell ultrastructure |
| cell ultrastructure | cellular anatomy revealed by electron microscope |
| scanning electron microscope | electron beam scans surface of sample which is coated with thin film of gold, beam excites electrons on surface and secondary electrons are detected by a device that translates the pattern of electrons into an electron signal on video screen, useful for the study of the surface of the specimen, gives a 3D image |
| transmission electron microscope | aims an electron beam through a very thin section of the specimen which has been stained with atoms of heavy metals that attach to certain cellular structures enhancing the electron density in areas of the cell, uses electromagnets as lenses to bend the paths of the electrons, shows internal ultrastructure of cells |
| light microscope | can see living cells |
| electron microscope | can only observe dead cells of colorized specimen |
| cytology | the study of cell structure |
| biochemistry | the study of the molecules and chemical processes of cells |
| cell fractionation | technique useful for studying cell structure and function by taking cells apart and separates the major organelles and other subcellular structures from one another, allows researchers to prepare specific cell components in bulk and identify their functions |
| plasma membrane, cytosol with organelles, ribosomes, chromosomes | all cells have __________________________________________ |
| eukaryotic cells | nuclei are found in what cells? |
| eukaryotic cells | internal membranes are found in what cells? |
| plasma membrane | selective barrier all cells have that allows sufficient passage of oxygen, nutrients, and wastes to service then entire cell; made up of phospholipids, proteins, and associated carbohydrates |
| cytosol | semifluid, jellylike substance that is enclosed by the membrane coning organelles and other components |
| chromosomes | structures that carry genes in the form of DNA |
| ribosomes | tiny complexes that make proteins according to instructions from the genes |
| nucleus | area where most of the DNA of a eukaryotic cell is found, bounded by a double membrane called nuclear envelope which has nuclear pores |
| nucleoid | area where DNA is concentrated in a prokaryotic cell, not membrane enclosed |
| cytoplasm | interior of a prokaryotic cell, also used to describe region between the nucleus and the plasma membrane of a eukaryotic cell |
| membrane bound organelle | prokaryotes lack these but eukaryotes have them |
| eukaryotic cells larger | difference in cell size |
| nuclear envelope | encloses the nucleus separating its contents from the cytoplasm, is a double membrane, has protein structure called pore complex which regulates entry and exit of proteins, RNAs, and macromolecules |
| nuclear lamina | lining of the nuclear side of the nuclear envelope, a netlike array of protein filaments, gives nucleus its shape |
| nuclear matrix | framework of fibers extending throughout the nuclear interior, possibly involved in organizing genetic material |
| chromosomes | structures that carry genetic info, can be in form of chromatin (proteins and DNA) |
| 46 | human cells have _____ chromosomes per cell |
| 23 | sex cells have _____ chromosomes per cell |
| chromatin | a complex of proteins and DNA |
| nucleolus | mass of densely stained granules & fibers adjoining next to part of chromatin, where rRNA is made, proteins are imported from cytoplasm and assembled with rRNA into large and small ribosomal subunits which exit through nucleur pores, may also regulate cell division |
| nucleus | makes mRNA which is transported out and translated to make primary structure of a specific polypeptide |
| nucleus | nuclear envelope, nuclear lamina, nuclear matrix, chromosomes, and the nucleolus are all part of the _____________ |
| ribosomes | made of rRNA & proteins, rate of protein synthesis is dependent on the number of ribosomes |
| free ribosomes | ribosomes suspended in cytosol that make proteins to functions within cytosol |
| bound ribosomes | ribosomes attached to ER or nucleus that make proteins for insertion into membranes |
| endomembrane system | nuclear envelope, ER, golgi apparatus, lysosomes, vacuoles, and the plasma membrane are all part of the __________________________ |
| ER | biosynthetic factory, composes more than 1/2 the total membranes of cell, made up of cisternae and ER lumen |
| cisternae | membranous tubules and sacs of the ER |
| ER lumen | internal compartment of ER |
| smooth ER | has no ribosomes; synthesizes lipids, oils, phospholipids,and steroids; site of metabolism of carbs; detoxification of drugs; stores calcium ions |
| liver cells | detoxifies drugs |
| muscle movement | calcium cells are used for |
