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141 Cards in this Set
- Front
- Back
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Prokaryotes |
1) their DNA is enclosed within a membrane 2) their DNA is not associated with histones; other proteins are associated with DNA 3) lack membrane enclosed organelles 4) their cell walls contain polysaccharide peptidoglycan 5) divide by binary fission. DNA is copied and the cell splits into two cells |
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Eukaryotes |
1) DNA is found in cell's nucleus with a nuclear membrane, and the DNA has multiple chromosome 2) DNA is associated with chromosomal proteins called histones and nonhistones 3) have membrane enclosed organelles 4) cell walls are chemically simple 5) cell division involved mitosis and result in two cells identical to each other |
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Shapes of Bacteria |
- coccus, bacillus, and spiral |
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Diplococci |
- coci that remain in pairs after dividing |
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Streptococci |
- thsoe that divide and remain attached in chainlike patterns |
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Tetrads |
- those that divide in two planes and stay in group of fours |
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Sarcinae |
- those that divided in three planes and remain attacehd in cubelike groups of eight |
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Staphylococci |
- those that divide in multiple planes and form grapelike clusters or broad sheets |
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Single Bacilli |
- a single rod of bacilli |
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Diplobacilli |
- appear in pairs after divison |
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Streptobacilli |
- occur in chains |
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Coccobacillus |
- other are oval and look so like cocci |
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Vibrios |
- bacteria that look like curved rods |
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Sprilla |
- have a helical shape like a cork screw and faily rigid bodies - use flagella to move |
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Spirochetes |
- another group of spirals that are helixal and flexible - move by means of axial filaments |
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Monomorphic |
- they mantain one shape |
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Pleomorphic |
- means they can have many shapes |
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Glycocalyx |
- substances surrounding cells - it is a viscous sticky, gelatinous polymer that is external to the cell wall - composed of polysaccharide, polypeptide, or both |
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Capsule |
- if the glycocalyx is organized and is firmly attched to the cell wall - presence can be determined by using negative staining - often protect pathogenic bacteria from phagocytosis by the cells of the host |
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Slime Layer |
- if the glycocalyx is unorganized and only loosley attached to the cell wall |
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Extracellular Polymeric Substance |
- a glycocalyx that helps the cells in a biofilm attach to their target environment and to each other - protects the cells within it, facilitates communication among them, and enables the cells to survive by attaching to various surfaces in thier natural environment |
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Flagella |
- long filamentous appendages that propel bacteria |
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Atrichous |
- bacteria that lack flagella |
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Peritrichous |
- flagella distributed over the entire cell |
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Polar |
- Flagella at one or both poles or ends of the cell - may be monotrichous: single flagella at pole |
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Filament |
- the outer most region of the flagella - contains globular protein flagellum arranged in several chains that intertwine and form a helix around a hollow core |
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Hook |
- attached the filament |
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Basal Body |
- which anchors the flagellum to the cell wall and plasma membrane - composed of small central rod inserted into a series of rings - gram negative: two pairs of rings - gram positive: one pair of rings |
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Movement of Flagella |
- moves through the rotation of the basal body - flagellar rotation depends on the cell's continuous generation of energy |
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Motility |
- the ability of on organism to move on its own - advantage: allows bacteria to move toward a more favorable environment or away from an adverse one |
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Taxis |
- the movement of bacterium to move toward or away from a particular stimulus |
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Axial Filaments or Endofalgella |
- bundles of fibrils that arise at the ends of the cell beneath an out sheath and spiral around the cell |
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Fimbriae |
- can occur at the poles of the bacterial cell or can be evenly distributed over the entire surface of the cell - purpose: attachment and transfer of DNA rather than for motility - found in many negative gram bacteria - helps bacteria adhere to each other and surfaces |
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Pili |
- are longer than fimbriae and number only one or two per cell - involved in motility and DNA transfer |
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Twitching Motility |
- a pilus extends by the additon of subunits of pilin, makes contact with a surface of another cell adn then retracts as the pilin subunits are disassemebled - grappling hook matter |
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Gliding Motility |
- the smotth gliding movement of myxobacteria - provides a mean for microbes to travel in environments with a low water content such as biofilm and soil |
