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SbyS Biochem
| Question | Answer |
|---|---|
| At which end of the tRNA is the aa bound? | The amino acid is covalently bound to the 3' end of the tRNA. |
| Can RNA polymerase initiate chains? | Yes. |
| Define transition. | Substituting purine for purine or pyrimidine for pyrimidine. |
| Define transversion. | Substituting purine for pyrimidine or vice versa. |
| Define tRNA wobble. | Accurate base pairing is required only in the first 2 nucleotide positions of an mRNA codon, so codons differing in the 3rd 'wobble' position may code for the same tRNA/amino acid. |
| Describe Euchromatin | Less condensed (vs. Heterochromatin), transcriptionally active |
| Describe Heterochromatin | Condensed, transcriptionally inactive |
| Describe key structural differences between nucleotides. | 1) Purines (A,G) have 2 rings. 2) Pyrimidines (C,T,U) have 1 ring 3) Guanine has a ketone. 4) Thymine has a methyl |
| Describe single-strand, excision repair. | Excision repair-specific glycosylase recognizes and removes damaged base. Endonuclease makes a break several bases to the 5' side. Exonuclease removes short stretch of nucleotides. DNA polymerase fills gap. DNA ligase seals. |
| Describe the difference between Eukaryotic Vs. Bacterial, viral and plasmid origin of replications | Eukaryotic genome has multiple origins of replication. Bacteria, viruses and plasmids have only one origin of replication. |
| Describe the main difference in eukaryotic and prokaryotic synthesis of RNA. | Eukaryotes have 3 different RNA polymerases ('I, II, III synthesize RMT') and prokaryotes have 1 RNA polymerase (which makes all 3 kinds of RNA). |
| Describe the method by which introns are removed from primary mRNA transcript. | Introns are precisely spliced out of primary mRNA transcripts. A lariat-shaped intermediate is formed. Small nuclear ribonucleoprotein particles (snRNP) facilitate splicing by binding to primary mRNA transcripts and forming spliceosomes. |
| Describe the number of bonds per purine-pyrimidine pair. Which is stronger? | G-C bond (3 H-bonds) A-T bond (2 H-bonds G-C bond is stronger |
| Describe the structure of Chromatin. | Condensed by (-) charged DNA looped around (+) charged histones (nucleosome bead). H1 ties the nucleosome together in a string (30 nm fiber) |
| Does RNA polymerase have a proof reading function? | No. |
| How do purines and pyrimidines interact, molecularly? | Purines and pyrimidines pair (A-T, G-C) via H-bonds |
| How does RNA polymerase II open DNA? | RNA polymerase II opens DNA at promoter site (A-T rich upstream sequence- TATA and CAAT) |
| How is the original RNA transcript processed in eukaryotes? (3) | 1) Capping on 5' end (7methyl G) 2)Polyadenylation on 3' end ( =200 As) 3) Splicing out of introns |
| In eukaryotes, what must occur before an newly synthesized RNA transcript leaves the nucleus? | Only processed RNA is transported out the nucleus of eukaryotes. |
| Name 3 types of RNA | 1) mRNA 2) rRNA 3) tRNA |
| Name the charged histones around which (-) charged DNA loops (nucleosome core). | H2A, H2B, H3, H4 histones |
| Name the enzyme responsible for the synthesis of RNA in prokaryotes. | RNA polymerase |
| Name the enzymes involved in ss-DNA repair. (5) | 1) specific glycosylase. 2) endonuclease. 3) exonuclease. 4) Dan polymerase. 5) DNA ligase. |
| Name the enzymes responsible for the synthesis of eukaryotic RNA. | RNA polymerase I RNA polymerase II RNA polymerase III |
| What are exons? | Exons contain the actual genetic information coding for a protein |
| What are four types of mutations that can occur in DNA? | 1) Silent 2) Missense 3) Nonsense 4) Frame shift |
| What are introns? | Introns are intervening noncoding segments of DNA |
| What are the four features of the Genetic Code? | 1) Unambiguous 2) Degenerate 3) Commaless, non-overlapping 4)Universal |
| What atoms link aa in a protein chain? | Amino acids are linked N to C |
| What changes occur in DNA structure during mitosis? | In mitosis, DNA condenses to form mitotic chromosomes |
| What codon sequence is found at the 3' end of all tRNAs? | All tRNAs, both eukaryotic and prokaryotic, have CCA at 3' end. |
| What direction is DNA synthesized in? | 5' > 3'. Remember that the 5' of the incoming nucleotide bears the triphosphate (energy source for the bond). The 3' hydroxyl of the nascent chain is the target. |
| What direction is protein synthesized in? | Protein synthesis also proceed in the 5' to 3' (5' > 3') |
| What direction is RNA synthesized in? | 5' > 3'. Remember that the 5' of the incoming nucleotide bears the triphosphate (energy source for the bond). The 3' hydroxyl of the nascent chain is the target. |
| What does the AUG mRNA sequence code for? | AUG codes for methionin, which may be removed before translation is completed. In prokaryotes the initial AUG codes for a formyl-methionin (f-met). |
| What does the P in P-site stand for? What does the A in A-site stand for? | P-site: peptidyl; A-site: aminoacyl; |
| What does the statement, 'the genetic code is commaless' mean? What is the exception to this rule? | The code is non-overlapping. The exception are some viruses |
| What does the statement, 'the genetic code is degenerate' mean? | More than one codon may code for the same amino acid |
| What does the statement, 'the genetic code is unambiguous' mean? | Each codon specifies only one amino acid |
