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DR-A&PCh3
Dragon Rises Anatomy and Physiology Chapter 3
| term or phrase | completion |
|---|---|
| cell | simplest structural and functional unit of life |
| all organisms are composed... | of cells |
| an organism's structure and functions... | are due to the activities of its cells |
| the activities of cells drive... | the workings of the human body |
| the activities of cells underlie... | the mechanisms of disease |
| the activities of cells determine... | the rationale of therapy |
| cells come from... | only pre-existing cells, not from non-living matter |
| cells of all species... | have many fundamental similarities in their chemical composition and metabolic mechanisms |
| cytology | scientific study of cells |
| there are ____ (number) types of cells in the human body | about 200 |
| squamous cells | thin and flat with nucleus creating a bulge - ex: epidermis, esophagus |
| cuboidal cells | squarish, about as tall as wide - ex: liver cells |
| columnar cells | taller than wide - ex: stomach and intestine epithelium |
| polygonal cells | irregularly angular shapes with four or more sides - ex: squamous, cuboidal, and columnar cells when examined from above |
| stellate cells | starlike shape - ex: cell body of nerve cells |
| spheroid to ovoid cells | round to oval - ex: egg cell, WBC |
| discoid cells | disc-shaped - ex: RBC |
| fusiform cells | thick in middle, tapered toward ends - ex: smooth muscle |
| fibrous cells | threadlike shape - ex: skeletal muscle, axons |
| the size of most human cells | 10-15 micrometers in diameter |
| oocyte | egg cells - largest cell, 100 micrometers in diameter, barely visible to the naked eye |
| sperm cell | a head of 5 micrometers by 3 micrometers and a tail of 50 micrometers long. granule cell of cerebellum is typically 4-4.5 micrometers long |
| nerve cell | can be 1 meter long. an axon can be as long as 6 feet. longest human cell, but too slender to be seen with the naked eye. |
| feature of cells: cells possess... | a genetic program and the means to use it |
| feature of cells: cells can... | replicate |
| feature of cells: cells acquire and utilize... | energy |
| feature of cells: cells carry out... | a variety of chemical reactions |
| feature of cells: cells respond... | to stimuli |
| feature of cells: cells can... | self-regulate |
| substances that make up the cell. percentage of water: | 75-80% |
| substances that make up the cell. percentage of proteins: | 10-20% |
| substances that make up the cell. percentage of lipids: | 2% |
| substances that make up the cell. percentage of carbohydrates: | 1% |
| substances that make up the cell. (1-5) | water, proteins, lipids, carbohydrates, electrolytes |
| in lean adults, body fluids constitute (percentage, male and female) | 55% of female and 60% of male total body mass |
| ICF | intracellular fluids (2/3 of body fluids) |
| ECF | extracellular fluids (1/3 of body fluids) - body's internal environment |
| two major subdivisions of ECF | interstitial fluid, intravascular fluid |
| interstitial fluid | fluid that fills the spaces between most cells of the body. about 80% of ECF, 15% of body weight |
| examples of interstitial fluids | lymph, cerebrospinal fluid, synovial fluid, aqueous humor and vitrous body (eyes) |
| lymph | ECF within lymphatic vessels |
| cerebrospinal fluid | ECF in and around brain and spinal cord |
| synovial fluid | ECF of joints |
| aqueous humor and vitrous body | ECF of eyes |
| intravascular fluid | ECF within blood vessels -- plasma (WBC, RBC and platelets are in this fluid. About 20% of ECF, 5% of body weight) |
| two fundamentally different types of cells | prokaryotic (eg. bacteria), eukaryotic (eg. animals, plants, fungi) |
| prokaryotes | means before 'nucleus' |
| eukaryotes | eu - true; karyon - nucleus. these cells possess a nucleus |
| eukaryotic cells consist of... | plasma (cell) membrane, cytoplasm, nucleus |
| plasma (cell) membrane | surrounds cell, defines boundaries; composition and function can vary from one region of the cell to another |
| surface extensions of plasma (cell) membrane | cilia, flagella, microvilli |
| cytoplasm | cytosol (contains ICF), organelles, cytoskeleton |
| unit membrane | forms the border of the cell and many of its organelles - appears as a pair of dark parallel lines around the cell under an electron microscope |
| plasma membrane | unit membrane at cell surface |
| functions of the plasma membrane: defines... | cell boundaries |
| functions of the plasma membrane: governs... | interactions with other cells |
| functions of the plasma membrane: controls... | passage of materials in and out of cell |
| intracellular face of plasma membrane | side that faces the cytoplasm |
| extracellular face of plasma membrane | side that faces outward |
| the plasma membrane is... | an oily film of lipids with diverse proteins embedded |
| percentage of molecules in plasma membrane that are lipids | 98% |
| percentage of plasma membrane lipids that are phospholipids | 75% |
| phospholipids in the plasma membrane are... | amphiphilic / amphipatic molecules arranged in a bilayer |
| phospholipids in the plasma membrane have hydrophilic phosphate heads that... | face the fluid on each side of the membrane |
| phospholipids in the plasma membrane have hydrophobic tails that... | are directed toward the center, avoiding fluid |
| in the plasma membrane, phospholipids drift... | laterally from place to place |
| the drifting laterally of phospholipids in the plasma membrane... | helps keep the membrane fluid |
| 20% of the membrane lipids | made up of cholesterol |
