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59 terms

Microbiology Chapter 3

Microbiology with Diseases by Taxonomy 3rd Edition
STUDY
PLAY
4 Processes of Life
growth, reproduction, responsiveness, metabolism
Prokaryotes
kind of cell without a nucleus
eukaryote
kind of cell with a nucleus
organelles
specialized structures that act like tiny organs to carry on the functions of the cell
glycocalyx
gelantious, sticky substance that surrounds the outside of a cell
capsule
a glycocalyx of a bacterium composed of organic chemicals firmly attached to the cell surface
slime layer
a loose water-soluble glycocalyx, protect cells from drying out
desciccation
drying out
flagella
long structures that extend beyond the cell surface and propel a cell through the environment
3 parts of a flagella
filament, hook, basal body
peritrichous flagella
flagella that cover the surface of a cell
polar flagella
flagella only at the end of a cell
endoflagella
flagella that spiral tightly around a cell instead of protruding
taxis
movement in response to stimuli
phototaxis
movement in response to a light stimulus
chemotaxis
movement in response to a chemical stimulus
fimbriae
sticky, bristle-like projections on bacteria to allow them to adhere to substance sin the environment or to each other
biofilms
slimy masses of microbes adhering to a substrate by means of fimbriae and glycocalyces
pili
tubules composed of a protein called pilin, longer than fimbriae, shorter than flagella
4 functions of a cell wall
1. provide structure and shape to the cell
2. protect the cell from osmotic forces
3.assists in attaching to other cells
4. resists antimicrobial drugs
cocci
spherical cells that appear singly, in chains, clusters, or cuboidal packets
bacilli
rod-shaped cells that appear singly or in chains
peptidoglycan
complex polysaccaharide that makes up cell walls
glycan portions of peptidoglycan
millions of NAG and NAM molecules that are covalantly linked in chains in which NAG alternates with NAM
peptido portion of peptidoglycan
crossbridges of 4 amino acids that attach chains of NAG and NAM
2 types of bacterial cell walls
Gram-positive and Gram-negative
cytoplasmic membrane
beneath the glcocalyx and the cell wall, also called the cell membrane or plasma membrane
phospholipid bilayer
structure of the cytoplasmic membrane
hydrophilic
attracted to water
hydrophobic
repelled by water
fluid mosaic model
membrane structure with mosaic indicating the membranes proteins arranged in a mosaic and fluid indicating the protein and lipids allowed to flow freely within the membrane
functions of a cytoplasmic membrane
1. controls passage of substances into and out of the cell
2. produces molecules for energy storage
3. harvest light energy in phosynthetic bacteria
selectively permeable
allows some substances to cross the membrane and prevents others from crossing
concentration gradient
difference in concentration of a chemical on the two sides of a membrane
electrical gradient
voltage across the membrane
diffusion
net movement of a chemical from an area of higher concentration to and area of lower concentration
facilitate diffusion
proteins in the cyctoplasmic membrane act as channels or carriers to allow certain molecules to diffuse in or out of the cell
osmosis
diffusion of water across a selectively permeable membrane
isotonic
when solutions on either side of a selectively permeable membrane have the same concentration of solutes
hypertonic
when the concentrations of solutions are unequal, the higher concentration of solutes
hypotonic
when the concentrations of solutions are unequal, the lower concentration of solutes
3 mechanisms of active transport
1. uniport - one chemical at a time
2. antiport - 2 chemicals in opposite directions
3. uniport couple with a symport - - 2 substances in the same direction
group translocation
active process in some bacteria, substance being transported across the membrane is chemically changed during transport
cytoplasm
gelatinous material inside a cell
cytosol
liquid portion of the cytoplasm
nucleoid
region of a prokayote that contains the cell's DNA
inclusions
deposits found withing bacterial cytosol, include lipids, starch, or compounds containing nitrogen, phosphate, or sulfur
Where do many bacteria store carbon and energy
in molecules of glycogen or in a liquid polymer called plyhydoxbutyrate
endospore
a structure produced by some bacteria to defend it from hostile conditions
ribosomes
site of protein synthesis in cells
cytoskeleton
internal network of fibers in a cell, helps to form a cell's basic shape
analagous structures
similar structure without having a common ancestor
hami
fimbriae-like structures that radiate out from archaea, like barbed wire, function to securely attached arahaea to biological and inanimate surfaces
Functions of eukaryotic gluycocalyces
1. helping to anchor animal cells to each other
2. strengthening the cell surface
3. providing some protection against dehydration
4. cell-to-cell recognition and communication
membrane rafts
assemblages of lipids and proteins that remain together, funtctions 1. signaling the inside of a cell 2. protein sorting 3. some kinds of cell movement
endocytosis
active transport that occurs when pseudopodia surround a substance and bring it into a cell
phagocytosis
when a solid is brought into a cell by endocytosis
pinocytosis
when a liquid is brought into a cell by endocytosis
exocytosis
reverse of endocytosis, enables substances to be exported from a cell