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Micro Study Guide 2
chapters 4 and 5
| Question | Answer |
|---|---|
| Name several general characteristics that could be used to define the prokaryotes? | Electron Microscope, DNA (genetic material), Lack of membrane--enclosed organelles, Cell wall composition (peptidoglycan), Cellular Division (binary fission-DNA makes copy of self and cell replicates, 2 mother and 2 daugher cells), and Two groups (bacteri |
| Do any other microbial groups besides bacteria have prokaryotic cells? | archaea |
| List five functions that the cell membrane performs in bacteria? | encases cytoplasm, regulates transport, secretion, respiration/ATP synthesis, enzymes, photosynthetic chromophores, receptor molcules |
| Explain the position of the glycocalyx? | "sugar coat" or "sugar cup", fiscus sticky gelationour made of polysaccharides--produced inside the cell moves to the outside of the cell, mucus like |
| An example of a glycocalyx is? | capsule, slime layer, biofilm |
| Prokaryote | Cell or organism lacking a membrane-bound, structurally discrete nucleus and other sub cellular compartments. Bacteria are examples of prokaryotes |
| Bacteria | oldest form of cellular life. They are also the most widely dispersed, occupying every conceivable microclimate on the plant earth |
| External structure of bacteria | include glycocalyx and appendage: flagella, fimbriae and pili |
| Nucleoid or Bacterial chromosome | comprised of condensed DNA molecules. DNA directs all genetics and heredity of the cell and cods for all proteins. |
| Pilus | an elongated, hollow appendage used in transfer of DNA to other cells. Only found in gram negative bacterial. |
| Outer membrane | Extra membrane similar to cell membrane but also containing lipopolysaccaride. Controls flow of materials and is toxic to mammals when released. |
| flagellum | Specialized appendage attached to the cell by a basal body that holds a long, rotating filament. The movement pushes the cell forward and provides motility. |
| Fimbriae | Fine, hairline substances bristles extending from the cell surface that help in adhesion to other cells and surfaces |
| Cell Wall | a semi rigid casing that provides structural support and shape for the cell |
| Cell membrane | A thin sheet of lipid and protein that surrounds the cytoplasm and controls the flow of materials into and out of the cell pool. |
| ribosomes | Prokaryotic cell. Tiny particles composed of protein and RNA that are the sites of protein synthesis. |
| Endospores | Dormant body formed within some bacteria that allows for their survival in adverse conditions. |
| cytoplasm | Water based solution filling the entire cell. |
| pili | thread-like structures present on some bacteria; pili are shorter than flagella, and are used to adhere bacteria to one another during mating and to adhere to animal cells. |
| What are the functions of slime layers and capsules? | protect the cell and in some cases, assist with adhesion |
| How is the presence of a slime layer evident even at the level of a colony? | protects call from loss of water and nutrients |
| Differentiate between pili and fimbriae? | pili--tubular made of protein only in gram negative bacteria and utilized in mating process. Fimbriae--hair like bristles assisting in adhesion |
| Describe the structure of a flagellum and how it operates. What are the four main types of flagella arrangement? | Flagella--Bacterial Propellers. Monotrichous-with a single flagella, Lophotrichous--small bunches or tufts of flagella emerging from the same site, Amphitrichous--with flagella at both poles of the cell, and Peritrichous--flagella are dispersed randomly |
| Pili are tubular shafts in _____ bacteria that serve as a means of _____. | gram negative; conjugation |
| amphitrichous | having a single flagellum or a tuft of flagella at opposite poles of a microbial cell |
| biofilm | a complex association that arise from a mixture of microorganisms growing together on the surface of a habitat |
| capsule | in bacteria, the loose, gel-like covering or slime made chiefly of polysaccharides. This layer is protective and can be associated with virulence. |
| chemotaxis | The tendency of organisms to move in response to a chemical gradient (toward an attraction or to avoid adverse stimuli) |
| fimbria | Short, numerous surfaces appendage on some bacteria that provides adhesion but not locomotion. |
| Glycocalyx | Structure of prokaryotic cell. a coating or layer of molecules external to the cell wall. It serves protective, adhesive, and receptor functions. It may fit tightly or be very loose. |
| lophotrichous | bacteria having a tuft or flagella at one or both poles |
| monotrichous | organism that bears a single flagellum |
| peritrichous | peritrichous |
| phagocytes | natural body defense that can engulf and destroy foreign cells through phagocytosis, this preventing infection |
| slime layer | The gelatinous outermost covering of certain bacteria; unlike capsules, which are tightly bound to cell walls. |
| Function of the glycocalyx? | coating of macromolecules to protect the call, and sometimes help it adhere to its environment. |
| Structure/function of slime layers? | some bacteria is covered in a loose shield that protects them from loss of water and nutrients. |
