Cellular Biochemistry Flashcards
Regulatory proteins that control cell cycle events; phase specific; activate CDKs
Cyclins
Phosphorylate other proteins to coordinate cell cycle progression; must be activated and inactivated at appropriate times for cell cycle to progress
Cyclin-CDK complexes
p53 induces what gene that then inhibits CDKs
p21
Effects of p21 inhibition of CDKs (2)
1) hypophosphorylation (activation) of Rb
2) inhibition of G1-S progression.
(Cell Type) Remain in G0, regenerate from stem cells
Permanent cells
(Cell Type) Enter G1 form G0 when stimulated
Stable (quiescent) cells
(Cell Type) Never go to G0, divide rapidly with a short G1. Most affected by chemotherapy.
Labile cells
The peroxisome is involved in four major processes
1) beta oxidation of very-long-chain fatty acids (VLCFA)
2) alpha oxidation
3) Catabolism of branched-chain fatty acids, amino acids, and ethanol
4) Synthesis of cholsterol, bile acids, and plasmalogens
Autosomal recessive disorder of peroxisome biogenesis due to mutated PEX genes. Hypotonia, seizures, hepatomegaly, early death.
Zellweger syndrome
Autosomal recessive disorder of alpha-oxidation. Phytanic acid not metabolized to pristanic acid. Scaly skin, ataxia, cataracts/night blindness, shortening of 4th toe, epiphyseal dysplasia. Treatment: diet, plasmapheresis.
Refsum disease
X-linked recessive disorder of beta-oxidation due to mutation in ABCD1 gene. VLCFA in adrenal glands, white (leuko) matter of brain, testes. Progressive disease that can lead to adrenal gland crisis, coma, and death.
Adrenoleukodystrophy
Barrel-shaped protein complex that degrades damaged or ubiquitin-tagged proteins. Defects in this system have been implicated in some cases of Parkinson disease.
Proteasome
A network of protein fibers within the cytoplasm that supports cell structure, cell and organelle movement, and cell division
Cytoskeletal elements
Inhibits Na+-K+ ATPase pump by binding to the K+ site
Ouabain
Directly inhibits the Na+-K+ ATPase, which then indirectly inhibits Na+/Ca2+ exchange. Increase in calcium leads to increase in cardiac contractility
Cardiac Glycosides (ex: Digoxin and digitoxin)
Most abundant protein in the human body. Organizes and strengthens the extracellular matrix
Collagen
(Collagen type) Most common variety. Featured in the bone, skin, tendons, dentin, fascia, cornea, and late wound repair.
Collagen Type I
(Collagen type) Featured in cartilage, vitreous body (part of eye), and nucleus pulposus (some jelly like shit in the vertebrae)
Collagen Type II
(Collagen type) Featured in reticulin fibers, skin, blood vessels, uterus, fetal tissue, granulation tissue
Collagen Type III
(Collagen type) Featured in the basement membrane (basal lamina) and lens of the eye
Collage Type IV
Six (generalized) steps of collagen synthesis
1) synthesis of collagen alpha chains (Gly-X-Y)
2) Hydroxylation of specific proline and lysine residues (requires Vit C)
3) Glycosylation of pro-alpha-chain hydroxylysine residues and formation of procollagen via hydrogen and disulfide bonds
4) exocytosis of procollagen into extracellular space
5) Proteolytic processing. Cleavage of disulfide-rich terminal regions of procollagen
6) Cross-linking
Genetic bone disorder also referred to as brittle bone disease. Most common form is autosomal dominant with decreased production of Type I collagen. Frequent fractures, blue sclerae (white of the eye), tooth abnormalities and hearing loss.
Osteogenesis Imperfecta
Faulty collagen synthesis causing hyperextensible skin, hypermobile joints, and tendency to bleed/bruise.
Ethlers-Danlos Syndrome
X-linked recessive connective tissue disease caused by impaired copper absorption and transport due to defective Menkes. Leads to decreased activity of lysyl oxidase and then defective collage. Brittle kinky hair, growth retardation, and hypotonia.
Menkes disease
Stretchy protein within skin, lungs, large arteries, elastic ligaments, and vocal cords.
Elastin
Elastase is normally inhibited by what from breaking down elastin?
alpha 1 antitrypsin
Autosomal dominant connective tissue disorder affecting seleton, heart, and eyes. Mutated gene results in defective fibrillin, a glycoprotein that forms a sheath around elastin. Findings: tall with long extremities, pectus carinatum ( rare chest wall deformity), hypermobile joints, long tapering fingers and toes, etc.. etc..
Marfan syndrome
