Chap 3&4 Micro Flashcards

Terms Definitions
developed classification system for scientific nomenclature (taxonomy) based on the Latin language: Genus and Species
the first part; the general term
the second part; the specific term
There is a 3rd designation term?
"strain" indicates slight difference between species members or documents specific isolation information.. Exam. E. Coli K12 or E. Coli 0157:H7
Taxonomy Rules
1. Genus name first; Capitalize first letter and spell out completely
2. Species name second; all small letters
3. Underline or italicize both words
4. Strain designation (optional) goes last; may include numbers and/or letters
Compound Light Microscopy
uses 2 sets of lens (ocular and objective) and visible light to visualize specimens
Total magnification
product of ocular and objective magnification
Resolution (resolving power) of microscope
ability of the lenses to distinguish fine detail
Refractive index
is the light-bending ability of a substance; light might bend in air so much that it misses the small high-magnification lens
What is immersion oil used for?
It is used to keep light from bending because it has the same refractive index as glass so light can pass through the specimen and two sets of lenses without being "deflected"
Simple stain
used for almost sny type of cell; uses one dye to color the entire cell
Special stain
more involved process to selectively color special parts of cells (nucleus, flagella, spores, etc..)
Differential stain
uses multiple dyes that react differently with different types of cells
Gram stain
very important stain in microbiology developed by Dr. Gram
Eukaryotic Cells
have nucleus and membrane- bound organelles; more complex cells
Prokaryotic Cells
No nucleus or membrane-bound organelles; simpler cells like bacteria
Microorganisms that lack peptidoglycan in cell wall; found in more atypical environments
all other microorganisms that contain peptidoglycan in cell wall; most common microorganism
Size of Prokaryotic cells?
very small relative to eukaryotic cells
There are 3 different shapes of prokaryotic cells?
Spherical, rodlike, spiral
coccus, cocci
bacillus, bacilli
Vibrio, spirillum, spirochete
most bacteria are consider these. they have 1 shape there whole life span
some bacteria are considered this; they have several different shapes during one life span exp. Corynebacteria sp
There are different types of arrangments of prokaryotic cells
Strepto, staphylo, and diplo
chains of cells ex. streptococcus, streptobacillus
grape-like clusters of cells ex. staphylococcus
paired cells ex. diplococcus
The external structure of bacteria consists of?
Glycocalyx, flagella, and pilus
sticky substance that surrounds some microorganisms cells
What are the two types of glycocalyx?
Capsule and slime layer
thick, smooth layer that helps with protection from the environment ex. streptococcus pneumoniae
Slime layer
diffuse, irregular layer which help attachment to allow colonization ex. streptococcus mutans (causes tooth decay) and Alcaligens viscolactis (causes ropy milk)
long filamentous appendages that rotate
What are the four different types of flagella?
Monotricgous, amphi, lopho, and peri
one flagella
two flagella one on each end
tuft a bunch on one end
have many around the whole cell
What is the function of flagella?
Chemotaxis which is the motility via random darting and tumbling in response to chemical "signal"
Pilus (pili) and fimbriae
short, hairlike, appendages
What is the function of pilus?
to allow microorganisms to attach to each other for reproduction
What is the funtion of fimbriae?
to allow microorganisms to attach for colonization
The cell wall of a prokaryotic cell consists of?
semirigid structure that maintains shape of the cell; very porous; composed of unique substance called peptidoglycan (PG); some bacteria have gram (+) or gram (-); some lack cell walls and some have a thick cell wall with a high lipid content
What is a cell walls function?
It is for defense against pathogens
natural enzyme found in tears, saliva, and mucus that disrupts PG layer for MO
Typical Gram (+) cell wall composition
Has peptidoglycan and teichoic acid molecules; It has 20 layers of PG
Typical Gram (-) cell wall composition
Consists of just a few PG, porin, lipoproteins, periplasmic space, lipopolysaccharides
What does the plasma (cell) membrane consist of?
thin layer of phospholipids and proteins that surrounds cytoplasm in a bilayer arrangement; has sterols; it is not rigid.
What are sterols?
a stabilizing agent
There are two types of transport through the cell membrane?
Active and passive
Active transport
movement of material against the concentration gradient ( from low to high concentration) requires ATP and special carrier proteins
Passive transport
movement of material with the concentration gradient (from high to low concentration) requires no input of energy
Different types of passive transport
simple diffusion, facilitated diffusion, and osmosis
Simple diffusion
moves gas molecules and ions
Facilitated diffusion
some larger compounds (glucose, amino acids) need help of carrier proteins called permeases to enter cell
movement of water through a semipermeable membrane
The internal Structure of bacteria consists of?
Cytoplasm, Nuclear region, ribosomes, inclusions, endospores
internal matrix 80% water
Nuclear region (nucleoid)
contains genetic material (DNA), chromosomes and plasmid
MO have single, long circular molecule of double-stranded DNA; contains genes essential for MO survival
short circular molecules of double-stranded DNS; contains nonessential DNA 'special genes"
site of protein synthesis; composed of RNA and protein' 1000's of ribosomes in bacteria cells but they are smaller then eukaryotic cells thats why antibiotics work on them cause they are smaller than eukaryotic cells
storage for reserve deposits of material
Types of Inclusions?
Metachromatic granules (volutin), polysaccharide granules, magnetosomes, gas vesicles, carboxysomes
Metachromatic granules (volutin)
excess phosphate for ATP, phospholipids synthesis
Polysaccharide granules
excess starch, glycogen for Energy sources; bacteria can also store extra lipid
iron oxide stores to provide orientation for soil and aquatic MO via magnetism
Gas vesicles
help maintain buoyancy for aquatic MO
contain enzymes that allow some bacteria to be photosynthetic
dormant stage formed when unfavorable conditions occur; only some MO (gram+) can do this
spores contain only DNA, RNA, ribosomes, enzymes and a unique chemical called dipicolinic acid; spores are very resistant to heat, cold, radiation, chemicals and dehydration; spores can remain dormant for 1000's of years
Eukaryotic Cells
Larger, have a true nucleus, multiple chromosomes, plasma membrane is more complex and more rigid, cytoplasm contains complex infrastructure, contains numerus intracellular organelles, larger ribosomes, have flagella and have cilia
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