| this holds phospholipids still and can stiffen the membrane | cholesterol |
| 5% of the membrane lipids | glycolipids |
| glycolipids are... | phospholipids with short carbohydrate chains on the extracellular face |
| glycolipids contribute to... | glycocalyx |
| glycocalyx | carbohydrate coating on the cell surface |
| in the plasma membrane, proteins make up... | 2% of the molecules |
| in the plasma membrane, proteins make up... | 50% of the weight |
| types of membrane proteins | transmembrane proteins, peripheral proteins |
| proteins that pass through the membrane | transmembrane proteins |
| proteins that have a hydrophilic region in contact with the cytoplasm and extracellular fluid | transmembrane proteins |
| proteins that have hydrophobic regions that pass back and forth through the lipid of the membrane | transmembrane proteins |
| most transmembrane proteins are... | glycoproteins |
| transmembrane proteins can drift... | freely about in the phospholipid film |
| some transmembrane proteins are anchored... | to the cytoskeleton |
| peripheral proteins adhere... | to one face of the membrane |
| these proteins are usually tethered to the cytoskeleton | peripheral proteins |
| functions of membrane proteins include... | receptors, second-messenger systems, enzymes, ion channels, carriers, cell-identity markers, cell-adhesion molecules |
| membrane protein - receptor | binds to chemical messengers such as hormones sent by other cells |
| membrane protein - enzyme | breaks down chemical messenger and terminates its effect |
| membrane protein - ion channel | constantly open and allows ions to pas into and out of the cell |
| membrane protein - gated ion channel | opens and closes to allow ions through only at certain times |
| membrane protein - cell identity marker | glycoprotein distinguishing the body's own cells from foreign cells |
| membrane protein - cell adhesion molecule | binds one cell to another |
| membrane proteins allow cell communication... | via chemical signals |
| on the surface of plasma membrane target cell | receptors |
| bind hormones and neurotransmitters | receptor proteins |
| cell membrane protein receptors... | are usually specific for one substrate |
| in a second-messenger system... | a messenger chemical binds to a surface receptor, which triggers changes within the cell that produce a second messenger in the cytoplasm |
| second messenger systems... | involve transmembrane proteins and peripheral proteins |
| enzymes in a plasma membrane... | carry out final stages of starch and protein digestion in small intestine |
| membrane proteins help produce... | second messenger systems (cAMP) |
| membrane proteins break down... | old chemical messengers, stops excessive stimulation |
| transmembrane proteins with pores... | allow water and dissolved ions to pass through membrane |
| some transmembrane proteins are... | constantly open, others are gated channels that open and close in response to stimuli |
| examples of transmembrane protein gated channels | ligand (chemically)-regulated gates), voltage-regulated gates, mechanically regulated gates (stretch and pressure) |
| transmembrane proteins with pores play an important role in... | the timing of nerve signals and muscle contraction |
| channelopathies | family of diseases that result from defects in channel proteins |
| carriers or pumps (wrt transmembrane proteins) | transmembrane proteins bind to glucose, electrolytes, and other solutes, transfer them across the membrane; pumps consume ATP in the process |
| cell-identity markers | enable our bodies to identify which cells belong to it and which are foreign invaders |
| cell-identity markers are made up of... | glycoproteins that contribute to the glycocalyx - carbohydrate surface coating - acts like a cell's "identification tag" |
| cell adhesion molecules (CAMs)... | adhere cells to each other and to extracellular material |
| cell adhesion molecules are necessary because... | cells do not grow or survive normally unless they are mechanically linked to the extracellular material |
| cell adhesion molecules - particular events | sperm-egg binding; binding of immune cell to a cancer cell requires CAMs |
| glycocalyx | unique fuzzy coat external to the plasma membrane |
| the glycocalyx is unique... | in everyone but identical twins |
| the glycocalyx is made up of... | carbohydrate moieties of membrane glycoproteins and glycolipids |
| functions of the glycocalyx | protection; immunity to infection; defense against cancer; transplant compatibility; cell adhesion; fertilization; embryonic development |
| microvilli | extensions of the membrane, serving to increase the cell's surface area |
| microvilli are best developed in cells specialized in... | absorption |
| microvilli give ____ (number to number) times more absorptive surface area | 15 to 40 |
| on some cells, microvilli are very dense and appear as a fringe, known as the... | brush border |
| actin filaments have this effect on microvilli | they shorten it, pushing absorbed contents down into the cell |
| cilia | plasma membrane structure, hairlike processes about 7-10 um long |
| found on nearly every cell (WRT cilia) | a single, nonmotile primary cilium. acts as the antenna for monitoring nearby conditions. plays sensory role in inner ear, retina, nasal cavity, and kidney |
| motile cilia are found... | in respiratory tract, uterine tubes, ventricles of the brain, efferent ductules of testes |
| the pattern of motile cilia movement | beat in waves; sweep substances across surface in same direction; have power strokes followed by recovery strokes |
