Clin relevance cell meme transport Flashcards
Zaise lec 7/30
Integral proteins
span entire lipid bilayer, weave in and out, interact w internal y external environment.
Polytopic transmembrane proteins
a type of integral protein: include transporters, ion channels, receptors
Peripheral proteins
loosely bound through electrostatic interactions w lipids or proteins
Lipid-anchored proteins
tethered to membranes via covalent attachment to a lipid
Nieman pic disease
deficiency in an enzyme called Acid Sphingomyelinase (A-SMase) This leads to accumulation of of SM in lysosomes of liver, spleen, CNS and bone marrow. thereby enlargement of liver y spleen. causes neurological damage
Acid Sphingomyelinase
a lysosomal enzyme that breaks down sphingomyelin into ceramide and phosphorylcholine
Hallmark of Niemann pick disease
Cherry red spot in eye-on macula; enlarged liver or spleen
Phosphatidylserine (PS) as marker for apoptosis
In healthy cells PS is only on innerleaflet; during programed apoptosis its transfered to outer; serves as tag/label
Distinguish apoptosis
Annexin and propodium iodide. Annexin tags PS on outerleaflet, PI binds to DNA after getting in from broken down membrane
ABO blood system
RBCs have ‘antigens’ called A.B or O, plasma could have Anti-A, Anti-B or both; incompatible transfusion could lead to hemolysis, renal failure y shock
Rh factor
RBCs express protein antigens called Rh factor. inherited in autosomal dominant, Rh+ express D antigen, Rh- dont.
Erythroblastosis fetalis
disease in which there is incompatibility betwn blood of mother and fetus, when mom is Rh- and baby Rh+ mom produces ABs which can cross fetus.
3 factors that influence membrane fluidity
Temp, lipid composition, cholesterol
cholesterol: on membrane
can both inc or dec membrane fluidity. if membrane too rigid Cholesterol intercalates into membrane and inc fluidity. If membrane fluid cholesterol stabilizes fluidity by fitting in gaps.
Spur cell anemia
a type of hemolytic anemia associated w advanced stages of alcohol liver cirrhosis that impairs cholesterol metabolism resulting in excess free cholesterol. Elevated levels of cholesterol bound to RBC membrane dec fluidity and flexibility. RBCs membrane break as pass thru capillaries. death in months. only potential cure is liver transplant
Spur cell anemia histology
RBCs with spike like projections.
Cystinuria
autosomal rec. defect in transporter that uptakes dimeric AA cystine y other dibasic AAs ie: arginine, lysine, ornithine. results in formation of cystine crystals or stones in kidney. Pt’s present w renal cholic (abd pain that comes in waves and is linked to kidney stones.
Hartnup disease
autosomal rec, defect in transporter for non-polar or neutral AA (alanine, threonine, leucine, tryptophan) primarily in kidneys y intestines. clinical findings: cerebellar ataxia, nystagmus, photodermatitis and photosensitivity
HARTNUP mnemonic
AR = autosomal rec T = tryptophan NU = neutral uptake is defective P = pellagra like dermatitis
cardiac glycosides
such as ouabain y digoxin act as cardiotonic (contraction-inducing) drugs, inhibit Na/K ATPase in cardiac myosites, leading to inc. in intracellular Na+, this impairs activity of 2ndary transporter ‘sodium calcium exchanger”(NCX) this leads to inc levels of Ca in sarco-endoplasmic reticulum. ; are extremely potent -fine line use
cystic fibrosis
auto rec disorder, mutation in CFTR which is a chloride ion channel that mediates active transport of Cl- from inside of cells to outside using ATP, defective causes buildup of Cl-, compensated by inc in Na which makes NaCl and water follows Na leaving surface mucous layer thereby thicker mucous layer susceptible to bacterial infections
