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A & P I Ch 3
Cells: The Living Units
| Question | Answer |
|---|---|
| Cell Theory | cell is the smallest structural & functional living unit..organismal functions depend on individual & collective cell functions..biochemical activities of cells are dictated by their specific subcellular structures..continuity of life has a cellular basis |
| The cell is the _____ & _____ | smallest structure & functional living unit |
| Organismal functions depend on _____ & _____ | individual & collective cell functions |
| Biochemical activities of cells are _____ | dictated by their specific subcellular structures |
| Developmental aspects of cells | all cells of the body contain same DNA but aren't identical..chem signals in the embryo channel cells into specific developmental pathways by turning some genes off..elimination of excess, injures, or aged cells occurs through programmed rapid cell death |
| All cell of the body contain _____ | the same DNA but are not identical |
| Chemical signals in the embryo channel _____ | cells into specific developmental pathways by turning some genes off |
| Development of _____ & _____ features in cells is called _____ | specific...distinctive...cell differentation |
| Call Differentiation | development of specific & distinctive features in cells |
| Apoptosis | programmed rapid cell death |
| Hypertrophy | enlargement of skeletal muscles |
| Theories of Cell Aging | wear & tear theory...immune system disorders...genetic theory |
| Wear & Tear Theory | little chemical insults & free radicals have cumulative effects |
| Immune System Disorders | autoimmune responses & progressive weakening of the immune response |
| Genetic Theory | cessation of mitosis & cell aging are programmed into genes...telomeres may determine the # of times a cell can divide |
| Telomeres | strings of mucleotides on the ends of chromosomes |
| Generalized Cell | all cells have common structures...human cells have 3 basic parts |
| 3 basic parts of human cells | plasma membrane...cytoplasm...mucleus |
| Cytoplasm | intracellular fluid containing organelles...water constitutes 60-80% |
| Nucleus | bound by bi layer membrane...distinctly seperated inside of cytoplasm |
| Mitochondrion | takes glucose & oxygen & makes ATP |
| Plasma Membrane | universal structure..bimolecular layer of lipids/proteins in a constantly changing fluid mosaic..plays dynamic role in cellular activity..seperates intracellular fluid from extracellular fluid..vital to transport of nutrients & waste products in/out cell |
| Phospholipid Bilayer | bimolecular layer of lipids & proteins |
| Tnterstitial Fluid = | ECF that surrounds cells |
| Extracellular Materials | body fluids...cellular secretions...extracellular matrix |
| Body Fluids | interstitial fluid...blood plasma...cerebrospinal fluid |
| Cellular Secretions | intestinal& gastric fluids...saliva...mucus...serous fluid |
| Extracellular Matrix | abundunt jellylike mesh containing proteins ^& polysaccharides in contact with cells |
| Membrane Lipids | 75% phospholipids (lipid bilayer)...5% glycolipids...20% cholesterol |
| 75% phospholipids | phosphate heads: polar & hydrophilic...fatty acid tails: nonpolar & hydrophobic |
| polar = | dipole pos & neg charge |
| Hydrophillic | water loving...water soluble |
| Hydrophobic | fear water...water insoulble |
| Hydrophillic = | libophobic...will not dissolve in lipids |
| Hydrophobic = | libophilic...will dissolve in lipids |
| 5% glycolipids | lipids with polar sugar groups on outer membrane surface that helps stabilize the membrane |
| 20% cholesterol | increases membrane stability & fluidity |
| Functions of Membrane Proteins | Transport...Receptors for signal transduction...attachment to cytoskeleton & extarcellular matrix...emzymatic activity...intracellular joining...cell-cell recognition |
| Transport Function of Membrane Proteins | protein that spans the membrane may provide a hydrophilic channel across the membrane that is selective for a particular solute |
| Receptors for Signal Tranduction | membrane protein exposes to the outside of the cell may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone |
| Attachment to the Cytoskeleton & Extracellular Matrix | elements of the cytoskeleton & the extracellular matrix may be anchored to the membrane proteins, which help maintain cell shape & fix the location of certain proteins |
| Cytoskeleton | cell's internal supports |
| Extracellular Matrix | fibers & other substances outside the cell |
| Plasma Membrane | Flexible outer boundary |
| Cyotplasm | intracellular fluid containing organelles |
| Nucleus | control center...bound by bi-layer membrane...distinctly seperated inside of cytoplasm |
