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517 Cards in this Set
- Front
- Back
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which resembles substrate: competitive or noncompetitive inhibitors?
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competitive
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what type of inhibitor binds at the active site and is overcome by increasing substrate?
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competitive
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what effect do competitive inhibitors have on Vmax?
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none
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what effect do noncompetitive inhibitors have on Vmax?
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decrease it
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what effect do competitive inhibitors have on Km?
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increase it
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what effect do noncompetitors have on Km?
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none
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the lower the Km, the higher the _____?
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affinity
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when does Km = [S]?
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at 1/2Vmax
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in the cell cycle, which phase is usually the shortest?
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mitosis
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most cells are at what point in the cell cycle?
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G0 - quiescent G1 phase
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rapidly dividing cells have a shorter ____?
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G1 (growth)
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this is the site of synthesis of secretory proteins and N-linked oligosaccharide addition to many proteins
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RER
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mucus-secreting goblet cells of SI and Ab-secreting plasma cells are rich in what cellular organelle?
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RER
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nissl substance is not found where?
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axon or axon hillock
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what do nissl bodies do?
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synthesize enzymes (e.g. ChAT) adn peptide neurotransmitters
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what is SER for?
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site of steroid synthesis and detoxification of drugs and poisons
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lipid hepatocytes and steriod-producing cells of the adrenal cortex are rich in what?
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SER
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where is mannose-6-phosphate added, and what does it do?
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golgi - added to specific lysosomal proteins, which targets them to the lysosome
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what is I cell disease?
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failure of addition of man-6-P to lysosome proteins, causing them to be secreted outside the cell instead of targeted to the lysosome; coarse facial features and restricted joint movement
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this is the distribution center of proteins and lipids from the ER to the plasma membrane, lysosomes, and secretory vesicles
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golgi
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the golgi modifies N-oligosaccharides on what amino acid?
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asparagine
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golgi adds O-oligosaccharides to residues of what?
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serine and threonine
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what organelle assembles proteoglycans from proteoglycan core proteins?
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golgi
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this organelle performs sulfation of sugars in proteoglycans and of selected tyrosine on proteins
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golgi
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what is the diameter of a microtubule?
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24 nm
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each dimer in microtubules has how many GTP bound to it?
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2
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mebendazole/thiabendazole, taxol, griseofulvin, vincristine/vinblastine, and colchicine all act on what structure?
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microtubules
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this syndrome is characterized by decreased phagocytosis as a result of a microtubule polymerization defect
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chediak-higashi syndrome
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microtubules are involved in what type of axoplasmic transport?
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slow
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how many polymerized tubulin dimers are there per circumference in microtubules?
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13
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this structure consists of a 9+2 arrangement of microtubules
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cilia
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dynein is reponsible for what direction of movement?
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retrograde
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kynesin is responsible for what direction of movement?
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anterograde
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this is an ATPase that links peripheral 9 doublets and causees bending of cilium by differential sliding of doublets
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dynein
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a high cholesterol or long saturated fatty acid content does what to melting temperature?
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increases it
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this is the only side of the plasma membrane that contains glycosylated lipids or proteins
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noncytoplasmic
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this is a major component of RBC membranes, myelin, bile, surfactant, and is also used in the esterification of cholesterol
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phosphatidylcholine
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H1, alpha1, V1, M1, & M3 are linked to which class of G protein?
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Gq (HAVe 1 M&M)
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Gq initiates what cascade?
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phospholipase C - PIP2 - IP3 - increased intracellular calcium (also PIP2 can yield DAG-PKC)
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beta1, beta2, D1, H2, V2 are linked to which class of G protein?
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Gs
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M2, alpha2, and D2 are linked to what class of G protein?
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Gi (MAD 2s)
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Gs/Gi stimulate/inhibit what cascade?
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adenylyl cyclase - cAMP - PKA
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what is the most abundant protein in the body?
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collagen
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90% of collagen is what type?