| rough ER | synthesis of secretory proteins and membranes |
| glycoproteins | most common secretory proteins, proteins that have carbohydrates covalently bonded to them, wrapped in vesicle and bud off from transitional ER |
| transport vesicles | vesicles traveling from one part of cell to another |
| golgi apparatus | shipping and receiving, receives many transport vesicles, especially useful in cells specialized for secretion, one cell has hundreds of stacks of cisternae that looks like pita bread |
| cis | receiving site of golgi apparatus is called the _____ |
| trans | shipping site of the golgi apparatus is called the ______ |
| modification | ___________ of ER products occurs during the transit of the products from the cis to trans |
| golgi apparatus | synthesizes certain macromolecules itself |
| lysosomes | digestive compartments, membranous sacs of hydrolitic enzymes that break down molecules, acidic |
| phagocytosis and autophagy | two types of examples of when lysosomes are used |
| phagocytosis | food vacuole and lysosome, macrophages |
| autophagy | recycle cell's own organic material |
| vacuoles | maintainance compartments, membrane bound, types: food, contractile, central |
| food vacuole | formed by phagocytosis |
| contractile vacuole | freshwater protists pump excess water from cell through these to maintain suitable concentration of ions and molecules inside the cell |
| central vacuole | found only in plants; formed by smaller vacuoles; contains organic compounds, inorganic compounds, pigments, and poisons; used for disposal and growth as well |
| mitochondria and chloroplasts | organelles that convert energy to forms that cells can use for work in eukaryotic cells |
| mitochondria | has two membranes, sites of cellular respiration, the metabolic process that generates ATP by extracting energy from sugars, fats, and other fuels with the help of oxygen |
| chloroplasts | found in plants and algae, has three membranes, sites of photosynthesis where they convert solar energy to chemical energy by absorbing sunlight and using to to drive the synthesis of organic compounds such as sugars from carbon dioxide and water |
| mitochondria | found in nearly all eukaryotic cells; most cells contain 100s-1000s; has two membranes, both which are phospholipid bilayers with a unique collection of embedded portwins, the outer layer is smooth, but he inner membrane is convoluted, with infoldings called cristae |
| cristae | foldings that cause increase in surface area which causes increase of cellular respiration productivity in mitochondria |
| inner membrane space | space between inner and outer membrane of the mitochondria |
| mitochondrial matrix | inside the inner membrane of mitochondria, contains enzymes, mitochondrial DNA, and ribosomes that help in cellular respiration |
| chloroplasts | capture light energy, member of plant organelles called plastids, contain chlorophyll, separated from cytosol by envelope with 2 membranes w/ narrow intermembrane space, contains thylakoids |
| thylakoids | membranous system in the form of flattened, interconnected sacs; stacked into grana (granum) and surrounded by the stroma |
| grana | stacks of thylakoids |
| stroma | fluid outside thylakoid, contains chloroplast DNA, ribosomes, and enzymes |
| peroxisomes | specialized metabolic compartment that is bounded by a single membrane and contains enzymes that transfer hydrogen from various substrates to oxygen, producing hydrogen peroxide |
| glyoxysomes | specialized peroxisomes found in fat-storing tissues of plant seeds that contain enzymes that initiate the conversion of fatty acids to sugar, which the emerging seedling uses as a source of energy and carbon until it can produce its own sugar by photosynthesis |
| peroxisomes | grow larger by incorporating proteins and lipids and grow in number by splitting in two |
| cytoskeleton | a network of fibers extending throughout the cytoplasm; plays a major role in organizing the structures and activities of the cell; is composed of microfilaments, intermediate filaments, and microtubules |
| cytoskeleton | supports cell shape with structure, allows cell motility by interactions with motor proteins, regulates biochemical activities in the cell in response to mechanical stimulation |
| microtubules | thickest of the 3 fibers that make up the cytoskeleton, hollow rods made up of globular protein: tubulin which is a dimer or a molecule made up of 2 subunits, 2 ends are slightly different - plus end grows and shrinks during cellular activities |
| centrosomes | region located near nucleus made up of a pair of centrioles each composed with 9 sets of triplet microtubules arranged in a ring, microtubules grow out from these |