| Structure/function of biofilms? | microorganisms, when left undisturbed, they gather in masses, cling to surfaces and capture available nutrients and moisture. (plaque on teeth) |
| spirochetes | corkscrew shaped bacteria |
| The major locomotor structures in bacteria are? | Flagellum: chemotaxis, rotary motion; counterclockwise "run", clockwise "tumble". |
| Structure/function of capsules? | capsules of repeating polysaccharide units of protein, bound more tightly that a slime layer, thicker gummy consistency that gives a prominently sticky mucoid character to the colonies and most encapsulated bacteria. |
| Structure/function of frimbriae | fine hair like bristles extending from cell surfaces that help in adhesion to other cells and surfaces |
| Structure/function of pili | rigid tubular structure made of protein (pilin), gram negative bacteria, mating process |
| Structure/function of flagella | function: motility or self propulsion. Extreme thinness, three parts: filament, hook and basal body. |
| 3 components of the prokaryotic flagella? | filament, hook and basal body |
| What function does the LPS layer serve? | Lipopolysaccaride layer. Gram negative membrane contains special types of polysaccharides and proteins. The uppermost layers of the OM contains lipopolysaccaride. Functions as antigens and receptors. |
| What is the Gram stain? | staining technique that delineates two generally different groups of bacteria--the differences between gram positive and gram negative is evident in the physical appearance of their cell envelopes. |
| What is there in the structure of bacteria that causes some to stain purple and others to stain red? | differences in the structure of the cell wall, and how it reactions to the series of reagents applied to the cells. |
| How does the precise structure of the cell walls differ in gram-positive and gram-negative bacteria? | Gram positive-two layers; thick cell wall (peptidoglycan) and cell membrane. Gram-negative; outer membrane, thin cell wall, and the cell membrane. |
| What is the periplasmic space, and how does it function? | Region between the cell wall and cell membrane of cell envelopes of gram negative cells. It is an important reaction site for large and varied pool of substances that enter and leave the cell. |
| What function does peptidoglycan serve? | call walls gain their rigid quality |
| Give a simple describe of it's structure (peptoglycan)? | repeating framework of long glycan chains cross-linked by short peptide fragments.` |
| What happens to a cell that has its peptidoglycan disrupted or removed? | it would rupture from internal pressure (lack of protection from osmosis absorption) |
| Which stain is used to distinguish differences between the cell walls of medically important bacteria? | Gram stain |
| The outcome of the gram stain depends on what? | Gram positive-two layers; thick cell wall (peptidoglycan) and cell membrane. Gram-negative; outer membrane, thin cell wall, and the cell membrane. |
| Which of the following is a primary bacterial cell wall function? | structural support |
| Which of the following is present in both gram-positive and gram-negative cell walls? | Both gram-positive and gram-negative bacteria have a cell wall made up of peptidoglycan and a phospholipids bilayer with membrane-spanning proteins |
| non-typical cell walls | several bacterial groups lack the cell wall structure of gram positive or gram negative and some bacteria have no cell wall at all. Resistance is the basis for the acid-fast stain used to diagnose tuberculosis and leprosy--hot carbol fuchsin dye attaches |
| mycoplasmas | bacteria that naturally lack a cell wall--stabilized by sterols and is resistant to lysis. Very small bacteria, found in plants, soil and animals. The most important medical species of mycoplasmas pneumonia which adheres to the epithelial cells in the l |
| L forms | some bacterial that ordinarily have a cell wall can lose it during part of their life cycle. |
| protoplast | when a gram positive cell is exposed to either of the two chemicals, it will lose the cell wall |
| spheroplast | a gram negative cell exposed to the same substances loses it peptidoglycan but retains its outer membrane |
| Peptidoglycan | the cell walls of most bacteria gain their relatively rigid quality from this, compound of repeating framework of long glycan chains cross linked by short peptide fragments to provide a strong but flexible support framework |
| Gram stain positive cell wall | Gram stain negative cell wall |
| Gram stain positive | two layers: thick cell wall (peptidoglycan), cell membrane. Stains purple. |
| Gram stain negative | three layers: outer membrane, a thin cell wall, and the cell membrane. Stains red. |
| Gram stain | staining technique that delineates two generally different groups of bacteria--the differences between gram positive and gram negative is evident in the physical appearance of their cell envelopes. |
| Structure/function of the plasma/cell membrane and the concept of the fluid mosaic model membrane? | just beneath the cell wall is the cytoplasm membrane, very thin flexible sheet molded completely around the cytoplasm. It is a lipid bilayer with proteins embedded to varying degrees. Because bacteria has no organelles, the cell membrane provides the fu |
