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33 Cards in this Set

  • Front
  • Back
rod shaped
curved or comma shaped
more than one shape
linking of cells in twos
linking in fours
clustered like grapes
in chains like a necklace
Explains the functions of the cell (or cytoplasmic) membrane
The cytoplasmic membrane defines the inside and outside of a cell. It contains transporters that pump desirable chemicals into cell using the cell's energy resources. It also prevents undesirable chemicals from entering the organism.
Describe the structure of peptidoglycan.
The structure of peptidoglycan is like a fishnet because the long polymers of glycan are cross-linked by shorter pieces of peptides.
Name two biologically active items that destroy the bact cell wall
lysozyme and PCN
What struct component is unique to gram neg bact?
An outer membrane is unique to gram neg bacteria.
What major chemical is unique to an outer membrane?
lipopolysaccharide is chemically unique to the outer membrane of gram neg bacteria
How does peptidoglycan vary between gram pos and gram neg organisms?
Gram pos orgs have many layers of peptidoglycan. Gram neg orgs have only one or a few layers of peptidoglycan
What layer of gram pos and gram neg bacteria is the same? What layer is completely different?
The cytoplasmic membrane is the same. The outer membrane is different because only gram neg bact have one.
List four steps of the gram stain and the funct of each.
1. stain with primary stain, crystal violet
2. fix the crystal violet with Gram's iodine so that is aggregates
3. Wash the aggregates from the porous gram neg bact with acetone-alcohol
4. Counterstain with safranin so the gram neg cells are readily visible.
What is the chemical makeup of the structure that coats a bacterium?
Polysaccharide is the coating's chemical makeup
What is the function of the polysaccharide?
The coating makes the bacterium slippery so that WBCs cannot capture and destroy it.
Describe the cell cytoplasm
The cytoplasmic compartment contains all the degradative and synthetic machinery to allow the cell to grow and make new copies of itself. It includes the cell's DNA, RNA, and proteins.
Distinguish the bacterial chromosome from plasmids.
The bact chromosome (like all chromosomes) contains thousands of genes, including those required for replication and gene expression. Some bacteria also contain plasmids, small pieces of DNA usually encoding fewer than fifty genes. Plasmids are often specialized, like those that code for resistance to a specific antibiotic.
What are the sizes of a complete bacterial ribosome and its two major components in S units? Compare them to eukaryotic ribosomes.
Prokaryotic ribosomes are 70S (one each of 30S and 50S subunits; eukaryotic ribosomes are 80S (one each of 40S and 60S)
Why do some bacteria harbor inclusions or granules?
The granules provide an energy source available for when cells have a special energy need.
What are granules, or inclusions, composed of?
Granules, or inclusions, are composed of polysaccharides or polyphosphates that contain much chemical energy.
What are the most environmentally stable of all known life forms? What genera produce from?
The most stable life forms are spores. Genera producing spores include the gram positive bacteria Clostridium and Bacillus.
What is a streak plate? What task does it accomplish?
The streak plate is a dish containing nutrient agar. It is used to grow individual cells into colonies to obtain pure isolates.
What is a colony? Why do we obtain isolated colonies?
A colony results when a single cell is streaked onto a plate in a well-separated manner so that the progeny can grow into a clump until they are sufficiently numerous to be seen by the naked eye. We obtain isolated colonies because they yield pure cultures in which every cell is identical, so the organism can be recognized.
List four methods used in the identification of bacteria
1. biochemical tests
2. immunological tests
3. genetic tests
4. direct DNA or RNA testing for org-specific sequences
List possible bact appendages and their functs
flagella- aid in motility
pili- gene transfer
fimbriae- attach to a given site
List the three major components of bacterial flagella
The three major components of bacterial flagella are the filament, hook, and basal body.
How do bacteria produce a propelling force?
Bacteria produce a propelling force by rotating their helical filaments against their watery environment.
Name two possible benefits of motility to a pathogenic organism.
Motility allows pathogens to spread and to escape capture by cells of the immune system.
What benefit does chemotaxis confer upon a bacterium?
Chemotaxis allows org to swim toward or away from chemicals.