| centrioles | made up of 9 sets of triplet microtubules arranged in a ring, is found in centrosome |
| flagella and cilia | microtubule-containing extensions that project from some cells, act as locomotor appendages, share a common ultrastructure, each has core of a ring of 9 doublets of microtubles sheathed in an extension of the plasma membrane with 2 single microtubules in the center, has "9+2" pattern |
| nonmotile | "9+0" pattern, anchored by basal body which is structure similar to centriole |
| dyneins | large motor proteins, connect doublets of microtubules, responsible for bending movements of organelles, "feet" that "walk" |
| microfilaments | actin filaments, solid rods, built from actin molecules which are globular proteins, twisted double chain of actin subunits, bear tensions (pulling forces), 3D network inside plasma membrane that provides shell shape & gives cortex gel-like consistency, makes up cores of microvilli which increases surface area, important in cell motility |
| microfilaments | important in cell motility because of part of contractile apparatus of muscle cells (actin and myosin), local contraction of actin and myosin allows amoeboid movement through extending pseudopodia, in plant cells helps with cytoplasmic streaming which allows circular flow of cytoplasm for quicker distribution of materials |
| muscle cells | microfilaments and myosin |
| amoeboid movement | pseudopods |
| cytoplasmic streaming | a circular flow of cytoplasm within plant cells for quicker distribution of materials |
| cortex | outercytoplasmic layer of a cell |
| intermediate filaments | specialized for bearing tension, diverse class of cytoskeletal elements and each type is constructed from a different molecular subunit belonging to a family of proteins whose members include the keratins, more permanent fixtures than other cytoplasmic elements - persist after cells die, important in reinforcing the shape of a cell and fixing the position of certain organelles |
| cell wall | found only in plants, protects plant cell, maintains shape, prevents excess water intake, make of microfibrils (cellulose) |
| primary cell wall | relatively thin and flexible wall first secreted by a young plant |
| middle lamella | thin layer rich in sticky polysaccharides called pectins, glues adjacent cells together with pectin, found between primary cells |
| secondary cell wall | between plasma membrane and primary wall, often deposited in several laminated layers, has a strong and durable matrix that affords the cell protection and support |
| extracellular matrix | found only in animal cells, main ingredient is glycoproteins secreted by cells |
| collagen | most abundant glycoprotein in extracellular matrix of most animal cells that forms strong fibers outside cells and is embedded in a network woven from proteoglycans, accounts for 40% of body's protein |
| proteoglycans | consists of a small core protein with many carbohydrate chains covalently attached, creates a network in which collagen fibers are embedded |
| fibronectin | some cells are attached to the ECM by other glycoproteins such as ____________, embedded in plasma membranes |
| integrins | membrane proteins, surface receptor protein of fibronectin, span the membrane and bind on their cytoplasmic side to associated proteins attached to microfilaments of the cytoplasm |
| plasmodesmata | main type of intercellular junction in plant cells, channels that perforate cell walls of plant cells, channels where cytosol passes between cells, water and small solutes can also pass freely from cell to cell |
| tight junctions, desmosomes, group junctions | three main types of intercellular junctions in animal cells, common in epithelial tissue |
| tight junctions | keeps plasma membrane pressed against each other, prevents leakage |
| desmosomes | fastens cells together, made of intermediate filaments, attaches muscle cells to each other |
| gap junctions | gap-like plasmodesmata, channels from one cell to adjacent cell, cell to cell communication |
| phospholipids | most abundant lipids in most membranes, amphipathic |
| amphipathic | has regions that are hydrophilic and regions that are hydrophobic |
| fluid mosaic model | the membrane is a fluid structure with a "mosaic" of various proteins embedded in or attached to a double layer (bilayer) of phospholipids |
| lipids and proteins | in 1915, membranes isolated from red blood cells were chemically analyzed and found to be composed of what? |
| Gorter and Grendel | in 1925, what two Dutch scientists reasoned that cell membranes must be phospholipid bilayers? |
| Davson and Danielli | in 1935, what two scientists proposed the sandwich model with a phospholipid bilayer in between two layers of proteins? |