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type I
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this type of collagen is found in bone, tendon, skin, dentin, fascia, cornea, late wound repair
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type I
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this type of collagen is found in cartilage, vitreous body, nucleus polposus
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type II
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this type of cartilage is found in skin, blood vessels, uterus, fetal tissue, granulaltion tissue
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type III
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this type of cartilage is found in basement membrane or basal lamina
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type IV
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this type of cartilage is found in the epiphyseal plate
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type X
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where are collagen alpha chains (preprocollagen) translated?
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on RER
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preprocollagen has the structure Gly-X-Y - what are X and Y?
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proline, hydroxyproline, or hydroxylysine
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hydroxylation of specific proline and lysine residues in the synthesis of collagen occurs where and requires what?
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ER; vitamin C
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in collagen synthesis, where does glycosylation of pro-alpha-chain lysine residues and formation of procollagen occur?
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golgi
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what is procollagen?
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triple helix of 3 collagen alpha chains
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what is formed when procollagen peptidases cleave terminal regions of procollagen? where does this occur?
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tropocollagen; occurs outside fibroblasts
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collagen fibrils are composed of what?
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many staggered tropocollagen molecules that are reinforced by covalent lysine-hydroxylysine cross linkages
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the step between pro-alpha-chains and triple helix formation/procollagen does not occur in what disease?
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osteogenesis imperfecta
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the step between peptide cleavage and collagen fibrils with crosslinks doesn't occur in what syndrome?
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ehlers-danlos
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vimentin stains what?
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connective tissue
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what does desmin stain?
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muscle
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what does cytokeratin stain?
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epithelial cells
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what do glial fibrillary acid proteins (GFAP) stain?
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neuroglia
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what do neurofliaments stain?
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neurons
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fatty acid oxidation (beta-oxidation), acteyl-CoA production, Krebs cycle occur where?
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mitochondria
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glycolysis, fatty acid synthesis, HMP shunt, protein synthesis (RER), steroid syntheis (SER) occur where?
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cytoplasm
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where do gluconeogenesis, urea cycle, and heme synthesis occur?
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both mitochondria and cytoplasm
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the 2 phosphoanhydride bonds in ATP have how many kcal/mol each?
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7 kcal/mole
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aerobic metabolism of glucose produces how many ATP via malate shuttle?
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38 (malate - mal8)
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aerobic metabolism of glucose produces how many ATP via G3P shuttle?
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36
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how many ATP per glucose does anaerobic glycolysis produce?
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2
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what is ATP composed of?
|
base (adenine), ribose, 3 phosphoryls, 2 phosphoanhydride bonds
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ATP + methionine = ?
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S-adenosyl-methionine (SAM)
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what does S-adenosyl-methionine do?
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transfers methyl units to a wide variety of acceptors (SAM the methyl donor man)
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regeneration of methionine (and thus SAM) is dependent on what?
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vitamin B12
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this yields CAMP via adenylate cyclase
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ATP
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this yields cGMP via guanylate cyclase
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GTP
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what is the intermediate between glutamate and GABA? what does it require?
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glutamate decarboxylase - requires vitamin B6
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|
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choline -> ACh via what?
|
choline acetyltransferase
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arachidonate yields what products via cyclooxygenase/lipoxygenase?
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prostaglandins, thromboxanes, leukotrienes
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what is the rate-limiting enzyme of glycolysis?
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phosphofructokinase (PFK)
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phosphofructokinase catalyzes fructose-6-P to what?
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fructose-1,6-bis-P
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what reaction does bisphosphoglycerate mutase catalyze?
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1,3-BPG to 2,3 BPG
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what is NADPH used in?
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1. anabolic processes, 2. respiratory burst, 3. P450
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this is usually used in catabolic processes to carry reducing equivalents away as NADH
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NAD+
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this is used in anabolic processes (steroid and fatty acid synthesis) as a supply of reducing equivalents
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NADPH - product of the HMP shunt
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where is hexokinase found?
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throughout the body
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where is glucokinase found?
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primarily in the liver (gLucokinase-Liver)
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this enzyme phosphorylates excess glucose to sequester it in the liver as G6P
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glucokinase
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what enzyme is feedback inhibited by G6P?
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hexokinase
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how do RBCS metabolize glucose? what do they depend on?
