A distinct, thick gelatinous material that surrounds some microorganisms
Movement of a cell toward or away from certain a chemical in the environment
A phospholipid bilayer embedded with proteins that surrounds the cytoplasm and defines the boundary of the cell
An extraordinary li resistant dominant cell produced by some types of bacteria
A type of structure used for cell movement
bacteria that have a cell wall characterized by a thin layer of Peptidoglycan surrounded by an outer membrane, when Gram stained, the cells are pink
Gram positive bacteria
Bacteria that have a cell wall characterized by a thick layer of peptidoglycan, when Gram stain, these cells are purple
Molecule that makes up the outer layer of the outer membrane of gram-negative bacteria
A macromolecule that provides strength to the cell wall, it is found only in bacteria
the gel-like material that fills the region between the cytoplasmic membrane and the outer membrane of gram-negative bacteria
cell surface structures that allow cells to adhere to certain material, some types are involved in a mechanism of DNA transfer
Extrachromosomal DNA molecule that replicates independently of the chromosome
Structure involved in protein synthesis
Mechanism cells use to transport nutrients and other small molecules across the cytoplasmic membrane
What two fundamental cell types did microscopic study reveal
Prokaryotic and eukaryotic
All the domains of bacteria and archaea are what type of cell?
Cells of all animals, plants, protozoa, fungi and algae are what type of cell?
.easier for them to take in nutrients and excrete waste products
-vulnerable to threats
.increase chance of survival
-cell processes take place within membrane-bound compartments
-Uses visible light and a series of lenses to magnify objects
-easy to use
-can magnify images 1000 X
-magnifies images 100, 000X
-fine details of cell structures
What is the most common type of light microscope?
What does a brightfield microscope do?
Evenly illuminates a field of view and generates a bright background
Call the modern light microscope
Series of lenses house in a tube immediately above the object being viewed
Ocular lens (eyepiece)
Close to the eye
What's your lenses are used in combination?
Objective and ocular lens
Most compound microscopes have a selection of objective lenses that are powers of?
4x, 10x, 40x, and 100x
Positioned between the light source and the specimen, does not magnify but focuses the light on the specimen.
-Determines how much detail can be seen in the observe specimen
-measure of the ability to distinguish two objects that are very close together
The resolving power of a microscope depends on?
-Quality of lens
-type of lens
-wavelength of the light
At 0.2 micrometers you can see the morphology of ____________ but you cannot distinguish the size of__________.
Resolution up to 10 nm
In order to obtain maximum resolution when using certain high power objective such as the 100x lens ___________ must be used to displace ________________.
-Immersion and oil
-displace are between lens and specimen
Bending of light rays that occurs when light passes from glass to air
How do we prevent refraction in using high power objectives
Oil immersion of the lens
Light microscopes include?
differential interference contrast
fluorescent scanning laser
Brightfield (light microscope)
-Illuminates an even field of view
-generatesa bright background
Dark field (light microscope)
-latest directed towards specimen at an angle
-unstained cells easier to see
-organism stand out as bright objects against dark background
Phase contrast (light microscope)
-increases contrast by amplifying differences in refractive index
-dense material appears darker than normal
Differential interference contrast (light microscope)
-two light beams pass through specimen and recombined
-specimen appears three-dimensional
Fluorescence (light microscope)
-projects ultraviolet light causing fluorescent molecules to emit longer wave length light
-observes cells stained or tagged with fluorescent dye
Scanning laser (light microscope)
-mirror skin laser beam across successive regions and planes of specimen from that information a computer constructs an image
-obtains three-dimensional image of structure that has been stained with fluorescent dye
-detailed sectional views of intact cells
Super resolution (light microscope)
-complex elimination mechanisms and merge data construct image
-higher resolving power than conventional fluorescence microscope
Electron microscopes include?
Transmission (electron microscope)
-Transmits a beam of electrons through specimen
-complicated specimen preparation required
Scanning (electron microscope)
-Beam of electrons scans back and forth over surface of specimen
-used to observe surface details
-produces three-dimensional effect
Atomic Force(Scanning probe microscope)
-pro moves in response to events latest force between it in the sample
-no special sample preparation required
-produces three-dimensional effect
What cannot be used to observe living cells because it kills them?