| Davson-Daneilli sandwich | by 1960s which structure became widely accepted as the structure of all of the cell's internal membrane? |
| not all membranes same and proteins are amphipathic | 2 major problems with Davson-Daneilli sandwich model? |
| Singer and Nicolson | in 1972, what two scientists proposed that membrane proteins are dispersed, individually inserted into the phospholipid bilayer with their hydrophilic regions protruding? |
| freeze fracture | Singer and Nicolson model was confirmed by what? |
| hydrophobic interactions | membranes are held together by ______________________ |
| laterally | most of the lipids of the membranes shift ____________ (some proteins as well) |
| 10^7/sec | lipids shift laterally at a rapid speed of ________ |
| cytoskeleton fibers | proteins also shift in membranes but are much bigger than lipids and must move via _______________ |
| solidifies | when temperature drops, the membrane eventually ____________ |
| unsaturated hydrocarbons | however, if temperature drops but there is a high number of _________________________ the membrane stays fluid |
| less fluid | when cholesterol is in between phospholipid molecules at higher temperatures, it causes the membrane to become _______________ by restraining phospholipid movement |
| stay fluid | when cholesterol is in between phospholipid molecules at lower temperatures, it causes the membrane to _________________ by hindering the close packing of the phospholipids |
| function | fluidity= |
| integral proteins | proteins that penetrate the hydrophobic core of the lipid bilayer, many are transmembrane proteins, which span the membrane, others extend only partway into the hydrophobic core |
| peripheral proteins | proteins that are not embedded in the lipid bilayer at all; they are appendages loosely bound to the surface of the membrane |
| cytoplasmic side | on the ____________________ of the plasma membrane, some membrane proteins are held in place by attachment to the cytoskeleton |
| extracellular side | on the ____________________ of the plasma membrane, certain membrane proteins are attached to fibers of the extracellular matrix |
| transport, enzymatic activity, signal transduction, cell to cell recognition, intercellular joinings, attachment to the cytoskeleton and extracellular matrix | 6 major functions of membrane proteins |
| transport | proteins that provide selective hydrophilic channel or change shape |
| glycoproteins | proteins that serve as identification tags that are specifically recognized by membrane proteins of other cells in cell to cell recognition |
| intercellular joining | membrane proteins of adjacent cells may hook together (ie gap junction or tight junctions) |
| glycolipids | membrane carbohydrates that are covalently bonded to lipids |
| carbohydrates | cells recognize other cells by binding to surface molecules, often to ___________________ on the plasma membrane |
| membrane carbohydrates | short, branched chains of fewer than 15 sugar units |
| glycoproteins | membrane carbohydrates covalently bonded to proteins |
| cell to cell recognition | used for sorting useful & harmful cells |
| blood type | practical application of membrane carbohydrates |
| ECM and cytosol | membranes have 2 sides _________ and _________ |
| first | synthesis of proteins, lipids, carbs in ER |
| second | in the Golgi apparatus molecule is modified |
| third | transported in vesicles |
| fourth | secretory proteins released, positioning carbohydrates on outside of plasma membrane |
| nonpolar | ___________molecules easily cross the lipid bilayer because of their hydrophobic interior |
| hydrophilic | polar molecules need help to cross the lipid bilayer because of their ____________ interior |
| channel proteins | transport proteins that function by having a hydrophilic tunnel that certain molecule or atomic ions use as a tunnel through the membrane |
| ions, aquaporins, water based | what can pass through channel proteins? |
| carrier proteins | transport proteins that hold onto their passengers and change shape in a way that shuttles them across the membrane |
| passive transport | transport where no energy is involved, includes diffusion, osmosis, and facilitated diffusion |
| diffusion | movement of molecules of any substance as it spreads out evenly |
| [high] to [low] | direction of diffusion |
| down | diffuses ________ the [gradient] |
| osmosis | water movement from low [solute] to high [solute] |
| water balance | osmosis is important for ________________ of cells without walls |
| tonicity | ability of a solution to cause a cell to gain/lose water |
| isotonic solution | no net movement of H2O across plasma membrane |