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anaerobically (no mitochondria) - therefore depend solely on glycolysis
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what catalyzes D-glucose -> G-6-P?
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hexokinase/glucokinase
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what catalyzes fructose-6-P -> fructose 1,6-BP?
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phoshofructokinase (rate-limiting step)
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what inhibits fructose-6-P -> fructose 1,6-BP?
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ATP, citrate
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what promotes fructose-6-P -> fructose 1,6-BP?
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AMP, frucotse-2,6-BP
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what catalyzes phosphoenolpyruvate -> pyruvate?
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pyruvate kinase
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what inhibits phosphoenolpyruvate -> pyruvate?
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ATP, alanine
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what promotes phosphoenolpyruvate -> pyruvate?
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fructose-1-6-BP
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what catalyzes pyruvate -> acetyl-CoA?
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pyruvate dehydrogenase
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what inhibits pyruvate -> acetyl-CoA?
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ATP, NADH, acetyl-CoA
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chronic granulomatous disease is related to a deficiency of what?
|
NADPH oxidase
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deficiencies in hexokinase, glucose phosphate isomerase, aldolase, triosephosphate isomerase, phosphate glycerate kinase, enolase, and pyruvate kinase are associated with what?
|
hemolytic anemia
|
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what does the pyruvate dehydrogenase complex require?
|
first 4 B vitamins plus lipoic acid: 1. pyrophosphate (B1, thiamine, TPP) 2. FAD (B2, riboflavin), 3. NAD (B3, niacin), 4. CoA (B5, panthotenate), 5. lipoic acid
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pyruvate + NAD+ + CoA -> ???
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acetyl-CoA + CO2 + NADH
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what happens in pyruvate dehydrogenase deficiency?
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causes backup of substrate (pyruvate and alanine), resulting in lactic acidosis - neuro defects
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what is the treatment for pyruvate dehydrogenase deficiency?
|
increase intake of ketogenic nutrients, e.g. high fat content or increased lysine and leucine
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what are the only purely ketogenic amino acids?
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lysine and leucine
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B1 deficiency in alcoholics can lead to what other deficiency?
|
pyruvate dehydrogenase
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how many ATP equivalents are needed to generate glucose from pyruvate?
|
6 ATP
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what serves as a carrier of amino groups from muscle to liver in pyruvate metabolism?
|
alanine
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what does the Cori cycle do?
|
transfers excess reducing equivalents from RBCs and muscle to liver, allowing muscle to function anaerobically - net 2 ATP
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what complex requires the same cofactors as the pyruvate dehydrogenase complex?
|
alpha-ketoglutarate dehydrogenase complex
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how many ATP/acetyl-CoA does the TCA cycle produce?
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12
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how many NADH per acetyl CoA does the TCA cycle produce? per glucose?
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3, 6
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how many FADH2 and GTP does the TCA cycle produce per acetyl CoA?
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1 of each (2 per glucose)
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how many CO2 does the TCA cycle produce per acetyl CoA?
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2 (CO2); 4 per glucose
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in the electron transport chain, 1 NADH yields what?
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3 ATP
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in the electron transport chain, 1 FADH2 yields what?
|
2 ATP
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what do rotenone, antimycin A, CN-, CO do?
|
directly inhibit electron transport, causing a decrease of proton gradient and block of ATP synthesis
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what does oligomycin do?
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directly inhibits mitochondrial ATPase, causing an increase of proton gradient, but no ATP is produced because electron transport stops
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what do uncoupling agents, e.g. 2,4 DNP, do to oxidative phosphorylation?
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increase permeability of membrane, causing a decrease of proton gradient and increased O2 consumption; ATP synthesis stops, electron transport continues
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what are the irreversible enzymes in gluconeogenesis?
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Pathway Produces Fresh Glucose: pyruvate carboxylase, PEP carboxykinase, fructose-1,6-bisphosphatase, glucose-6-phosphatase
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what does pyruvate carboxylase catalyze? where does it occur?
|
pyruvate -> oxaloacetate; in mitochondira
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this step of gluconeogenesis requires biotin and ATP, and is activated by acetyl-CoA
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pyruvate -> oxaloacetate
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what catalyzes oxaloacetate -> phophoenolpyruvate? where does this step of gluconeogenesis occur?