| What does the statement, 'the genetic code is universal' mean? What are the exceptions (4)? | The same code is used in all lifeforms. The exceptions are 1. mitochondria, 2. archaeobacteria, 3. Mycoplasma, 4. some yeasts |
| What enzyme is responsible for 'charging' tRNA? How does it work? | Aminoacyl-tRNA synthetase. This enzyme (one per aa, uses ATP) scrutinizes aa before and after it binds to tRNA. If incorrect, bond is hydrolyzed by synthetase. The aa-tRNA bond has energy for formation of peptide bond. |
| What inhibits RNA polymerase II? | alpha-amanitin inhibits RNA polymerase II |
| What is a conservative missense mutation? | Mutation results in a different aa encoded, but that new aa is similar in chemical structure to the original code |
| What is a frameshift mutation? What is usually the effect on the encoded protein? | A change in DNA resulting in misreading of all nucleotides downstream. Usually results in a truncated protein. |
| What is a missense mutation? | Mutation results in a different aa encoded. |
| What is a nonsense mutation? | A change in DNA resulting in an early stop codon. |
| What is a promoter? | Site where RNA polymerase and multiple other transcription factors bind to DNA upstream from gene locus. |
| What is a silent mutation? What usually causes a silent mutation? | Mutation results in the same aa encoded. Often the base change is in the 3rd position of the codon |
| What is a snRNP? What is its function? | snRNP = small nuclear ribonucleoprotein. snRNPs facilitate splicing by binding to primary mRNA transcripts and forming spliceosomes. |
| What is an enhancer? | Stretch of Dan that alters gene expression by binding transcription facts. May be located close to, far from, or even within (an intron) the gene whose expression it regulates. |
| What is an Okazaki fragment? | The discontinuous DNA synthesized on the lagging strand during DNA replication |
| What is hnRNA? | hnRNA = heterogeneous nuclear RNA The initial RNA transcript is called hnRNA |
| What is responsible for the accuracy of amino acid selection during peptide synthesis? | Aminoacyl-tRNA synthetase and binding of charged tRNA to the codon are responsible for accuracy of amino acid selection. |
| What is the broad classification of nucleotides? (2) | Purines (A, G) and Pyrimidines (C, T, U) |
| What is the difference between hnRNA and mRNA? | hnRNA = the initial RNA transcript mRNA = capped and tailed transcript |
| What is the difference between thymine and uracil? | Uracil found in RNA Thymine found in DNA |
| What is the function of DNA ligase during DNA Replication? | DNA ligase seals synthesized DNA into a continuous strand |
| What is the function of DNA polymerase during DNA Replication? (2) | 5'®3' exonuclease activity of DNA polymerase I degrades RNA primer; 3'®5' exonuclease activity of DNA polymerase 'proofreads' each added nucleotide. |
| What is the function of DNA topoisomerase during DNA Replication? | DNA topoisomerases create a nick in the helix to relieve supercoils |
| What is the function of primase in DNA Replication? | Primase makes an RNA primer on which DNA polymerase can initiate replication. |
| What is the function of RNA polymerase I? | RNA polymerase I makes rRNA |
| What is the function of RNA polymerase II? | RNA polymerase II makes mRNA |
| What is the function of RNA polymerase III? | RNA polymerase III makes tRNA |
| What is the mRNA initiation codon? | AUG, or rarely GUG |
| What is the mRNA stop codons? (3) | UGA (U Go Away) UAA (U Are Away) UAG (U Are Gone) |
| What is the result of 'mischarged' tRNA? | A mischarged tRNA (bound to wrong aa) reads usual codon but inserts wrong amino acid. |
| What is the role of endonuclease in ss-DNA repair? | Endonuclease makes a break several bases to the 5' side. |
| What is the role of excision repair-specific glycosylase in ss-DNA repair | Recognizes and removes damaged base. |
| What is the role of exonuclease in ss-DNA repair? | Exonuclease removes short stretch of nucleotides. |
| What prevents an incorrect aa-tRNA pairing? | If incorrect, the aa-tRNA bond is hydrolyzed by aminoacyl-tRNA synthetase. |
| What role does histone H1 play in chromatin structure? | H1 ties the nucleosome together in a string (30nm fiber) |
| What supplies the energy for formation of peptide bond? | The aa-tRNA bond has energy for formation of peptide bond. |
| What would most likely be the result of a mutation of the promoter sequence? | Promoter mutation commonly results in dramatic decrease in amount of gene transcribed. |
| When is ATP used in protein synthesis? When is GTP used in protein synthesis? | ATP is used in tRNA charging, whereas GTP is used in binding of tRNA ribosome and for translocations. |
| When is recombination involved in DNA repair? | If both strands are damaged, repair may proceed via recombination with undamaged homologous chromosome. |
| Where does RNA processing occur in eukaryotes? | RNA processing occurs in the nucleus. |
| Which is the largest type of RNA? | mRNA (massive) |
| Which is the most abundant type of RNA? | rRNA (rampant) |
| Which is the smallest type of RNA? | tRNA (tiny) |
| Which nucleotide position in the codon has room for 'wobble'? | Codons differing in the 3rd 'wobble' position may code for the same tRNA/amino acid |
| How do you do a Northern Blot? | Electrophorese RNA on a gel transfer to a filter expose filter to a labeled DNA probe visualize the DNA probe annealed to the desired RNA |
| How do you do a Southern Blot? | Electrophorese DNA on a gel transfer to a filter and denature the DNA expose to a labeled DNA probe visualize probe annealed to desired DNA fragment |
