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Terms in this set (72)
"prenucleus": DNA is not contained within a membrane and is usually a singular circularly arranged chromosome. DNA is not associated with histones; they lack membrane enclosed organelles; their cell walls almost always contain the complex polysaccharide peptidoglycan. They usually divide by binary fission (cell copies DNA, and the cell splits into two cells).
"true nucleus". DNA is found in the cell's nucleus, and DNA is also found in multiple chromosomes. DNA is associated with histones and nonhistones. Contain membrane-enclosed organelles (mitochondria, endoplasmic reticulum, lysosomes, etc). Cell walls, when present, are simple. Cell division involves mitosis.
Basic shapes of bacteria (prokaryotic)
1. coccus: usually round, plural cocci
2. bacillus: rod-shaped, plural bacilli
cocci that remain in pairs after dividing
cocci that divide and remain attached in chainlike patterns
cocci that divide in two planes and remain in groups of four
cocci that divide in three planes and remain attached in cubelike groups of eight
cocci that divide in multiple planes and form grapelike clusters or broad sheets
bacilli that appear in pairs after division
bacilli that appear in chains after division
bacilli that are oval shaped and appear to be the same shape as cocci
spiral bacteria that look like curved rods
spiral bacteria that have a helical shape, like a corkscrew, and fairly rigid bodies
spiral bacteria that are helical and flexible
bacteria that maintain a single shape
bacteria that are able to have many shapes
a viscous, gelatinous polymer that surrounds prokaryotic cells. If it is organized and firmly attached to the cell wall, it is called a capsule. If the substance is unorganized and only loosely attached to the cell wall, it is described as a slime layer.
extracellular polymeric substance (EPS)
a glycocalyx that helps cells in a biofilm attach to their target environment and to each other
bacteria that lack flagella (without projections)
flagella that are distributed over the entire cell
flagella that are at one or both poles or ends of the cell
a single flagellum at one pole of the cell
a tuft of flagella coming from one pole
flagella at both poles of the cell
three parts of the flagellum
1. filament: the long outer most region that is constant in diameter and contains the globular protein flagellin arranged in several chains that intertwine and form a helix around a hollow core.
2. hook: slightly wider part that is attached to the filament
3. basal body: anchors the flagellum to the cell wall and plasma membrane
the movement of a bacterium toward or away from a particular stimulus
the movement of bacterium away from chemical stimulus
the movement of bacterium away from light
a flagellar protein useful for distinguishing among serovars, or variations within a species or gram-negative bacteria.
axial filaments (endoflagella)
bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell
hairlike appendages that are shorter, straighter and thinner than flagella and are used for transfer of DNA and attachment more than motility. They are involved in forming biofilms and other aggregations on surfaces, and help bacteria adhere to epithelial surfaces in the body.
usually longer than fimbriae and number only one or two per cell. Are involved in motility and DNA transfer.
grappling hook method of motility: the pilus extends by the addition of subunits of pilin, makes contact with surface or another cell and then retracts (powerstroke) as the pilin subunits are disassembled. Results in short, jerky movements
the smooth gliding movement of myxobacteria. Provides a means for microbes to travel in environments with a low water content, such as biofilms or soil
the transfer of DNA from one cell to another. The pili are then called conjugation (sex) pili
complex, semirigid structure responsible for the shape of the cell. Major function is to prevent bacterial cells from rupturing when the water pressure inside the cell is greater than outside the cell.
also called murein, consists of a repeating disaccharide attached by polypeptides to form a lattice that surrounds and protects the entire cell.