| Osmosis | movement of solvent (water)...across a selectively permeable membrane |
| Membrane Transport | plasma membranes are selectively permeable...some molecules easily pass through the membrane; others do not |
| Types of Membrane Transport | passive processes...active processes |
| Passive Processes | No cellular energy (ATP) required...substance moves down its concentration gradient |
| Active Processes | Energy (ATP) required...occurs only in living cell membranes |
| What determines whether or not a substance can passively permeate a membrane? | lipid solubility of substance (because membrane is a phospholipid bilayer)...channels of appropriate size (proteins provide a channel for movement)...carrier proteins |
| Types of passive processes | simple diffusion...carrier-mediated facilitated diffusion...channel-mediated facilitated diffusion...osmosis |
| Simple Diffusion | Lipophilic (Nonpolar lipid-soluble)(hydorphobic) substances diffuse...directly through the phospholipid bilayer |
| Facilitated Diffusion | certain lipophobic (hydrophilic) (water soluble) molecules use carrier proteins or channel proteins |
| Carrier proteins & channel proteins both _____ | exhibit specificity (selectivity)...are saturable (rate is determined by # of carriers or channels)...can be regulated in terms of activity & quantity |
| Facilitated Diffusion using Carrier Proteins | Transmembrane integral proteins transport specific polar molecules (e.g. sugars & amino acids)...binding of substrate cause shape change in carrier...Is a passive process so no energy (ATP) required |
| Facilitated Diffusion using Channel Proteins | Is a passive process so no energy (ATP) required...aqueous channels formed by transmembrane proteins selectively transport ions or water |
| 2 Types of Facilitated Diffusion using Channel Proteins | Leakage Channels...Gated Channels |
| Leakage Channels are _____ | always open |
| Gated Channels are _____ | controlled by chemical (smell, taste) or electrical or mechanical (hearing) signals...No energy required |
| Osmosis | No energy req..movement of solvent (H2O) across a selectively permeable membrane..H2O conc. is determined by solute concentration..osmolarity..when solutions of different osmolarity are seperated by a membrane, osmosis occurs until equilibrium is reached |
| Water concentration is determined by _____ | Solute Concentration |
| Water concentration is determined by solute concentration because _____ | Solute particles displace water molecules |
| Osmolarity | the measure of total concentration of solute particles |
| Importance of Osmosis | When osmosis occurs, water enters or leaves a cell...change in cell volume disrupts cell function |
| Tonicity | the ability of a solution to cause a cell to shrink or swell |
| Isotonic | A solution with the same solute concentration as that of the cytosol...cells retain their normal size & shape...same solute/water concentration as inside cells...water moves in & out |
| Hypertonic | solution having greater solute concentration than that of the cytosol...cell shrink because H2O leaves cell...cells lose H2O by osmosis & shrink |
| Hypotonic | a solution having lesser solute concentration than that of the cytosol...cells take on water by osmosis until they become bloated & burst |
| Differences b/w Active & Passive Processes | Active processes require expenditure of energy...ALL active processes require a carrier protein...Gradient independent (can move either way (usually uphill)) |
| 2 types of Active Processes | Active Transport...Vesicular Transport |
| Active Transport | requires energy...requires carrier proteins...moves solutes against a concentration gradient...moves solutes from low to high concentration...2 types |
| 2 Types of Active Transport | Primary active transport...Secondary active transport |
| Primary Active Transport | Energy from hydrolysis of ATP causes shape change in transport protein so that bound solutes (ions) are "pumped" across the membrane |
| Primary Active Transport ~ Sodium-Potassium Pump | located in all plasma membranes...involved in primary & secondary active transport of nutrients & ions...maintains electrochemical gradients essential for functions of muscle & nerve tissues...moves sodium out & potassium in...requires Hydrolysis of ATP |
| Secondary Active Transport | depends on an ion gradient created by primary active transport...energy stored in ionic gradients is used indirectly to drive transport of other solutes |
| Secondary Active Transport ~ Cotransport | always transports more than one substance at a time...2 types |
| 2 Types of Cotransport | Symport System...Antiport System |
| Symport System | 2 substances transported in some direction |