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PEP carboxykinase; cytosol
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what catalyzes fructose 1,6-bisphophate -> fructose-6-P? where does it occur?
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fructose-1,6-bisphosphatase; cytosol
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what reaction does glucose-6-phosphatase catalyze?
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glucose-6-P -> glucose (in cytosol)
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where are the enzymes of gluconeogenesis found?
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liver, kidneys, intestinal epithelium (muscle cannot participate in gluconeogenesis)
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what do deficiencies of the key gluconeogenesis enzymes cause?
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hypoglycemia
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what is the role of the pentose phosphate pathway (HMP shunt)?
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1. produces ribose 5P from G6P for nucleotide synthesis 2. produces NADPH from NADP+ for fatty acid and steroid biosynthesis and for maintaining reduced glutathione inside RBCs
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all reactions of the HMP shunt occur where?
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cytoplasm
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how much ATP is used and produced in the HMP shunt?
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none
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in what sites does the HMP shunt occur?
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lactating mammary glands, liver, adrenal cortex - all sites of fatty acid or steroid synthesis
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what are the ketogenic essential amino acids?
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leucine, lysine
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what are the glucogenic/ketogenic essential amino acids?
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Ile, Phe, Trp
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what are the glucogenic essential amino acids?
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Met, Thr, Val, Arg, His
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which amino acids are required during periods of growth?
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Arg, His
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what is the most basic amino acid?
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arginine
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arginine and lysine are found in high amounts where?
|
histones, which bind to negatively charged DNA
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at body pH (7.4), acidic amino acids aspartic acid (Asp) and glutamic acid (Glu) have what charge?
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negative
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at body pH, basic amino acids Arg and Lys have what charge?
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positive
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what net charge does basic amino acid histidine have at body pH?
|
no net charge
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what amino acids have an extra NH3 group?
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Arg and Lys
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what cycle degrades amino acids into amino groups?
|
urea cycle
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the urea cycle accounts for what percent of nitrogen in urine?
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90%
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where in the body does the urea cycle take place?
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liver
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where in the cell does carbamoyl phosphate incorporation (in urea cycle) take place?
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mitochondria
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all steps of the urea cycle except for carbamoyl phosphate incorporation occur where?
|
cytosol
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histamine is derived from what amino acid?
|
histidine
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porphyrin -> heme comes from what amino acid?
|
glycine
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creatine, urea, and nitric oxide all come from what amino acid?
|
arginine
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GABA is derived from what amino acid?
|
glutamate
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tyrosine (->thyroxine) -> dopa (->melanin) -> dopamine -> NE -> epi originates from what amino acid?
|
phenylaline
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niacin, serotonin, melatonin all come from what amino acid?
|
tryptophan
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what coenzyme is used by pyruvate dehydrogenase to convert pyruvate to acetyl CoA (in the absence of this, pyruvate accumulates and can be converted by lactate dehydrogenase to lactate, which is spilled in the blood causing lactic acidosis)
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thiamine
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waht do exopeptidases do?
|
can remove amino acids from the amino- or carboxyl-terminus of a protein
|
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what do endopeptidases do?
|
cut AA bond within a molecule
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what is the rate-limiting enzyme of glycolysis?
|
phosphofructokinase
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what are the essential amino acids?
|
lysine, isoleucine, leucine, threonine, valine, tryptophan, phenylaline, methionine, histidine (& tyrosine b/c synthesized from phenylaline; arginine required for growth)
|
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what areas of the body don't need insulin for glucose uptake into cells?
|
brain, RBCs, intestine, cornea, kidney, liver
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|
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where are GLUT2 receptors found?
|
beta cells
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where are GLUT4 receptors found?
|
muscle and fat
|
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what are the anabolic effects of insulin?
|
(1) increases glucose transport, (2) increases glycogen synthesis and storage, (3) increases TG synthesis and storage, (4) increases Na retention in kidneys, (5) increases protein synthesis
|
|
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what does glucagon do to glycogen synthase and phosphorylase?
