Bacteria Flashcards
Are Archaea pathogenic
No known pathaogens.
Used to think they were extremfiles, but currently are finding them everywhere. Slow to grow
How are bacteria different from Archaea?
Archaea have distinct in there cellular processes and biochemistry. (Uniques membrane phospholipids)
Compare and contract Prokaryotes and Eukaryotes in terms of the following: DNA, Chromosome(s), organelles (membrane bound), Cell wall, Cell division.
DNA: Pro = No, Eu = Yes
Chromosome(s): Pro = Circular, usually one, Euk = linear, many can be diploid or haploid. In humans have 23 pairs
Plasmids: Pro = often, Euk = rare
Organelles: Pro = No, Euk = yes
Cell wall= Pro = Bacteria = peptidoglycan either Gram (+) or (-). Archaea = yes, Euk = no in animals, yes in plants (Cellulose), Fungi yes (Chitin), Protists (Varies)
Cell division: Pro = binary fission, Euk = mitosis, meiosis
What do prokaryotes lack?
Nucleus and other membrane bound organelles
Where is the DNA found in a Bacteria?
In the nucleotide region.
Typically are circular chromosomes.
What is a plasmid?
Small rings of DNA (found in some strains) that help Bacterium live in unique environments (ie antibiotic resistance)
What does it use to stick to surfaces?
A pious
What is unique about plasmids?
They can be exchanged by bacteria that are not the same species.
Why is it important that prokaryotes have unique ribosomes (smaller/different proteins) than Eukaryotes?
Can design drugs to specially attack the prokaryotic ribosomes.
How to prokaryotes divide?
By binary fission.
The chromosome will duplicate, attach to cell membrane, and the cell will split in half
What is peptidoglycan?
It’s a carbohydrate/peptide molecule used for cell walls in bacteria.
What is an endospore?
A resistant/dormant structure of a prokaryote.
What is a pili/fimbriae?
A proteinceous structure for attchment/sex pilus for conjugation
What is flagella
Protein used for motility/swimming
What is a glychocalyx capsule?
Carbohydrate layers of attachment end evasion of the immune cells
What is a biofilm?
Carbohydrates and glycoproteins secretions that allow microbes to live as a community on. Surface. Very hard to get ride of
How are bacteria classified?
Historically: based off of shape, response to stains (microscope obs), biochemical characterization, more recent using serological (recognize specific antibodies) and compare DNA sequence. (Use the genes to rRNA)
What shape is a coccus?
Circle
What shape is a bacillus?
Rod
What shape is a vibrio?
Banana
What shape is a sprillum?
Spiral
What is a diplo?
A pair of cells.
What does Straphlo mean?
A cluster of cells
What does strepto mean?
A chain of cells
What were prokaryotes initially grouped with due to the presence of a cell wall found outside the membrane?
Plants
What does peptidoglycan broken down into?
Peptide= protein Gly= carbohydrate.
Chemically describe a peptidoglycan
Peptidoglycan is made up of a polysacchride ( carbohydrate = glycan) with a backbone of covalently-bound polypeptides (proteins = peptides)
What stains Gram + and what does it mean?
Crystal violet stains gram positive. It means it has a thick layer of peptidoglycan outside the membrane.
What is an example of gram +
Streptococcus
Staphylococcus
Bacillus
What purpose does peptidoglycan serve?
It forms a strong mesh-like structure that protects the cell from osmotic pressure and provides the cell with shape and support.
How does the drug Penicillin work?
It interferes with peptidoglycan synthesis and weakens it. The cell easily burst due to osmotic pressures.
What do you stain with Safranin red?
Gram -
Why can’t you use Crystal violet to stain gram - bacteria?
Crystal violet doesn’t stick to gram (-) so need to you safranin red to stain. It’s double membrane system keeps Crystal violet out.
Describe a gram (-) wall/membrane.
Has a thin layer of peptidoglycan sandwiched between the cell membrane and a second ‘outer membrane’
Give an example of a gram (-)
Neisseria
Escherichia coli
What is unique about the outermost layer of a gram (-) membrane.
Has LPS (Lipopolysaccharide) and endotoxin (unique to bacteria)
What is the space called where peptidoglycan is on a gram (-)
The periplasm
What is the benefit to Gram (-) bacteria about the periplasm?
The periplasm acts as a storage compartment for things like enzymes that can degrade toxins and antibiotics to help in its survival.
What is LPS and how is it effective in resistance to the immune cell?
Lipopolysccharide is an endotoxin (can cause severe immune rxn). This outter membrane also helps prevent many types of antibiotics from entering the cell.
What is an acid-fast cell wall?
It’s a staining tech. (Fusia colour)for bacteria that contain mycolic acid (a waxy substance) and resists most stains
What are bacteria that have the mycolic acid referred to as?
Mycobacteria
Do Gram (-) or (+) produce endospores?
Gram positive