| Antiport System | 2 Substances transported in opposite directions |
| Vesicular Transport | transport of large particles, macromolecules, & fluids across plasma membrane...requires cellular energy...vesicules that transport the materials, is made up of a phospholipid bilayer |
| Vesicular Transport Functions | Exocytosis...Endocytosis...Transcytosis...Substance (vesicular Trafficking |
| Exocytosis | transport out of the cell |
| Endocytosis | transport into the cell |
| Transcytosis | transport into, across, & then out of the cell |
| Substance (vesicular) Trafficking | transport from one area or organelle in the cell to another |
| Endocytosis & Transcytosis | involve formation of protein-coated vesicles...often receptor mediated therefore very selective |
| Type of Endocytosis | phagocytosis...pinocytosis...receptor-mediated |
| Phagocytosis | Solid phase endocytosis...cell engulfs a large particle (solid) by forming projecting pseudopods ("false feet") around it & enclosing it w/ a membrane sac called a phagosome...phagosome is combined w/ a lysosome |
| After phagocytosis | undigested contents remain in the vesicle (now called a residual body) or are ejected by expcytosis |
| 2 Examples of Phagocytosis | Macrophages...some white blood cells |
| Lysosome | digesting body |
| Phagosome | eating body |
| Pinocytosis | Fluid-phase endocytosis...plasma membrane infolds "gulps" bringing extracellular fluid & solutes into tiny vesicles inside of the cell...no receptors are used, so the process is nonspecific |
| Example of Pinocytosis | nutrient absorption in the small intestine |
| Receptor-Mediated Enducytosis | receptors provide main route for endocytosis & transcytosis...Extracellular substances bind to the specific receptor proteins, enabling the cell to ingest & concentrate specific substances |
| Ligands | the specific substances that are being taken in by Receptor-Mediated endocytosis |
| Receptor-Mediated Endocytosis examples | uptake of enzymes, low-density lipoproteins, iron, & insulin |
| Exocytosis exampples | hormone secretion...neurotransmitter release...mucus secretion...ejection of wastes |
| Membrane Potential | seperation of oppositely charged particles (ions) across a membrane creates a membrane potential (potential energy measured as voltage)...resting membrane potential (RMP)...electrical & chemical |
| RMP | Resting membrane potential...voltage measured in resting state in all cells...ranges from -50 to -100 mV inside different cells...results from diffusion & active transports of ions (mainly K+) |
| Generation & Maintenance of RMP | Na+~K+ pump continuously ejects Na+ from cell & carries K+ back in..some K+ continually diffuses down its conc. gradient out of the cell through K+ leakage channels..membrane interior becomes neg. (relative to exterior) b/c of large anions trapped in cell |
| Generation & Maintenance of RMP ~~~~~CONTINUED~~~~~ | Electrochemical gradient begins to attract K+ back into cell...RMP is est. @ the point where the electrical gradient balances the K+ concentration gradient...A steady state is maintained |
| Cell-Enviroment Interactions | Involves glycoproteins & proteins of glycocalyx |
| Roles of Cell Adhesion Molecules | anchor cells to extracellular matrix or to each other...assist in movement of cells past one another...CAMS of blood vessel lining attract white blood cells to injured or infected areas...stimulate synthesis or degradation of adhesive membrane junctions |
| Roles of Cell Adhesion Molecules ~~~~~CONTINUED~~~~~ | Transmit intracellular signals to direct cell migration, proliferation, & specialization |
| Cytoplasm | located b/w plasma membrane & nucleus...contains cytosol, cytoplasmic organelles, & inclusions |
| Cytosol | composed of 80% of H2O along with solutes (protein, salts, sugars, etc.) |
| Cytoplasmic Organelles | metabolic machinery of cell...all organelles in the cell are enveloped in a phospholipid bilayer membrane which helps compartmentalize work in the cell & lends to specialized function & increases surface area which organizes the metabolism of the cell |
| Inclusions | granules of glycogen or pigments, ;ipid droplets, vacuoles, & crystals |
| Endosymbiotic | into...sharing space or life with each other |
| 2 Types of Cytoplasmic Organelles | membranous...nonmembranous |
| Membranous Cytoplasmic Organelles | mitochondria, peroxisomes, lysomes, endoplasmic reticulum, golgi apparatus |
| Nonmembranous Cytoplasmic Organelles | cytoskeleton, ribosomes |
| Mitochondria | double-membrane structure (phospholipid bilayer) w/ shelflike cristae...provides most of the cell's ATP via aerobic cellular respiration...contain their own DNA 7 RNA...able to replicate |