| the saline layer at the cell surface is due to these... | chloride pumps which move Cl- out of the cell. Na+ and H2O molecules follow |
| cystic fibrosis | hereditary disease in which cells make chloride pumps but fail to install them in the plasma membrane. this means that these chloride pumps fail to create an adequate saline layer on the cell surface. |
| the effects of cystic fibrosis | thick mucus plugs pancreatic ducts and respiratory tracts; inadequate digestion of nutrients and absorption of oxygen; chronic respiratory infections; life expectancy of 30 |
| the only functional flagellum | the tail of sperm |
| a flagella is... | a whiplike structure identical to cilium; much longer than cilium; stiffened by coarse fibers that support the tail |
| the movement of flagella | undulating, snakelike - no power stroke or recovery stroke as in cillia |
| plasma membrane | a barrier and a gateway between the cytoplasm and ECF |
| plasma membrane is ____ permeable | selectively; allows some things through, and prevents other things from entering and leaving the cell |
| passive transport mechanisms... | require no ATP; the random molecular motion of particles provides the necessary energy |
| examples of passive transport mechanisms | filtration, diffusion, osmosis |
| active transport mechanisms | consumes ATP; active transport and vesicular trnasport |
| carrier-mediated mechanisms... | use a membrane protein to transport substances from one side of the membrane to the other; active transport and facilitated diffusion |
| filtration | process in which particles are driven through a selectively permeable membrane by hydrostatic pressure |
| hydrostatic pressure | force exerted on a membrane by water |
| examples of filtration | filtration of nutrients through gaps in blood capillary walls into tissue fluids; filtration of wastes from the blood in the kidneys while holding back blood cells and proteins |
| simple diffusion... | needs only concentration gradient |
| simple diffusion | the net movement of particles from area of high concentration to area of low concentration (moves down the concentration gradient), due to their constant, spontaneous motion |
| factors affecting diffusion rate through a membrane | temperature (+ temp, + motion of particles); molecular weight (larger molecules move more slowly); steepness of concentrated gradient (+ difference, + rate of diffusion); membrane surface area (+ area, + rate); membrane permeability (+ permeable, +rate) |
| example of simple diffusion | oxygen or water diffusing into a cell and CO2 diffusing out |
| osmosis | flow of water/solvent through a semi-permeable membrane from an area of higher water concentration (lower solute conc) to one of lower water conc (higher solute conc), therefor UP a solute conc gradient |
| aquaporins | channel proteins in plasma membrane specialized for passage of water |
| cells can increase rate of osmosis by... | installing more aquaporins |
| cells can decrease rate of osmosis by... | removing aquaporins |
| phospholipid regions of the plasma membrane are hydrophobic, however... | significant amounts of water diffuse through the membrane |
| one osmole = | 1 mole of dissolved particles |
| osmolarity | the number of osmoles of solution per liter of solution |
| osmotic pressure | amount of hydrostatic pressure required to stop osmosis |
| reverse osmosis | pressure applied to one side, overrides pressure, drives against concentration gradient |
| an example of reverse osmosis in the cardiovascular system | the heart drives water out of the capillaries by reverse osmosis - capillary filtration |
| tonicity | ability of a solution to affect fluid volume and pressure in a cell by changing its water content |
| isotonic solution | solute concentration same on both sides of the membrane. most cells in the body are in isotonic solution. causes no change in cell volume or shape. |
| hypotonic solution | less solute (more water). cells absorb water and rupture (lyse) |
| hypertonic solution | high solute concentration (less water), cells lose water and shrivel (crenate) |
| carrier mediated transport | transport proteins in the plasma membrane that carry solutes from one side of the membrane to another |
| carrier-mediated transports have specificity, meaning: | they are specific for a certain ligand. solutes bind to a specific receptor site on carrier protein |
| carrier proteins, unlike enzymes... | do not chemically change their ligand; carriers simply pick ligands up on one side of the membrane and release them, unchanged, on the other |
| carrier-mediated transports recognize saturation, meaning: | as the solute concentration rises, the rate of transport rises, but only to a point - transport maximum (Tm) |
| types of carrier-mediated transport proteins | uniport, symport, antiport |
| carrier-mediated transport, uniport: | carries only one solute at a time |
| carrier-mediated transport, symport: | carries two ore more solutes simultaneously in the same direction (cotransport) |
| carrier-mediated transport, antiport: | carries two or more solutes in opposite directions (counter-transport) - example: sodium-potassium pump brings in K+ and removes Na+ from cell |
| two types of carrier-mediated transport | facilitated diffusion and active transport |
| facilitated diffusion | carrier mediated transport of solute through a membrane down its concentration gradient |
| facilitated diffusion requires... | both a concentration gradient and a protein channel |
| facilitated diffusion differs from active transport because... | facilitated diffusion does not consume ATP |
