Term
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Definition
| Inhibits prokaryotic RNA pol. Used to treat TB and bacterial meningitis. |
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Term
| How does RNA pol know when to stop in prokaryotes? |
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Definition
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Term
| Types of eukaryotic RNA Pol and what they do? |
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Definition
RNA Pol 1 - rRNA (except for 5S rRNA)
RNA Pol 2 - mRNA, some snRNA
RNA Pol 3 - tRNA, 5S rRNA (and all the other odds and ends) |
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Term
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Definition
-Inhibits eukaryotic RNA Pol II
-Found in poison mushroom
-Destroys liver |
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Term
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Definition
-Sequence in 5' UTR (untranslated region) of prokaryotic mRNA
-Needed for initiation of translation
-Comparable to the 5' cap in eukaryotes |
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Term
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Definition
-7-methylguanosine
-Uses a triphosphate link to mRNA
-Protects from degradation and helps in recognition
-Comparable to the Shine Dalgarno sequence in prokaryotes |
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Term
| What is the makeup of prokaryotic ribosomes? |
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Definition
-50S subunit and a 30S subunit
-A 16S subunit is within the 30S subunit and serves to recognize that Shine Delgarno sequence |
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Term
| What is the makeup of eukaryotic ribosomes? |
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Definition
-Contains a 60S subunit and a 40S subunit
-The smaller subunit is the one that binds the 5' cap
-Remember, all of the rRNA in here is going to be made by RNA pol 1 except for the 5S RNA in the larger subunit |
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Term
| Klein-Waardenburg syndrome? |
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Definition
-Results from a mutation in a PAX-3 gene (similar to HOX genes)
-presents with distopia canthorum (lateral displacement of the corner of the eye), frontal white blaze of hair, patchy hypopigmentation, congenital deafness, and limb abnormalities |
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Term
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Definition
-Caused by translocation of c-myc (proto-onco gene for DNABP) from chromosome 8 to 14 and being under control of IgG enhancer
-Presents with swollen jaw (from tumor), loose teeth, swollen lymph nodes |
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Term
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Definition
-Hereditary persistance of fetal hemoglobin
-Often from a mutation of the LCR region (promotor) |
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Term
| Can be used to increase HbF? |
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Definition
-Decitabine which contains 5-Azacytosine (a cytosine analog)
-Works because there is an N where cytosine would have methyl group attached to deactivate a part of DNA (HbF's) |
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Term
| What induces class switching in Igs? |
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Definition
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Term
What transcription factors have the following DNA binding domains;
Zinc finger?
Leucine zippers?
Helix-turn-helix?
Helix-loop-helix? |
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Definition
-Steroid hormone receptors
-CREB
-Homeodomain proteins
-MyoD protein |
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Term
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Definition
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Term
| How are AAs and tRNA put together? |
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Definition
| -By amino acyl tRNA synthetase -Makes a high energy ester bond between the AA and the terminal adenosyl residue of the CCA sequence at the 3' end of the tRNA. |
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Term
| What catalyzes peptide bond formation and in what ribosomal subunit? |
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Definition
| -Peptidyl transferase in the large subunit. |
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Term
| What is the sequence of events for initiation of translation? |
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Definition
| -Small unit binds to mRNA near start codon, amino acyl-tRNA with Met binds to start codon, large subunit binds with the tRNA in the P site |
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Term
| What does the elongation and what does it need? What blocks it? |
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Definition
-EF2 (elongation factor), GTP for energy
-Diphtheria toxin blocks EF2 |
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Term
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Definition
-Needed to bind incoming amino-acyl tRNA to A site
-Hydrolyses GTP in process |
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Term
| Where are proteins destined for the membrane made? |
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Definition
| -In the rough ER -Doesn't matter whether it's for excreting, or for actually in the membrane |
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Term
| Penetrance vs expressivity? |
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Definition
-Whether symptoms show at all
-What what is the range of symptoms and severity |
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Term
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Definition
| -One disease causes a variety of symptoms, often seeming unrelated |
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Term
| What does mitochondrial inheritance look like? |
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Definition
| -Affected females, but not affected males pass the disease on |
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Term
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Definition
-X-linked (lethal in males)
-Causes a swirled cutaneous pigmentation on skin
-Pattern is wartlike/blistering earlier in life
-Pattern caused by lionization (x-inactivation)
-Also causes nail and teeth anomalies along with mental retardation |
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Term
| In imprinting, what is the state of somatic verses gamete DNA? |
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Definition
| -The somatic cell in a male will have the maintained imprinting (female and male), while the gametes will revert to the male only imprinting; This exemplifies the reversibility of imprinting |
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Term
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Definition
-Most commonly caused by a deletion of 15q11-13 (70%) on the paternal chromosome
