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115 Cards in this Set
- Front
- Back
Mechanism of alcohol induces hypoglycemia
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NADH increase prevents gluconeogenesis by shunting pyruvate and oxaloacetate to lactate and malate
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51 yo man wih black spots in sclera and black urine upon standing
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alkaptonuria
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woman with cramps and dark urine after exercise
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McArdle's dz
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Alcoholic with rash, diarrhea, and AMS
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Pellagra (vit B3)
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What are the primary deficiencies in B-complex deficiencies
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dermatitis, glossitis, diarrhea
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What are the sxs of Vit A deficiency
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night blindness and dry skin
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What are the sxs of Vit B1 (thiamine deficiency
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Beriberi -- dry --polyneuritis, musc wasting; wet--high output CF (dil cardiomyopathy)
Wernicke-Korsakoff |
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What is the function of Vit A
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Visual pigments -- retinal
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What is the function of Thiamine B1
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cofactor for oxidative decarboxylation of a-keto acids (pyruvate, a-ketoglutarate)
cofactor fo transketolase in HMP shunt |
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What are the sxs of Vit B2 deficiency (riboflavin)
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angular stomatitis, cheilosis, corneal vascularization
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What is the function of B2 (riboflavin
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cofactro in oxidation and reduction --FADH2 and FAD/FMN --> 2ATP
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What is the B3 deficiency called
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Pellagra
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What are the primary sxs of pellagra
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Diarrhea, Dermatitis, and Dementia and beefy glossitis
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What are some causes of pellagra
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Hartnup dz (decrease tryptophan absorption)
malignant carcinoid syndrome (increased tryptophan metab) Isoniazid ( decrease vitamin B6) |
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What is the function of B3 (niacin)
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Constituent of NAD+ and NADP+; used in redox rxns; derived from tryptophan using B6.
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What are the sxs of B5 (pantothenate) deficiency
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Dermatitis, enteritis, alopecia, adrenal insufficiency 2/2 insufficiency of fatty acid synthase
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What is the function of B5 (pantothenate)
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constituent of CoA (cofactor for acyl transfers) and component in fatty acid synthase
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What are the sxs of B6 (pyridoxine) deficiency
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convulsion, hyperirritability --> deficiency due to INH and oral contraceptives
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What is the fx of B6 (pyridoxine)
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converted to pyridoxal phosphate-- cofactor used in transamination (ALT/AST), decarboxylation, and heme synthesis
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What are the sxs of B12 (cobalamin) deficiency
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Macrocytic, megaloblastic anemia, neurologic sxs (optic neuropathy, SCD, paresthesia), glossitis
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What is the function of B12 (cobalamin)
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cofactor in homocysteine methylation --> xfer CH3 --> Methionine + THF
and methylmalonyl-CoA handling stored in liver, large reserve pool synthesized by micro-organisms |
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What are the causes of B12 deficiency
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found only in animal products;
caused by malabsorption --> sprue, diphyllobothrium latum, lack of intrinsic factor (pernicious anemia), absence of terminal ileum (crohns) |
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what test is used to detect B12 deficiency
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Schilling test --radioactive B12 given orally, and elimination in urine measured; if urine conc. is low, either malabsorption or IF deficiency. Give IF and B12 again, to rule out absorption
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What causes myelin abnlities seen in B12 deficiency
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decreased methionine or increase methylmalonic acid
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What are the sxs of folic acid deficiency
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macrocytic, megaloblastic anemia (no neuro sxs)
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What is the function of folic acid
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coenzyme (Tetrahydrofolate--THF) for 1-carbon transfers, important for synthesis of nitrogenous bases in DNA and RNA
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What causes folic acid deficiency
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lack of green vegetables -->
PABA is folic acid precursor in bacteria; sulfa drugs and dapsone --> PABA analogs |
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What happens with folic acid deficiency in pregnancy
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neural tube defects
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What are the sxs of biotin deficiency
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dermatitis, enteritis
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what causes biotin deficiency
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antibiotic use and ingestion of raw eggs
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What is the function of biotin
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cofactor for carboxylations
1.) pyr --> oxa 2.) AcetylCoA --> malonyl-CoA 3.) Prorionyl-CoA --> methylmalonylCoA |
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What are the sxs of vit C (ascorbic acid) deficiency
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Scury -- swollen gums, bruising, anemia, poor wound healing
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What is the function of vit C
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necessary for hydroyxlation of Proline and lysine in collagen synthesis
facilitates Fe absorption by keeping Fe in reduced state necessary as cofactor in DA --> NE |
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What are the sxs fo VitD deficiency
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Rickets in kids; osteomalacia in adults and hypocalcemic tetancy
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What are the sxs of vit D excess
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Hypercalcemia, loos of appetite, stupor --> seen in Sarcoidosis where Mphages convert vitD to active form
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What type of vitD is found in milk
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D2
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What type of vitD is formed in skin
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D3
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What is the storage form of vitD
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24,25-OH D3 or 25-OH D3
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What are the sxs of Vit E deficiency