| in facilitated diffusion, a solute attaches to a binding site on carrier, and then... | the carrier changes conformation, and releases the solute on the other side of the membrane |
| big hydrophilic substances need protein channels for diffusion through hydrophobic parts of the plasma membrane because... | of their size and electrical charge |
| example of facilitated diffusion | glucose or amino acids moving from blood into a cell |
| passive transport... | equalizes concentrations of substances on both sides of the plasma membrane |
| when cells need to maintain a greater concentration of a given substance on one side of its membrane, it uses... | active transport |
| active transport depends on... | concentration gradient, electric gradient, membrane potential, electrochemical gradient |
| examples of active transport | pumping of glucose into cells that line the small intestines; sodium-potassium pump for ICF/ECF |
| in active transport, molecules move through a transport protein, but now... | energy must be expended to move them against their concentration gradient (using ATP) |
| active transport involves... | the transport of solute through a membrane up (against) its concentration gradient |
| active transport makes use of... | ATP energy - consumed to change carrier |
| examples of active transport | sodium-potassium pump keeps K+ concentration higher inside the cell; bringing amino acids into cell; pumping Ca2+ out of the cell |
| during maintenance of membrane potential in a cell... | each pump cycle consumes one ATP and exchanges three Na+ for two K+ |
| during maintenance of membrane potential in a cell... | keeps the K+ concentration higher and the Na+ concentration lower within the cell than in ECF |
| during maintenance of membrane potential in a cell... | pump keeps inside more negative, outside more positive |
| maintenance of membrane potential in a cell is... | necessary for nerve and muscle function |
| thyroid hormone increases the number of... | Na+-K+ pumps |
| as a byproduct of the consumption of ATP, active transport... | produces heat |
| vesicular transport | processes that move large particles, fluid droplets, or numerous molecules at once through the membrane in vesicles (bubble-like enclosures of membrane) |
| endocytosis | vesicular processes that bring material into the cell |
| three types of endocytosis | phagocytosis, pinocytosis, receptor-mediated endocytosis |
| phagocytosis | cell-eating, engulfing large particles - pseudopods, phagosomes, macrophages |
| pinocytosis | cell drinking, taking in droplets of ECF containing molecules useful in the cell. occurs in all human cells. "bulk phase" endocytosis. involves "pinocytic vesicles" |
| receptor-mediated endocytosis | selective endocytosis. particles bind to specific receptors on plasma membrane; clathrin-coated vesicle; update of LDL, HIV virus, insulin from bloodstream to cell |
| exocytosis | discharging material from the cell - utilizes motor proteins energized by ATP |
| phagocytosis keeps tissues free of... | debris and infectious microorganisms |
| the first step in the process of receptor-mediated endocytosis | extracellular molecules bind to receptors on the plasma membrane; receptors cluster together |
| the second step in the process of receptor-mediated endocytosis | plasma membrane sinks inward, forms clathrin-coated pit |
| the third step in the process of receptor-mediated endocytosis | pit separates from plasma membrane, forms clathrin-coated vesicle containing concentrated molecules from ECF |
| importance of exocytosis | secretory cell liberating hormones, enzymes, etc, neurotransmitters released by nerve cells |
| first step of exocytosis | secretory vesicle approaches the plasma membrane and docks on it by means of linking-proteins. the plasma membrane caves in at that point to meet the vescile |
| second step of exocytosis | plasma membrane and vesicle unite to form a fusion pore through which the vesicle contents are released |
| cell interior contains... | nucleus and cytoplasm |
| cytoplasm is located... | inside the plasma membrane but outside the nucleus |
| most cellular activities take place... | in the cytoplasm |
| the cytoplasm consists of... | structures (organelles, cytoskeleton, inclusions) and cytosol (gelatinous substance containing structures) |
| this is the largest organelle | the nucleus - 5 um in diameter |
| often centrally located within the cell | nucleus |
| contains DNA | nucleus |
| these cells contain no nuclues | red blood cells - incapable of division |
| these cells are multinucleated | skeletal muscle cells - cells fuse during development so many cells appear as one cell, allowing for a faster rate of AP conduction |
| nuclear envelope | two unite membrane; encloses DNA |
| nuclear envelope pores | allows RNA but not DNA through |
| chromatin | DNA wrapped around associated proteins when cell is not dividing (i.e. during interphase) |
| chromosomes | chromatin folds up to form chromosomes when cell is dividing. |
| nucleoplasm | material in nucleus - chromatin, threadlike matter composed of DNA and protein |
| nucleolus | one or more dark masses - site of ribosomes production; ribosomes move out of nucleus to RER |
| cytoskeleton | a collection of filaments and cylinders |
| the cytoskeleton determines... | the shape of cell, lends structural support, organizes its contents, directs movements of substances through the cell, and contributes to the movements of the cell as a whole |
| the cytoskeleton is composed of... | microfilaments, intermediate fibers, microtubules |
