Cells (Procaryotic cell structure and function)
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krystalanneflores on February 6, 2012
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Aviles- Lecture 5
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69 terms
Terms | Definitions |
|---|---|
 basic shape | spherical, cubical, cylindrical |
| internal content | cytoplasm, surrounded by a membrane |
| two basic cell types | eucaryotic & procaryotic |
| eucaryotic cells | animals, plants, fungi, and protist |
| eucaryotic cells | contain double- membrane bound nucleus with DNA chromosomes |
| eucaryotic cells | contain membrane-bound organelles compartmentalize the cytoplasm and preform specific functions |
| procaryotic cells | bacteria and archaea. no nucleus or other membrane bound organelles |
| Appendages | Motility, Attachment, Channels |
| Motility | flagella, and axial filaments |
| Attachment | fimbriae |
| Channels | Pili |
| Glycocalyx | surface coating.... Capsule, slime layer- protects the cells from dehydration and nutrient loss |
| Flagella | What moves the cell through their environment; rotates 360 degrees |
| filament | long, thin, helical structure composed of protein flagellin |
| hook | curved shealth |
| basal body | stack of rings firmly anchored in cell wall |
| External Procaryotic cell characteristics | Appendages, Flagella, Pili, Frimbriae, Glycocalyx, Capsule, Slime layer |
| Characteristics of procaryotic cell envelope | cell wall, cell membrane |
| Internal characteristics of procaryotic cells | cytoplasmic matrix, ribosomes, inclusions, nucleoid/ chromosome, actin cytoskeleton, endospore |
| chemical stimuli (flagella) | Chemotaxis; positive and negative |
| light stimuli (flagella) | phototaxis |
| rotary motion | Signal of stimulus sets flagella into ______ ______. |
| Counterclockwise (flagella movement) | results in smooth linear direction-run |
| clockwise (flagella movement) | tumbles- very slow |
| monotrichous | single flagellum at one end |
| lophotrichous | small bunches arising from one end of cell |
| Amphitrichous | flagella at both ends |
| peritrichous | flagella dispersed over surface of cell; slowest |
| The cell envelope | external covering outside the cytoplasm; 2 basic layers (cell wall and cell membrane); maintains cell integrity; 2 different groups |
| gram-positive bacteria | thick wall (peptidoglycan and cell membrane) (RESPIRATORY) |
| gram- negative bacteria | outer cell membrane, thin peptidoglycan layer and cell membrane (DIGESTIVE) |
| slime layer | loosley organized and attached |
| capsule | highly organized, tightly attached |
| Glycocalyx | coating external to the cell wall ( sugars and/or proteins); protect cells from dehydration and nutrient loss, inhibit killing by whit blood cells by phagocytosis contributing to pathogenicity; Attachment- formation of biofilms |
| anibioticts | used to treat bacterial infections. |
| Characteristics of gram-positive cell wall | Thick (20-80nm) layer of peptidoglycan & cell membrane Maintenance and enlargement during cell division Move cations across the cell envelope stimulate specific immune responses use red blood cells to get nutrients |
| Characteristics of gram-negative cell wall | Protective structure but sensitivity to lysis Outer membrane (LPS) Contains lipopolysaccharides(LPS) and lipoproteins contains porin- regulate |
| fimbriae | fine, proteinaceous, hairlike bristles from the cell surfaces |
| Pili | Transfer; found in only gram negative cells; rigid tubular structure made of pilin protein; function to join bacterial cells for partia DNA transfer called conjugation |
| Axial filaments | Periplasmic- internal flagella, enclosed between cell wall and cell membrane of spirochetes... Produce cellular motility by contracting and imparting twisting or flexing motion |
| 2 types of bacteria with gram negative cell wall | Cholera & Salmonella |
| Structure of cell walls | determines cell shape, prevents lysis (bursting) or collapsing due to changing osmotic pressures |
| Mycobacterium and Nocardia (Gram +) | Cell wall structure with lipid mycolic acid- pathogenicity and high degree of resistance to certain chemicals and dyes; basis for acid fast stains used for diagnosis of infection |
| mycoplasma(no cell wall) | Cell wall is stablized by sterols; Pleomorphic (extreme variations in shape) |
| PLASMIDS | Small circular, double-stranded DNA Free or integrated into the chromosome Duplicated and passed on to offspring Not essentialto bacterial growth and metabolism Encode proteins that confers antibiotic resistance, tolerance to toxic metals, enzymes and toxins Used in genetic engineering-readily manipulated and transferred from cell to cell |
| RIBOSOMES | Made of 60%ribosomal RNA and 40%protein Two subunits: large (50S)and small (30S) Procaryoticdiffer from eucaryoticribosomesin sizeand number of proteins Site of protein synthesis Present in all cells S= SVEDVENG UNITS |
| INCLUSIONS AND GRANULES | Intracellular storagebodies Bacteria use them when environmental sourcesare depleted. glycogen, poly--hydroxybutyrate, gas vesiclesfor floating, sulfurand phosphategranules (metachromaticgranules) |
| Magnetosomes | Involved in navigation (magnetic properties) |
| Vegetative | active and growing |
| Endospore | when exposed to adverse conditions; high resistance and long-term survival |
| sporulation | formation of endospores |
| endospores | Hardiest of all life forms Withstands extremes in heat, drying, freezing, radiation and chemicals No reproduction (unlike fungi) |
| CYTOPLASM | Dense gelatinous solution of sugars, amino acids, and salts. 70-80% water (solvent for materials used in all cell functions) |
| CHROMOSOME | Single, circular, double-stranded DNA (contains all the genetic information required by a cell) DNA is tightly coiled around a protein, aggregated in a dense area called the nucleoid 30 |
| PLASMIDS | if a bacteria is resistant to antibiotic, the tolerance issue is located in the ______ |
| PLASMIDS | Small circular, double-stranded DNA Free or integrated into the chromosome Duplicated and passed on to offspring Not essentialto bacterial growth and metabolism Encode proteins that confers antibiotic resistance, tolerance to toxic metals, enzymes and toxins Used in genetic engineering-readily manipulated and transferred from cell to cell |
| germination | return to vegetative growth |
| PROPERTIES OF ENDOSPORES | Resistancelinked to high levels of calciumand dipicolinicacid Dehydrated, metabolically inactive Thickcoat Long-term survival -25,250 million years. Resistantto ordinary cleaning methods and boiling Pressurized steam at 120oC for 20-30minuteswill destroy them 36 |
| Coccus | spherical (marbles) |
| Bacillus | Rod (long spaghetti) |
| coccobacillus | very short and plump |
| vibrio | gently curved ( banana) |
| Spirillum | helical, comma, twisted rod (snakes and STD's) |
| spirochete | spring like |
| Cocci | singles diplococci-in pairs chains tetrads-groups of four cubical packets irregular clusters |
| kill endospores | 120 degrees celcius for 20-30 minutes |
| Species | collection of cells sharing overall similar pattern of traits |
| Serological | antibodies in the blood |
| ARCHAEA: THE OTHER PROCARYOTES | More close to Eukaryathan to bacteria Unique genetic sequences in their rRNA. Unique membrane lipids and cell wall Live in the most extreme habitats (extremophiles) Adapted to heat, salt, acid pH, high pressure methane producers hyperthermophiles extreme halophiles sulfur reducers |
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