| Gram stain: | Ready diagnosis for bacteria. Gram positive (purple) Gram negative (red/pink) |
| peptidoglycan | a network of polysaccharides chains cross-linked by short peptides that forms the rigid part of bacterial cell walls. Gram-negative bacteria have a smaller amount of this rigid structures than do gram positive bacteria. |
| mycolic acids | associated with peptoglycan (non typical cell walls) |
| The order and significance of each step of the gram stain | 1. crystal violet stains all bacteria purple. 2. add iodone to large cyrstals in the peptidoglycan of cell wall. (positive peptidogylcan is thicker). 3. apply alcohol to dissolve lipids on the outer membrane and remove the dye from peptidoglycan lay |
| organisms with non-typical cell walls and organisms that are cell wall deficient | Non typical cells walls (do have peptiglycan) (mycolic acid) and can stain gram positive. Mycobaterium spp. Nocardia spp. Cell wall deficient bacteria: mycoplasma, L forms, protoplast and spheroplast. |
| Compare the composition of the bacterial chromosome (nucleoid) and plasmids? | DNA in bacteria is not enclosed by a nuclear membrane, but instead aggregated in a dense area of the call called the nucleoid. Plasmids are nonessential pieces of DNA. |
| What are the functions of each bacterial chromosome (nucleoid)? | Chromosome is the minimal genetic requirement for bacterial survival. Plasmids carry nonessential pieces of DNA. These tiny strands exist as separate double-stranded circles of DNA and can become integrated into chromosomes. During conjugation, they ma |
| What is unique about the structure of bacterial ribosomes? | Svedberg unit, rate the molecular size of parts that have been spun down and separate by molecular weight and shape in centrifuge. |
| How do bacterial ribosomes function? | Svedberg unit, rate the molecular size of parts that have been spun down and separate by molecular weight and shape in centrifuge. |
| Where are they located? ribosomes | throughout cytoplasm and cell membrane |
| Actin cytoskeleton | Prokaryotic cell. Long fibers of proteins that encircle the cell just inside the cell membrane and contribute to the shape of the cell. |
| Inclusion/Granule | Prokaryotic cell. Stored nutrients such as fat, phosphate, or glycogen deposited in dense crystals or particles that can be tapped into when needed. |
| Bacterial endospores function in | Bacterial endospores serves the survival of the bacteria. The bacteria will change form into an endospores when conditions for survival is unfavorable. In this state they are hardier, resist many environmental changes, require no nutrients or water and ca |
| The purpose of the ribosomes, prokaryotes; where they are found in the cell? | Found in cytoplasm, site of protein synthesis, some are scattered freely in the cytoplasm and others are associated with RER. Some "bound" to plasma membrane to export outside the cell. Svedberg's units apply. Made of RNA and protein. |
| Function of the endospores | Bacteria that will withstand hostile conditions and facilitate survival. Dormant bodies produced by bacillus, chlostridium and sporosarcina, with a two phase life cycle--vegatative and metabolically active and growing entity that can bbe induced by enfor |
| inclusion bodies | cytoplasm storage granules, glycogen, fat or some other aggregate metabolic product. |
| magnetosomes | contain iron oxide, acts like magnetic align itself in earth's magnetic field; to move to areas and decrease O2 to survive in anaerobic environment (type of inclusion bodies--reserve deposits |
| Function of the nucleoid, plasmid? | inside cytoplasm, no nuclear membrane, 60% DNA 30% RNA 10% protein, attached to cellmembrane, supercoiled. Plasmids are exttra chromosomal material, double strangded circulear DNA and non essential pieces of DNA. Importat for drug resistance and toxin p |
| plasmids | extra chromosomal genetic units characterized by several features. A plasmid is a double stranded dank that is smaller than and replicates independently of the cell chromosome; it bears genes that are not essential for cell growth; it can bear genes that |
| single | bacterial arrangement: 1 rod |
| diplococci | bacterial arrangement: pairs |
| tetrads | bacterial arrangement: 4's |
| clusters | bacterial arrangement: grape like clusters |
| chains | bacterial arrangement: ooooooo--chain like (strep) |
| curved | bacterial cell shape: spirochete (helic, flexible), vibrio (curbed rods "commas"), spirilla (helic, corkscrew, rigid) |
| bacillus | bacterial cell shape that is cylindrical (longer than it is wide), little staff, rod shaped |
| cocci | sphere-shaped bacteria, "berries" spherical/round |
| palisades | bacterial arrangement: corynebacterium cells resembling a row of fence posts and created by snapping. |
| The four classification of the bacteria in Bergey's Manual of Systemic Bacteriology | based upon the nature of the cell wall: gracilicutes-gram neg cell walls, thus thin skinned, firmicutes-gram postive cell walls that are thick and strong, tenericutes-lack a cell wall and are soft, mendosicutes-archaea, primitive procaryotes with unusual |