| microfilament | 6nm thick, actin, mainly in cell periphery; forms terminal web; for movement and support |
| intermediate fibers | 8-10nm, support, strength, structure; stabilize organelles, help attachments between cells |
| microtubules | 25nm, tubulin, movement; support, maintain cell shape and rigidity, not permanent structures |
| endoplasmic reticulum | system of interconnected channels called cisternae enclosed by unit membrane |
| rough endoplasmic reticulum | composed of parallel, flattened sacs covered with ribosomes |
| rough endoplasmic reticulum is continuous... | with outer membrane of nuclear envolope |
| rough endoplasmic reticulum produces... | the phospholipids and proteins of the plasma membrane |
| rough endoplasmic reticulum synthesizes... | proteins that are packaged in other organelles or secreted from cell |
| smooth endoplasmic reticulum lack... | ribosomes |
| smooth endoplasmic reticulum has cisternae thought to be... | continuous with those of the rough ER |
| smooth endoplasmic reticulum synthesizes... | steroids and other lipids |
| smooth endoplasmic reticulum inactivates and detoxifies... | alcohol and other drugs |
| smooth endoplasmic reticulum manufactures... | all membranes of the cell |
| smooth endoplasmic reticulum stores and releases... | Ca ions in muscle cells |
| rough and smooth endoplasmic reticulum are functionally... | different parts of the same network |
| organelles are... | structures internal to the cell which carry out specialized metabolic tasks |
| organelles have... | specialized structures, characteristic shapes, and specialized functions |
| examples of membranous organelles | nuclues, mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, and Golgi complex |
| examples of nonmembranous organelles | ribosomes, centrosomes, centrioles, basal bodies |
| ribosomes | tiny granules of RNA and protein; both free and attached; required for protein synthesis; found in nucleoli, in cytosol, on outer surfaces of rough ER, and nuclear envelope |
| golgi complex | a small system of cisternae that synthesize carbohydrates and put the finishing touches on protein and glycoprotein synthesis |
| golgi complex receives... | newly synthesized proteins from rough ER |
| golgi complex processes, sorts, packages, and delivers... | proteins and lipids to plasma membrane, and packages the protein into membrane-bound Golgi vesicles |
| golgi vesicles form... | lysosomes and secretory vesicles |
| some golgi vesicles migrate... | to plasma membrane and fuse to it |
| lysosomes | package of enzymes bound by a single unit membrane; extremely variable in shape |
| the function of lysosomes | intracellular digestion of proteins, nucleic acids, complex carbohydrates, phospholipids, and other substances |
| autophagy | digest and dispose worn out mitochondria and other organelles |
| autolysis | "cell suicide", some cells destroy themselves after the completion of their function |
| peroxisomes | resemble lysosomes but contain different enzymes and are not produced by the Golgi complex |
| function of peroxisomes | use molecular oxygen to oxidize organic molecules |
| reactions initiated by peroxisomes produce... | hydrogen peroxide (H2O2) |
| catalase | breaks down exes peroxide to H2O and O2 |
| peroxisomes neutralize... | free radicals, detoxify alcohol, other drugs, and a variety of blood-borne toxins |
| peroxisomes break down... | fatty acids into acetyl groups for mitochondrial use in ATP synthesis |
| peroxisomes are found in... | all cells, but abundant in liver and kidney |
| mitochondria | the main site for ATP generation - powerhouse of the cell |
| mitochondria are... | large organelles where O2 combines with food to produce ATP |
| shapes of mitochondria... | spheroid, rod-shaped, kidney-shaped, or threadlike |
| mitochondria are surrounded by... | a double unit membrane |
| the inner membrane of mitochondria has folds called... | cristae |
| the spaces between cristae in the inner membrane of mitochondria are called... | matrix |
| the matrix in the inner membrane of mitochondria contains... | ribosomes, enzymes used for ATP synthesis, small circular DNA molecule (mitochondrial DNA) |
| classes of diseases that cause muscle weakness and neurological disorders due to malfunctioning mitochondria: | mitochondrial myopathy, mitochondrial encephalomyopathy, etc |
| centriole | a short cylindrical assembly of microtubules arranged in nine groups of three microtubules each |
| centrosome | small, clear area of cytoplasm where two centrioles lie perpendicular to each other |
| two kinds of inclusions | stored cellular products, foreign bodies |
| examples of stored cellular products (inclusion) | glycogen granules, pigments, and fat droplets |
| examples of foreign bodies (inclusion) | viruses, intracellular bacteria, dust particles, and other debris phagocytized by a cell |
| inclusions are never enclosed... | in a unit membrane |
| inclusions are not... | essential for cell survival |
| making DNA involves... | replication/duplication - making a copy of the genetic material in preparation for cell division |
| before a cell divides, it must... | duplicate its DNA, so each daughter cell has a complete copy of all its genes |
| DNA replication must be... | exact, because DNA controls all cellular function |
| during DNA replication, hydrogen bonds between nucleotides break... | and the double stranded DNA helix unwinds. This occurs during S phase mitosis. |
| during DNA replication, a new strand is formed by pairing... | complimentary bases from cytoplasm with the old strand. New hydrogen bonds form. |