| How do you do a Southwestern blot? | Separate protein by electrophoresis transfer to a filter expose to a labeled DNA probe visualize DNA bound to desired protein |
| How do you do a Western Blot? | Separate protein by electrophoresis transfer to a filter expose to a labeled antibody visualize Ab bound to desired protein |
| How do you do PCR? (4 steps) | 1. Heat DNA to denature. 2. Cool DNA and let the primers aneal. 3. Heat-stable polymerase replicates DNA following each premer 4. Repeat |
| What are some genetic diseases detectable by PCR? (11) | SCID, Lesh-Nyhan, CF, familial hypercholesterolemia retinoblastoma, sickle cell, Bthalassemia, hemophilia A and B, von Willebrand's dz, lysosomal dz, and glycogen stroage dz |
| What gene is involved in cystic fibrosis? | CFTR |
| What gene is involved in familial hypercholesterolemia? | LDL-R |
| What gene is involved in Lesh-Nyhan syndrome? | HGPRT |
| What gene is involved in retinoblastoma | Rb |
| What gene is involved in SCID? | adenosine deaminase |
| What gene is involved in Sickle cell and ?-thal? | ? globin gene |
| What is an ELISA (enzyme linke immunosorbant assay)? | Rapid lab test in which an antibody or an antigen (usually collected from a patient) is exposed to an Ag or Ab liked to to an enzyme. A positive test results in a Ag-Ab match and is usually indicated by a color change |
| What is PCR? | Lab procedure used to synthsize many copies of a desired fragment of DNA |
| Von Geirke's disease is a result of? | Glucose-6-phosphatase deficiency; also known as Type I Glycogen Storage disease |
| A build up of sphingomyelin and cholesterol in reticuloendothelial and parenchymal cells and tissues is found in what disease | Niemann-Pick disease |
| A child is born with multiple fractures and blue sclera what is the diagnosis | Osteogenesis imperfecta;disease of abnormal collagen synthesis resulting in fractures and translucent Conn tiss over chorioid causing the blue sclera |
| A congenital deficiency of tyrosinase would lead to | Albinism, can't synthesize melanin from tyrosine |
| A patient presents with cataracts, hepatosplenomegaly, and mental retardation, what is the Dx? | Galactosemia |
| A patient presents with corneal clouding and mental retardation that is, based on family history, inherited in an Autsomal recessive pattern, you impress your intern with a Dx of | Hurler's syndrome |
| A patient presents with 1. Hyperextensible skin 2. Tendency to bleed 3. Hypermobile joints you astutely Dx them with | Ehlers-Danlos syndrome |
| Absence of Galactosylceramide Betagalactosidase leads to thebuild up of what compound in what disease | accumulation of galactocerebroside in the brain; Krabbe's disease |
| Absence of hexosaminidase A results in the acumulation of what molecule that is characteristic of what disease | GM2-ganglioside accumulation; Tay-Sachs disease |
| albinism increase risk of developing what | skin cancer |
| Autosomal dominant defects will effect what members of a family | male and female |
| Autosomal recessive disorders often result in what kind of defect/deficiencie? | enzyme deficiencies |
| Autosomal recessive disorders usually effect how many generations in a family? | usually only one generation |
| Bloom's syndrome is characterized by sensitivity to what as a result of | sensitivity to radiation as a result of a DNA repair defect |
| Creatine and Urea are both made from? | Arginine |
| Defects in structural genes often follow what pattern of inheritance? | Autosomal dominant |
| Defiency of arylsulfatase A results in the accumulation of what molecule where | sulfatide in the brain, kidney, liver, and peripherla nerves. Characteristic of Metachromatic Leukodystrophy |
| define genetic imprinting | when differences in phenotype depend on whether the mutation is of paternal or maternal origin |
| define incomplete penetrance | when not all individuals with a mutant genotype show the mutant phenotype |
| define Linkage Disequilibrium | the tendency for certain alleles at two linked loci to occur together more often thatn expected by chance, as measured in a population |
| define pleiotropy | one gene has more than one effect on an individual's phenotype, autosomal dominant defects are oftne pleiotropic |
| Define variable expression | nature and severity of the phenotype varies from one individual to another |
| Fanconi's anemia is caused by what typr of agents | cross-linking agents |
| Ganglioside is made up of what | Ceramide + oligosacharide + sialic acid |
| Gaucher's disease is caused by a deficiency of | Beta-glucocerebrosidase |
| Glucocerebroside accumulation in the brain, liver, spleen, and bone marrow are characteristic of | Gaucher's disease |
| Hglycine is used to make what important compound | Porphyrin which is then used to make Heme |
| Histamine is synthesized form what compound | Histidine |
| How does adenosine deaminase defiency cause SCID | Purine salvage pathway. ADA normal converts adenosine to inosine without it ATP & dATP build up inhibiting ribonucleotide reductase which prevents DNA synthesis lowering lymphocyte production |
| How is Lesch-Nyhan syndrome inheritied andwhat is the result and symptoms | X-linked recessive; increase in uric acid production. Retardation, self mutalation, aggression, hyperuricemia, gout, and choreathetosis |
| Hunter's syndrome is characterised by what biochemical problem and how is it inherited | deficiency of iduronate sulfatase; X-linked recessive mild form of Hurler's |
