Phase A/ Biochem Flashcards
Why do mycoplasma and chlamydia stain poorly?
no peptidoglycan
What mediates endotoxin activity of LPS?
Lipid A
which bacteria form spores?
gram + only
polyenes with broad antifungal activity
bind to membrane sterols (ergosterol) and causes membrane disruption by acting as a pore
amphotericin B
nystatin
Use (amphotericin B): invasive fungal infections -> Candida, Aspergillus, Cryptococcus,
prevent ergosterol synthesis by inhibition of 14-alpha-demethylase
"azoles" voriconazole itraconazole fluconazole terconazole
systemic imidazole antifungal that inhibits CYP3A4
ketoconazole
Many drug interactions
at high dose, inhibits adrenal steroid biosynthesis
antifungal that disrupts mitotic spindles and is used for hair, nails and skin infections
Griseofulvin
inhibits squalene epoxidase, causing decreased ergosterol and increased squalene (toxic to fungus)
terbinafine (Lamisil)*
buenafine
naftifine
tolnaftate (Tinactin)
inhibits synthesis of beta(1,3)-D-glucan
caspofungin*
micafungin
anidulafungin
converted to 5-FU in fungal cells and phosphorylated to 5-FdUMP to inhibit thymidylate synthase; also disrupts protein synthesis when incorporated in to RNA
flucytosine
antiviral agent resistance mechanism
mutation in viral thymidine kinase
viral nucleoside analogs require activation by viral thymidine kinase.
sources of acid in the blood
sulfuric acid -> dietary sulfate, s-containing amino acids carbonic acid -> CO2 from TCA lactic acid -> anaerobic glycolysis pyruvic acid -> glycolysis citric acid -> TCA & diet
what cells have high levels of carbonic anhydrase?
RBCs
charge of DNA
charge of histone
negative
positive (due to lysine & arginine)
histone not in nucleosome core
H1
2A, 2B, H3, H4 all in nucleosome core
highly condensed and transcriptionally inactive
heterochromatin
transcriptionally active
euchromatin
methylation here represses transcription
CpG islands
location of ETC
inner mitochondrial membrane
The cristae increase the SA of the IMM
purines
adenine
guanine
pyrimadines
cytosine
uracil
thymine
template for mRNA synthesis
sense strand
smooth ER in skeletal muscle
sarcoplasmic reticulum
site of lipid synthesis & is more abundant in cells which synthesize hormones
smooth ER
adds carbohydrates & lipids to proteins from RER
Golgi apparatus
protein structure characterized by large number of H-bonds
beta pleated sheet
synthesized from thiamine
chelates Mg2+ which then binds tightly to enzyme
Fxn: decarboxylation of alpha keto acids and utilization of pentose phosphates in Pentose Phosphate Pathway
TPP
thiamine pyrophosphate
coenzyme that bind to lysines in carboxylases
biotin
from panthothenate
forms thioesters with acyl groups
CoASH
from vit B6
reactive aldehyde that forms covalent intermediate with amino groups of Schiff bases
pyridoxal phosphate (PLP)
coenzyme from niacin & ATP
NAD+
bind irreversibly to active site on enzyme and inhibit it
suicide inhibitors
concentration of substrate to reach 1/2 Vmax
Km
regulatory protein of the Ca2+ ATPase of the ER
calmodulin
the Ca2+ ATPase is activated to pump calcium from the cytosol into the lumen of the ER when a rise in intracellular concentration causes calcium binding to calmodulin, followed by its dissociation from the transporter
cAMP-regulated chloride channel
CFTR
integral membrane receptors which recognize lysosomal enzymes in the Golgi
mannose 6-phosphate receptors
B3
niacin
NAD+
B2
riboflavin
FAD, FMN
B1
thiamine
TPP
B5
pantothenic acid
CoA
B6
pyridoxine
PLP
B7
biotin
B9
folate
B12
cobalamin
vit C
ascorbic acid
vitamin used to treat measles and AML (M3)
antioxidant
essential for normal differentiation of epithelial cells
visual pigments
vitamin A = retinol
Deficiency causes night blindness, dry, scaly skin, alopecia, keratomalacia, immune suppression.
Excess: arthralgia, scaly skin, alopecia, cerebral edema, pseudotumor cerebri, osteoporosis, hepatic abnormalities; TERATOGEN
cofactor for: pyruvate dehydrogenase (glycolysis -> TCA) alpha-ketoglutarate dehydrogenase (TCA) transketolase (HMP shunt) branched-chain ketoacid dehydrogenase
thiamine (B1)
Dx deficiency: increased RBC transketolase activity after giving B1
damage to medial dorsal nuclei of thalamus/mamillary bodies
confusion, ataxia, confabulation, personality change
permanent memory loss
vitamin B1 def
Wernicke-Korsakoff syndrome
causes beriberi
thiamine deficiency
dry beriberi: polyneuritis, symmetrical muscle wasting
wet beriberi: high output cardiac failure, edema
cofactor for redox reactions (ex: succinate dehydrogenase reaction in TCA)
cheilosis, corneal vascularization
riboflavin (B2)
FAD & FMN
“flav-o-flav has 2 gold teeth, smooth lips and drinks beri soda”
Diarrhea, Dementia, Dermatitis (3 D’s)
Glossitis
niacin (B3)
pellagra
cofactor for acyl transfers (CoA) & fatty acid synthase
pantothenate (B5)
“pento”thenate
Cofactor for carboxylase reactions
Biotin
Coenzyme synthesized from niacin and ATP
NAD
