Biochem p.72-81, 102-104 Flashcards
What regulates cell cycle and activates CDKs?
Cyclines
What complex activates other proteins to coordinate cell cycle progression?
Cyclin-CDK complex
Does Rb gene need to be in a hypophosphorylated or hyperphosphorylated state in order to inhibit G1 to S phase?
Hypoooo
Gene mutations causing Li-Fraumeni syndrome?
p-53, Rb
Two examples of quiescent cells?
Hepatocytes, lymphocytes
Which 2 cell types are rich in RER?
Mucus-secreting goblet cells of the small intestine and antibody-secreting plasma cells
What is RER called in neurons?
Nissl bodies
What are 2 functions of RER?
Synthesis of secretory (exported) proteins and of N-linked oligosaccharide addition to many proteins.
What synthesizes cytosolic and organellar proteins?
Free ribosomes
Which cells are rich in SER?
Liver hepatocytes and steroid hormone–producing cells of the adrenal cortex and gonads
What are 3 functions of Golgi?
Modifies N-oligosaccharides on asparagine. Adds O-oligosaccharides on serine and threonine. Adds mannose-6-phosphate to proteins for trafficking to lysosomes
Another name for I-cell disease?
Inclusion cell dz
What kind of storage disorder is I-cell dz?
inherited lysosomal storage disorder
Defective enzyme in I-cell dz?
defect in N-acetylglucosaminyl-1-phosphotransferase
Failure of the Golgi to phosphorylate mannose residues on glycoproteins causes the decrease of what substance in which dz?
decr mannose -6-phosphate
I-Cell dz
What are some findings in I-cell dz?
coarse facial features, clouded corneas, restricted joint movement, and high plasma levels of lysosomal enzymes
Absent or defective Signal recognition particle (SRP) causes what?
Protein accumulation in the cytosol
LDL receptor activity is an example of?
receptor mediated endocytosis/ Endosomes
Mode of transport of Clathrin?
trans-Golgi –> lysosomes; plasma membrane–> endosomes
Name the membrane-enclosed organelle involved in catabolism of very-long-chain fatty acids, branched-chain fatty acids, and amino acids?
Peroxisome
Name the barrel-shaped protein complex that degrades damaged or ubiquitin-tagged proteins?
Proteasome
Defects in the ubiquitin-proteasome system have been implicated in some cases of?
Parkinson dz
Example of Microfilaments?
Actin
Examples of intermediate filaments:
Vimentin, desmin, cytokeratin, lamins, glia fibrillary acid proteins (GFAP), neurofilaments
Example of microtubules:
Cilia, flagella, mitotic spindle, axonal trafficking, centrioles.
Stain used for Connective tissue?
Vimentin
Stain used for Muscle?
desMin
Stain used for Epithelial cells?
Cytokeratin
Stain used for NeuroGlia?
GFAP
Stain used for neurons?
Neurofilaments
Cylindrical structure composed of a helical
array of polymerized heterodimers of α- and
β-tubulin
Microtubule
Drugs that act on microtubules? (Microtubules
Get Constructed Very Poorly):
Mebendazole (antihelminthic) Griseofulvin (antifungal) Colchicine (antigout) Vincristine/Vinblastine (anticancer) Paclitaxel (anticancer)
retrograde transport to microtubule (+ to −).
Dynein
anterograde transport to microtubule (− to +)
Kinesin
stuctural arrangement of microtubule
9 + 2
Name the ATPase that links peripheral
9 doublets and causes bending of cilium by
differential sliding of doublets?
Axonemal dynein
Another name for Kartagener syndrome
1° ciliary dyskinesia
Whats the defect in Kartgner syndrome?
immotile cilia due to a dynein arm defect
Which dz can cause bronchiectasis, recurrent
sinusitis, and situs inversus
Kartagener dz
What are the risks of pregnancy in Kartagners pts? and why?
dysfunctional fallopian
tube cilia can cause ectopic
pregnancy
What poison inhibits Sodium-potassium pump by binding to K+ site.
Ouabain
Digoxin inhibits which pump directly and which one indirectly?
directly inhibit the Na+-K+ ATPase, which
leads to indirect inhibition of Na+/Ca2+
Digoxin incr HR or contractility or both?
contractility
Most abundant protein in the human body?
Collagen
Where does Collagen get organizes and strengthened?
extracellular matrix
Most common (90%) type of collagen?
type I
Which type of collagen is for late wound repair?
type I
Type of collagen in vitreous body and nucleus pulposus.
Type II
Type of collagen in the lens?
type IV
Skin is made out of which 2 types of collagen?
typeIII and I
what type of collagen is granulation tissue?
type III
2 Path associated with collagen type IV?
Alport syndrome, Goodpasture syndrome.
What is preprocollagen?
Translated collagen α chains containing Gly-X-Y (X and Y are proline or lysine).
Which collagen synthesis steps take place in RER?
1) Synthesis (translation)
2) Hydroxylation
3) Glycosylation
What collagen synth steps happen outside fibroblasts?
proteolytic processing, cross-linking
In which step of collagen sysnth is vit C required?
Hydroxylation of proline and lysine residues
Problems forming what structure in which step is seen in Osteogenesis Imperfecta?
formation of triple helix in Glycosylation step–> can’t make Procollagen
2 Paths with cross-linking of collagen fibrils?
Ehlers-Danlos syndrome, Menkes disease.