| In ataxia-telangiectasia DNA damage caused by what source cannot be repaired | X-rays |
| in G6PD deficiency the decrease in NADPH can lead to _____ if exposed to _____ | hemolytic anemia;oxidizing agents( fava beans, sulfonamides, primaquine) and antituberculosis. |
| In PKU what builds up and what can be found in the urine | phenyalanine builds upe leading to phenylketones in the urine |
| In PKU, what amino acid becomes essential | tyrosine. |
| in the Hardy-Weinberg equation, what are the p and q and what is 2pq | p and q are each separate alleles; 2pq = heterozygote |
| no male to male transmission is characteristic of what type of genetic disorders? | X-linked recessive |
| Pompe's disease is caused by a defect in? | lysosomal alpha-1,4glucosidase defiency |
| Sickle cell anemia is caused by what defect and what is it's prevalence | AR single missense mutation in the beta globin; 1:400 blacks |
| Siclkle cell anemia patients often present with | recurrent painful crisis and increased susceptibility to infections |
| Skin sensitivity to UV light secondary to a DNA repair defect is characteristic of what? | xeroderma pigmentosum |
| Sphingosine + fatty acid yields | ceramide |
| the COL1A gene mutation is associated with what disease and what type of mutation is this | Osteogenesis imperfecta;dominant negitive mutation |
| The main defect in Ataxiatelangiectasi is a ___ | DNA repair defect |
| The most common form of Osteogenesis imperfecta has what genetic problem and inheritance | abnormal Collagen Type I synthesis;Autosomal dominant |
| the transporter for what amino acids is defective in cystinuria | COLA: Cys,Ornithine, Lysine and Arginine |
| Thymidine dimers are formed by exposure of DNA to UV light, are the dimers formed on the opposing strands of a DNA molecule or on the same side? | dimers are on same side |
| Tryptophan can be used to make what three chemicals | Niacin, 'Serotonin, melatonin |
| Type III Glycogen storage disease is a defiency of ? | deficiency of debranching enzyme alpha-1,6glucosidase |
| What is the cause Tx and symptoms of Lactase intolerance? | Lactase defiency, avoid diary products or add lactse pills to diet symptoms bloating, cramps, osmotic diarrhea |
| What % of kids born to father with mitochondrial myopathie will be effected | none, mitochondrial myopathies are inherited from mitochondria which is only inherited from the mother |
| What are the clinical signs of Krabbe's disease | optic atrophy, spasticity, early death |
| What are the components of Cerebroside | Ceramide + glucose/ galactose |
| What are the components of Sphingomyelin | Ceramide + phosphorylcholine |
| What are the components of sphingosine | serine + palmitate |
| What are the findings and treatment of pyruvate dehydrogenase | neurologic defects; increase intake of ketogenic nutrients |
| What are the findings in McArdles's disease and what is the problem | increased glycogen in skeletal muscle due to a Glycogen phosphorylase defiency strenuous exercise cause myoglobinuria and painful cramps |
| What are the findings in PKU and what is the treatment | Mental retardation, fair skin, eczema, musty body odor Tx. Decreasee phenylalanin (nutrasweet) and increase tyrosine |
| What are the findings in Pompe's disease and what is it alternate name | Cardiomegaly and systemic findings, leading to early death. Pompe's trashes the Pump. (Heart, Liver and muscle) Type II Glycogen storage disease |
| What are the findings in Von Gierke's disease | severe fasting hypoglycemia, increased glycogen in the liver |
| What are the four assumptions of the HardyWeinberg equilibrium | 1.There is no mutation occuring at the locus 2. There is no selection for any of the geno types at the locus 3. Random mating 4. no migration in or out |
| What are the purely ketogneic amino acids | lysine and leucine |
| What are the signs and symptoms of essential fructosuria | asymptomatic, benign, Fructose appears in blood and urine |
| what are the signs and symptoms of Homocystinuria | Homocysteine accumulates in urine and cystine becomes essential Methionine and it's metabolites build up in blood Mental retardation, osteoporosis, dislocation of the lens |
| What are the symptoms of Alkaptonuria | Dark Urine from alkapton bodies; also connective tissue is dark, may have arthralgias. Bengin disease |
| What are the symptoms of Fructose intolerance | hypoglycmeia, jaundice, cirrhosis |
| What are the symptoms of Maple syrup Urine disease | CNS defects, mental retardation and death. Urine smells like maple syrup |
| What biological chemicals are derived form phenylalanine | tyrosine, thyroxine Dopa dopamine NE, Epinephrine and Melanin |
| What causes Essential Fructosuria | defect in fructokinase |
| What causes Lesch-Nyhan syndrome | Absence of HGPRTase, (normally converts hypoxanthine to IMP and guanine to GMP) Lacks Nucleotide Salvage (LNS)purines |
| What do melanin and Norepinephrine have in common | both derived directly from dopamine Phenylalanine to tyrosine to Dopa to Dopamin |
| What enzyme defiencies are associated with hemolytic anemia | Glycolytic enzyme deficiencies 1. Hexokinase 2.glucose-phosphate isomerase 3.aldolase 4.triose-phosphate isomerase 5. phosphate-glycerate kinase enolase pyruvate kinase |
| What event in embryology can cause albinism | lack of migration of neural crest cells to skin (form melanocytes) |
| What genetic error can cause Severe Combined Immnuodeficiency (SCID)? | Adenosine deaminase deficiency |
| what group of people can be seen with pyruvate dehydrognease deficiency | alcoholics due to B1 defiecincy |
