shosh: cell bio

• Tightly packed
• Present during mitosis
• Associated with methylated DNA

• Usely packed
• Transcribed
• Associated with acetylated histones

• Precursor of purine synthesis
• Elevated in OTC deficiency (defective urea cycle) and orotic aciduria (inability to convert orotic acid to dUMP, presents with megaloblastic anemia)

• Defective purine salvage pathway results in excess ATP, which inhibits ribonucleotide reductase (needed for purine synthesis)
• SCIDs

• HGPRT deficiency results in defective purine salvage pathway
• Excess uric acid production --> gout
• Retardation, self-mutilation, choreoathetosis

• Defective nucleotide excision repair (thymidine dimers)
• Skin cancer

Defective mismatch repair

Checks that the right AA is attached to the tRNA

GTP

• mRNA--5-->3
• Proteins--N-->C

Inhibits G1-->S transition

Codes for p21, which inhibits the cyclin-CDK complex that allows the cell to progress from G1 to S

Site of secretory protein synthesis and N glycosylation

• Site of steroid hormone synthesis and drug detox
• Hepatocytes and adrenocortical cells have a lot of SERs

• Directs proteins to the cell membrane, lysosomes, or extracellular environment, via COP I, COP II, or clathrin coats
• Modification of N glycosylation
• Mannose-6-P addition to lysosomal enzymes (defective in I-cell disease)
• O glycosylation

• Defective microtubule polymerization
• Impaired phagocytosis
• Albinism, peripheral neuropathy

• Mutant dynein impairs cilia
• Infertility
• Bronchiectasis
• Recurrent sinus infections
• Associated with situs inversus

Stain for CT

Stain for muscle

Stain for epithelial cells

Stain for glial cells

• Defective extracellular collagen cross-linking
• Hyperextensible skin, bleeding, hypermobile joints
• Associated with Berry aneurysms
• Type III collagen is affected worst

• Defective glycosylation of type I collagen
• AD
• Mutliple fractures
• Blue sclera

• Abnormal type IV collagen (BM)
• XR
• Hereditary nephritis and deafness

Defective fibrillin