| hypertonic solution | more non-penetrating solute, cell loses H2O to environment and shrivels up and dies |
| hypotonic solution | less non-penetrating solute, cell gains H2O from environment and swells up and bursts |
| lyses | when a cell bursts |
| osmoregulation | the control of water balance |
| exerts pressure | when H2O increases, cell wall ________________ because of more water entering the cell |
| turgid | when cells w/ walls reach their max capacity of water |
| hypotonic | plants want ____________ solutions |
| flaccid | in isotonic solutions, cells w/ walls become ___________ |
| shrivel and die | in hypertonic solutions, cells w/ walls ________________ |
| facilitated diffusion | passive transport via solute specific proteins |
| ion channels | channel proteins |
| gated channels | ion channels function as _____________ which open or close in response to a stimulus |
| carrier proteins | proteins that undergo a subtle change in shape that somehow translocates the solute-binding site across the membrane, changes in shape may be triggered by the binding and release of the transported molecule |
| active transport | transportation of a solute across a membrane against its [gradient] which requires energy |
| carrier proteins | active transport is done completely by ____________________ |
| ATP | _________is used for most active transport |
| sodium potassium pump | one transport system that is powered by ATP by having a phosphate group transferred to the transport protein |
| voltages | all cells have ____________ across plasma membrane ranging from -50 to -200 millavolts |
| voltage | electrical potential energy |
| negative | cytoplasm is ___________ in charge relative to the extracellular fluid |
| positive | extracellular membrane is ___________ in charge relative to the cytoplasm |
| cations, anions | a cell at rest favors _________ into the cell and _________ out |
| chemical force and electrical force | 2 forces that drive diffusion |
| electrochemical gradient | chemical forces and electrical forces acting together |
| electrogenic pump | a transport protein that generates voltage across a membrane |
| sodium potassium pump | major electrogenic pump in animal cells |
| proton pump | main electrongenic pump in plant cells |
| cotransport | substance pumped across membrane helps transport of other molecules |
| exocytosis | the cell secretes certain biological molecules by the fusion of vesicles with the plasma membrane |
| endocytosis | the cell takes in biological molecules and particulate matter by forming new vesicles from the plasma membrane |
| phagocytosis | known as "cellular eating", cell engulfs a particle by wrapping pseudopodia around it and packaging it within a membrane-enclosed sac that can be large enough to be classified as a vacuole, the particle is digested after the vacuole fuses with a lysosome containing hydrolytic enzymes |
| pinocytosis | "cellular drinking", most nonspecific, cell "gulps" droplets of extracellular fluid into tiny vesicles. It is not the fluid itself that is need by the cell, by the molecules dissolved in the droplets, because any and all included solutes are taken into the cell, pinocytosis is nonspecific in he substances in transports |
| receptor mediated endocytosis | enables the cell to acquire bulk quantities of specific substances, even though those substances may not be very concentrated in the extracellular fluid, embedded in the membrane are proteins with specific receptor sites exposed to the extracellular fluid, the receptor proteins are usually already clustered in regions of the membrane called coated pits which are lined on their cytoplasmic side by a fuzzy layer of coat proteins, the specific substances (ligands) bind to these receptors, when binding occurs the coated pit forms a vesicle containing the ligand molecules |
| metabolism | chemical reactions |
| metabolic pathway | begins with a specific molecule which is then altered in a series of defined steps, resulting in a certain product |
| catabolic pathway | breakdown pathway (ie cellular respiration) |
| anabolic pathway | biosynthetic pathway (ie protein synthesis) |
| bioenergetics | the study of how energy flows through living organisms |
| kinetic, thermal, potential, chemical | forms of energy |
| kinetic energy | energy associated with relative motion of objects |
| thermal energy | kinetic energy associated with the random movement of atoms or molecules |
| potential energy | energy that matter possesses because of its location or structure |
| chemical energy | potential energy available for release in a chemical reaction |
| thermodynamics | the study of the energy transformations that occur in a collection of matter |
| energy is conserved/transferred | first law of thermodynamics |