| What is a complication of cystinuria | cystine kidney stones |
| What is a dominant negitive mutation? | a mutation that exerts a dominant effect because the body cannot produce enough of the normal gene product with only one allele functioning normally |
| What is a good pnuemonic for the four glycogen storage diseases | Very-Von Gierke's PoorPompes Carbohydrate-Cori's Metabolism-McArdles |
| What is commonly associated with xeroderma pigementosa? | dry skin, melanoma and other cancers |
| What is crucail to the diagnosis of an Autosomal dominant disease? | Family history |
| What is genetic anticipation? | the severity of the diseas worsens or age of onset of disease is earlier in succeeding generations |
| What is inheritance of G6PD dfiency and what population is effected more often | X-linked recessive; blacks |
| What is NAD/NADP made form | Niacin, 'Serotonin, melatonin |
| What is osteogenesis imperfecta often confused with | child abuse |
| What is the biochemical defect in Metachromatic leukodystrophy and what is the inheritance pattern | deficiency of arylsulfatase A; Autosomal recessive |
| What is the biochemical defect in Nieman-Pick disease and how is it inherited | deficiency of Betaglucocerebrosidase; autosomal recessive |
| What is the biochemical effect of G6PD defiency | decrease in NADPH which is necessary to reduce glutathione which in turn detoxifies free radicals and peroxides |
| What is the cause of Cystinuria and what are the signs/symptoms | inheritied defect o the tubular amino acid transporter for Cystine, ornithine, Lysine and Arginine in kidneys excess cystine in urine |
| What is the cause of Fabry's disease and what is the common clinical problem | Alpha-galactosidase A deficiency; gives accumulation of ceramide trihexoside causing renal failure |
| What is the cause of galactosemia? | Absence of galactose-1phosphate uridyltransferase; accumualtion of toxic substances (galactitol) |
| What is the characteristic defect in Hurler's syndrome | Alpha-L-iduronidase defiency leads to corneal clouding and mental retardation |
| What is the characteristic findings in Neurofibromatosis | Multiple café-au-lait spots, neurofibromas increased tumor susceptibilty |
| What is the clinical picture of a patient with cystic fibrosis | pulmonary infections, exocrine pancreatic insufficiency, infertility in men |
| What is the clinical picture of Duchenne's muscular dystrophy | muscular weakness and degeneration |
| What is the defect in Maple Syrup Urine disease | decreased Alpha-ketoacid dehydrogenase. blocks degradation of branched amino acids Ile. Val. Leu |
| What is the epidemiology of lactose intolerance | Age-dependnet and/or hereditary (blacks and Asians) |
| What is the etiology of Homocystinuria | defect in cystathionine synthase. Two forms: 1. deficiency 2. decreased affinity of synthase for pyridoxal phosphate (cofactor) |
| What is the finding of Hunter's syndrome on H & P | mild mental retardation but no corneal clouding |
| What is the formula for Hardy-Weinberg equilibrium? | p^2 +2pq + q^2 =1 and p +q=1 |
| What is the genetic mech. Of Cystic fibrosis and it's inheritance | AR; multiple loss-of-function mutations in a chloride channel |
| What is the genetic mechanism of Duchenne's muscular dystrophy | X-linked recessive;caused by multiple loss-of-funtion mutations in a muscle protein |
| What is the genetic mechanism of Fragile X MR | X-linked; progressive expansion of unstable DNA causes failure to express gene-encoding RNA-binding protein |
| what is the genetic mechanism of Neurofibromatosis | AD, multiple loss-of function mutations in a signaling molecule |
| What is the genetic problem in Down's Syndrome | trisomy 21 chromosomal imbalance |
| What is the inheritance of Krabbe's disease | Autosomal recessive |
| what is the inheritance pattern and carrier frequency in Tay-Sach's | Autosomal recessive; 1:30 in Jews of European descent and 1:300 in the general populaition |
| What is the inheritance pattern of Ehlers-Danlos syndrome | 10 types of this syndrome Type IV-Auto Dominant Type VI-Auto Recessive Type IXX-linked recessive |
| What is the inheritance pattern of Gaucher's disease | Autosomal recessive |
| What is the inheritance pattern of xeroderma pigmentosa | autosomal recessive |
| What is the inheritiance pattern of Fabry's disease | X-linked recessive |
| What is the lab symptoms of G6PD defiency | Heinz Bodies: altered hemoglobin precipitate in RBC |
| What is the most distinguishing finding in TaySach's disease on Physical exam | cherry red Macula; these patients die by 3 |
| What is the pathogneumonic cell type founde in Gaucher's disease | Gaucher's cells with the characteristic 'crinkled paper' appearance of enlarged cytoplasm |
| What is the pattern of inheritance of Leber's hereditary optic neuropathy? | mitochondrial inheritance |
| What is the phenotype in Osteogenesis imperfecta | increased susceptibility to fractures;connective tissue fragility |
| What is the phenotype of Down's syndrome | Mental and growth retardation, dysmorphic features, internal organ anomalies especially heart problems |
| What is the phenotype of Fragile X | mental retardation, characteristic facial features, large testes |
| What is the predominant problem in Ehlers-Danlos syndrome | Faulty collagen synthesis |
| What is the prevalance of cystic fibrosis | 1:2000 whites; very rare among Asians |
| What is the prevalandce of Neurofibromatosis | 1:3000 with 50% being new mutations |