| mutations | changes in DNA structure due to replication errors or environmental factors (radiation, viruses, chemicals) - some mutations cause no ill effects |
| law of complimentary base pairing | base sequence of one DNA strand determines the sequence of the other |
| the double helix unwinds from... | histones |
| this opens one short segment of helix at a time to expose nitrogenous bases | DNA helicase |
| replication fork | point where DNA is opened up |
| DNA polymerase | move along each strand of opened DNA during replication |
| DNA polymerase read... | exposed bases and match complementary free nucleotides |
| the two separated strands of DNA are copied by separate polymerase molecules, proceeding in... | opposite directions |
| DNA ligase | joins short segments of DNA strand together |
| these cells contain identical genes | all body cells except sex cells and some immune cells |
| different cells activate... | different genes |
| any given cell uses _____ to _____ (fractions) of its genes | one third to two thirds |
| genes not used by a cell... | remain dormant and may be functional in other types of cells |
| DNA | genetic material for coding proteins |
| types of RNA | mRNA, rRNA, tRNA |
| mRNA - messenger RNA | contains genetic information. it is a copy of a portion of the DNA |
| rRNA - ribosomal RNA | the site of protein assembly. |
| ribosomes assemble amino acids in the order... | directed by the codons of mRNA |
| tRNA - transfer RNA | transports and positions amino acids on ribosomes on RER (rough endoplasmic reticulum) in final stage of protein synthesis |
| DNA and RNA are polymers formed... | from monomer nucleotides through dehydration synthesis |
| two kinds of nucleic acids | DNA (deoxyribonucleic acid, inherited genetic material); and RNA (ribonucleic acid; relays instructions from genes to gene product - protein). |
| involved in the storage and flow of information from gene to gene product | both DNA and RNA |
| there are _____ (number) DNA molecules in the nucleus of most human cells | 46 |
| DNA and other nucleic acids are... | polymers of nucleotides |
| each nucleotide consists of... | one sugar (deoxyribose for DNA), one phosphate group, one nitrogenous base |
| four DNA nitrogenous bases | A - adenine, G - Guanine, C - Cytosine, T - Thymine |
| two DNA nitrogenous bases that are purines (double ring) | Adenine and Guanine |
| two DNA nitrogenous bases that are pyrimidines (single ring) | Cytosine and Thymine |
| DNA base pairing | A-T; C-G |
| molecular shape of DNA | double helix |
| sidepiece of DNA double helix is a backbone composed of... | phosphate groups alternating with the sugar deoxyribose |
| the steplike connections between the DNA double helix backbones are... | pairs of nitrogenous bases |
| the nitrogenous bases in DNA are united by | hydrogen bonds |
| gene | a segment of DNA that codes for a specific protein |
| genes | genetic instructions for synthesis of proteins |
| genome | all the genes of a person |
| humans have an estimated _____ to _____ genes (number to number) | 20,000 to 25,000 |
| the genome in one person comprises _____ (percentage) of their total DNA | 2% |
| ______ (percentage) of DNA is noncoding | 98% |
| non-coding DNA... | plays a role in chromosome structure; regulation of gene activity; possibly no function at all ("junk" DNA) |
| human genome project | identified the nitrogenous base sequences of 99% of human genome |
| genomics | study of genome and how its genes and non-coding DNA interact to affect the structure and function of the whole organism |
| histones | disc-shaped cluster of eight proteins; DNA molecules winds around this cluster |
| nucleosomes | apparent division if histones into segments |
| nucleosome consists of | core particle (histones with DNA around them); linker DNA (short segments of DNA connecting core particles) |
| a nucleosome is one-third shorter... | than DNA alone |
| a chromatin-protein complex is... | thrown into complex, irregular loops and coils; 1000 times shorter than original molecule |
| the chromatine is not a static strucrue... | in nondividing cells |
| in nondividing cells, chromatin... | changes moment to moment according to genetic activity of cell; genes get turned on and off |
| chromatin | fine filamentous DNA material complexed with proteins |
| chromatin occurs as... | 46 long filaments called chromosomes |
| in non-dividing cells, chromatin... | is so slender it cannot be seen with light microscope |
| chromatin, under an electron microscope... | has a granular appearance |
| each chromosome consists of... | sister chromatids (2 parallel filaments of identical DNA) joined at a centromere |
| chromatin visible with light microscope when... | in prophase, final coiling and condensing |
| RNA is much smaller... | than DNA |
| DNA averages ____ (number) base pairs | 100 million |
| mRNA - messenger RNA has over _____ bases | 10,000 |
| tRNA - transfer RNA has ___ to ___ (number to number) bases | 70 to 90 |
| RNA has only _____ (number) nucleotide strand | one |
| the sugar in RNA is... | ribose, not deoxyribose |
| the nitrogenous bases of RNA | U (uracil), A (adenine), G (guanine), C (cytosine) |
| in RNA, uracil replaces... | the thymine of DNA as a nitrogenous base |
| essential functions of RNA | interprets code in DNA; uses DNA instructions for protein synthesis; leaves nucleus and functions in cytoplasm |
| number of amino acids that act as the bases of all proteins in the body | 20 |
| number of nucleotides that code for all genes | 4 (AT,CG) |
| genetic code | a system that enables these four nucleotides to code for the amino acid sequence of all proteins |
