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87 Cards in this Set
- Front
- Back
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What molecule is modified by diptheria toxin? Describe the reaction and its effect
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EF-2 is ADP-ribosylated, which inhibits eukaryotic translation
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Which main translation factors are involved in elongation? Describe their roles
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EF-Tu brings aa-tRNA into A site, EF-Ts dissociates EF-Tu from GDP allowing its reuse, EF-G moves tRNAs through the ribosome
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What is the start codon? What are the stop codons?
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Start - AUG
Stop - UAA UAG UGA |
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What are the primary modifications of mRNA before it is used in translation?
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5' m7G - TP cap, 3' polyAdenylation
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What is the role of aa-tRNA synthetases?
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Charges tRNAs - bonds appropriate amino acid to each tRNA
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How are viral RNAs able to "hijack" eukaryotic translation?
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The IRES domain on viral mRNA binds eIF-4G directly, bypassing PABP and eIF-4Es role in initiation
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In which direction are proteins translated?
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From N to C terminals
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What are the functions of TIM and TOM proteins?
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Transport of proteins through the mitochondrial membranes - Chaperones deliver proteins to TOM, which lines up with TIM to allow transport through both membranes
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What are translocons?
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Protein channels such as TIM/TOM (mito), PEX (peroxisomes), and Sec (ER) that recognize targeting signal sequences to allow peptides to be transported into organelles
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What is the role of Ran-GTPase
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gating nuclear transport - GTP hydrolyzed during export process
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What is GPI?
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glycosylphosphatidyl isositol - a membrane anchor that soluble proteins are post-translationally attached to in ER, associates with lipid rafts
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What is the role of Rab-GTPase
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involved in SNARE docking, the Rab effector protein is on the target compartment
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Which amino acids are K, Q, D and E
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K - lysine, Q - glutamine, D - aspartic acid, E - glutamic acid
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Describe the changes in tertiary structure associated with the two conformations of PrP
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PrPc is rich in a-helixes, PrPsc has exposed anti-B sheets
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What are the typical symptoms of parkinsons disease?
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diminished facial expression, depressed mood, stooped posture, shortened gait, rigidity and tremor
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What are Lewy Bodies and what disease are they associated with?
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eosinophilic inclusions in surviving neurons composed of a-synculin and ubiquitin filament aggregates. found in parkinsons disease
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What is a-synculin's presumed function in the healthy neuron?
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Transporting dopamine vessicles down axons
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What neurodegenerative disease is correlated with trinucleotide (CAG) repeats?
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Huntingtons
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What is "anticipation" as it relates to neurodegenerative diseases and what causes it?
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Progressively earlier onset of symptoms with inheritance - due to the lengthening of repeating regions during DNA replication - stem loop mechanism
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Name some examples of Prion diseases
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Kuru, BSEs (mad cow disease), Creutzfield - Jakob Syndrome
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What is the role of lysyl oxidase? What is a necessary cofactor?
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cross links collagen and elastin fibers - needs copper
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Which is stiffer? Fibrillin or elastin
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Fibrillin - it stretches by rearranging trandem domains
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Which ECM components have anti-thrombin activity? Why
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acidic proteoglycans or GAGs (namely heparin) due to their strong anionic character
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Which cellular receptors are largely responsible for binding to extracellular glycoproteins
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integrins
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What is tenascin? Where is it found?
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ECM glycoprotein that forms octamers, tendon and mesenchyme
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What is von Willebrand's factor? What is its role?
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blood glycoprotein, involved in hemostasis, binds to clotting factors and collagen
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Which enzymes are inactive in scurvy?
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Prolyl hydroxylase and lysyl hydroxylase
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What are some symptoms of Ehler Danlos syndrome?
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stretchy skin, loose joints, heart valve problems
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A mutation in which protein is responsible for marfans syndrome?
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fibrillin 1
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Where is laminin found? What is a condition associated with its mutation?
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In the basal lamina, junctional epidermolysis bullosa
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What is normal serum [HCO3-]
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24 mEq/L
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Why does the body lower the [HCO3-] following increases in production of organic acids such as ketone bodies?
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To maintain electrical neutrality in the blood
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Which three ions are used in calculating the AG?
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Na HCO3 and Cl
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What is the typical cause of saline-responsive metabolic alkalosis?
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Large volume loss - low filtration rate of HCO3-, plus angiotensin upregulation of Na/H transporter leads to increase [HCO3-]
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What is Bartter's syndrome? What are its typical indications?
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tubular defect in Na+ reabsorption -> decreased BP -> Na/K pump -> metabolic saline responsive alkalosis with muscle weakness and hypokalemia
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What is a normal AG?
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12-16 mEq/L
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What receptors are responsible for the adhesion of immune cells such as macrophages and leukocytes to endothelial cells during chemotaxis
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selectins
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What AA sequence on fibronectin is considered most vital to integrin adhesion
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RGD
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What is oncotic pressure? Describe its importance to the cardiovascular system
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The osmostic pressure of the plasma due to plasma proteins. Its balance with hydrostatic pressure controls the filtration and reabsorption of fluid in the capillaries
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Do a-helices or B-sheets have a regular repeated pattern of residue interaction?
