Question | Answer |
Bacillus | rod shaped bacteria |
Coccus | spherical shaped bacteria |
Vibrio | curved/comma shaped bacteria |
Spirochete | helical shaped bacteria |
Pleomorphic | bacteria that can be more than one shape |
Diplo | linking of cells in 2s |
Tetra | linking of cells in 4s |
Staphylo | celles clustered like grapes |
Strepto | cells in chains like a neclace |
Explain the functions of the cell (or cytoplasmic) membrane | defines inside/outside of a cell--contains protein trasporters that pumb desirable chemicals into the cell using the cells energy sources--keeps undesirable chemicals out. |
Describe the structure of peptidoglycan | like a fishnet--long polymers of glycan are cross-linked by shorter pieces of peptides |
Name 2 biologically active items that destroy the bacterial cell wall | lysozyme and penicellin |
What structural component is unique to gram-negative bacteria? | outer membrane |
What major chemical is unique to gram-negative bacteria? | Lipopolysaccharide (LPS) |
How does peptidoglycan vary between gram-positive and gram-negative organisms? | gram-positive-many layers of peptidoglycan--gram-negative-one or a few layers of peptidoglycan |
what layer of gram-positive & gram-negative bacteria is the same? What layer is completely different? | same-cytoplasmic membrane--different-outer membrane because only gram-negative bacteria have one |
List the 4 steps of the gram stain and the function of each | 1-stain with crystal violet-- 2-fix crystal violet with gram's iodine so it aggregates--3-was aggregates from porous gram-neg bacteria with acetone-alcohol--4-counterstain with safranin so gram-neg cells are readily visible |
What is the chemical makeup of the structure that coats a bacterium? | polysaccharide |
What is the function of the structure of polysaccharide? | coating makes bacterium slippery so that wbc's can't capture and destroy it. |
Describe the cell cytoplasm | contains all the degradative and synthetic machinery to allow cell growth and make copies of itself. includes the cell's DNA, RNA, and proteins |
Distinguish the bacterial chromosomes from plasmids | chromosomes--contain thousands of genes including those required for replication and gene expression--plasmids--small pieces of DNA usually encoding fewer than 50 genes--specialized--code for resistance to a specific ABT |
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-(1 each of 30S and 50S)--eukaryotic ribosomes are 80S-(1 each of 40S and 60S) |
Why do some bacteria harbor inclusions or granules? | granules provide energy source available for special energy need |
What are granules, or inclusions, composed of? | polysaccharides or polyphosphates that contain much chemical energy |
What are the most environmentally stable of all know life forms? What genera produce them? | spores--genera producing spores include the gram-pos. bacteria Clostridium and Baacillus |
What is a streak plate? What task does it accomplish? | streak plate is a dish containing nutrient agar--used to grow individual cells into colonies to obtain pure isolates |
What is a colony? | a colony results when a single cell is streaked onto a plate in a well-separated manner so the progeny can grow into a clump until they are sufficiently numerous to be seen by the naked eye. |
Why do we obtain isolated colonies? | because they yeild pure cultures in which every cell is identical, so the organism can be recognized |
List 4 methods used in the identification of bacteria | 1--biochemical tests-2--immunological tests-3--genetic tests-4--direct DNA/RNA testing for organism-specific sequences |
List possible bacterial appendages and their functions | flagella-aid in motility--pili-gene transfer--fimbriae (holdfasts)-attach to given site |
List the 3 major components of bacterial flagella | filament, hook, and basil body |
How do bacteria produce a propelling force? | by rotating their helical filaments against their watery environment |
Name 2 possible benefits of motility to a pathogenic organism | spread and to escape capture by cells of the immune system |
what benefit does chemotaxis confer upon a bacterium? | allows organisms to swim toward or away from chemicals |