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Increase fragility of RBC, neuro dysfx
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what is the fx of Vit E
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Antioxidant (protect erythrocytes from hemolysis)
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What are the sxs of VitK
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neonatal hemorrhage, increased PT and PTT with nl bleeding time
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what factors are vit K dependent
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II, VII, IX, X and protein C and S
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What is the function of vit K
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catalyzed gamma-carboxylation of glutamic acid residues on various clotting proteins; synthesized by intestinal flora;
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what can cause vit K deficiency
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prolonged use of broad spectrum antibiotics
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What are the sxs of zinc deficiency
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delayed wound healing, hypogonadism, decreased adult hair(axillar, facial, pubic)
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What is the limiting reagent in ETOH metabolism
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NAD+
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What is the first setp of ETOH metabolism
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Ethanol --> Acetaldehyde by ETOH dehydrogenase and NAD+ --> NADH
zero order kinetics |
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What is the 2nd step of ETOH metab
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Acetaldehyde --> Acetate by Acetaldehyde dehydrogenase and NAD+ --> NADH
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What is the Disulfram rxn
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Disulfram inhibits acetaldehyd dehydrogenase --> acetaldehyde accumulation --> hangover sxs
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What is the mechanism of ETOH hypoglycemia
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increased NADH/NAD+ ratio --> diversion of pyruvate to lactate and OAA to malate, --> inhib of gluconeogenesis --> hypoglycemia
and shunt to fatty acid synthesis (causes hepatic fatty change) |
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What differentiates Kwashiokor from marasmus
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Kwashiokor -- protein malnutrition --> skin lesion, edema, liver malfx (small child with swollen belly)
Marasmus-- energy malnutrition --> tissue and muscle wasting, no subq fat and variable edema |
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what is heterochromatin
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condensed, transcriptionally inactive DNA
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which nucleotides are purines
what are pyrimadines |
A, G
CUT |
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Which form three H-bonds
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G and C
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What AA forms Purines
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Aspartate, CO2, Glycine, THF, Glutamine
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What AA forms Pyrimidines
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Aspartate and Carbamoyl Phosphate
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Which has multiple origins of replication
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Eukaryotes, AT-rich base pairs
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Which have single origin of replication
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Prokaryotes --> bidirectional DNA synth with Okazaki on lagging strand
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What does DNA topoisomerase do
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creates nick in helix to relieve supercoils
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What does primase do
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makes RNA primer on which DNA polyIII initiates replication
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What does DNA poly III do
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elongates chain (5'-->3' synthesis) and has 3'-->5' exonuclease activity
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What does DNA poly I do
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degrades RNA primer and fills with DNA; excises the 5'-->3' exonuclease
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What does DNA ligase do
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seal the strands
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what disorder has damaged nucleotide excision repair
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Xeroderma pigmentosa
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what disorder has impaired mismatch repair
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HNPCC
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What direction are DNA and RNA synthesized
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5'--> 3' (5' end has phosphate group)
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RNAs -- which is most abundant, largest, aand smallest
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rRNa, mRNA, and tRNA
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What do RNA polymerase I, II, and III synthesized respectively
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I -- rRNA
II -- mRNA III -- tRNA in the order of protein synthesis |
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What are the Three stop codons
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UGA, UAG, UAA
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What AA is the coded for by the start codon
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methionin (AUG or GUG)
formyl-methionine in prokaryotes |
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What is the promotor segment
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site of RNA poly and other transcription factors bind DNA upstream of the gene locus
Typically, AT rich wih TATA adn CAAT boxes |
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What are the typical effects of promotor mutation
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decrease in gene transcription
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What is the Enhancer
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segment of DNA that alters gene expression by binding transcription factors
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What is an operator sequence
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site where negative regulators (repressors) bind
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Which are expressed -- introns or exons
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Exons
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What are the steps of RNA processing
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Occurs in nucleus
1.) 5' end capping (7-methyl-G) 2.) PolyA tail -- 3' end 3.) Splicing of introns only processed RNA is transported out of the nucleus |
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Which end of tRNA is the AA attached
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3'
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What enzyme charges tRNA
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aminoacyl-tRNA synthase, consumes 1 ATP, has proofreading function for proper tRNA charging
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What are the 3 steps of protein synthesis
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initiation, elongation, and termination
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what is Initiation in protein synth
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initiation factors assemble 30S ribosomal subunit with the initiator tRNA
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What are the roles of ATP and GTP in protein synthesis
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ATP is hydrolyzed in tRNA charging
GTP is used for translocation of the ribosome |
