Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
Bacterial morphologies:
What is described as a coccus? |
a cell that is spherical or ball-shaped
*can exist as perfect spheres, oval, bean-shaped or even pointed variants |
|
|
Bacterial morphologies:
What is described as a bacillus? |
*a cell that is cylindrical (longer than wide) like a rod
|
|
|
Bacterial morphologies:
When is a bacteria termed coccobacillus? |
* when a rod is short and plump
|
|
|
Bacterial morphologies:
When is a bacteria termed vibrio? |
* when a rod is gently curved
|
|
|
Bacterial morphologies:
When is a bacteria termed spirillum? |
* when a bacterium has the shape of a curviform or spiral shaped cylinder
* it is a rigid helix, twisted twice or more along its axis (like a corkscrew) |
|
|
Bacterial morphologies:
When is a bacteria termed spirochete? |
* when a bacterium has the shape of a curved spiral shaped cylinder
* more flexible form * resembles a spring * may be longer than spirilla |
|
|
Bacterial arrangement:
What are the main factors influencing the arrangement of a particular cell type? |
* pattern of division
* how the cells remain attached afterward |
|
|
Bacterial arrangement:
Diplococci |
* cocci bacterium as singles, in pairs
|
|
|
Bacterial arrangement:
Tetrads |
* cocci in groups of four
|
|
|
Bacterial arrangement:
Staphylococci |
* cocci in irregular clusters
|
|
|
Bacterial arrangement:
Streptococci |
* chains of a few to hundreds of cells
|
|
|
Bacterial arrangement:
Palisades |
*arrangement is formed when the cells of a chain remain partially attached by a small hinge region at the ends
|
|
|
Bacterial arrangement:
Why are bacilli less varied in arrangement? |
* they divide only in the transverse plane (perpendicular to axis)
|
|
|
Bacterial arrangement:
Sarcina |
* cube of cells (tetrad but in 3D)
|
|
|
Bacterial arrangement:
diplobacillus |
pairs of rods
|
|
|
Bacterial arrangement:
streptobacillus |
chains of rods
|
|
|
Bacterial arrangement:
pallisades |
rods attached with a hinge (two rods placed on top of e/o - be sure not to refer to it as diplobacillus because diplobacillus does not exist)
|
|
|
Bacterial morphology:
Why do cocci have so many different arrangements? |
* different planes of cell division
* division in one plane produces diplococci and streptococci *division in two planes at right angles produces tetrads * division in several planes produces irregular clusters |
|
|
Describe cyanobacteria
|
* blue-green in color
* bacteria with a gram-negative cell wall * can be unicellular or occur in colonial groups * have an extra internal membrane called a thylakoid (which contains photosynthetic pigments, e.g. chlorophyl, and perform photosynthesis) * have includion bodies of gas which allows them to float * found in freshwater and seawater |
|
|
Describe sulfur bacteria
|
* green and purple bacteria
* also photosynthetic * have a thylakoid membrane * different pigment than cyanobacteria -> bacteriachlorophyll * live in an anerobic environment * produce sulfide granules from hydrogen sulfide gas * found in sulfur springs, swamps and freshwater lakes |
|
|
What are some basic characteristics of archeabacteria?
|
* single celled simple organisms
* prokyaryotic in structure and share many bacterial characteristics * evolutionarily more similar to eukaryotes than bacteria * some are extremophiles ( love extreme conditions) * some get their energy from non-traditional molecules (ammonia, metal ions, or hydrogen gas) * represents up to 40% of plankton biomass * no known pathogens * we know little about then because they are a newer domain |
|
|
What are Rickettsias?
|
*obligate (restricted to a particular fcn/mode) parasitic very sm bacteria
* gram negative * live inside eukaryotic cells * transmitted between mammals by fleas, ticks and lice * agent of rocky mountain spotted fever and typhus |
|
|
What is the importance of cell walls in prokaryotes?
|
* provide stability, protection, and protection from swelling and bursting (lysis) or shriveling up
|
|
|
What is the importance of cell membranes in prokaryotes?
|
* semi-permeable
* regulate transport of nutrients into cell * molecules embedded into the membrane allow the cell to sense its surroundings |
|
|
What is it about an endospore that makes it so resistant?
|
* heat resistance is linked to high content of calcium and dipicolinic acid
- cell is dehydrated by calcium dipicolinate, since there is no water, the cell is less vulnerable to the destruction of proteins and DNA * metabolically inactive * thick, impervious cortex and spore coats protect against radiation and chemicals |