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Conjugation |
- when some pili are used to bring bacteria together allowing the transfer of DNA from one cell to another |
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Cell Wall |
- a complex semirigid structure responsible for the shape of the cell - surrounds the underlying plasma membrane and protects it and the interior of the cell from adverse changes in the outside environment |
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Cell Wall Function |
- prevent bacterial cells from rupturing when the water pressure inside the cell is greater than that outside of the cell - helps maintain the cell shape and serves as a point of anchorage for flagella - contributes to the ability of some species to cause disease and is the site of action of some antibiotics |
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Peptidogylcan |
- bacterial cell wall is compsoed of this macromolecular network which is either present alone or in combination with other substances - formed by repeating disaccharide attached by polypeptides to form a lattice that surrounds and protects the entire cell - Disaccharide: made up of monosaccharides called NAG and NAM |
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Disaccharide |
- made up of monosaccharides called NAG and NAM - part of a component of peptidoglycan |
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Polypeptides |
- component of peptidoglycan - connects adjacent rows of disaccharide - consists of tetrapeptide side chains - consists of peptide cross- bridge |
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Lysis |
- destruction caused by rupture of the plasma membrane and the loss of cytoplasma |
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Gram Positive Cell Walls |
- cell walls consists of many layers or peptidoglycan forming a thick rigid structure |
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Teichoic Acids |
- found in gram positive cell walls - contain teichoic acids which consists primarily of an alcohol and phosphate - teichoic acids may bind and regulate the movement of cations into and out of the cell - prevent extensive wall breakdown and possible cell lysis - provide much of the wall's antigenic specificity and make gram positive possible |
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Gram Negative Cell Walls |
- cell walls that contain only a thin layer of peptidoglycan - peptidoglycan is bonded to lipoproteins in the outer membrane and is between the outer membrane and cell plasma |
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Periplasma |
- area between the outer membrane and cell plasma - contains a high concentration of degradative enzymes and transport proteins |
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Outer Membrane |
- in gram negative cells - consists of lipopolysaccharides, lipoproteins, and phospholipids - negative charge is important in evading phagocytosis - provides barreir to certain antiboitics, digestive enzymes, |
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Porins |
- allows permeability in the outer membrane due to the proteins in the membrane that form channels - permit the passage of molecules such as nucleotides, disaccharides, peptides, amino acids, vitamin B12, and iron |
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Lipopolysaccharide (LPS) |
- makes up the outer membrane - large complex molecule that contains lipids and carbohydrates and consists of three components: lipid A, a core polysaccharide, a O polysaccharide |
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Lipid A |
- makes up lipopolysaccharide - is the lipid portion of LPS - embedded in the top layer of the outer membrane - release lipid A when gram negative bacteria die - responsible for symptoms associated with infections by gram negative bacteria such as fever, dilation of of blood vessels, shock, and blood clotting |
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Core Polysaccharide |
- it is attached to lipid A and contains unusual sugars - provides stability |
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O Polysaccharide |
- extends outward from the core polysachharide and is composed of sugar molecules - functions as an antigen and is useful for distinguishing species from gram negative bacteria |
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Crystal Violet |
- primary stain - stains both gram positive and gram negative cells because dye enters both cytoplasm of both cells |
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Iodine |
- it forms large crystals with the dye that are too large to escape through the cell wall |
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Alcohol |
- dehydrate peptiodgylcan of gram positive cell walls to make it more impermeable to the crystal violet iodine - in negative gram cells the alcohol dissolves the outer membrane and leaves small holes in the thin peptidoglycan layer through which crystal iodine diffuses |
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Safranin |
- provides a contrasting color to the primary stain - gram negative turn pink/red - gram positive stay purple or turn darker |
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Acid Fast Staining |
- used to identify all bacteri of the genus Mycobacterium and pathogenic species of Nocardia - bacteria contain high concentration of mycolic acid that prevents uptake of dye - can be stained with carbolfuchsin because it penetrates the cell wall, binds to cytoplasm |
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Lysozyme |
- a digestive enzyme that can damage the cell wall - occurs naturally in eukaryotic cells - particularly active on the major cell wall components of gram positive bacteria - it catalyzes hydrolysis of the bonds between the sugars in the repeating disaccharide of peptidoglycan |
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Protoplast |
- ceullular contents that remain surronded by the plasma membrane may remian intact if lysis does not occur - spherical and is till capable of carrying metabolism |
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L Forms |
- when cells lose thier cell walls and swell into irregularly shaped cells - form spontaneously or in response to penicillin or lysozyme |
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Sheroplasts |