Which enzyme need copper for cross-linking?
Lysyl oxidase
What is Tropocollagen?
Procollagen that becomes insoluble by cleavage of it’s disulfide-rich terminal regions
What is the MC form of AD dz with decreased production of type I collagen?
Osteogenesis imperfecta
T or F? OI pts have normal limb growth.
False! limb shortening due to multiple fractures
T or F? Ehler-Danlos can be AD or AR.
T
dermatosparaxis and kyphoscoliosis types–> AR
arthrochalasia, classical, hypermobility, vascular forms–>AD
Name the 3 types of Ehler-Danlos dz and their collagen type defects?
-MC type: Hypermobility type (joint instability)
-Classical type (joint and skin symptoms): caused
by a mutation in type V collagen.
-Vascular type (vascular and organ rupture):
deficient type III collagen.
Brittle, “kinky” hair, growth retardation, and hypotonia is seen in which X-linked recessive connective tissue dz?
Menkes
What gives elastin its elastic properties?
Cross-linking that takes place extracellularly
Which glycoprotein forms a sheath around elastin? And a defect in it is seen in which path?
fibrillin, Marfan syn
A diagnostic tool for neonatal HIV, herpes encephalitis is?
PCR
2 essential components needed for PCR?
DNA fragment of interest
primers for the specific DNA regions
polimerase
Confirmatory test for HIV after
⊕ ELISA?
Western blot
Blot that would identify transcription factors?
SouthernWestern-blot for DNA-binding proteins
Blot used for gene expression.
Northern blot to studying mRNA levels
Whats the difference btw Southern and Northern blot?
Sother uses DNA sample and Northerner uses RNA.
Which methos is used to profile gene expression levels of thousands of genes simultaneously to study certain diseases and treatments.
Microarrays
Which method is able to detect single nucleotide polymorphisms (SNPs) and copy number variations (CNVs) for a variety of applications including genotyping?
Microarrays
Which method is used to detect the presence of either a specific antigen or a specific antibody in a patient’s
blood sample?
ELISA
Is this method Direct or Indirect ELISA?
uses a test antibody to see if a specific antigen is present. The antibody is directly coupled to a color-generating enzyme to detect the antigen.
This methos is used for specific localization of genes and direct visualization of anomalies (e.g., microdeletions), it is called?
Fluorescence in situ
hybridization
At which sites does HMP-shunt occur?
lactating mammary glands, liver, adrenal cortex (sites of fatty acid or steroid synthesis), RBCs.
HMP-shunt provides a source of —— from abundantly available ——.
NADPH, glucose-6-P
which ptw of pentose phosphate pathway is irreversible?
Oxydative
what is the RLE in the oxidative HMP-shunt?
G-6-PD
What agents can decr NADPH in RBCs?
Sulfonamides, primaquine, antituberculosis drugs. Infection
Bite cells are result from what process?
the phagocytic removal of Heinz bodies by splenic macrophages.
What is the most common human enzyme deficiency?
X-linked recessive G-6-PD
What enzyme is defective in Essential fructosuria?
Fructokinase
What enzyme defi presents with hypoglycemia, jaundice, cirrhosis, vomiting after consumption of honey. Urine dipstick will be ⊝ (tests for glucose only);
Occurs with fruit and juice as well. Hereditary deficiency of aldolase B.
What substance accumulates in Fructose intolerance?
Fructose-1-phosphate accumulates
Enzyme def that presents with infantile cataracts, failure to track objects or to develop a social smile?
Galactokinase deficiency
Enzyme def that causes accumulation of toxic substances including galactitol, which accumulates in the lens of the eye?
galactose-1-phosphate uridyltransferase
What bacterial infection can be seen in Classic galactosemia?
E. coli sepsis in neonates.
What cellshave only aldose reductase?
Schwann cells, retina, and kidneys, Lens (primary)
What cell uses aldose reductase and Sorbitol dehydrogenase?
Liver, ovaries, and seminal vesicles
Decrease of sorbital dehydrogenase can cause what pathologies?
osmotic damage: cataracts, retinopathy, and peripheral neuropathy seen with chronic hyperglycemia in diabetes
Lactose tolerance test shows: —– pH and —–hydrogen content in breath.
decr, incr
Acidic AAs?
Aspartic acid (Asp) and glutamic acid (Glu). Negatively charged at body pH.
Basic AAs?
Arginine (Arg), lysine (Lys), histidine (His). “HAL”
Arg is most basic.
His has no charge at body pH.
Ammonia intoxication presents as?
tremor (asterixis), slurring of speech, somnolence, vomiting, cerebral edema, blurring of vision
How does Lactulose work in what condition?
Lactulose acidifyes the GI tract and trap NH4+ for excretion in Hyperammonemia
Which drug decr colonic ammoniagenic bacteria?
Rifaximin
Which 2 drugs bind amino acid and lead to excretion of NH4? Also may be given to dcr ammonia levels?
Benzoate and phenylbutyrate, phenyacetate
Ito cells when quiescent store — in ECM.
vit A
Anaerobic glycosis is seen in:
RBC, WBC, kidney medulla, lens, testes, cornea
