Nucleotides Flashcards
organic molecules consisting of nucleoside and a phosphate
nucleotides
these are made of nitrogenous base, and a five carbon carbohydrates
nucleosides
nucleotides and nucleotides serve as ____ units of the nucleic acid polymers DNA and RNA
monomeric
nucleotides are obtained in the
diet
nucleotides are synthesized from common nutrient by the
liver
the linkage between sugar and base
n-B-glycosidic bonds
the linkage between phosphate and sugar
phosphoester bond
has an absence of the hydroxyl group on the 2’ carbon
deoxyribose
an organic compound containing 4 N atoms, 2 carbon rings, and is made of a pyrimidine ring fused to an imidazole ring
purine
an organic compound containing 2 nitrogen atoms and only contains 1 carbon ring
pyrimidine
function of purines and pyrimidines
serves as a form of energy for cells, essential for production of DNA and RNA, proteins, starch, regulations of enzymes, and cell signaling
requirements for purine de novo synthesis
glutamine, glycine, aspartate, tetrahydrofolate (vit b9), ATP, CO2
this a pathway in which biological products is produced from intermediates in the degradative pathway of its own or a similar substance
salvage pathway
a specific salvage pathway where nucleotides are synthesized from intermediates in their degradative pathway
nucleotide salvage pathway
nucleotide salvage pathways are used to recover bases and nucleosides that are formed during degradation of
DNA and RNA
why is nucleotide salvage pathways important?
in some organs, some tissues cannot undergo de novo synthesis, the salvage products can then be converted back into nucleotides
the end product of purine catabolism in humans is
uric acid
uric acid is primarily formed in the ____ and excreted by the _____ into the urine
liver; kidney
an elevation of uric acid level in blood
hyperuricemia
serum uric acid concentration exceeding 7 mg/dl in males and 6 mg/dl in females
hyperuricemia
condition where increased excretion of uric acid in urine
uricosuria
due to the accumulation of urate crystals in the synovial fluid resulting in inflammation leading to acute arthritis
gout
this is when uric acid is deposited in cooler areas of the body that cause _____ , seen in the distal joints of the foot
tophi
increased excretion of uric acid may cause deposition of uric acid crystals in the urinary tract leading to
calculi or stone formation
about 10% of cases of primary gout are
idiopathic
causes of primry gout
glutamine PRPP amidotransferase, active PRPP synthase, deficiency of enzymes of salvage pathway, glucose-6-phoshatase deficiency
increased production of uric acid may be due to the enhanced turnover rate of nucleic acid as seen in rapidly growing malignant tissues, increased tissue breakdown after treatment, increased tissue damage due to trauma and raised rate of catabolism as in starvation
secondary hyperuricemia
reduced excretion rate in secondary hyperuricemia as seen in
renal failure, treatment with thiazide diuretics lactic acidosis and keto-acidosis
____ leads to accumulation of lactic acid
alcohol
an x-linked inherited disorder of purine metabolism, characterized by HGRPTase deficiency, rate of salvage pathway is decreased resulting in accumulation of PRPP
lesch-nyha syndrome
requirements for pyrimidine de novo synthesis
glutamine, aspartate tetrahydrofolate (vit b9), ATP, CO2
pyrimidines are ultimately catabolized to CO2, H2O, and urea, this mainly occurs in the
liver
this pyrimidine deficiency results from the absence of OPRTase and OMP decarobxylase
orotic aciduria
this is characterized by excessive excretion of orotic acid in urine because of the inability to convert orotic acid to UMP causing megaloblastic anemia, and may be associated with mental and physical developmental delays
orotic aciduria
treatment of orotic aciduria is done through administration of
UMP or uridine triacetate