- in gram negative cells - a spherical cell structure that contains the cellular contents, plasma membrane, and remaining outer wall layer - for negative gram cells EDTA must first be added in order to weaken the ionic bonds in the other membrane, giving lysosomes access to the peptidoglycan layer |
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Plasma Membrane |
- thin strucutre lying inside the cell wall and enclosing the cytoplasma of the cell - consists primarily of phospholipids for prokaryotes and proteins - Eukaryotes also contain carbohydrates, and sterols |
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Lipid Bilayer |
- plasma membranes are arranged into a two layered strucutre - two dark lines with light space between the lines - polar heads are on the two surfaces of the lipid bilayer |
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Pheripheral Proteins |
- are easily removed form the membrane by mild treatments and lie at the inner and outer surface of the membrane - function as enzymes that catalyze chemical reactions and as mediators of changes in membrane shape during movements |
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Integral Proteins |
- can be removed from the membrane only after disrupting the lipid bilayer - penetrate the membrane completely and are called transmembrane proteins - are channels that have a pore or hole through which substances either enter and exit the cell |
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Glycoproteins |
- proteins on the outer surface of the plasma membrane that have carbohyrdates attached to them - help protect and lubricate the cell and are involved in cell to cell interactions |
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Glycolipids |
- lipids attached to carbohydrates - help protect and lubricate the cell and are involved in cell to cell interactions |
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Fluid Mosaic Model |
- dynamic arrangement of phospholipids and proteins |
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Functions of Plamsa Membrane |
- serve as a selective barrer through which materials enter and exit the cell - important to breakdown of nutrients and the production of energy - enzymes are capable of catalyzing the chemical reactions that break down nutrients and produces ATP |
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Selective Permeability |
- indicates that certain molecules and ions pass through the membrane buth that others prevent form passing through it - large molecules cannot pass through the plasma membrane |
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Chromatophores |
- pigments and enzymes involved in photosythesis are found in infoldings of the plasma membrane that stend into the cytoplasma |
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Mesosomes |
- bacterial plasma membranes that contain one or more large, irregular folds - are artifacts and not true cell structures - believed to be folds in the plasma membrane that develop by the process used for preparing specimens for electron microscopy |
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Passive Process |
- substances that cross the membrane from an area of high concentration to an area of low concentration with any expenditure of ATP |
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Active Process |
- cell must use energy to move substances form low concentration to areas of higher concentration |
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Simple Diffusion |
- net movement of molecules or ions form an area of high concentration to an area of lower concentration - rely on it to transport small molecules like oxygen and carbon dioxide |
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Equilibrium |
- the point where there is an equal distribution of molecules on both ends |
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Facilitated Diffusion |
- mebrane proteins function as channels or carrier that facilitate movement for ions or large molecules across the membrane - transporters permit the passage of mostly small inorganic ions that are two hydrophilic to penetrate the nonpolar interior of the lipid bilayer |
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Extracellular Enzymes |
- enzymes that break down large molecules into simpler ones - released by bacteria into the surrounding medium |
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Osmosis |
- net movement of solvent molecules across a selectively permeable membrane from an area of high concentration of solvent molecules to an area of low concentration of solvent molecules |
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Osmotic Pressure |
- pressure required to prevent movement of pure water into a solution containing some solute - the pressure needed to stop the flow of water across the selectively permeable membrane |
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Isotonic Solution |
- medium in whcih the overall concentration fo the solutes equals that found inside a cell - are at equilibrium |
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Hypotonic Solution |
- oustide the cell is a medium whose concentration solutes is lower than the inside of the cell |
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Hypertonic Solution |
- medium having a higher concentration of solutes than inside the cell has - water leaves the cell by osmosis |
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Active Transport |
- the cell uses energy in form of ATP to move substances across the plasma membrane - substances actively transported: ions, amino acids, and simple sugars |
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Group Translocation |
- occurs in prokaryotes - the substance is chemically altered during transport across the membrane |
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Cytoplasm |
- substances of the cell inside the plasma membrane - major structures in cytoplasms are: nucleoid, ribosomes, and inclusions |
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Nucleoid |
- in bacteria, usually contains a single long continous, and frequentliy circulalry arranged thread of double stranded DNA (Bacterial Chromosome) |
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Bacterial Chromsome |
