Flashcards
301 Recap 3
Cards in this deck (37)
- 1How wide is the cytoplasmic membrane?6-8 nanometers wide
- 2What are some other features of the cytoplasmic membrane?Embedded with proteins, stabilized by hydrogen bonds and hydrophobic interaction. Magnesium and calcium ions help stabilize the membranes by forming ionic bonds with negative charges on the phospholipids. The membrane is somewhat fluid.
- 3What is peptidoglycan?A rigid layer that provides strength to bacterial cell wall. A polysaccharide composed of amino acids, lysine, and N-actyl acids.
- 4Is peptidoglycan cross linked differently in gram-negative and gram-positive bacteria?Yes
- 5Up to what percentage of peptidoglycan do gram-positive cell walls contain?90%
- 6What substances are commonly embedded in the cell wall?Teichoic acids (acidic substance). These can be covalently bound to membrane lipids (lipoteichoic acids)
- 7What percentage of a gram negative bacteria's cell wall is made up of peptidoglycan?~10%
- 8What is most of the gram negative cell wall composed of?Outer membrane (lipopolysaccharide/LPS layer)
- 9What is the toxic component of LPS?Endotoxin
- 10What are some examples of gram negative bacterias?E. coli, salmonella enterica, helicobacter pylori, vibrio cholerae
- 11What are the lipopolysaccharide components?Lipid A (anchors the LPS in the outer membrane and is toxic), Core (genus specific) and Antigen (eg O, species/serotype/strain specific)
- 12What stain can divide bacteria into gram positive and negative?Gram staining
- 13What colour are gram positive organisms stained?Purple
- 14What colour are gram negative organisms stained?Red by safranin
- 15There are more frequent _______ cross linking in Gram positive peptidoglycaninterpeptide
- 16There are multiple layers of peptidoglycan in gram ______ and fewer layers of peptidoglycan in gram ______positives, negatives
- 17What stain is used for detecting Myobacterium species?Ziehl-Nielson acid fast stain
- 18What are the three steps involved in this staining?Stain with carbolfuchsin (red), decolourise with HCl acid, counter stain with methylene blue
- 19What stain do acid fast bacteria retain?The bright red carbolfuchsin stain
- 20What colour do non acid fast bacteria stain?Blue (methylene blue)
- 21What are two examples of bacteria with acid fast cell walls?Myobacterium tuberculosis, myobacterium leprae
- 22What does API stand for? (API strip)Analytical Profile Index
- 23What is an API strip/what does it measure?A strip with a limited number of wells in which biochemical reactions take place. It helps to identify closely related bacteria by measuring metabolism
- 24What sort of things does a bacterial dichotomous tree assess?The types of biochemical reactions bacteria utilises - since each bacteria should have different DNA/be able to synthesize different protein enzymes
- 25Capsules are _________ layerspolysaccharide
- 26Capsules assist in attachment to _________ and protect against _______Surfaces, phagocytosis
- 27What are two examples of encapsulated bacteria?Streptococcus pneumoniae, Haemophilus influenza
- 28What are fimbriae?Filamentous protein structures. They enable organisms to stick to structures or form pellicles (bacterial skin)
- 29What are pili?Filamentous protein structures. They are typically longer than fimbriae. They assis in surface attachment and facilitate genetic exchange between cells (conjugation). Type IV pili are involved in twitching motility
- 30How might pili aid virulence?Help bacteria adhere to surface of host, make it easier to colonise
- 31What are flagella?Structures that assist in swimming. They have different arrangements. Can be helical in shape.
- 32What are some examples of flagellated bacteria?E. coli, salmonella typhimurium, helicobacter pylori, vibrio cholerae
- 33Flagella can be monotrichous, amphitrichous, lophotrichous or peritrichous, meaning what?Single flagellum, flagellum at either end, 3 flagella working in unison, or multiple flagella
- 34What assay is used to detect motility?Soft agar assay
- 35Why do the bacteria migrate through the semi solid medium?They utilise the nutrients underlying the growing colony. This creates a nutrient gradient
- 36Bacteria which ________ chemotactic motility would be able to swim to higher concs of chemicals. This is seen as a halo of bacterial growth surrounding the point of innoculation.possess
- 37How can motility of bacteria in liquid media be directly observed?By observing bacteria in broth under the microscope - aided by the use of time lapse video recording.
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- Flashcards on 301 Recap 3, created by mereana.matairan on 19/03/2015.
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