Term
What type of ribosomes are in eukaryotes? |
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Definition
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Term
T/F Most bacteria possess peptidoglycan |
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Definition
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Term
T/F Prokaryotic mRNA is usually spliced before it can be translated. |
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Definition
false! prokaryotic mRNA does not need processsing |
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Term
What are the four steps of the gram stain? |
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Definition
step 1= crystal violet for 1 min, rinse step 2= Gram's Iodine for 1 min, rinse step 3= decolorizer (alcohol or acetone) for 30-60 seconds and rinse step 4= safranin red |
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Term
What color are gram positive and gram negative bacteria on a gram stain? |
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Definition
gram + are blue, gram - are red |
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Term
What color do acid fast positive bacilli stain? |
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Definition
stain red (while acid fase - bacteria stain blue) |
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Term
What are the steps for acid fast staining? |
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Definition
primary stain (carbolfuchsin red) for 5 minutes then rinse, decolorizer (HCl, alcohol), and then counterstain with methylene blue or malachite green for 1-3 minutes |
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Term
What are capsules made out of? |
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Definition
high MW polysaccharide or peptide like N-acetylmuramic acid (NAM) and N-Acetylglucosamine (NAG) |
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Term
How do capsules help bacteria evade the immune system? |
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Definition
protect against complement and are anti-phagocytic. Also capsules facilitate adherence of bacteria to surfaces. |
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Term
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Definition
most range in size .25-1 um wide and 1-3 um long |
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Term
In gram staining, idion acts as a ____ and complexes with crystal violet in the cytoplasm of bacteria. |
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Definition
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Term
What factors can affect the results of gram staining? |
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Definition
old cultures of g+ may appear G variable. Antibiotic treated cells can give false gram reactions. Also cell walls with LCFA are difficult to decolorize with acetone/alcohol and appear as poorly stained gram + |
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Term
T/F All bacteria have cell walls. |
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Definition
false, ex. mycoplasma doesn't |
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Term
What determines if a bacteria is acid fast or not? |
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Definition
presence of LCFA (mycolic acids) in bacterial cell walls make them AF |
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Term
What are the two methods for acid fast staining? |
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Definition
hot (Ziehl-Neelsen) or cold (Kinyoun) methods. Cold is more often used today |
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Term
What do acid fast + bacteria look like on acid fast stain? |
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Definition
AF+ are red, AF- are blue or green |
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Term
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Definition
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Term
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Definition
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Term
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Definition
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Term
spindle shaped bacteria = |
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Definition
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Term
"seagull" or comma-shaped bacteria= |
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Definition
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Term
Corkscrew shaped bacteria= |
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Definition
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Term
What are the common cell arrangements of bacteria? |
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Definition
single, pairs, tetrads, clusters, chains |
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Term
production of bacterial capsule depends on... |
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Definition
environmental and growth conditions |
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Term
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Definition
a less organized form of a capsule that is a polysaccharide film over the surface of bacterial cells |
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Term
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Definition
slime layer that appears as a matrix of fibers, even less organized than the glycocalyx |
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Term
What is the outer membrane of a bacteria composed of? |
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Definition
bilayer of LPS and phospholipids |
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Term
Which bacteria have outer membranes? why? |
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Definition
gram negative, they function as an initial barrier to the environment |
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Term
What are LPS made out of? |
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Definition
repeating sugar residues attached to core sugars which are then attached to a disaccharide-diphosphate with fatty acid moieties. Repeating sugar residues are useful for bacterial typing (Oantigen), impart a hydrophilic nature ot the bacterial cell |
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Term
What is the bioactive portion of LPS? |
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Definition
lipid A= disaccharide diphosphate with fatty acid chains |
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Term
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Definition
proteins scattered throughout the LPS which control the passage of small water soluble nutrients and other molecules like antibiotics, and specialized transport proteins for larger hydrophobic compounds |
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Term
What is the purpose of the lipoproteins scattered throughout bacterial LPS? |
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Definition
anchor the outermembrane to the next deeper layer in the cell envelop, the cell wall |
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Term
What's another name for the peptidoglycan layer? |
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Definition
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Term
What is the function of the peptidoglycan layer? |
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Definition
found in both gram + and gram - bacteria; gives bacteria cell shape and strength to resist osmotic changes in teh environment. Protects against mechanical damage and provides some barrier effect against larger substances |
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Term
What is the peptidoglycan layer/murein layer composed of? |
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Definition
disaccharide-pentapeptide subunits which are N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Crosslinked via peptide bridges between NAM to form sheets of peptidoglycan. Sheets of peptidoglycan are then crosslinked. |
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Term
What's the different b/t the peptidoglycan layer of G+ and G-? |
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Definition
in G+, the peptidoglycan layers have teichoic or mycolic acids (acid-fast) to fortify cell walls |
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Term
What is the periplasmic space? |
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Definition
in G- bacteria, bounded by the internal surface of the outermembrane and the external surface of the cytoplasmic membrane. Contains thin layer of peptidoglycan. |
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Term
T/F The cytoplasmic membrane of bacteria generates ATP. |
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Definition
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Term