-Also often caused by maternal uniparental disomy (25%) of chromosome 15 (only imprinted alleles are inherited)
-Frequency is about 1/10k and causes hypogonadism, infertility, and obesity due to hyperphagia
-Also have mild mental retardation and behavior problems
-Connection is with Angelman's |
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Term
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Definition
-CTG repeat expansion (will probably lead to increased methylation due to CG units being around)
-A disease of anticipation
-Frontal baldness with long face and small jaw |
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Term
| Fragile X syndrome and biochemical basis? |
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Definition
-CGG repeat expansion in FMR1 gene (>200ish)
-Works because the CG bases form CpG islands leading to increased methylation of the FMR1 gene, resulting in FMR protein deficiency from it being silenced
-Disease of anticipation
-Most common hereditary cause of mental retardation |
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Term
| What is the initiator of translation in prokaryotes and what inhibits it? |
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Definition
-fMet tRNA initiates by binding to P site; has the start anticodon
-Inhibited by aminoglycosides (e.g. *streptomycin, kanamycin, neomycin, gentamycin)
-They work by binding the 30S subunit |
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Term
| What drugs bind the 30S subunit in prokaryotes? Uses? |
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Definition
-Streptomycin (an AMINOGYCOSIDE); causes misreading (wrong AAs and early termination) and inhibition of fmet tRNA to P SITE to initiate; used for TB and bubonic plague
-TETRACYCLINS; inhibit aminoacyl-tRNA by binding to A SITE; useful for treating diseases caused by Rickettsiae (e.g. Rocky Mountain spotted fever, mycoplasma pneumoniae, chlamydiae), also for uncomplicated gonococcal infections -Doxycycline is a specific example |
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Term
| What drug inhibits peptide bond formation? |
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Definition
-Chloramphenicol which is produced by streptomyces venezuelae
-Binds reversibly to the 50S unit to inhibit transpetidation reaction |
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Term
| What drug inhibits translocation step? |
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Definition
-Erythromycin (a Macrolide)
-Binds to 50S unit
-Effective against respiratory tract infections like whooping cough, and in diphtheria, pertussis, and staph infections |
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Term
| What do the following do; Aminoglycosides? Chloramphenicol? Erythromycin? Tetracycline? Diphtheria Toxin? |
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Definition
-Aminoglycosides; binds 30S at the P Site, blocks fmet tRNA and causes misreading (e.g. kanamycin & streptomycin)
-Chloramphenicol; binds 50S, blocks peptide bond formation
-Erythromycin; binds 50S, inhibits translocation from A to P site (type of macrolyde)
-Tetracycline; binds 30S, inhibits aminoacyl-tRNA binding to A Site
-Diphtheria Toxin; blocks eukaryotic EF-2 (translocation) |
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Term
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Definition
-Iodide capture and oxidation to neutral state
-I + Tyrosine = MIT
-I + MIT = DIT
-MIT + DIT = T3 (TIT - most active form)
-DIT + DIT = T4 (tyroxine - most secreted one)
-some de-iodination before secretion of T4 occurs, either making it into the more active T3 or the deactivated "reverse T3" |
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Term
| What are the transporters for thyroid hormones? |
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Definition
-Major one is thyroxine binding globulin (TBG)
-The rest hitches a ride on albumin or prealbumin (transthyretin) |
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Term
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Definition
-thyrotropin releasing hormone made in hypothalamus and acting on the pituitary to stimulate TSH secretion
-Gq coupled so leads to increased DAG, IP3, Ca2+, and eventually PKC in pituitary gland |
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Term
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Definition
-AKA thyrotropin
-secreted by pituitary in response to hypothalamic TRH
-TSH receptors are Gs coupled so we get increased cAMP and PKA levels to stimulate hormone production and secretion |
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Term
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Definition
-Passively enter cells and bind nuclear receptors (TR)
-T3-TR complex then binds with retinoic acid receptor (RXR), another trans factor
-Finally, the whole complex binds to the TRE upstream elements to displace repressors and recruit coactivators |
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Term
| What actions does thyroid hormone have? In hypothyroidism, what do we see (if applicable)? |
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Definition
| 1. Thermogenis via increasing uncoupler 1 protein in brown adipose tissue; cold intolerance 2. Increases BMR by stimulating cytochromes, cyt c oxidase, & Na/K ATPase; weight gain 3. Increases both lipolysis and lipogenisis(first) 4. Increased cardiac contractility by increasing myosin protein levels; slow heart 5. Needed to convert carotene to Vit A in liver; orange skin 6. Increased GI motility; constipation 7. Tissue growth and maturation by promoting IGF-1 production; severe hypo may cause CRETINISM 8. Regulate fetal gene expression, esp in the brain; mental retardation (note; opposites are true for hyperthyroidism, as in graves) |
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Term
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Definition
-Puffy face
-Can be caused by severe hypothyroidism in adults (or in cretinism)
-Caused by deposition of GAGs which increases osmotic pressure and leads to edema |
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Term
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Definition
-Most common cause of hypothyroidism
-Caused by autoimmune destruction of thyroid via antibodies directed against thyroid peroxidase & thyroglobulin
-Typically presents with a multilobular goiter
-Gives low T4 and high TSH |
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Term
| What can cause hypothyroidism? |
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Definition
| -Hashimoto's thyroiditis -Iodine def. -Goitrogenic foods and drugs |
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Term
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Definition
-Hyperthyroidism
-Have smooth diffuse goiter, and graves opthalmopathy (forward eye movement from lymphocytes directed to eye muscle, and periorbital edema) |
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Term
| What are the mechanistic actions of TRH, TSH, T3, and T4? |
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Definition
TRH; Gq
TSH; Gs
T3 & T4; steroidal |
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