Biochemistry - Cellular Flashcards
Acetylation of HISTONE
Acetylation of the Histone makes DNA ACTIVE!
- Relaxes the coiling, allows for transcription
Methylation of DNA and Histone
Methylation makes DNA Mute regardless of whether its a histone or CpG Island
AAs needed for Purine Synthesis
GAG
Glycine
Aspartate
Glutamate
AAs need to pyrimidine synthesis
Aspartate
Adenosine Deaminase Deficiency (ADA)
Purine Salvage Deficiency
SCIDS
- results in reduced lymphocyte production because of dec. DNA synthesis
Mechanism:
- No ADA means that Adenine cannot be converted back into IMP–> results in excess ATP and dATP –> negative feedback–> prevents DNA synthesis –> dec. lymphocyte count
Lesch-Nylan Syndrome
Purine Salvage Deficiency Defect in HGPRT (converts guanine to GMP, and Hypoxanthine to IMP) Accumulation of uric acid H: hyperuricemia G: Gout P: Pissed off R: retarded T: DysTonia
DNA replication direction and enzymes
DNA pol3= synthesize the strands in eukaryotes
-Direction of DNApol3= 5’-3’ direction for leading and lagging
-Direction of exonuclease activity= 3’-5’
Topoisomerase= Double and single stranded breaks to add/remove supercoils
DNA ligase: synthesized a phosphodiester bond to join the lagging strand fragments or to seal breaks due to DNA editing
Missense mutation example
Sickle Cell
- Glutamic Acid replaced by valine
Frameshift mutation
Duchenne muscular dystrophy
- results in dysfunctional/truncated protein
Nucleotide Excision Repair
Disease: Xeroderma Pigmentosum (can’t repair pyrimidine dimers because of lack of NER)
NER: used to repair helix-distorting lesion- resects oligonucleotides and replaces with DNA pol 3 and seals with ligase
- occurs in the G1 phase of the cell cycle
Base Excision Repair
Base specific glycoslyase cleaves the base out and makes it apurinic/apyrimidinic
AP-endonuclease at the 5’ end, lyase at the 3’ end
DNA pol B and ligase fill the gap
- USED FOR SPONTAENOUS/TOXIC DEAMINATION
DNA mismatch Repair
Newly synthesized strand is recognized and editing for mismatched nucleotides- the mismatch nucleotides are removed and the gap is filled-
- Occurs during the G2 PHASE of the cell
- Defective in HNPCC
Non-homologous End joining (DNA repair)
Double stranded DNA repair
Brings two ends of DNA together, DNA may be lost because may not be homologous
ATAXIA TELANGIECTASIA
FACONI ANEMIA
Start Codon
AUG (EUK)
- methionine
fMET (PROK)
- stimulates NT chemotaxis
Stop Codon
UGA (U GO AWAY)
UAA (U ARE AWAY)
UAG (U ARE GONE)
RNA Polymerase I, II, III
RNA pol 1: rRNA
RNA pol 2: mRNA
RNA pol 3: tRNA
P- Bodies
Cytoplasmic bodies where the mRNA is stored, also responsible for quality control
contain: microRNA, decapping enzymes, exonucleases
Antibodies to snRNP (anti-smith)
associated with SLE
- snRNP: associated with splicing introns
- lariat intermediate
Antibodies to U1-RNP
mctd
mixed ct tissue disorder
Permanent Cell
Neurons, skeletal muscle, cardiac muscle, and RBC
G0 permanently
stem cell reproduction
Stable (quiescent cell)
When stimulated go from G0- >G1
hepatocytes, lymphocytes
Labile
Constantly reproducing (highly mitotic) Colon, hair, bone marrow, germ cells
Collagen Type I
Bone, tendons, dentin, fascia, CORNEA, late wound repair
Dec prodcution in Type 1 osteogenesis imperfecta
Collagen Type 2
Cartilage, inc hyline, vitreous body, nucleous pulposus
Collagen Type 3
Skin, BV, fetus, uterus, and granulation tissue (early wound healing)
Ehlers-Danlos syndrome
Collagen Type 4
BM, basal lamina, lens
Goodpastures syndrome, Alports
Osteogenesis Imperfecta
Genetic disorder that results in brittle bones
- dec production of Type 1 collagen
SX: multiple fractures with little force, BLUE SCLERA, minimal dentin, Hearing loss, curved bones
Menkes Diseases
X linked recessive disorder that results in loss of protein (ATP7A) necessary to absorb and transport copper –> results in loss of lsysl oxidase activity (requires copper) –> loss of collagen crosslinking
sx: brittle kinky hair, growth retardation, and hypotonia
Marfan Syndrome
Defect in fibrillin- a glycoprotein that forms a sheath around the elastin
