Purines - adenine, guanine - PURe As Gold, have 2 rings

Pyrimidines - cytosine, thymine, uracil - CUT the PY

**deamination of cytosine makes uracil

GAG -Glycine, Aspartate, Glutamine

**only aspartate and carbamoyl phosphate for pyrimidines

purines are made from IMP precursor, pyrimidines are made from orotate precursor with PRPP added later

**Orotic Aciduria = failure to convert orotic acid to UMP in pyrimidine synthesis.  findings = high orotic acid in urine, megaloblastic anemia (not solved with B12 or folic acid), failure to thrive, no hyperammonemia (as in ornithine transcarbamoylase deficiency = urea cycle)

treat with oral uridine

Adenosine deaminase deficiency: leads to an excess of (d)ATP backing up the salvage pathway by inhibition of ribonucleotide reductase --> prevents DNA synthesis and thus low lymphocyte count = SCID (happens to kids)  

Lesch Nyan:  X-linked, absence of HGRPT (He's Got Purine Recovery Trouble) - converts hypoxanthine to IMP and guanine to GMP.  findings: retardation, self mutilation, aggression, hyperuricemia, gout, choreoathetosis

Silent = same AA, Missense = changed AA but with similar chemical structure (conservative), Nonsense = change in STOP codon (STOP the Nonsense!)

order of damage: nonsense>Missense>Silent

Frame Shift = change results in a misreading of all downstream nucleotides, typically makes a truncated or nonfunctional protein.

fluoroquinolines act by inhibiting DNA gyrase, which creates original nick in DNA for replication

nucleotide excision repair - mutated in xeroderma pigmentosum, dry skin, melanoma, cancers

mismatch repair - mutated in hereditary nonpolyposis colorectal cancer

Think APE: A site for aminoacyl tRNA, P site for elongating polypeptide, E site for holding tRNA before it exits

aminoglycosides inhibit formation of the initiation complex,chloramphenicol / macrolides / clindamycin all inhibit 50S of prokaryotic synthesis.

total energy cost in 4 phospho bonds (ATP --> AMP,

2 x GTP --> GDP).