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a-helices do (every fourth AA is H bonded) but B sheets do not. They may have interacting residues that are very separate in primary structure
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What is the EF hand motif and what is its function?
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a helix-turn-helix separated by 12 residues, conjugates with Ca2+
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Which binds aa-tRNA: EF-Tu GDP or EF-Tu GTP?
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EF-Tu GTP
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What is the cause and presentation of Williams Beuren syndrome?
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Deletion of a region of chromosome 7 - leads to "elfin" facial expression, mild retardation, and extremely outgoing personality
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A DNA point mutation results in mRNA that encodes a shorter protein than the wild type gene, what kind of mutation is this?
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nonsense
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Define gene dosage
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number of gene copies in the genome
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A single nucleotide is inserted in the DNA sequence of a gene, what kind of mutation will this result in?
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Frameshift
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How many dogs is ok for a family to have?
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1 or 2, 10 is certainly too many
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how does acetylation of histones affect gene activity?
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increases gene expression by loosening chromatin structure for transcription
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what genetic modification is largely responsible for inheritable cell phenotype?
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epigenetic DNA modification - cytosine methylation patterns
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which nucleotides have 3 H bonds, 2?
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CG pairs have 3 H bonds, AT pairs have 2
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Which strand of DNA is identical to transcribed RNA, but with T->U?
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coding strand
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what enzyme unwinds DNA supercoils to relieve stress on the molecule during replication?
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topoisomerase
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what type of RNA is associated with gene regulation?
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micro RNA
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what is the sir protein?
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silent information regulators - deacetylates active nucleosome histones and stabilized heterochromatin structure
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in which direction is dna polymerized?
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5->3
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describe penicillins mechanism of action
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acts as a suicide inhibitor of gycopeptide transpeptidase - inhibits synthesis of bacterial cell wall
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what class of drug is allopurinol? what condition is it used to treat?
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suicide inhibitor of xanthine oxidase - used to treat gout
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what are ACE inhibitors used for? give an example
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to reduce blood pressue by blocking conversion of angiotensin I to II, captopril
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what antiviral drug was used as an example? what is its mechanism of action?
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acyclovir - acts as a nucleoside analogue, non specific viral kinase enzymes incorporate it into infected cells DNA - kills infected cells
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what is an apozyme? a holozyme?
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apozyme - enzyme without its cofactor, holozyme - enzyme cofactor combo
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what is the chemical role of vitamin B and other water solube vitamins
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metabolic cofactors
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what is an abzyme?
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a catalytic antibody - an antibody to the transition state
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how will Km change with increasing [E]
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no change
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How does Vmax change with increasing [E]
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linearly
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what is the function of DNA polymerase alpha?
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gap filling and synthesis of lagging strand
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what is the function dna polymerase delta?
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processive leading strand synthesis
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what is the function of dna polymerase gamma?
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mitochondrial dna synthesis
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what is the role of single stranded DNA binding protein?
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to remove hairpin structures from SS dna after helicases separate the strands
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what is the role of single stranded DNA binding protein?
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to remove hairpin structures from SS dna after helicases separate the strands
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what is the role of single stranded DNA binding protein?
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to remove hairpin structures from SS dna after helicases separate the strands
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Km decreases with the addition of inhibitor, what kind of inhibitor is being added?
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competitive
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Vmax decreases but Km remains constant with which kind of inhibitor?
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non competitive
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what is an uncompetitive inhibitor?
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binds to ES complex, both Vmax and Km change
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what kind of inhibitor results in parallel lines on lineweaver plot?
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uncompetitive
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what is an uncompetitive inhibitor?
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binds to ES complex, both Vmax and Km change
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what kind of inhibitor results in parallel lines on lineweaver plot?
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uncompetitive
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in lineweaver plot, addition of inhibitor results in lines with an intersection not on either axis, what is this type?
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mixed noncompetitive
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how is catalytic efficiency measured?
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kcat/km
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What is southern blotting used for?
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To detect specific sequence in dna genome
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what is activated flow cytometry? what is it used for?
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cells marked with flourescent markers are detected while flowing through sorting device. used to quantify cell populations or markers
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which is cytochrome c's role in cell signalling?
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signals apoptosis
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What is MERRF?
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myoclonic epilepsy and and ragged red fiber disease - mitochondrial disease - uncontrolled muscle jerking and misshaped mitochondria with crystalline inclusions
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give an example of mitochondrial materials that are supplied by nuclear DNA
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DNA polymerase gamma, nucleotide carrier, and dna helicase
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what is western blotting used for?
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to detect specific proteins in solution - separated by electrophoresis and fluorescently tagged with antibody
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what are quinolones?
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drugs that inhibit dna replication by inhibiting topoisomerases
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what is the mechanism of action of the erythromycin antibiotics?
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interferes with aminoacyl transfer in the 50s subunit of bacterial ribosomes
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what is an operon?
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in prokaryotes - a collection of genes forming similar functions which are arranged together on the genome and regulated in concert
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