|
glucagon phosphorylates stuff : turns glycogen synthase OFF and phosphorylase ON
|
|
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what does insulin do to glycogen synthase and phosphorylase?
|
insulin dephosphorylates stuff - turns glycogen synthase ON and phosphorylase OFF
|
|
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where does fatty acid degradation take place?
|
where its products will be consumed - in the mitochondrion
|
|
|
urine test for ketones does not detect what?
|
beta-hydroxybutyrate (favored by high redox state)
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what are ketone bodies made from?
|
HMG-CoA
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|
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what are ketone bodies metabolized into by the brain?
|
2 molecules of acetyl-CoA
|
|
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what catalyzes the rate-limiting step in cholesterol synthesis?
|
HMG-CoA reductase, which converts HMG CoA to mevalonate
|
|
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2/3 of plasma cholesterol is esterified by what?
|
lecithin-cholesterol acyltransferase (LCAT)
|
|
|
what is the role of pancreatic lipase?
|
degradation of dietary TG in the small intestine
|
|
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what degrades TG in circulating chylomicrons and VLDLs?
|
lipoprotein lipase
|
|
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what is the role of hepatic TG lipase?
|
degradation of TG remaining in IDL
|
|
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what degrades TG in stored adipocytes?
|
hormone-sensitive lipase
|
|
|
what is the role of alipoprotein A-I?
|
Activates LCAT (A-activate)
|
|
|
which apolipoprotein binds to the LDL receptor?
|
apo B-100
|
|
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what is the role of apo C-II
|
cofactor for lipoprotein lipase
|
|
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what apolipoprotein mediates extra (remnant) uptake?
|
apo E (E-extra)
|
|
|
this lipoprotein delivers dietary triglycerides to peripheral tissues and cholesterol to the liver; secreted by intestinal epithelial cells
|
chylomicron
|
|
|
excess of this lipoprotein causes pancreatitis, lipemia retinalis, and eruptive xanthomas
|
chylomicron
|
|
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what apolipoprotein mediates secretion of chylomicrons?
|
apo B-48
|
|
|
what lipoprotein delivers hepatic triglycerides to peripheral tissues? what is it secreted by?
|
VLDL - secreted by liver
|
|
|
this lipoprotein is formed in the degradation of VLDL & delivers TG and cholesterol to the liver, where they are degraded to LDL
|
IDL
|
|
|
what is the role of LDL?
|
delivers hepatic cholesterol to peripheral tissues
|
|
|
what lipoprotein is formed by lipoprotein lipase modification of VLDL in the peripheral tissue?
|
LDL
|
|
|
excess of this lipoprotein causes atherosclerosis, xanthomas, and arcus corneae
|
LDL
|
|
|
what is the role of HDL?
|
mediates transport of cholesterol from periphery to liver; acts as a repository for apoC and apoE
|
|
|
from where is HDL secreted?
|
both liver and intestine
|
|
|
what is the first step in heme synthesis? what catalyzes it?
|
succinyl CoA + glycine … catalyzed by ALA synthetase
|
|
|
what occurs in lead poisoning?
|
inhibition of ferrochelatase and ALA dehydrase
|
|
|
what accumulates in urine in lead poisoning?
|
coproporphyrin and ALA
|
|
|
what is deficient in acute intermittent porphyria?
|
deficiency in uroporphyrinogen I synthetase
|
|
|
what accumulates in acute intermittent porphyria?
|
porphobilinogen and delta-ALA
|
|
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what is the deficiency in porphyria cutanea tarda?
|
uroporphyrinogen decarboxylase
|
|
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waht accumulates in urine in porphyria cutanea tarda? what else is this associated with?
|
uroporphyrin accumulates (tea-colored urine); associated with photosensitivity
|
|
|
painful abdomen, pink urine, polyneuropathy, psych disturbances, precipitated by drugs?
|
symptoms of porphyrias
|
|
|
which form of hemoglobin has a higher affinity for O2?
|
relaxed form (300x affinity of taut form)
|
|
|
increased Cl-, H+, CO2, 2,3-BPG and temp favor what form of Hb? Which way does the O2 curve shift?