-easiest way to microscopically examining specimen
-observe living microorganisms
-consists of drop of liquid specimen and coverslip
Only single dye is used to stain specimen
Basic dyes include
- methylene blue
Procedure that colors the background
What type of dyes are used in negative staining?
multi stop procedure used to stain cells and distinguish one group of microorganisms from another
Two most frequently used differential staining techniques?
- Gram stain
- acid-fast stain
-Used to separate bacteria into two groups
-reflects the difference in structure of cell walls
-used to detect organisms that do not easily take up stains
Used to stain specific cell structures
-stands out as a clear area surrounding cell
Stains a type of dormant cell that does not readily take up stains, produced by bacillus and clostridium species
Staining agent that adheres to and coats then flagella
Fluorescent dyes and tags
Absorb ultraviolet light, then emit light of longer wavelength
Some Vines you compounds found in all cells, others buying two compounds specific only to certain types of cells
Antibodies to which a fluorescent molecule has been attached are used to tag specific molecules
95% alcohol, removes dye-iodine complex from gram-negative but not gram-positive bacteria.
Applied to give different color to now colorless gram-negative bacteria, red safranin commonly used
Gram staining is more reliable?
Less than 24 hours old
Use the tag specific cell components with fluorescent dye attached to an antibody
What two general shapes are most common bacteria?
What is the difference between Bacillus and bacillus?
A rod so short that it might be mistaken for a coccus is called?
Rod-shaped bacteria that is not bacillus?
Type of cell with a short curved rod
Cell with a curved Long rod enough to form spirals
Long spiral shape cell with a flexible cell wall and a unique mechanism of motility
Bacteria that characteristically vary in their shape
Greatest diversity of cell shapes is found in?
Low nutrient aquatic environments
Summit aquatic bacteria have _______ giving them a star like appearance?
Cells found in low nutrient aquatic environments have a large surface area that helps them to?
Archaeal cells that have been found in salt ponds have a _________ appearance?
Square, tile like
Process where one cell divides into two
Cells often stick to each other following division, forming _______ _______?
Cocci that typically occur in pairs
An important clue in the identification of neisseria gonorrhea is its characteristic?
Cells like streptococcus form?
Most prokaryotes divide by?
The cell envelope of the prokaryotic cell consist of?
-capsule (if present)
Cell envelope of a prokaryotic cell?
Surface layers of a prokaryotic cell
Enclosed within the envelope of the prokaryotic cell is?
Fix substance filled with nutrients ribosomes and enzymes fluid portion of which is called cytosol
Joe lake region in cytoplasm where the cell's chromosome is found
Nucleoid is ____ enclosed by a membrane in a prokaryotic cell.
Filamentous appendages (prokaryote)
Composed of protein subunits that form a helical chain
Provide the most common mechanism of motility
-Different types have different function
-common type fembriae
-allow cells to eat here to surfaces
-certain types used for twitching / gliding mobility
Sex pili involved in? (prokaryote)
Distinct in gelatinous
allows bacteria to adhere to specific surfaces
allows some organisms to avoid body's defense systems causing disease
Slime layer (prokaryote)
-Diffuse / irregular
-allows bacteria to adhere to specific surfaces
What provides rigidity to the cell wall of a prokaryote that stops it from lysing?
Gram positive (prokaryote)
Thick layer of peptidoglycan that contains teicholic acids and lipoteicholic acids.
Thin layer of peptidoglycan surrounded by an outer membrane (outer layer of membrane is lipopolysaccharide).
Cytoplasmic membrane (prokaryote)
-Phospholipid bilayer embedded with proteins
-separates from external environment
-transmits information about external environment to inside cell
Carries genetic information of the cell
-Carries the genetic information required by a cell
-single circular double stranded DNA molecule
-found in the nucleoid
irregularly-shaped region within the cell of a prokaryote that contains all or most of the genetic material. Not surrounded by a nuclear membrane.
Generally carries only genetic information that may be advantageous to a cell in certain situations
Type of dormant cell that is extraordinary only resistant to heat, desiccation, ultraviolet light, and toxic chemicals.
Protein framework involved in cell division and control of cell shape.
Gas vesicles (prokaryote)
Small, rigid structures that provide buoyancy to a cell
Accumulations of high - molecular - weight polymers, synthesized from a nutrient available in relative excess
-Involved in protein synthesis
-two subunits (30S& 50S join to form the 70S ribosome)