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132 Cards in this Set
- Front
- Back
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Name the histone not included in the nucleosome core.
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H1
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What amino acids are the main components of histones?
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Arginine
Lysine (positively charged) |
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What reaction converts Cytosine to Uracil?
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Deamination - conversion of NH2 to O
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Which nucleotide has a methyl group?
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Thymine
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Which nucleotide has a ketone group?
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Guanine
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What amino acids are necessary for purine synthesis?
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Glycine
Aspartate Glutamate |
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What amino acid is necessary for pyrimidine synthesis? What is the other component necessary?
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Aspartate
Carbamoyl phosphate |
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What precursor molecule leads to purines? To pyrimidines?
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Purines are made from IMP precursor
Pyrimidines are made from orotate precursor (PRPP added later) |
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What metabolic pathways require carbamoyl phosphate?
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De novo pyrimidine synthesis
Urea cycle |
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What is the mechanism of action of hydroxyurea?
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Inhibition of ribonucleotide reductase, resulting in decreased dUDP and decreased CTP
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What is the mechanism of action of 6-mercaptopurine?
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Blocking of de novo purine synthesis, so decreased AMP, GMP
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What is the mechanism of action of 5-fluorouracil?
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Inhibition of thymidylate synthase, thus decreasing dTMP
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What is the mechanism of action of methotrexate?
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Inhibition of dihydrofolate reductase, thus decreasing dTMP
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What is the mechanism of action of trimethoprim?
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Inhibition of bacterial dihydrofolate reductase, thus decreasing dTMP
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座る（に）
すわる すわします |
to sit down
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What reaction is catalyzed by thymidylate synthase?
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dUMP --> dTMP
with N5N10 Methylene Tetrahydrofolate --> Dihydrofolate |
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What amino acid is required for the reaction of orotic acid (plus PRPP) to UMP?
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Aspartate
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What amino acids are required for conversion of ribose-5-phosphate to PRPP?
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Glycine, aspartate, glutamate
Also tetrahydrofolate |
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What reaction is catalyzed by ribonucleotide reductase?
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UDP --> dUDP, CTP
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What enzymes are defective in orotic aciduria?
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Orotic acid phosphoribosyltransferase
or Orotidine 5'-phosphate decarboxylase |
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What are the findings in orotic aciduria?
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Increased orotic acid in urine, megaloblastic anemia (not corrected with folate or B12), FTT
NO hyperammonemia!!! |
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What reaction is not being catalyzed in adenosine deaminase deficiency?
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Adenosine --> Inosine
Results in excess ATP and dATP imbalancing the nucleotide pool, and causes feedback inhibition of ribonucleotide reductase, which is necessary for pyrimidine synthesis |
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What reactions are catalyzed by xanthine oxidase?
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Hypoxanthine --> Xanthine
Xanthine --> Uric acid |
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What reaction is catalyzed by HGPRT?
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Hyopxanthine --> IMP
Guanine --> GMP Results in excess uric acid production |
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What NT sequence codes for a start codon?
What three sequences code for stop codons? |
Start: AUG
Stop: UGA, UAA, UAG |
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What is added to RNA post-transcription on the 5' end and the 3' end?
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5' end: 7-methylguanosine cap
3' end: Polyadenylation (200 As) |
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What is the polyadenylation signal?
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AAUAAA
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What NT sequence is found at the 3' end on all tRNA?
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CCA
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What is the mechanism of action of Tetracyclines?
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They bind the 30S subunit, preventing attachment of aminoacyl-tRNA
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What is the mechanism of action of Aminoglycosides?
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Inhibition of the formation of the initiation complex, causing misreading of mRNA
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What is the mechanism of action of Chloramphenicol?
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Inhibition of 50S peptidyltransferase
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What is the mechanism of action of Macrolides? Clindamycin?
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Binding of 50S, thus blocking translocation
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What two tumor suppressors inhibit G1-S progression?
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Rb
p53 |
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What organs/tissues are rich in RER?
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Mucus-secreting globlet cells of the small intestine
Antibody-secreting plasma cells |
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What are Nissl bodies?
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RER in neurons, which synthesize enzymes and peptide neurotransmitters
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What organs/tissues are rich in SER?
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Liver hepatocytes
Steroid hormone-producing cells of the adrenal cortex |
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What is the role of COP I?
COP II? |
COP I - retrograde vesicular transport, from Golgi to ER
COP II anterograde vesicular transport, from RER to cis-Golgi |
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What is the role of Clathrin?
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Clathrin helps form vesicles from the trans-Golgi to lysosomes, and to the plasma membrane
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What is I-cell disease?
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Inclusion cell disease - inherited lysosomal storage disorder.