|
R form; shifts to right, leading to increased O2 unloading
|
|
|
this is an oxidized form of Hb (ferric, Fe3+) that does not bind O2 as readily but has an increased affinity for CN-
|
methemoglobin
|
|
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what do you administer in cyanide poisoning?
|
nitrates to oxidize Hb to methemoglobin form
|
|
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with what do you treat toxic levels of methemoglobin?
|
methylene blue
|
|
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CO2 binding to Hb favors what form?
|
T (taut)
|
|
|
phospholipids and sphingolipids are what type of molecules? what type of vesicles do they form?
|
ampiphathic molecules - two hydrophobic tails; form bilayer vesicles
|
|
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where does beta-oxidation of very long chain fatty acids occur?
|
peroxisomes
|
|
|
where does degradation of DNA occur?
|
lysosomes
|
|
|
where does oxidative phosphorylation occur?
|
mitochondria
|
|
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where does post-translational modification of proteins occur?
|
golgi
|
|
|
when NO is released and diffuses into a smooth muscle cell, what does it turn on?
|
guanylate cyclase, which makes the second messenger cGMP, which triggers smooth muscle relaxation
|
|
|
what synthesized nitric oxide from arginine?
|
nitric oxide synthase - produces citrulline as a by-product
|
|
|
this is used to form nucleotids by adding a phosphoribosyl group to a nitrogenous base
|
phosphoribosyltransferase
|
|
|
what covers most microvilli & apparently helps to prevent them from trauma?
|
layer of glycocalyx
|
|
|
what is glial fibrillary acidic protein?
|
intermediate filament found in astrocytes
|
|
|
how are chromatids pulled apart during anaphase?
|
kinetochore microtuules from each of the two spindle poles attach to teh kinetochore plates of the centromere to pull the chromatids apart during anaphase
|
|
|
gap junctions are made of a hexagonal lattice of tubular rotein subunits called what?
|
connexons - form hydrophilic channels connecting the cytoplasm of adjacent cells
|
|
|
what structure are sealing strands found in?
|
tight junctions
|
|
|
what are tonofilaments found in?
|
desmosomes and hemidesmosomes
|
|
|
what contains type IV collagen, glycoproteins including laminin, and proteoglycans, including heparan sulfate?
|
basal lamina
|
|
|
what involves unfolding a fully translated protein, transporting it into the mitochondria, and then refolding it using other HSP proteins?
|
import of mitochondrial proteins from the cytosol into the mitochondria
|
|
|
what type of gene is the Rb gene?
|
tumor suppressor
|
|
|
what is the role of calreticulin?
|
binds to misfolded proteins and prevents them from being exported to the golgi
|
|
|
where does synthesis of the LDL receptor begin?
|
in cytosol on free ribosomes - completed on ribosomes bound to RER
|
|
|
what happens if a protein cannot refold properly?
|
it is targeted for degradation by proteases
|
|
|
the formation of a junctional complex relies on what?
|
homotypic interaction between E-cadherin proteins on adjacent cells - initiates the formation of zona adherens, including signaling pathways, which are then activated to initiate the formation of zona occludens and desmosomes
|
|
|
what are microvilli made of?
|
extensions of bundles of actin filaments, or microfilaments; myosin is associated
|
|
|
during contraction of a skeletal muscle, what maintains its uncontracted length?
|
A band
|
|
|
what quality control chaperone in the RER binds to misfolded membrane proteins and prevents them form proceeding to the golgi?
|
calreticulin
|
|
|
what quality control chaperone binds to misfolded soluble proteins and prevents them from going to the golgi?
|
calnexin
|
|
|
what do antibodies attack in pemphigus vulgaris?
|
desmoglein
|
|
|
what is the transmembrane cadherin that forms intercellular linkages at desmosomes?
|
desmoglein
|
|
|
what organelle is responsible for sorting and packaging of proteins?
|
RER
|
|
|
what protein property is birefringence related to?
|
beta-pleated sheet secondary structure
|
|
|
the crystalline core of an eosinic granule contains what?
