biochemistry and cell stuff Flashcards
Colourless colonies (non-lactose fermenting) on macConkey agar
Mona Lisa and Ella Fitzgerald too (2) are clearly Pros - salmonella, shigella, proteus, pseudomonas
Lactose-fermenting gram negatives: (PINK ones) on macConkey
EECK – enterobacter, E.Coli, Citrobacter, Klebsiella
Endotoxin vs exotoxin
which is gram neg, which is gram pos
endotoxin gram Neg, as stuck onto outer cell membrane
Exotoxin can be gram pos or neg
cell wall is made of what in bacteria
peptidoglycan
why do gram positives retain dye and gram negatives don’t
gram negatives have an outer surface membrane (in addition to the inner membrane) sandwiching the (thinner) peptidoglycan wall between the membranes. Whereas the gram positives have the cell wall on the outside, which absorbs the dye
Endotoxin vs exotoxin
which is lipid, which is polypeptide
endotoxin is lipid A - is stuck to outer cell lipid bilayer membrane
exotoxin is polypeptide
Endotoxin vs exotoxin
which is heat stable. which is not.
endotoxins are heat stable
exotoxins are often inactivated by heating (e.g. you heat up bottles before bottling to kill botulinum toxin
what is the toxin from E. Coli and meningococcus - endo or exotoxin
endotoxin - gram negative sepsis from E. Coli
and Waterhouse Friedrichson syndrome from meningococcal disease
what are the toxins for shigella, anthrax and botulism - endo or exo?
exotoxins - inactivated by heating
mode of action of metronidazole?
diffuses into anaerobe
becomes a short-lived free radical
which damages bacterial DNA
which ABx are Peptidyltransferase Inhibitors
macrolides
Pep rally, cheerleader group called the Macros?
most common non-epithelial vaginal cancer is
rhabdomyosarcoma (?)
what is Pendrin and where is it found?
Pendrin was initially identified as a chloride-iodide exchanger
subsequent studies showing that it also accepts formate and bicarbonate as substrates
in thyroid and inner ear
trimethoprim is a dihydrofolate reductase inhibitor, but what effect does that actually have?
DHFR is crucial for synthesis of nucleotides and DNA
where is the SRY gene
on the short (p) arm of the Y chromosome
60% of the volume of ejaculate comes from the
seminal vesicles
what are gap junctions
Gap junctions are a type of cell junction in which adjacent cells are connected through protein channels and directly connect the cytoplasm of two cells
half life of LH
20 minutes
half life of FSH
3-4 hours
half life of hCG
24 hours
what is the Arias-Stella reaction?
a benign change in the endometrium due to progesterone/the presence of chorionic tissue, e.g. due to pregnancy, GTD or hormone administration. Historically, it was misdiagnosed as endometrial ca. as it can look cytologically like malignancy.
effect of granulosa cell tumour on the endometrium
proliferative (tumour secretes oestrogen)
how does Lancefield grouping of streptococci work?
based on the carbohydrate composition of bacterial antigens found on their cell walls
precursor for nitrous oxide
L-arginine