Lysosomal enzymes are secreted outside the cell instead of inside because mannose-6-phosphate is not added to lysosome proteins Results in coarse facial features, clouded corneas, restricted joint movement, high plasma levels of lysosomal enzymes. Often fatal |
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How does the Golgi apparatus affect asparagine? Serine? Threonine? Lysosomal proteins? Proteoglycans and tyrosine?
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Addition of O-oligosaccharides to Serone, Threonine
Modification of N-oligosaccharides on Asparagine Addition of Mannose-6-Phosphate to specific lysosomal proteins Sulfation of sugars in proteoglycans and of selected tyrosine on proteins |
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List some drugs that act on microtubules.
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Griseofulvin
Mebendazole/Thiabendazole Vincristine/Vinblastine Paclitaxel Colchicine |
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What is Chediak-Higashi syndrome?
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A microtubule polymerization defect resulting in decreasd phagocytosis. Results in recurrent pyogenic infections, partial albinism and peripheral neuropathy
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What is the structure of microtubules?
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24 nm thick
A cylindrical structure composed of a helical array of polymerized dimers of alpha and beta tubulin 2 GTP bound to each dimer |
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Where is Dynein ATPase located?
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At the axonemal dynein
The ATPase links peripheral doublets of microtubule doublets |
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What is Kartagener's syndrome?
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Immotile cilia due to a dynein arm defect
Results in male and female infertility, bronchiectasis, and recurrent sinusitis Associated with situs inversus |
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Where do you find actin and myosin?
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Microvilli
Muscle contractions Cytokinesis Adherens junctions |
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Where do you find microtubules?
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Cilia
Flagella Mitotic spindles Neurons Centrioles |
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Where do you find intermediate filaments?
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Vimentin
Desmin Cytokeratin Glial fibrillary acid proteins Neurofilaments |
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What stain do you use for Neuroglia?
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GFAP
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What immunohistochemical stain do you use for neurons?
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Neurofilament
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What immunohistochemical stain do you use for Epithelial cells?
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Cytokeratin
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What immunohistochemical stain do you use for Muscle?
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Desmin
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What immunohistochemical stain do you use for connective tissue?
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Vimentin
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What is the mechanism of action of Ouabain?
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Inhibition of NaK ATPase by binding to K+ binding site
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What is the mechanism of cardiac glycosides?
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Digoxin, Digitoxin
Directly inhibit the Na+K+ ATPase, leading to indirect inhibition of Na/Ca exchange - increased [Ca] = increased cardiac contractility |
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What is the most abundant type of collagen and where do you find it?
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Type I
Bone, skin, tendon, dentin, fascia, cornea, late wound repair |
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Where do you find type II collagen?
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Cartilage (including hyaline)
Vitreous body, nucleus pulposus |
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Where do you find type III collagen?
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Reticulin - skin, blood vessels, uterus, fetal tissue, granulation tissue
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Where do you find type IV collagen?
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Basement membrane or basal lamina
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Which step in collagen synthesis requires vitamin C?
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Hydroxylation of specific proline and lysine residues
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What is formed by cleavage of terminal regions of procollagen?
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Tropocollagen
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What enzyme is responsible for reinforcement of staggered tropocollagen molecules by covalent lysine-hydroxylysine cross-linkage?
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Lysyl oxidase
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In what disease is there an inability to cleave peptides from procollagen?
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Ehlers-Danlos
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In what disease is there a failure to form the triple helix (procollagen) step in collagen formation?
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Osteogenesis imperfecta
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What disease mostly affects type III collagen?
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Ehlers Danlos syndrome
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What disease affects type I collagen?
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Osteogenesis imperfecta
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What disease affects type IV collagen?
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Alport's syndrome
Usually XLR Progressive hereditary nephritis and deafness - may have ocular disturbances |
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What disease is caused by a defect in fibrillin?
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Marfan's syndrome
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What disease results from excess elastase activity secondary to an enzyme deficiency?
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Emphysema, secondary to alpha-1 antitrypsin deficiency
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What disease has a cell-signaling defect of fibroblast growth factor receptor 3?
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Achondroplasia
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What disease has a deletion on chromosome 3 and results in constitutive expression of HIF and activation of angiogenic growth factors?
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Von Hippel Lindau disease - findings include hemangioblastomas of retina, cerebellum, medulla; multiple bilateral renal cell carcinomas
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List some of the X-linked recessive disorders.
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Bruton's agammaglobulinemia
Wiskott-Aldrich syndrome Fabry's disease G6PD deficiency Ocular albinism Lesch-Nyhan syndrome Duchenne's muscular dystrophy Becker muscular dystrophy Hunter's Syndrome Hemophilia A, B |
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What disease is caused by a deletion of the dystrophen gene?
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Duchenne's muscular dystrophy
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What disease, associated with chromosomal breakage, is the second most common cause of genetic mental retardation after Down syndrome?