| What is the prevalence of Down's syndrome and what are the risk factors | 1:800; increased risk with advanced maternal age |
| What is the prevalence of Duchenne's musc. dys. | 1:300; 33% new mutations |
| What is the prevalence of Fragile X- associated mental retardation | 1:1500 males: can be in feamales is a multi-step process |
| What is the prevalence of osteogenesis imperfecta | 1:10000, |
| What is the prevalence of Phenylketonuria | 1:10000 |
| What is the priamry defect in Fructose intolerance and how is it inherited? | defiency of aldolase B, autosomal recessive |
| What is the primary defect in Alkaptonuria | congenital defiency of homogentisic acid oxidase in the degradative pathway of tyrosine |
| What is the primary defect(s) found in Phenylketoneuria | either 1.decreased phenylalanie hydroxylase or 2. decreased tetrahydrobiopterin cofactor |
| What is the rate-limiting enzyme in the HexoseMonophosphate shunt? | Glucose-6-phosphate dehydrogenase |
| What is the result of pyruvate dehydrognease deficiency | backup of substrate (pyruvate and alanine) resulting in lactic acidosis |
| What is the specific defect in Xeroderma pigmentosa | defective excision repair such as uvr ABC exonuclease; have inability to repair thymidine dimer formed by UV light |
| What is the treament of Cystinuria and what is a possible consequence of not treating | Acetazolide to alkinlize the urine cystine kidney stones due to excess cysteine |
| What is the treatment of fructose intolerance? | decrease intake of both fructose and sucrose (glucose + fructose) |
| What is the treatment of Homocystinuria | 1. For a defiency in cystathionine synthase tx by decrease Met and increase Cys in diet 2. for decreased affinity of synthase Tx by decrease vitamin B6 in diet |
| What is the Tx of galactosemia? | Exclude galactose and lactose (galactose +glucose) form diet |
| what offspring of females affected with a mitochondrial inherited disease will be effected? | all offspring can be effected |
| what percent of offspring from two autosomal recessive carrier parents will be effected? | 0.25 |
| what percent of sons of a heterazygous mother carrying an x-linked disease will be effected? | 0.5 |
| What period of life do autosomal dominant defects present in? | often present clinically after puberty |
| What three phenyl ketones build up in the urine of PKU patients | phenylacetate, phenyllactate, phenylpyruvate |
| What to thyroxine and Dopa have in common | both derived form tyrosine |
| What type of genetic error is usually more severe autosomal recessive or dominant? | AR disorders are often more severe |
| What type of inheritance is transmitted only through mothers? | mitochondrial |
| When do patients usually present with autosomal recessive disorders? | present in childhood |
| Why are RBC so susceptible to Glycolytic enzyme def. | RBC's metabolize glucose anaerobically (no mitochondria) and depends on glycolysis |
| Why do people with fructose intolerance become hypoglycemic? | deficent aldolase B causes the accumulation of Fructose 1phosphate which acts as a phosphate sink and traps the phosphate. Decreased phosphate availability inhibits glycogenolysis and gluconeogenesis |
| X-linked recessive disease is aften more severe in | males |
| 1,3-BPG | 2,3-BPG via bisphosphoglycerate mutase |
| Acyl | coenzyme A, lipoamide |
| aldehydes | TPP |
| Arachidonate | prostaglandins, thromboxanes, -leukotrienes |
| Associate the following signal molecule precursors. | j |
| At body pH, what AA are negatively charged? | Arg and Lys His is neutral at pH 7.4 |
| At body pH, what AA are positvely charged? | Asp and Glu |
| ATP | cAMP via adenylate cyclase |
| By what rxn order kinetics does alcohol dehydrogenase operate? | zero order kinetics |
| CH(3) groups | SAM |
| Choline | CDP-choline |
| Choline | ACh via choline acetyltransferase |
| CO(2) | biotin |
| Contrast glucagon and insulin. | glucagon phosphorylates stuff, -turns glycogen synthase off and phosphorylase on |
| Contrast hexokinase and glucokinase. | hexokinase throughout the body, -GK in liver and has lower affinity but higher capacity for glucose |
| Contrast hexokinase and glucokinase. | only HK is feedback inhibited by G6P |
| Does insulin affect glucose uptake of brain, RBC's and liver? | No |
| Does insulin inhibit glucagon release by alpha cells of pancreas? | yes |
| electrons | NADH, NADPH, FADH(2) |
| Fructose-6-phosphate | fructose-1,6-bis-P via PFK (rate limiting step of glycolysis) |
| Glucose | UDP-Glucose |
| glutamate | GABA via glutamate decarboxylase (requires vit. B6) |
| GTP | cGMP via guanylate cyclase |
| How are ketone bodies excreted? | in urine |
| How are ketone bodies formed? | FA and AA converted to acetoacetate and bhydroxybutyrate |
| How do the statin drugs work? | they inhibit HMG-CoA reductase |
| How does disulfiram work? | inhibits acetylaldehyde dehydrogenase |
| How does FA enter the cytosol? | via citrate shuttle |
| How does FA enter the mitochondria? | via the carnitine shuttle |
| How does lead affect heme synthesis? | inhibits ALA dehydratase and ferrochelatase prevents incorporation of Fe |
| How does the brain metabolize ketone bodies? | to 2 molecules of acetyl coA |
| How is bilirubin removed from the body? | collected by liver, conjugated with glucuronate excreted in bile |
| How is ethanol metabolized? | ethanol oxidized to acetylaldehyde by alcohol dehyd and NAD+ acetalaldehyde ox to acetate by acetylaldehyde and NAD+ |
| How is FA entering the mitochondria inhibited? | by cytoplasmic malonyl-CoA |