| pleomorphism | normal variability of cell shapes in a single species |
| obligate intracellular parasites | bacteria (rickettsias and chlamydias) have adapted to life inside their host cells |
| halophiles | A microbe whose growth is either stimulated by salt or requires a high concentration of salt for growth. |
| methanogens | methane producers |
| Organisms belonging to the Archaea group | Single celled microorganisms. Methanogens (convert CO2 to methane gas) and halophiles (need salt to survive), thermophiles (grow ↑ temps) and psychcrophilic (grow at very low temps) |
| thermophiles | a microorganism that thrives at a temperature of 50 degree C or higher. |
| Structure/function of the plasma/cell membrane and the concept of the fluid mosaic model membrane? | No peptidoglycan. (fungi, algae and protozoa) |
| Both flagella and cilia are found primarily in | protozoa |
| The cell wall is found in which eukaryotes? | Fungi and Algae |
| Yeasts are ____ fungi and molds are _____fungi? | unicellular, filamentous |
| In general, fungi derive nutrients through? | digesting organic substrates |
| Eukaryote | Cell or organism with membrane-bound, structurally discrete nucleus and other well-developed subcellular compartments. Eukaryotes include all organisms except viruses, bacteria, and bluegreen algae |
| nucleolus | granular mass containing RNA that is contained within the nucleus or a eukaryotic cell |
| define the endosymbiotic theory and who proposed it? | Dr. Lynne Margulis. Re orgination of the eucaryotic cell. Eucaryotic cells arose when a larger procaryotic cell engulfed smaller bacterial cells that began to live and produce inside procaryotic cell. |
| cilia | tiny, hair like structures on the outside of some cells, providing mobility |
| Structure/function of cilia | In eucaryotice cells, very smililar to flagells, but are shorter and more numerous, and found only on a single group of protozoe and certain animal cells. |
| cristeae | unfolded inner membrane of a mitochondrion that is the site of the respiratory chain and oxidative phosphorylation. |
| The purpose of the ribosomes, eukaryotes; where they are found in the cell? | protein synthesizers: dotted appearance in the cytoplasm |
| endocytosis | The process whereby solid and liquid materials are taken into the cell through membrane invagination and engulfment into a vesicle. |
| lysosome | cytoplasm organelle containing lysozyme and other hydrolytic enzymes |
| Structure/function of the Golgi body | in eucaryotic cells, site where proteins are modified and send to their final destinations. It is a discrete organelle consisting of a stack of several flattended disc shaped sacs called cisternae. |
| Structure/function of the mitochondria | bulk of energy generated in most eucaryotes, round or elongaged particles caterred throughout the cytoplasm. |
| structure/function of the chloroplast | Photosynthesis machines, orgaanelle found in algae and plant cells that are capable of converting the energy of sunlight into chemical energy. They resemble mitrochondria, a bit larger and more varied in shape. |
| Structure/function of the ER, distinguish between the RER and SER | endoplasmic reticulum (Rough--location of protein synthesis and contains ribosomes and Smooth (no ribosomes)) |
| nuclear pores/membrane | nutrients can go into nucleus, and excrete waste |
| nucleoplasm | The part of the nucleus that is contained by, but is distinct from, the nuclear envelope. |
| phagocytosis | type of endocytosis in which the cell membrane actively engulfs large particles or cells into vesicles. Lysosomes |
| phagosomes | a body formed in a phagocyte, consisting of a union between a vesicle containing the ingested particle (the phagosome) and a vacuole of hydrolitic enzymes (the lysosome) |
| Function of the nucleus and it's components and their functions? | nucleus-dirdcts activities through a structural and chemical network. Membrane bound structure and contains genetic material. |
| Function of lysomes and the relationship with endosomes | Lysosomes: contains enzymes, and involved with food digestion and protect against invading microorganisms, and removal of cell debris. Endosomes: vacuolar compartments that confine bacteria after enforced endocytosis or after phagocytosis. |
| Structure of the cell wall for fungi, algae, and protozoa "pellicle" and their difference from bacteria | Fungi: (chitin) polysaccharide with nitrogen allows fungal cell walls to be flexible and strong with cellulose polysaccharide also. Algae: pectin, cellulose and mannans (polymers of sugar mammose) Protozoa: no cell wall but pellicle--flexible protein |
| parasite | organism that lives on or within another organism (host) from which it obtains nutrients and enjoys protection. The parasite produces some degree of harm in the host. |
| Are frimbriae, pili, flagella and cilia associated with eukaryotes and which with prokaryotes | frimbriae and pili and flagella with prokaryotes and cilia with eukaryotes |
| Composition of the cytoplasm | 70-80% water, thick elastic, semi transparent, contains: proteins, AA, carbs and other nutrients, etc. |
| pinocytosis/pinosomes | engulfment or endocytosis of liquids by extensions of the cell membrane |
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JulianeSn