T/F The cell membrane mediates chromosomal seperation during bacterial replication. |
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Definition
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Term
What are pili composed of? |
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Definition
subunits of protein called pilin, which are found in a pool together with assembly machinery in the periplasmic space |
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Term
What are the two types of pili? |
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Definition
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Term
What is the function of common pili? |
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Definition
fimbriae or type IV pili mediate adhesion to host eukaryotic cells with specialized tipstructures to recognize specific carbs |
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Term
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Definition
serve as conduits for passage of DNA from one bacterial cell to another ina process known as conjugation |
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Term
Rapid extension and retraction of type ___ ili results in a form of locomotion known as _____. |
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Definition
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Term
T/F Pili and flagella are antigenic. |
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Definition
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Term
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Definition
long helical filaments composed of a rotary motor (a basal body complex with assoc proteins), a flexible universal joine (the hook), and a rigid propeller (a filament composed of a single protein-flagellin) |
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Term
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Definition
the antigen for flagellin (highly antigenic) |
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Term
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Definition
the antigen for flagellin (highly antigenic) |
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Term
What powers the flagella motor? |
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Definition
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Term
What is the purpose of inclusion bodies in bacteria? |
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Definition
store reserve granules (glycogen and polyphophate are the MC) |
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Term
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Definition
highly coiled bacterial chromosome intermixed with RNA, polyamines, and support proteins |
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Term
What are two different types of plasmids? |
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Definition
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Term
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Definition
a resting phase of bacteria when living conditions get tough, NOT A REPRODUCTIVE STRUCTURE |
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Term
Endospores are resistent to... |
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Definition
desiccation, light, heat, many disinfectants, radation, etc. |
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Term
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Definition
autoclaving, high heat for a period of time and right concentrations of certain disinfectants |
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Term
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Definition
invaginations of the cytoplasmic membrane, involved in septation |
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Term
How do bacteria bring in nutrients? |
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Definition
passive and carrier mediated diffusion, active transport, group translocation |
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Term
What substances do bacteria bring in to the cell via passive and carrier mediated diffusion? |
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Definition
water, O2, carbon dioxide, and simple sugars enter by virtue of a concentration gradient |
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Term
What nutrients do bacteria bring in via active transport? |
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Definition
energy dependent pumps in the cell envelope bring certain sugars, most amino acids, organic acids, and many inorganic ions into the cell |
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Term
What do bacteria bring into the cell via group translocation? |
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Definition
similar to active transport but the nutrient being transported gets chemicallymodified before being brought into the cell; many sugars, purines, pyrimidines, and fatty acids are brought in this way |
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Term
T/F If possible, bacteria would rather use preformed compounds like amino acids, vitamines, nucleotide phosphates, etc. rather than synthesize them de novo. |
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Definition
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Term
What are fastidious growers? |
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Definition
bacteria that have lost the ability to synthesize substances essential to growth and will only thrive in their hosts |
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Term
What two general mechanisms do bacteria use to generate ATP? |
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Definition
substrate level phosphorylation and oxidative phosphorylation |
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Term
How do bacteria cause dental caries? |
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Definition
oral S. mutans takes in sucrose and rapidly ferments it into acids which then eat into tooth enamel |
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Term
What does it mean for a bacteria to be microaerophilic? |
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Definition
can only handle small amounts of oxygen otherwise it will be toxic |
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Term
Trimethoprim inhibits what bacterial enzyme? |
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Definition
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Term
How does trimethoprim specifically inhibit bacterial dihydrofolate reductase and spare human DHFR? |
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Definition
human enzyme needs 50,000 x bacterial dose for inhibition |
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Term
Peptidoglycan is synthesized from monomeric units composed of ____ coupled to either NAG or NAMA. |
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Definition
uridine diphosphate (UDP) |
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Term
UDP-NAG and UDP-NAMA are polymerized then crosslinked to each other by means of a __ reaction. |
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Definition
transpeptidation reaction |
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Term
What's a really complicated name for the glycolytic or anaerobic pathway? |
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Definition
EMP (Emden-Myerhof-Parnas) |
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Term
What are the end products of fermentative metabolism? |
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Definition
acids, alcohols, carbon dioxide, and hydrogen |
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Term
What are different ways to distinguish between different bacteria? |
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Definition
staining, selective media, differential media, sequence 16S ribosomal RNA |
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Term
What are some examples of bacterial aerobes? |
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Definition
mycobacterium tuberculosis, pseudomonas aeruginosa, and bacillus anthracis |
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Term
What are some examples of anaerobe bacteria? |
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Definition
clostridium botulinum, bacteriodes melaningenicus |
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Term
What are some examples of bacterial facultative aerobes? |
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Definition
E coli, shigella dysenteriae, s. aureus |
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Term
What is an example of a bacterial microaerophilic? |
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Definition
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Term
Who created the first antibiotic and what was it? |
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Definition
prontosil rubrum (prodrug of sulphanilamide) by Gerhard Domagk |
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