Prokaryotic & Eukaryotic Cell – Flashcards
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| prokaryotic cell structure |
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| glycocalyx - capsule (slime layer): layer of gelatinous material covering the cell. - - composition varies with species: polypeptides, polysaccharides, glycoprotein |
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| function of glycocalyx (capsule or slime layer) |
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| - ahesion to surfaces - osmotic barriers (protection from pressure) - protect bacteria from phagocytosis - storage of nutrient |
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| prokaryotic cells |
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| - pro = before karyon = kernel - kingdom monera - no true nucleus - genetic material is in "nucleiod" region - no membrane bound organelles |
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| flagella |
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| fx. locomotion/motility - peritrichous (all around) - amphitrichous (both ends) - monotrichous (one end) - lophotrichous (a group, but going at one end) |
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| fimbriae and pili |
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| - small hair-like projection |
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| function of fimbrae and pili |
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| -sexual conjugation - pili form tubes for transfer of genetic material - surface adhesion -bacteriophage receptors - some viruses attach to pili - NOT involved in motility |
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| function of cell wall |
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| - maintains shape of the cell - physical protection - enables the cell to escape rupture (lysis) in a hypotonic environment - lattice/net-like structure - consists of peptidoglycan units that repeat over and over |
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| gram positive structure |
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| - many layers of peptidoglycan - forms a thick rigid structure - contains techoic acid |
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| gram negative structure |
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| -thin layer of peptidoglycan - looser lattice (less rigid cell wall) - high lipid content - no teichoic acid (largely lipid) |
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| plasma membrane |
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| - regulates diffusion in and out of cell - contains active transport system - site of enzymes involved in ATP production |
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| fluid mosaic model |
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| - phospholipid bilayer - a "dynamic" arrangement of phospholipids and proteins |
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| chromatophores |
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| - contains chlorophyll - only found in photosynthetic bacteria |
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| nuclear material |
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| - 1 chromosome (DNA) loose in the cytoplasm in the nucleoid region - bacteria often contain small circular, double-stranded DNA molecules called plasmids. |
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| ribosomes |
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| - granules scattered throughout the cytoplasm - protein synthesis, not membrane bound, organelle in both pro. and euk. - protein synthesis = assemble a.a. into polypeptides |
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| cytoplasmic inclusions |
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| -accumulated stored materials, valuable stored materials -metachromatic granules (volutin) stored form of phosphate. primary in gram negative. take up stain more readily (suck up stain fast) - polysaccharide granules - lipid inclusions |
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| magnetosomes |
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| -inclusions of iron oxide - act like magnets - may protect cells from accumulation of hydrogen peroxide |
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| endospores |
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| -highly resistant stucture - produced by certain bacteria - all members of the family Bacillaceae produce endospores - e.g. Genus Bacillus and Clostridium - Resistance : the most resistant of all living cells - highly resistant to: dessication (drying out), heat and toxic chemicals - low metabolic activity (dormant) - low water content - thick spore coat - heat resistant chemicals (calcium and dipicolinic acid) - formation of endospores: not a reproductive process - vegetative cell forms a single spore - germinates to form one vegetative cell |
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| eukaryotic cells |
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| - eu - true or good, karyon = kernel - kingdoms: protista, plantae, fungi, animalia - true nucleus containing genetic material - contain membrane bound organelles |
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| cytoskeleton |
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| -network of fibers that form a dynamic framework for support and movement |
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| microfilaments, actin filaments, intermediate filaments |
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| microtubules |
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| - form: cilia, flagella, and centrioles |
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| organelles |
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| - specialized structures that perform specific functions - sequester reactions - many contain folded membranes (increased surface area) |
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| nucleus |
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| spherical or oval, contains DNA |
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| nuclear envelope/membrane |
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| - double membrane perforated by pores - maintains nuclear shape and regulates transport in and out of the nucleus |
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| nucleolus |
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| - one or more spherical bodies within the nuclear envelope - functions in the synthesis of ribosomal RNA |
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| rough ER |
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| - studded with ribosomes - site for synthesis of secretory proteins and membrane molecules |
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| smooth ER |
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| - lack ribosomes - synthesizes phospholipids, fats, and steroids |
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| ribosomes (euk.) |
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| - formed of 2 subunits: 60S and 40S - free ribosomes:suspended in the cytoplasm - bound ribosomes: attached to ER - sites of protein synthesis |
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| golgi apparatus |
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| - flattened sacs, stacked on one another (pancakes) - receive and modify products from the ER - packages products in vesicles that transport, secretory, and storage - lysosomes: membrane-enclosed sac of hydrolytic enzymes - functions in phagocytosis, recycling cells own organic material - programmed cell destruction |
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| lysosomal storage disease |
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| - lysosomes lack one of the hydrolytic enzynmes - i.e. Tay-Sachs diseas: lack enzyme to digest lipid. excess lipid accumulates and damages brain cells |
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| mitochondria |
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| "power house of the cell" - synthesis of ATP, sites of cellular respiration - inner membranes folds into cristae |
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| plasma membrane |
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| -semipermeable/selectively permeable - controls what enters and leaves the cell - maintains the cells "homeostasis" (homo = same; stasis = standing) - keeps the internal chemical composition within narrow limits |
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| transport |
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| the movement of materials across the plasma membrane |
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| passive transport |
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| does not require energy from cell |
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| simple diffusion |
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| molecules move from an area of greater concentraiton ot an area of lesser concentraion |
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| facilitated diffusion |
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| a carrier protein combines with a specific substance and moves it across the membrane |
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| osmosis |
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| the diffusion of water through a semipermeable membrane (water moves from a higher to lower concentration) - water moves toward a region of higher solute (dissolved substance)concentration. |
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| osmoregulation |
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| the control of water balance |
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| isotonic |
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| -(iso = same; tonus = tension) - concentration of dissolved substances are the same inside and outside the cell; no net flow of water |
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| hypertonic |
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| -(hyper = above/exceeding) - high solute concentration |
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| hypotonic |
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| hypo = lower/below - low solute concentration |
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| plasmoptysis |
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| - (osmotic lysis) bursting of a cell in a hypotonic solution n(taking up the water) |
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| plasmolysis |
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| - shrinkage of the cytoplasm due to loss of water in a hypertonic solution |
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| channel proteins |
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| proteins which form channels through the membrane allowing passage of certain molecules. - gated channels: some can act as "gates" that open and close |
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| active transport |
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| -can move substances against their concentration gradient - requires that the cell extend energy (ATP) e.g. sodium-potassium pump |
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| transport of large particles |
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| - endocytosis - exocytosis |
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| endocytosis |
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| - phagocytosis (cell eating) - pinocytosis (cell drinking) - receptor-mediated endocytosis |
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| exocytosis |
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| -vacuole fuses with plasma membrane and expels contents from cell |