- carries all the information required for the cell's structures and functions - are not surrounded by nuclear envelope and do not include histones - attached to the plasma membrane |
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Plasmids |
- double stranded DNA molecules - molecules are extrachromosomal genetic elements - are associated with plasma membrane proteins - may carry genes for such activities as antibiotic resistance, tolerance to toxic materials, the production of toxins, and the synthesis of enzymes |
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Ribosomes |
- function as the sites for protein sythesis - composed of two subunits: protein and a type of RNA called ribosomal RNA |
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Inclusions |
- several kinds of reserve deposits - used to accumulate certain proteins and then used when the environment is deficient |
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Metachromatic Granules |
- large inclusions that take their name from the fact that they sometimes stain red with certian blue dyes - collectively known as vultin - reserve of inorganic phosphate that can be used in the synthesis of ATP - are found in algae, fungi, protozoa, and bacteria |
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Polysaccharide Granules |
- typically consist of glycogen and starch - presence can be demonstrated when iodine is applied |
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Lipid Inclusions |
- appear in various specieds of Mycobacterium, Bacilus, Azotobacter, and other generea - common lipid storage - inclusions revealed when cells with fat soluble dyes |
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Sulfur Granules |
- serve as an energy reserve |
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Carboxysomes |
- inclusions that contain the enzyme ribulose - photosynthetic bacteria use carbon dioxide as their sole source of carbon and require this enzyme for carbon dioxide fixation |
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Gas Vacuoles |
- Hollow cavities found in many aquatic prokaryotes - consists of rows of several individual gas vesicles which are hollow cylindrical covered by protein - maintain buoyancy so that the cell can remain at the depth in the water appropriate for them to receive sufficient amounts of oxygen, light, and nutrients |
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Magnetosomes |
- inclusions of iron oxide surronded by invaginations of plasma membrane - formed by several gram negative bacteria and act like magnets - bacteria use them to move downward until they reach a suitable attachment site - protect the cell against hydrogen peroxide accumulation |
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Endospores |
- gram positive bacteria from these specialized resting cells that are essential when nutrients are depleted - highly durable dehydrated cells with thick walls and additional layers - formed internal to the bacterial cell membrane |
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Sporogenesis or Sporulation |
- the process of endospore formation within a vegetative cell takes several hours |
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First Stage of Sporulation |
- newly replicated bacterial chromosome and small portion of cytoplasm are isolated biy an ingrowth of the plasma membrane - peptidoglycan are laid down between two membranes |
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Final Stage |
- the diameter of the endospore may be the same as the vegetative cell - when the endospores matures, the vegetative cell wall ruptures, killing the cell, and freeing the endospore |
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Germination |
- when endospores return to its vegetative state - triggered by physical or chemical damage of the endospore coat |
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Flagella |
- projections are few and are long in relation to the size of the cell - anchored to the plasma membrane by a basal body and both consist of nine pairs of microtubules of the ring and another two microtubules in the center - rotates when moves |
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Cilia |
- projections that are numerous and short, ` - anchored to the plasma membrane by a basal body and both consist of nine pairs of microtubules of the ring and another two microtubules in the center - wave like movement when moves |
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Microtubules |
- are long hollow tubes made up of a protein called tubulin |
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Glycocalyx |
- in eukaryotes, it covers the plasma membrane - it is a layer of material containing substantial amounts of sticky carbohydrates - some are covalently bonded to proteins and lipids in the plasma membrane - strengths the cell surface, helps attach cells together, and may contribute to cell to cell recognition |
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Plasma Membrane |
- eukaryotic and prokaryotic are very similar - different in types of proteins found in it - eukaryotic contain carbohydrates - eukaryotic also contain sterols |
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Sterols |
- complex lipids not dound in prokarytoic plasma membranes - associated with the ability of the membranes to resist lysis resulting from increased osmotic pressure |
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Endocytosis |
- this occurs when a segment of plasma membrane surronds a particle or large molecule encloses it and brings it into the cell - three types of endocytosis |
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Phagocytosis |
- cellular projections called pseudopods engulf particles and bring them into the cell - used by white blood cells to eliminate foreign substances |
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Pinocytosis |
- the plasma membrane folds inward, bringing extracellular fluid into the cell along with whatever substances are dissolved in the fluid |
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Receptor Mediated Endocytosis |
- substances bind to receptors in the membrane - when binding occurs, the membrane folds inward - receptor mediated endocytosis is one of the way viruses can enter the animal cell |
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Cytoplasma |