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Fragile X Syndrome
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What are the trinucleotide repeat segments for...
Huntington's Disease Myotonic Dystrophy Fragile X Syndrome Friedreich's Ataxia |
Huntington's: CAG
Myotonic dystrophy: CTG Fragile X: CGG Friedreich's ataxia: GAA |
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What would the pregnancy quad screen results be for Down syndrome?
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Decreased AFP, Estriol, Inhibin A
Increased beta-HCG |
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What is the most common mechanism behind Trisomy 21?
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Meiotic nondisjunction of homologous chromosomes associated with advanced maternal age
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What disease is associated with a microdeletion of the long arm of chromosome 7, including the part that codes for the elastin gene?
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William's syndrome
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What metabolic disorder(s) are associated with William's syndrome?
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Hypercalcemia (secondary to vitamin D sensitivity)
Cardiovascular problems |
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List the B vitamins...
Number, chemical name, and related cofactors/energy carrying molecules |
B1 - Thiamine - TTP
B2 - Riboflavin - FAD, FMN B3 - Niacin - NAD+ B5 - Pantothenic acid - CoA B6 - Pyridoxine - PLP B12 - Cobalamine |
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For what enzymes/reactions is Vitamin B1 a cofactor?
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Thiamine pyrophosphate (B1) is a cofactor for...
Pyruvate dehydrogenase (glycolysis) alpha-ketoglutarate dehydrogenase (TCA cycle) Transketolase (HMP shunt) Branched-chain AA dehydrogenase |
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What regions of the brain are damaged in Wernicke-Korsakoff?
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Medial dorsal nucleus of thalamus
Mammillary bodies |
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From what amino acid is Niacin derived?
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Tryptophan
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What vitamin is required for Niacin synthesis?
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Vitamin B6
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What are signs of pantothenate deficiency?
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Dermatitis, enteritis, alopecia, adrenal insufficiency
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What is the role of Vitamin B6?
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It is converted to pyridoxal phosphate, a cofactor used in transamination, decarboxylation reactions, glycogen phosphorylase, cystathione synthesis, heme synthesis
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For what two enzymes is cobalamin a cofactor?
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Homocysteine methyltransferase
Methylmalonyl-CoA mutase |
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What reaction is catalyzed by homocysteine methyltransferase?
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Homocysteine + N-methyl-tetrahydrofolate --> Methionine + Tetrahydrofolate
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What reaction is catalyzed by methylmalonyl-CoA?
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Methylmalonyl-CoA --> Succinyl-CoA
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What is the role of folic acid?
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It is converted to tetrahydrofolate, which is a coenzyme for 1-carbon transfer/methylation reactions - important for the synthesis of nitrogenous bases in DNA, RNA.
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What is the role of S-adenosyl methionine?
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It donates methyl groups, required for conversion of norepinephrine to epinephrine
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For what enzymes is biotin a cofactor?
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Pyruvate carboxylase (Pyruvate --> Oxaloacetate)
Acetyl-CoA carboxylase (Acetyl-CoA --> Malonyl-CoA) Proprionyl-CoA carboxylase (Proprionyl-CoA --> Methylmalonyl-CoA) |
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What are the functions of Vitamin C?
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1. Facilitates iron absorption by keeping iron in Fe2+ reduced state
2. Necessary for hydroxylation of proline and lysine in collagen synthesis 3. Necessary for dopamine beta-hydroxylase which converts dopamine to NE |
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What are signs of Vitamin E deficiency?
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Increased erythrocyte fragility
Muscle weakness Posterior column and spinocerebellar tract demyelination |
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What reactions are catalyzed by Vitamin K?
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Catalyzes gamma-carboxylation of glutamic acid residues on various proteins concerned with blood clotting: Factors II, VII, IX, X, Protein C, Protein S
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What are signs of Zinc deficiency?
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Delayed wound healing
Hypogonadism Decreased adult hair Dysgeusia Anosmia |
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What transcription factor motif relies on zinc?
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Zinc fingers
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What is the role of Fomepizole?
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Inhibits alcohol dehydrogenase and is an antidote for methanol or ethylene glycol poisoning
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What is the role of Disulfiram (Antabuse)?
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Inhibits acetaldehyde dehydrogenase (acetaldehyde accumulates, contributing to hangover symptoms)
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Where is alcohol dehydrogenase located?
Where is acetaldehyde dehydrogenase located? |
Alcohol dehydrogenase - in cytosol
Acetaldehyde dehydrogenase - in mitochondria |
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What two reactions occur along with ethanol metabolism to replenish the NAD+ supply in the liver?
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Pyruvate --> Lactate
Oxaloacetate --> Malate |
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What metabolic processes take place only in mitochondria?