| entropy is increasing | second law of thermodynamics |
| entropy | disorder or randomness |
| Gibbs | man who defined free energy change |
| free energy change | calculation of a system's energy to perform work when temperature and pressure are uniform throughout the system |
| spontaneous | free energy change calculates if a given reaction is _____________________ |
| spontaneous | occurring naturally |
| delta G= delta H - T delta S | formula for change in free energy |
| enthalpy | delta H |
| entropy | delta S |
| enthalpy | total energy |
| spontaneous reaction | negative delta G |
| nonspontaneous reaction | delta G is greater than or equal to 0 |
| delta G | measure of a system's instability |
| unstable | high delta G |
| stable | low delta G |
| stable | reactions favor a _________ state |
| equilibrium | no net change in products or reactants, low delta G |
| exergonic reaction | reaction with a net release of free energy, has -delta G -> spontaneous |
| endergonic reaction | reaction that absorbs free energy from surroundings, stores free energy in molecules, has +delta G -> nonspontaneous |
| dead | cell that reaches equilibrium is ________ |
| living | cell not in equilibrium experiences constant flow of materials in/out of cell meaning cell is __________ |
| chemical, transport, mechanical | three main kinds of work of a cell |
| chemical work | the pushing of endergonic reactions, which would not occur spontaneously, such as the synthesis of polymers from monomers |
| transport work | the pumping of substances across membranes against the direction of spontaneous movement |
| mechanical work | such as the beating of cilia, the contraction of muscle cells, and the movement of chromosomes during cellular reproduction |
| adenosine triphosphate | ATP, composed of ribose, adenine, and 3 phosphate groups |
| exergonic, phosphate, ADP, energy | hydrolysis of ATP is __________ reaction with products ____________________________________ |
| energy coupling | with the help of specific enzymes, the cell is able to use the energy released by ATP hydrolysis directly to drive chemical reactions that, by themselves, are endergonic, if the delta G of an endergonic reaction is less than the amount of energy released by ATP hydrolysis, then the two reactions put together are exergonic |
| phosphorylation | the transfer of phosphate from ATP to reactant to carry out reaction |
| ATP | ________ cause change in protein shape and ability to bind to another molecule |
| regeneration of ATP | ADP + Pi --> ATP + H2O |
| 10 million molecules | _________________ of ATP are consumed/regenerated per second per cell |
| catalyst | enzyme |
| lowering energy barriers | enzymes speed up reactions by |
| rich | proteins, DNA, and other complex molecules are _____ in free energy and have potential to breakdown spontaneously but at temperatures typical for cells, only few can get over activation hump, however although heat speeds up a reaction, can kill cells and denature proteins |
| delta G, activation energy | enzymes don't affect __________ only reduces _________________ |
| substrate | reactant molecule that the enzyme works on |
| enzyme substrate complex | when substrate is bound to enzyme |
| active site | binding site of enzymes called _____________ |
| induced fit | when substrate is bound to enzyme the enzyme changes slightly for a better fit called the _____________ |
| faster reaction | higher temperature equals a _____________ in enzyme activity |
| denaturation | if temperature exceeds optimal temperature for reaction in enzymes --> |
| denaturation | increased production in optimal pH but outside range --> |
| cofactors | nonprotein inorganic helpers for catalytic activity |
| coenzyme | an organic cofactor (ie vitamins) |
| competitive inhibitors | block substrates by mimicking substrate |
| noncompetitive inhibitors | bind to other parts of enzymes to change its shape so substrates cant bind to enzymes |
| allosteric regulation | binding at one site is affected by binding on another site |
| subunits | most enzymes with allosteric regulation have 2 or more __________ |
| activator | regulatory molecule that stabilizes shape of functional active sites |
| inhibitor | regulatory molecule that stabilizes shape of inactive enzyme |
| cooperativity | one substrate molecule primes an enzyme to accept additional substrate molecules more readily |
| enzyme regulation | allosteric regulators are attractive drug candidates for ___________________ because they exhibit higher specificity for particular enzymes than do inhibitors that bind to an active site |
| feedback inhibition | metabolic pathway turned off by inhibitory binding |
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