| How is glutamate converted to a-ketogluturate | By the loss of amonium and reduction of NADP |
| How is glutamine converted to glutamate? | By the loss of amonium |
| How is heme catabolized? | scavenged from RBC's and Fe +2 is reused |
| How is LDL uptake undergone? | by target cells through receptor-mediated endocytosis |
| How is most plasma cholesterol esterfied? | LCAT(lecethin-cholesterol acyltransferase) |
| How is NAD+ generally used metabolically? | catabolic processes |
| How is NADPH generally used metabolically? | anabolic processes (steroid and FA synthesis), repiratory burst, P-450 |
| How is TCA regulated? | by need for ATP and supply of NAD+ |
| How many ATP's per acetyl CoA? | 12 |
| How many ATP equivalants are needed to generate glucose from pyruvate? | 6 |
| How many enzyme activities does pyruvate dehydrognase possess | 3 |
| How many moles of ATP are generated aerobically through G3P shuttle? | 36 ATP |
| How many moles of ATP are generated aerobically through malate shuttle? | 38 ATP |
| How many moles of ATP are generated anaerobically? | 2 ATP |
| In what tissue does heme synthesis occur (2)? | liver and bone marrow |
| Insulin mneumonic | insulin moves glucose into cells |
| Is Serum C peptide present with exogenous insulin intake? | No |
| Kwashikor results from a protein deficient MEAL (mneumonic) | Malabsorption, Edema, Anemia, Liver (fatty) |
| Mnemonic for gluconeogenesis irreversible enzymes? | Pathway Produces Fresh Glucose |
| Mnemonic for SAM. | SAM the methyl donor man |
| Name 6 common products of pyruvate metabolism? | glucose, lactate, Acetyl CoA +CO2, OAA, Alanine |
| Name the activated carriers with associated moleclues (one carbon units). | tetrahydrofolates |
| phosphoryl | ATP |
| T/F. Uncouplers stop ATP production? | FALSE |
| Underproduction of heme causes what anemia? | microcytic hypochromic anemia |
| What AA are required during periods of growth? | Arg and His |
| What are clincial syndromes of this disorder? | xanthomas, atherosclerosis homozygotes MI by age 30 |
| What are major pathways occur in the liver (8)? | most including gluconeogenesis, etc. |
| What are the activators of glycgenolysis? | cAMP, and calcium ion |
| What are the cofactors of pyruvate dehydrogenase (5)? | pyrophosphate, lipoic acid, CoA, FAD and NAD |
| What are the components of a cholymicron remnant? | TG, FFA and apo E |
| What are the components of a cholymicron? | TG, apo C-II, apo E, B-48, apo A |
| What are the components of IDL? | less TG, CE, B-100 and E |
| What are the components of LDL? | CE and B-100 |
| What are the components of VLDL? | TG, Cholesterol ester, B-100, CII and E |
| What are the degradation product steps (3)? | heme to biliverdin to bilirubin |
| What are the effector hormones of cholesterol synthesis? | insulin increases, glucagon decreases |
| What are the effector hormones of glyc and pyr ox? | decreased glucagon and increased insulin |
| What are the effector hormones of glycogenolysis? | insulin decreases, epi and glucagon increases |
| What are the effector hormones of lipogenesis (2)? | insulin increases, glucagon decreases |
| What are the electron transport chain inhibitors? | rotenone, antimycin A, CN-, CO |
| What are the essential glucogenic/ketogenic AA? | Ile, Phe, Try |
| What are the essential gluconeogenic AA? | Met, Thr, Val, Arg, His |
| What are the essential ketogenic AA? | Leu and Lys |
| What are the irreversible enzymes of gluconeogenesis (4)? | -pyruvate carboxylase, -PEP carboxykinase,-fructose-1,6bisphosphotase, -glu-6phosphotase |
| What are the irreversible enzymes of glycolysis (4)? | -glucokinase/hexokinase,PFK,-pyruvate kinase,pyruvate dehdrogenase |
| What are the main substrates used by adipose tissue (2)? | -glucose, -lipoprotein triacylglycerol |
| What are the main substrates used by brain? | -glucose, -aa and ketone bodies when starved, polyunsat FA in neonates |
| What are the main substrates used by heart? | FFA, -some glucose, -lactate, -ketone bodies, VLDL and cholymicrom triacylglycerol |
| What are the main substrates used by liver? | FFA, -glucose, -lactate, glycerol, fructose, -AA |
| What are the major activators of gluconeogenesis? | Acetyl CoA for pyruvate carboxylase and cAMP for PEP carboxykinase and F-1,6bis-P |
| What are the major activators of glycolysis and pyruvate oxidation? | AMP, fructose2,6-bis-P, fructose 1,6-bis-P in muscle, CoA, NAD, ADP and pyruvate |
| What are the major metabolic pathways of the adipose tissue (2)? | - esterfication of FA's lipolysis |
| What are the major metabolic pathways of the brain (2)? | -glycolysis,-aa metabolism |
| What are the major metabolic pathways of the heart? | Aerobic pathways like B oxidation and TCA cycle |
| What are the major products of the adipose tissue (2)? | -FFA, -glycerol |
| What are the major products of the brain? | lactate |
| What are the major products of the liver (10)? | glucose,-VLDL,-HDL,-ketone bodies,-urea,-uric acid, -bile acids, -plasma proteins |
| What are the major regulatory enzymes of gluconeogenesis (3)? | pyruvate carboxylase, PEP carboxykinase and F-1,6bis-P |
| What are the major regulatory enzymes of glycolysis and pyruvate oxidation? | PFK and pyruvate dehydrogenase |
| What are the major regulatory enzymes of cholesterol synthesis? | HMG-CoA reductase |
| What are the products of the liver in the fasting state? | glucose and ketone bodies |
| What are the products of the liver in the fed state? | glycogen and fats/VLDL |