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Fatty acid oxidation (beta-oxidation)
Acetyl-CoA production TCA cycle Oxidative phosphorylation |
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What metabolic processes take place only in the cytoplasm?
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Glycolysis
Fatty Acid Synthesis HMP Shunt Protein synthesis (RER) Steroid synthesis (SER) |
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What metabolic processes take place in both the cytoplasm and the mitochondria?
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Heme synthesis
Urea cycle Gluconeogenesis |
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What is the rate determining enzyme for...
TCA cycle? HMP shunt? De novo purine synthesis? De novo pyrimidine synthesis? Fatty acid synthesis? Fatty acid oxidation? |
TCA cycle - Isocitrate dehydrogenase
HMP shunt - G6PD De novo purine - Glutamine-PRPP amidotransferase De novo pyrimidine - CPS II Fatty acid synthesis - Acetyl-CoA carboxylase Fatty acid oxidation - Carnitine acyltransferase I |
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What reaction is catalyzed by galactokinase?
Name the deficiency disease? |
Galactose --> Galactose-1 phosphate
Mild galactosemia |
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What reaction is catalyzed by galactose-1-phosphate uridyltransferase?
Name the deficiency disease? |
Galactose-1 phosphate --> Glucose-1 Phosphate
Severe galactosemia |
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What reaction is catalyzed by hexokinase/glucokinase?
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Glucose --> Glucose-6 Phosphate
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What reaction is catalyzed by glucose-6-phosphatase?
Name the deficiency disease? |
Glucose-6 Phosphate --> Glucose
von Gierke |
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What reaction is catalyzed by G6PD?
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Glucose-6-Phosphate --> 6-Phosphogluconolactone
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What reaction is catalyzed by Transketolase?
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Ribulose-5-Phosphate --> Fructose-6-Phosphate
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What reaction is catalyzed by Phosphofructokinase 1?
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Fructose-6-Phosphate --> Fructose 1,6-bisphosphate
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What reaction is catalyzed by Fructose 1,6 Bisphosphtatase?
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Fructose 1,6 bisphosphate --> Fructose-6 phosphate
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What reaction is catalyzed by Fructokinase?
Name the deficiency disease? |
Fructose --> Fructose-1 Phosphate
Essential fructosuria |
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What reaction is catalyzed by Aldolase B?
Name the deficiency disease? |
Fructose-1 Phosphate --> DHAP, Glyceraldehyde
Fructose Intolerance |
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What reaction it catalyzed by pyruvate kinase?
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Phosphoenolpyruvate --> Pyruvate
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What reaction is catalyze by pyruvate dehydrogenase?
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Pyruvate --> Acetyl-CoA
(Requires Thiamine) |
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What reaction is catalyzed by HMG-CoA Reductase?
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HMG-CoA --> Mevalonate
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What reaction is catalyzed by pyruvate carboxylase?
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Pyruvate --> Oxaloacetate
(Requires Biotin) |
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What reaction is catalyzed by phosphoenolpyruvate carboxykinase?
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Oxaloacetate --> Phosphoenolpyruvate
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What reaction is catalyzed by Citrate synthase?
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Oxaloacetate --> Citrate
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What reaction is catalyzed by isocitrate dehydrogenase?
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Isocitrate --> alpha-ketoglutarate
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What reaction is catalyzed by alpha-ketoglutarate dehydrogenase?
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alpha-ketoglutarate --> Succinyl CoA
(Also requires thiamine) |
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What reaction is catalyzed by ornithine transcarbamoylase?
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Ornithine --> Citrulline
(Requires Carbamoyl phosphate) |
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What is the effect of fructose 2,6 bisphosphate on glycolysis?
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Activates phosphofructokinase 1
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What is inhibited by arsenic?
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Lipoic acid
Findings: vomiting, rice water stools, garlic breath |
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What cofactors are required by the pyruvate dehydrogenase complex?
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Cofactors: Pyrophosphate (B1, thiamine - TPP), FAD (B2, riboflavin), NAD (B3, niacin), CoA (B5, pantothenate), Lipoic acid
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What are the two purely ketogenic amino acids?
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Lysine, Leucine
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What are the different pathways of metabolism of pyruvate (4)?
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Alanine - carries amino groups to the liver from muscle
Oxaloacetate - can replenish TCA cycle or be used in gluconeogenesis Acetyl-CoA - Transition from glycolysis to the TCA cycle Lactate - End of anaerobic glycolysis |
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What are four things that directly inhibit electron transport and block ATP synthesis?
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Rotenone
CN- Antimycin A CO |
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What directly inhibits mitochondrial ATPase, causing an increased proton gradient?
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Oligomycin
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What two things are considered uncoupling agents, and increase permeability of the membrane, thus preventing a proton gradient from being set up?
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2,4-DNP
Aspirin Also thermogenin in brown fat |
