Cell Bio Flashcards
HIstone NOT in nucleorsome core
H1
condensed chromatin
heterochromatin
transcriptionally active chromatin
euchromatin (non condensed)
inactivates DNA
histone methylation
Purines
adenosine, guanine (PURe As Gold)
Pyrimidines
Cytosine, Thyamine, Uracil (CUT the PY)
amino acids needed for purine sythesis
Glycine, aspartate, Glutamine (GAG)
drug disrupting purine base production pathway
6-MP
drugs disrupting pyramidine base production
hydroxyurea, 5-FU, Methotrexate
megaloblastic anemia - unresponsive to B12/Folic acid, failure to thrive, no hyperammonenia
orotic aciduria (treat with oral uridine)
excess ATP and dATP imbalances nucleotide via feedback inhibition of ribonucleotide reductase. Leads to
SCID
defective purine salvage owing to absence of HGPRT - leads to
Lesch-Nylan
retardation, self-multition, aggression, hyeruricemia, gout
Lesch-Nylan
mutation causing same amino acid to be produced
silent
mutation causing different amino acid to be produced
missense
mutation causing early stop codon to be produced
nonsense
mutation causing misreading of all downstream nucleotides downstream results in truncated, nonfunctioning protein
frameshift
unwinds DNA template at replication fork
helicase
relives supercoils
topoisomerases
joins Okazaki fragments
DNA ligase
adds DNA to 3’ end of chromosomes ro avoid loss ot genetic material with duplication
telomerase
xeroderma pigmentosum has loss of
nucleotide excision repair
HNPCC has loss of
mismatch repair
ataxia telangiectaisa has loss of
nonhomologous end joining
direction of DNA synthesis
5’ to 3’
mRNA reading direction
3’ to 5’
energy source for DNA nucleotide bonds
triphosphate on the 5’ end of the incoming nucleotide
start codon
AUG
stop codons
UGA, UAA, UAG
promotor region on gene usually results in
dramatic loss of transcription