| What are the products of the TCA cycle? | 3NADH, 1FADH2, 2CO2, 1GTP per Acetyl CoA |
| What are the some causes of hyperbilirubinemia (4)? | massive hemolysis, -block in catabolism, -diplaced from binding sites on albumin, decreased excretion |
| What are the sources of hyperbilirubinemia (2)? | conjugated (direct/ glucuronidated) and unconjugated(indirect/ insoluble) |
| What are the specialist enzymes of muscle (2)? | -lipoprotein lipase, and well developed resp chain |
| What are the specialist enzymes of the adipose tissue (2)? | -lipoprotein lipase,-hormone sensitive lipase |
| What are the specialist enzymes of the heart (2)? | -lipoprotein lipase, respiratory chain welldeveloped |
| What are the specialist enzymes of the liver? | -glucokinase,-glu-6phosphotase,-glycerol kinase, -PEP carboxykinase, fructokinase,-arginase,-HMG coA synthase and lyase, -7ahydroxylase |
| What are the three sites in the electron transport chain for active proton transfer? | NADH dehydrogenase, Cyt b/ c1, and cytochrome oxidase aa3 |
| What can occur as an excess of cholymicrons (3)? | pancreatitis, lipemia retinalis and eruptive xanthomas |
| What can occur as an excess of VLDL? | pancreatitis |
| What catalyzes cholymicron to cholymicron remnant? | lipoprotein lipase |
| What catalyzes IDL to LDL? | hepatic TG lipase |
| What catalyzes VLDL to IDL? | lipoprotein lipase |
| What causes a hangover? | acetylaldehyde accumulates |
| What color is bilirubin and what is the condition of excess? | yellow, jaundice |
| What complex is pyruvate dehydrogenase similar to? | a-ketogluturate dehydrogenase complex |
| What do LT c4, D4 and E4 do (4)? | bronchconstriction, vasoconstriction, contract smooth muscle, increase vascular permeability |
| What does breath smell like during ketoacidosis? | fruity(acetone) |
| What does excess LDL cause (3)? | atherosclerosis, xanthomas, and arcus corneae |
| What does oligomycin do to ETC? | ATPase inhibitor that increases proton gradient but not ATP production |
| What does PGI stand for? | platelet gathering inhibitor |
| What does the COX pathway yield? | thromboxanes, prostaglandins and prostacyclin |
| What does the lipooxygenase pathway yield? | leukotrienes |
| What does this stand for? | Ornithine, citrulline, carbamoyl-p, aspartate, arginosuccinate, fumurate, arginine, urea |
| What enzyme catalyzes the rate limiting step of cholesterol syn.? | HMG-CoA reductase |
| What induces the PPP? | insulin |
| What is a major component of atherosclerotic plaque? | modified LDL |
| What is an uncoupling agent to the ETC? | 2,4 DNP (dynamite) |
| What is cofactor required for methionine (SAM) regeneration? | vitamin B12 |
| What is does PGI 2 inhibit (2)? | platelet aggregation and vasodilation |
| What is familial hypercholesteremia? | AD genetic defect in LDL receptor |
| What is Kwashikor? | protein malnutrition |
| What is LT B4? | neutrophil chemotactic agent |
| What is Marasmus? | Protein-calorie malnutrition resulting in tissue wasting |
| What is the activator of lipogenesis? | Citrate |
| What is the activator of PPP? | NADP+ |
| What is the clinical picture of Kwashikor? | small child with swollen belly |
| What is the committed step of heme synthesis? | glycine+succ CoA to deltaaminolevulinate |
| What is the composition of ATP? | Base(adenine), ribose, 3 phosphoryls |
| What is the consequence of accumulated intermediates of heme synthesis? | porphyrias |
| What is the easy way to remember the cofactors of PDH complex? | First 4 B vitamins + lipoic acid |
| What is the effector hormone for glycogenesis? | Glucagon |
| What is the energy content of the 2 phosphoanhydride bonds? | 7 kcal/mol each |
| What is the functiion of HDL (2)? | transfers cholesterol from periphery to liver acts as a repository for apoC and apoE |
| What is the functioin of lipoprotein lipase? | FA uptake to cells from choly's and VLDL's |
| What is the function of aminolevulinate (ALA) synthase ? | rate limiting step of heme synthesis converts succinyl CoA and glycine to ALA |
| What is the function of cholymicrons (2)? | delivers dietary TG to peripheral tissues delivers dietary cholesterol to liver |
| What is the function of hormone sensitive lipase? | degradation of stored TG's |
| What is the function of LDL? | delivers hepatic cholesterol to peripheral tissues |
| What is the function of phospholipase A2? | liberates arachidonic acid from cell membrane |
| What is the function of PPP (3)? | -produces ribose-5-P from G6P for nucleotide synthsesis,-produces NADPH,-part of HMP shunt |
| What is the function of SAM? | transfers methyl units to wide variety of receptors |
| What is the function of the Cori Cycle? | transfers excess reducing equivalants from RBC's and muscle to liver to allow muscle to function anaerobically |
| What is the function of Tx A2 (2)? | platelet aggregation and vasoconstriction |
| What is the function of VLDL? | Delivers hepatic TG to peripheral tisssue |
| What is the inhibitor of lipogenesis (2)? | long-chain acyl-CoA, -cAMP |
| What is the inhibitor of PPP? | NADPH |
| What is the limiting reagent of ethanol metabolism? | NAD+ |
| What is the main substrate of fast twitch muscle? | glucose |
| What is the main substrate of slow twitch muscle? | ketone bodies, -FFA, triacylglycerol |
| What is the major function of fast twitch muscle? | rapid movement |
| What is the major function of slow twitch muscle? | sustained movement |
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megankirch
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