Gram positive bacteria: many layers of peptidoglycan
Gram negative bacteria: thin layer of peptidoglycan
destruction of a cell caused by the rupture of the plasma membrane and the loss of cytoplasm
channels in the outer membrane of gram-negative cells that permit the passage of molecules into the cell.
a wall-less cell
a gram-negative cell that has been lysed-it has a damaged outer cell wall, but not as damaged as a protoplast
the rupture that occurs when a protoplast or spheroplast are placed in water or dilute sugar/salt solutions
plasma (cytoplasmic) membrane
the inner membrane which is a thin structure lying inside the cell wall and enclosing the cytoplasm
fluid mosaic model
the dynamic arrangement of phospholipids and proteins in the wall of a cell
simple diffusion, facilitated diffusion and osmosis. Does not use energy (ATP) of the cell.
active transport: uses energy from ATP
group translocation: a form of active transport that chemically alters the substance being brought into the cell so that it can not pass back out of the cell again, even though the substance may be in low concentrations outside the cell.
in a prokaryotic cell, the substance of the cell inside the plasma membrane
contains a single long, continuous and frequently circularly arranged thread of double-stranded DNA called the bacterial chromosome
molecules that are extrachromosomal genetic elements. They replicated separately from the chromosomal DNA of the cell. May carry genes for such activities as antibiotic resistance, tolerance to toxic metals, the production of toxins and the synthesis of enzymes.
site of protein synthesis in both eukaryotic and prokaryotic cells.
reserve deposits of certain nutrients in the cytoplasm of prokaryotic cells.
large inclusions that are collectively known as volutin. This is a reserve of inorganic phosphate that can be used in the synthesis of ATP
inclusions that consist of glycogen and starch, and their presence can be demonstrated when iodine is applied to the cells-the glycogen molecules appear reddish brown and the starch granules appear blue.
found in many aquatic prokaryotes, they are hollow cavaties that maintain buoyancy so that the cells can remain at the depth of water appropriate for them to receive sufficient amounts of oxygen, light and nutrients
inclusions of iron oxide that act like magnets
specialized "resting" cells that are highly durable dehydrated cells with thick walls and additional layers. They are formed internal to the bacterial cell membrane.
sporulation or sporogenesis
the process of endospore formation within a vegetative cell. Begins when a key nutrient, such as carbon, becomes scarce or unavailable.
the process by which an endospore returns to its vegetative state.
the layer of sticky carbohydrates that covers the plasma membrane of eukaryotic cells; it strengthens the cell surface, helps attach cells together and may contribute to cell-cell recognition
the process in which eukaryotic cells use a segment of their plasma membrane to surround a particle or large molecule, enclose it, and bring it into the cell
a type of endocytosis that uses cellular projections called pseudopods to engulf particles and bring them into the cell. It is used by white blood cells to destroy bacteria and foreign substances
a type of endocytosis that uses the plasma membrane to fold inward, bringing extracellular fluid into the cell, along with whatever other substances are in the fluid. This is how viruses can enter animal cells
in eukaryotic cells, it is formed of microfilaments, intermediate filaments and microtubules, and forms a complex internal structure. It provides support and shape and assists in transporting substances through the cell.
the movement of eukaryotic cytoplasm from one part of the cell to another, helping to distribute nutrients and moving the cell over a surface
structures with specific shapes and specialized functions, including the nucleus, endoplasmic reticulum, Golgi complex, lysosomes, vacuoles, mitochondria, chloroplasts, peroxisomes and centrosomes and only found in eukaryotic cells
helps transport the proteins synthesized by the ribosomes
formed from Golgi complexes and look like membrane-enclosed spheres. They contain as many as 40 digestive enzymes capable of breaking down various molecules.
a space or cavity in the cytoplasm of the cell that is enclosed by a membrane called a tonoplast. Used to store materials or metabolic wastes of the cell. Those in plants fill with water and provide rigidity to leaves and stems
powerhouse of the cell, they produce ATP
contained in algae and green plants. Contains chlorophyll and the enzymes which enable photosynthesis. Chlorophyll is contained in flattened sacs called thylakoids, and stacks of thylakoids are called grana
contain enzymes that oxidize various organic substances. Contain catalase, which helps decompose H2O2, which is produced by cell during oxidation reactions.
located near nucleus, consists of the pericentriolar area and centrioles. These areas are the organizing center for the mitotic spindle, which plays a critical role in cell division.
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