review questions for exam 3 pt 1.

3 components of glycerophospholipids are

glycerol backbone, fatty acid chain at sn1/sn2 position, phospho-head group

what are the various phospho-head groups

choline, ethanolamine, serine, glycerol

cardiolipin is a

special glycerophospholipid which has shared glycerol as head group

glycerophospholipid synthesis by remodel pathway

head groups of PC, PS, PE can be interconverted into each other

glycerophospholipid synthesis by de novo pathway

the fatty acid chains can be switched between different glycerophospholipids by acyltransferase

3 components of sphingolipids

sphingosine backbone, fatty acid chain, head group

which sphingolipid has H as the head group

ceramide

which sphingolipid has phosphocholine as the head group

sphingomyelin

which sphingolipid has sugars as the head group

glycosphingolipids

what is gaucher disease an example of

a lysosome storage disease

what is deficient in gaucher disease

glucosidase

what is glucosidase

a lysosomal hydrolase that hydrolyzes glucosylceramide in ceramide

what effect does gaucher disease have on the body

it causes accumulation of glucosylceramide in lysosomes leading to gaucher disease due to deficiency in glucosidase

what are gangliosides

they are glycosphingolipids with a polysaccharide chain which contains sialic acid

what is the function of gangliosides

they polysaccharide chain of gangliosides can serve as receptor for bacterial proteins

what an example of polysaccharide chains of gangliosides serving as a receptor

where cholera toxin binds to ganglioside GM1

how are sphinoglipids metabolized

primarily degraded by lysosomes by lysosomal hydrolases

what does deficiency in lysosomal hydrolase activity result in

accumulation of precursor for the hydrolase in lysosomes causing lysosome storage diseases

what is the effect of folate deficiency on nucleotide biosynthesis

it decreases availability of carbon donors for IMP de novo synthesis OR inhibits folate recycling thus resulting in inhibition of conversion of dUMP to TMP

folate deficiency inhibits

de novo synthesis of both purine and pyrimidine nucleotides

what is the critical role of ribonucleotide reductase (RNR) in deoxyribonucleotide biosynthesis

RNR can reduce all ribonucleoside diphosphate (NDP) to deoxyribonucleoside diphosphate (dNDP)

what enzyme is the bridge linking RNA and DNA synthesis

ribonucleotide reductase (RNR)

what are risk factors for gout development

diet, tumor, renal disease, drug treatment, etc.

what drug is used for treatment of gout

allopurinol

how does allopurinol help treat gout

it inhibits xanthine oxidase causing decreased uric acid thus decreasing MSU crystal formation

what is the precursor for synthesis of all nucleotides both in de novo and salvage pathways

PRPP

what does overexpression of PRPP synthetase cause

it results in overproduction of purine nucleotides leading to hyperuricemia

what is gout arthritis mainly due to

the deposition of monosodium urate (MSU) crystals in the joints which induce inflammation and pain

what happens if monosodium urate (MSU) crystals is in the joints

it induces inflammation and pain

what is uric acid in salt form called

monosodium urate (MSU)

what are the 3 endogenous anti-coagulation systems

anti-thrombin, TFPI, protein C system

what is anti-thrombin activated by

heparin

what causes prolonged APTT

assess intrinsic pathway

what causes prolonged PT

assess extrinsic pathway

what causes prolonged TCT

assess final common pathway

what is the pharmacology of an antiplatelet drug

it blocks ADP receptor signaling, enhances cAMP signal by PDE inhibition, inhibit TXA2 production/action by aspirin, GPIIb-IIIa antagonists block platelet aggregation

what is the function of lipoprotein lipase (LPL)

convert chylomicron to its remnant; convert VLDL to its remnant = IDL

what is the remnant of VLDL

IDL

what is the function HTGL

converts VLDL remnant (known as IDL) into LDL

what are different types of lipoprotein

chylomicron, VLDL, HDL, IDL, LDL

what are the sources of chylomicron

in the intestine

what are sources of VLDL and HDL

in the liver

what are sources for IDL and LDL

derived from VLDL by lipase

which lipoprotein has the highest triglycerides

chylomicron

which lipoprotein has the highest cholesterol

LDL

what is structural role of apolipoproteins

needed for de novo synthesis

which lipoproteins are de novo synthesized

VLDL, HDL, chylomicron

which lipoproteins are dervied from VLDL

IDL and LDL

which apolipoprotein is used for chylomicron

Apo B48

which apolipoprotein is used for VLDL, IDL, and LDL

Apo B100

which apolipoprotein is used for HDL

Apo A

which lipoprotein receptor is regulated by intracellular cholesterol

LDLR

which lipoprotein receptor is not regulated by intracellular cholesterol

scavenger receptor

what is foam cell formation due to

the continuous uptake of oxidized LDL by scanvenger receptor

types of acyltransferase

LCAT and ACAT

what does LCAT do

in HDL it converts free cholesterol to cholesterol

what does ACAT do

inside the cells it converts free cholesterol to cholesterol and is then stored in lipid droplets

what are the structural components of a nucleotide

consist of base, pentose sugar, and phosphate at carbon 5

without a phosphate a nucleotide is considered a

nucleoside

which pathway preferred to synthesize purine nucleotides

salvage pathway due to recycling performed bases, and less energy cost

difference between de novo and salvage pathway for nucleotide biosynthesis

de novo builds nucleotide from beginning (from small precursor), salvage recycles components that already exist (from free nitrogenous base)

what 2 enzymes in thymine formation can be subject to drug targets

thymidylate synthase and dihydrofolate reductase

thymidylate synthase inhibitor

fluorocytosine convert to FdUMP → inhibits thymidylate synthase → TMP production

dihydrofolate reductase inhibitor

blocks folate recycling → prevents TMP production

what does blockade of thymine formation do

it inhibits DNA synthesis WITHOUT affecting ribonucleotide biosynthesis

what is unique biosynthesis pathway for TMP production

thymine formation

why can thymine formation pathway be a target for cancer treatment

due to cancer cells needing large amount of thymidine nucleotides in order to replicate their DNA rapidly

inhibiting thymidylate synthase causes

prevention of adequate TMP production thus interfereing with DNA synthesis

what drug inhibits dihydrofolate reductase (DHFR)

methotrexate

what drug inhibits thymidylate synthase

5-fluorouracil by FdUMP

what disease is due to deficiency of HGPRT

Lesch-Nyhan syndrome (X-linked recessive disorder)

what symptoms occur due to Lesch-Nyhan syndrome

hyperuricemia and gout arthritis

what does HGPRT deficiency cause

hypoxanthine not recycled to salvage pathway → accumulation of hypoxanthine → increase uric acid produced

upregulation of de novo purine synthesis → accumulation of hypoxanthine → increase uric acid produced