| base triplet | a sequence of three DNA nucleotides that stands for one amino acid |
| codon | the 3-base sequence in mRNA |
| there are _____ (number) possible codons that represent the 20 amino acids | 64 |
| _____ (number) codons code for amino acids | 61 |
| stop codons | UAG, UGA, UAA - signal "end of message" |
| start codon | AUG - codes for methionine, and begins the amino acid sequence of the protein |
| genomic medicine | application of our knowledge of the genome to predict, diagnose, and treat disease |
| disorders where genomic medicine is applied | cancer, Alzheimer disease, schizophrenia, obesity, AIDS, tuberculosis |
| genomic medicine allows for... | the early detection of diseases, more effective clinical intervention |
| genomic medicine expands the potential for... | gene-substitution therapy |
| protein synthesis involves... | transcription and translation |
| protein synthesis: transcription | copying - making RNA; transferring genetic code from DNA to RNA |
| protein synthesis: translation | making proteins; from mRNA to proteins |
| DNA contains genetic template for... | proteins |
| process of protein synthesis: | DNA -> mRNA -> protein |
| making protein from DNA is a ____ (number) step process | two |
| first step in making protein from DNA | transcription |
| second step in making protein from DNA | translation |
| transcription occurs... | in the nucleus |
| description of transcription in protein synthesis | mRNA copy of the gene made and carried to cytoplasm through nuclear pores to RER in cytoplasm |
| translation occurs... | in the cytoplasm |
| description of translation in protein synthesis | mRNA template serves as a series of codes for the amino acid sequence of the protein |
| transcription | copying genetic instructions from DNA to RNA |
| RNA polymerase | enzyme that binds to the DNA and assembles the mRNA |
| RNA polymerase opens up the DNA helix about... | 17 base pairs at a time |
| RNA polymerase... | reads base from one strand of DNA and makes a corresponding mRNA strand |
| where RNA polymerase finds a C on the DNA | it adds G to the mRNA |
| where RNA polymerase finds an A on the DNA | it adds U to the mRNA (unlike DNA replication, where T would be added) |
| RNA polymerase rewinds... | the DNA helix behind it during transcription |
| one gene can code for... | more than one protein |
| exons | 'sense' portion of the immature RNA - will be translated to protein |
| introns | 'nonsense' portion of the immature RNA - must be removed before translation |
| exons can be spliced together... | into a variety of different mRNAs |
| translation | the process that converts the language of nucleotides into the language of amino acids |
| ribosomes | translate sequence of nucleotides into the sequence of amino acids |
| ribosomes occur mainly... | in cytosol, on the surface of RER, and on the nuclear envelope |
| ribosomes consist of... | two granular subunits, large and small; each made of several rRNA and enzyme molecules |
| mRNA molecule begins with... | a leader sequence |
| leader sequnce of mRNA acts as... | a binding site for small ribosomal subunit |
| a ribosmoe pulls mRNA through it like a ribbon... | reading the bases as it goes |
| when the start codon (AUG) is reached... | protein synthesis begins |
| all protein synthesis begins with | methionine |
| translation | process where ribosomes synthesize proteins using the mature mRNA transcript produced during transcription |
| mRNA moves from nucleus to cytoplasm, where... | its codon binds to rRNA in a ribosome |
| ribosome binds and holds tRNA with its... | specific amino acid |
| tRNA's in cytoplasm attach to... | free amino acids in the cytoplasmic "pool" |
| tRNA carries its specific amino acid... | to the ribosome |
| amino acid consists of triplet anticodon, which is a... | complementary pair of codon of mRNA |
| enzyme releases amino acid to pair... | with mRNA codon at ribosomes |
| polyribosome | one mRNA holding multiple ribosomes |
| one ribosome can assemble a protein of ____ (number) amino acids in ____ (number) seconds | 400, 20 |
| ______ (number) identical mRNA molecules may be undergoing simultaneous translation | 300,000 |
| a cell can produce _____ (number) protein molecules per second | 150,000 |
| once the primary structure (amino acid sequence) of protein synthesis has been completed | protein synthesis is not yet finished |
| to be functional, an amino acid structure... | must coil or fold into precise secondary and tertiary structures |
| proteins to be used in the cytosol are likely to be made... | on free ribosomes in the cytosol |
| proteins destined for packaging into lysosomes ore secretion from the cell... | are assembled on rough ER and sent to the Golgi complex for packaging |
| endoplasmic reticulum modifies protein by... | posttranslational modification |
| posttranslational modification of proteins by the endoplasmic reticulum consists of... | removing some amino acid segments, folding the protein, stabilizing protein with disulfide bridges; adding carbohydrates |
| vesicles fuse and unload proteins... | into Golgi cisterna |
| Golgi complex further modifies... | the protein, which is then released by exocytosis |
| protein processing and secretion, first stage: | protein formed by ribosomes on rough ER |
| protein processing and secretion, second stage: | protein packaged into transport vescile, which budes from ER |
| protein processing and secretion, third stage: | transport vesicle fuse into clusters that unload protein into Golgi complex |
| protein processing and secretion, fourth stage: | Golgi complex modifies protein structure |