| Ribosomes | granules containing protein & rRNA...site of protein synthesis...free ribosomes synthesize soluble proteins...membrane-bound ribosomes (on rough ER) synthesize proteins to be incorporated into membranes or exported from the cell |
| Endoplasmic Reticulum (ER) | endoplasmic = inside cytoplasm...interconnected tubes & parallel membranes enclosing cisternae...continuous w/ nuclear membrane...2 varieties |
| Cisternae | great big sacs that hold a variety of things (mainly proteins) |
| 2 varieties of ER | Rough ER & Smooth ER...both play a significant role in the Endomembrane System (all structures in the cell that are tubelike & contain cisternae) |
| Rough ER | external surface studded w/ ribosomes...manufactures all secreted proteins...synthesizes membrane integral proteins & phospholipids |
| Smooth ER | tubules arranged in a looping network...enzyme (integral protein) functions |
| Enzyme functions of smooth ER in Liver, with hormones, & in Intestinal cells | in the liver - lipids & cholesterol metabolism, breakdown of glycogen, & along w/ the kidneys, detox of drugs, pesticides, & carcinogens...synthesis of steroid-based hormone...in intestinal cells - absorption, synthesis, & transport of fats |
| Enzyme functions of smooth ER in skeletal & cardiac muscle | called Sarcoplasmic Reticulum...storage & release of calcium (required for muscle to contract) |
| Golgi Apparatus | stacked & flattened membranous sacs...warehouse of the cell...proteins, fats, lipids, etc ar packaged in trafficking vessicles & move to Golgi, then remodified, repackaged & transported to secretory vesicles |
| What organelles do lysosomes originate from? | Golgi Apparatus |
| Phagolysosome | formed by the combining of lysosome & phagosome...vital to the digestion of ingested materials in the cell (toxins, viruses, bacteria, etc.) |
| Lysosomes | Spherical membranous bags containing digestive enzymes (acid hydrolases)...digest ingested bacteria, viruses, & toxins...degrade nonfunctional organelles...breakdown & release glycogen (imp in body that needs additional energy) |
| Lysosomes (Continued) | breakdown bone to release Ca2+...dstroy cells in injured or nonuseful tissue (autolysis) |
| Endomembrane System overall function | produce, store, & export biological molecules...degrade potentially harmful substances |
| Peroxisomes | membranous sacs containing powerful oxidases & catalases (take Hydrogen Peroxide (2H2O2) & turns it into O & H2O)...detoxify harmful or toxic substances...neutralize dangerous free radicals (highly reactive chemicals w/ unpaired electrons) |
| Cytoskeleton | water insoluble fibrous proteins...an elaborate series of rods throughout cytosol (microtubules, microfilaments, intermediate filaments) |
| Microfilaments | Dynamic actin strands attached to cytoplasmic side of plasma membrane...involved in cell motility, change in shape, endocytosis, & exocytosis |
| Intermediate Filaments | tough, insoluble ropelike protein fibers...resist pulling forces on the cell & attach to cell junctions of other cells...H2O insoluble |
| Microtubules | Tubulin (spherical protein subunits) create dynamic hollow tubes that contract...determine overall shape of cell & distribution of organelles |
| Motor Molecules | protein complexes that function in motility (e.g. movement of organelles & contraction)...powered by ATP |
| Cellular Extensions | Cilia & Flagella...microvilli |
| Cilia & Flagella | whiplike, motile extensions on surfaces of certain cells...contain microtubules & motor molecules...Cilia move substances across cell surfaces...longer flagella propel whole cells (tail of sperm) |
| Microvilli | fingerlike extensions of plasma membrane...increase surface area for absorption...core of actin filaments for stiffening |
| Nucleus | genetic library w/ blueprints for c-ular proteins..responds to signals & dictates kinds & amts of proteins to be synthesized..most c's are uninucleate, red blood c's are anucleate..skeltal musc c's, bone destruction c's, & some liver c's are multinucleate |
| Nucleolus | function is synthesis of ribosomes |
| Nuclear Envelope | double-membrane barrier containing pores...outer layer is continuous with RER & bears ribosomes...inner lining (nuclear lamina) maintains shape of nucleus...pore complex regulates transport of large molecules into & out of mucleus |
| Nucleoli | involved in rRNA synthesis & ribosome subunit assembly |
| Chromatin | condensed chromosomes...threadlike strands of DNA, histone proteins (bases to stabilize DNA & RNA) & RNA...arranged in fundamental units called nucleosomes...condense into barlike bodies called chromosomes when the cell starts to divide |
Created by:
retazba
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