- compases the substacnes inside the plasma mebrane and outside the nucleus - substance in which various cell components are found - in eukaryotic cell: has a complex internal structure consists of exceedingly small rods and cylinders |
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Cytoskeleton |
- provides support and shape and assists in transporting substances through the cell |
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Cytoplasmic Streaming |
- the movement of eukaryotic cytoplasm form one part of the cell to another which helps distribute nturients and move the cell over a surface |
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Ribosomes |
- attached to the outer surface of rough endplasmic recticulum and also found in free in cytoplasm - separately made in the nucleolus and the exit and join the cytoplasm |
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Free Ribosomes |
- are not attached to anything - synthesize protein used inside the cell |
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Membrane boudn Ribosomes |
- attach to the nuclear membrane and the ER - ribosomes synthesize proteins destined for insertion in the plasma membrane or for export from the cell |
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Organelles |
- are structures with specific shapes and specialized functions and are characteristic of eukarytic cells |
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Nucleus |
- usually spherical or oval, is frequently the larges structure in the cell and contains alomst all of the cell's information - surrounded by nuclear envelope: a double membrane |
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Nuclear Pores |
- tiny channels in the nucleus - allow the nucleus to communicated with the cytplasm - control the movements of substances between the nucleus and the cytoplasm |
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Nucleoli |
- actually condensed regions of chromosomes where ribosomal RNA is beind sythesized - contains most the cell's DNA, which is combined with several proteins, including basic proteins called histones |
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Chromatin |
- DNA and its associated proteins appar as a threadlike mass when the cell is not reproducing |
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Chromosomes |
- when chromatin is coiled into shorter and thicker rodlike bodies |
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Rough ER |
- continous with the nuclear membrane and usally unfolds into a serios of flattened sacs - the outer surface of the ER is studded with ribosomes - proteins made by the ER enter cisternae within the ER for processing and sorting - factory for synthesis secretory proteins and membrane molecules |
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Smooth ER |
- extends from the rough ER to form a network of membrane tubules - smooth ER doesn't have ribosomes on the outer surface of its membrane - contains unique enzymes that make it functionally more diverse than the rough ER - synthesis phospholipids as does rough ER - synthesis fats and steroids - inactivate or detoxify drugs and other potentially harmful substances |
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Golgi Complex |
- recieves proteins form the rough ER - proteins buds from the membrane surface to form a transport vesicle - the transport vesicle fuses with cistern, releasing proteins in the cistern |
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Transfer Vesicle |
- proteins are modified in the cistern and moved form one cistern to another - enzymes in the cisternae modify the proteins to form glycoproteins, glycolipids, and lipoproteins |
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Secretory Vesicle |
- method in which the process protiens leave in - detach from the cistern and deliver the proteins to the plasma membrane, where they are discharged by exocytosis |
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Lysosomes |
- fomed form the golgi complex - have a single membrane and lack internal structure - contains 40 different kinds of powerful digestive enzymes capable of breaking down various molecules - can digest bacteria that enter the cell |
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Vacuoles |
- a space in or cavity in the cytplasm of a cell that is enclosed by a membrane called tonoplast - derive from the golgi complex - serve as temporary storage organelles for substances such as proteins, sugars, organic acids, and inorganic ions - from during endocytosis to help bring in food - store metabolic waste and poisons that would otherwise harm the cell -take up water for plants |
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Mitochondria |
- consists of a double membrane - have a series of folds called cisternae - center of the mitochondria the is semifluid is the matrix - large surface area for chemical reactions to occur - have their own DNA in order to replicate |
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Chloroplasts |
- algae and green plants contain them - membrane enclosed structure that contains both the pigment chlorophyll and the enzymes required for the lighter gathering phases of photosynthesis |
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Thylakoids |
- flattened membrane sac where the chlorophyll is stored - capable of multiplying by themselves |
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Perixomes |
- similar in strucute to lysosomes but smaller - they form from preexisting peroxisomes - contain one more enzymes that oxidize various organic substances - can oxidize toxic substnaces such as alcohol - decompose H2o2 |
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Centrosome |
- locared near the nucleus - consists of two areas: the pericentriolar area and centrioles |
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Pericentriolar Area |
- region of the cytosol composed of dense netwoerk of small protein fibers - this area is the organizing center for the mitotic spindle |
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Centrioles |
- within thin the pericentriolar material is centriles - are composed of nine cluster of three microtubules arranged in a circular pattern |
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Endosymbiotic Theory |
- the theory explaining the origin of eukaryotic cells form prokaryotes - pioneered by Lynn Margulis |