| protein processing and secretion, fifth stage: | Golgi vesicle containing finished protein is formed |
| protein processing and secretion, sixth stage: | secretory vesicles release protein by exocytosis |
| cell cycle is made up of... | cell division (mitosis) and interphase |
| cell division | the process by which a parent cell reproduces itself by dividing into 2 cells (daughter cells) |
| two types of cell division | somatic cell division; reproductive cell division |
| somatic cell division | to replace dead, worn-out cells; results in diploid cells |
| mitosis | nuclear division |
| cytokinesis | cytoplasmic division |
| somatic cell division results in... | diploid cells |
| reproductive cell division | product of gametes |
| reproductive cell division results in... | haploid cells |
| meiosis | two cell division |
| cell cycle | the cell's live cycle that extends from one division to the next |
| stages of cell cycle | 1) mitosis + cytokinesis (M phase), 2) interphase |
| mitosis | nuclear division; preserves diploid number of chromosomes |
| cytokinesis | cytoplasmic division; cell divides into two daughter cells |
| interphase | phase between mitotic divisions - not part of mitosis |
| cell cycle duration varies... | between cell types |
| interphase, first stage: | G1: cell growth |
| interphase, second stage: | S: DNA replication |
| interphase, third stage: | G2: cell growth and preparation for division |
| M phase consists of... | mitosis and cytokinesis |
| during mitosis, DNA condenses... | into chromosomes |
| during mitosis, the cell... | replicates its nucleus and divides between 2 daughter cells |
| four sub-phases of mitosis for cell replication: | prophase, metaphase, anaphase, telophase |
| during cytokinesis the cell's cytoplasm... | divides, forming distinct cells |
| interphase is the collection of these phases: | G1, S, and G2 phases |
| the G1 phase portion of interphase: | the first gap phase; the interval between cell division and DNA replication |
| during the G1 phase portion of interphase: | accumulates materials needed to replicate DNA; growth occurs as organelles double |
| the S phase portion of interphase: | synthesis phase; duplicates centrioles |
| during the S phase portion of interphase: | DNA replication occurs as chromosomes duplicate |
| the G2 phase portion of interphase: | the second gap phase; interval between DNA replication and cell division |
| during the G2 phase portion of interphase: | finishes centriole duplication; synthesizes enzymes that controll cell division; repairs DNA replication errors; growth occurs as cell prepares to divide |
| the M phase (not interphase) | mitotic phase |
| during the M phase | cell replicates its nucleus; pinches in two to form new daughter cells; mitosis and cytokinesis occur |
| the G0 (G zero) phase: | cells that have temporarily or reversibly stopped dividing for a "rest" |
| during the G zero phase | cells are said to have entered a state of quiescence |
| cells that enter into a G zero phase: | muscle and nerve cells |
| interphase preceeds... | mitosis |
| two processes that occur during interphase: | protein synthesis, DNA replication |
| protein synthesis during interphase is needed... | to maintain cell for cell growth and cell activities |
| DNA replication occurs during interphase... | to prepare for cell division |
| G1 phase is the beginning... | of DNA synthesis. no replication, but biosynthetic activities increase. cells increase in size and synthesize protein. |
| S phase of interphase... | involves DNA replication |
| during G2 phase of interphase... | there are two complete diploid sets of chromosomes |
| prophase | the first stage of mitosis |
| metaphase | second stage of mitosis |
| anaphase | third stage of mitosis |
| telophase | fourth stage of mitosis |
| early stage of prophase | chromatin fibers shorten into distinct chromosomes |
| late stage of prophase | nucleolus and nuclear membrane break down and disappear |
| mitotic spindle | an assembly of microtubules that forms from centrioles |
| during late stage of prophase... | centrioles move to opposite poles of the cell |
| during late stage of prophase... | microtubules extend in length between the centrosomes |
| during late stage of prophase... | eventually the spindle extends between two opposite poles of cell |
| metaphase is characterized by... | the "metaphase plate" |
| the metaphase plate is... | a midpoint region within the cell that is formed/defined by chromosomes (2 sister chromatids joined at centromere) aligning along the microtubules at the center of the miotic spindle |
| during anaphase, the centromeres... | split into two, separating the chromatid pair |
| during anaphase, the spindle fibers... | pull separated sister chromatids (chromosomes) to the opposite pole of the cell |
| during anaphase, microtubules pull chromosomes... | and so they appear to be "V" shaped |
| telophase begins... | after the chromosomal movement stops |
| during telophase, sets of chromosomes at opposite poles of the cell... | uncoil and revert to chromatin form |
| during telophase, a new nuclear envelope... | forms around each chromatin mass. |
| during telophase, within each new nuclear envelope... | new nucleoli appear |
| during telophase, eventually... | the miotic spindle breaks up |
| cytokinesis | division of cells cytoplasm and organelles into two identical cells through formation of a cleavage furrow |
| during cytokinesis, a cell and its contents... | divide into two daughter cells |
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jcoletaylor
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