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What are the three sites of the ribosome and what is each function
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A site -- incoming Aminoacyl tRNA
P site -- accommodates growing peptide E site-- hold Empty tRNA as it exits |
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What are the 3 step of elongation in protein synthesis
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1. Aminoacyl tRNA binds to A site
2. peptidyl transferase catalyzes peptide bond formation and transfers polypeptide to AA in A-site 3. Ribosome advances the nucleotides (3' direction) moving peptidyl RNA to Psite |
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What takes place in termination of protein synthesis
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release of protein and dissociation of ribosome
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What are some post-translational modifications of proteins
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Trimming -- removal of N- or C-terminal pro-peptides
Covalent alteration--phophorylatioin, glycosylatioin, hydroxylation Proteasomal degradation--ubiquitination of defective proteins |
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What regulates transitions between cell cycle phases
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cyclins
cdk tumor suppressors |
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What are the stages of the cell cycle
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Mitosis (pro, meta, ana, telo)
G1--Growth S- synthesis G2-- |
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What phase and type of cells remain in the following:
Permanent Stable Labile |
Permanent: G0--neurons, skeletal, cardiac muscle, RBC
Stable: G1 from G0 when stim--> hepatocytes and lymphocytes Labile: G1 -- bone marrow, gut epithelium, skin, hair follicles |
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What is the function of the RER
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site of synthesis of secrete proteins and N-linked oligosaccharide addition
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What types of cell are rich in RER
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mucus-secreting cells -- Goblet cells;
plasma cell secreting Ab neurons-- Nissl bodies -- enzymes and peptide NTs |
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What is the function of SER
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site of steroid synthesis and detoxification of drugs and poisons
Liver cells and adrenal cortex cells rich in SER |
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What are some functions of the Golgi system
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1. Distribution of proteins and lipids
2. Modify n-oligosaccharides on asparagine 3. add O-oligosacc to serine and threonine 4. mannose-6P targets protein to lysosome 5. proteoglycan assemble 6. sulfation of sugars in PGs and tyr proteins |
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What is I-cell dz
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failure to add mannose6P to lysosome proteins--> proteins then secreted; sxs include coarse facial feature, clouded corneas,
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What are the 3 primary vesicular trafficking proteins
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COPI --- Retrograde (Golgi-->ER)
COPII -- Anterograde (RER --> cisGolgi) Clathrin -- trans Golgi --> lysosomes, PM --> endosomes |
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What is the role of microtubules
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incorporated into flagella, cilia, and mitotic spindles
involved in slow axoplasmic transport in neurons |
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What are drugs that act on microtubules
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1. Mebendazole (antihelminthic)
2. Taxol (breast Ca) 3. Griseofulvin (antifungal) 4. Vincristine (Cancer) 5. Colchicine (gout) |
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What dz is due to microtubule polymerization defect leading to decreased phagocytosis
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Chediak-Higashi (staph/strep infxn, neuropathy, albinism)
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what is the composition of microtubules
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alpha and beta tubulin (13 per circumference)
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What is the structure of cilia
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9+2 Arrangement of microtubules
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What links the microtubules in cilia
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Dynein (ATPase) -- retrograde
Kinesin (anterograde) |
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What is Kartagener's syndrome
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immotile cilia 2/2 dynein arm defect --> infertility, bronchiectasis and sinusitis --> situs inversus
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Where is Type I collagen found
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Bone, Skin, Tendon, late wound repair
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Where is Type II collagen found
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Cartilage, nucleus pulposus
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Where is Type III collagen found
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Reticulin -- skin, bv, uterus, granulation tissue
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Where is Type IV collagne found
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basement membrane and basal lamina
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What is synthesis of collagen
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RER -- alpha chains -- preprocollagen--Gly-X-Y (X and Y are proline, hydroxyproline and hydroxylysine)
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Where does hydroxylation of collagen take place
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in ER, hydroxylation of proline and lysine requiring vitC
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What are the six steps of collagen synthesis
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Synthesis (RER)
Hydroxylation of proline and lysine(ER--VitC) --> Glycosylation of lysine (Golgi-Procollagen) -- triple helix Exocytosis Proteolytic processing (terminal cleavage --> tropocollagen) Cross-linking (lys--hydroxylysin by lysyl oxidase) -- collagen fibrils |
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What is Ehlers-Danlos syndrome
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faulty collagen synthesis
1. hyperextensible skin 2. easy bruising 3. hypermobile joints Collagen III most commonly affected; a/w berry aneurysms |
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What is osteogenesis imperfecta
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Auto Dominant
gene defect in collagen synthesis (collagen type I most common) sxs: multi fx, blue sclerae, hearing loss, and dental imperfections |
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What tissue stains witht eh following:
vimentin, desmin, cytokeratin, GFAP, neurofilaments |
vimentin (CT), desmin (musc), cytokeratin (epithelial cells), GFAP (neuroglia), neurofilaments (neurons)
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What disorder involves defective elastin and fibrillin
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Marfans (fibrillin) where elastin is tropoelastin with fibrillin scaffolding
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What types of metabolism take place in mitochondria
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FA Oxidation, Acetyl-CoA production, and Kreb cycle
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What types of metabolism take place in cytoplasm
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Glycolysis, FA synthesis, HMP shunt, Protien synth (RER), steroid synth (SER)
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What metabolism takes place in both cytoplasm and mitochondria
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Gluconeogenesis, urea cycle, heme sythesis
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