|
major basic protein - appears to function in the destruction of parasites
|
|
|
name 3 sites where elastic fibers are found
|
large arteries (esp. aorta), vocal cords, and ligamenta flava (which connect the vertebrae); small amounts also found in skin
|
|
|
acini in what salivary gland are almost pure mucous cells?
|
sublingual, submandibular, parotid
|
|
|
acini in what salivary gland are a mixture of serous and mucuous cells?
|
submandibular
|
|
|
acini in what salivary gland are mostly pure serous cells?
|
parotid
|
|
|
striated muscle under voluntary control is found in what part of the esophagus?
|
upper third; middle third is roughly half striated and half smooth; lower third contains only smooth
|
|
|
primordial eggs remain stopped in what stage from before birth until ovulation?
|
diplotene stage of first meotic division
|
|
|
what is the appropriate stain for pneumocystis?
|
methenamine silver
|
|
|
what cells of the anterior pituitary stain pink?
|
somatotropes - GH, mammotropes - prolactin
|
|
|
what cells of the anterior pituitary stain blue on H&E?
|
corticotropes - ACTH, gonadotropes - FSH & LH, thyrotropes - TSH
|
|
|
what is the only site of the kidney in which epithelial cells have a brush border made of microvilli?
|
proximal convoluted tubule
|
|
|
how do fascial straps (retinacula) and fascial coverings of muscles or muscle groups attach to nearby bones?
|
blending with the covering periosteum; no deep attachments are made by fascia
|
|
|
what are the three phases of spermatogenesis?
|
spermatocytogenesis, meiosis, spermiogenesis
|
|
|
what type of cell is the germ cell closest to the basal lamina in the seminiferous tubule?
|
spermatogonia
|
|
|
what ear structure contains hair cells?
|
organ of corti (from the cochlear branch of CN VII)
|
|
|
what is a good stain for fungi?
|
methenamine silver
|
|
|
why is cartilage particularly vulnerable to infection?
|
because it is relatively avascular - immune system cannot access it effeciently
|
|
|
calcification of what is notorious for producing 'phantom' lung lesions?
|
hyaline cartilage of the costal cartilages
|
|
|
what type of cell is spindle-shaped like a fibroblast but contains several bundlese of microfilaments in its cytoplasm?
|
myofibroblast
|
|
|
where is fenestrated epithelium seen?
|
liver
|
|
|
what is responsible for producing the majority of new bone after a fracture?
|
periosteum
|
|
|
what catalyzes the irreversible conversion of pyruvate to acetyl CoA?
|
pyruvate dehydrogenase
|
|
|
if pyruvate dehydrogenase is absent, what will it be converted to?
|
alanine via alanine aminotransferase;
|
|
|
what is the porphyrin ring of heme derived from?
|
TCA cycle intermediate succinyl-CoA and AA glycine; this initial synthetic step, which is rate-limiting, is catalyzed by aminolevulinic acid synthase
|
|
|
vitamin K is an important coenzyme for what?
|
gamma-gluyamylcarboxylase, an enzyme that catalyzes a post-translational modification of a group of calcium-binding proteins
|
|
|
how does vitamin K deficiency manifest in infants?
|
GI bleeding, skin hemorrhages, intracranial hemorrhage
|
|
|
absence of vitamin B12 results in the accumulation of what?
|
methylmalonyl-CoA (B12 is a cofactor in the conversion of methylmalonyl-CoA to succinyl-CoA)
|
|
|
what is the clinical picture associated with galactokinase deficiency?
|
very mild disease - only significant complication is cataract formation
|
|
|
what does homozygous deficiency of galactose-1-phosphate uridyltransferase lead to?
|
severe disease, culminating in death in infancy: impaired renal tubular absorption leading to aminoaciduria, GI symptoms, hepatosplenomegaly, cataracts, bleeding diatheses, hypoglycemia, and MR
|
|
|
what is the process of glycolysis?
|
converts glucose into pyruvate with concomitant production of ATP
|
|
|
name three ketone bodies
|
acetoacetate, beta-hydroxybutyrate, and acetone
|
|
|
when/how are ketone bodies produced?
|
produced by liver in the fasting state by beta-oxidation of fatty acids
|
|
|
this condition is associated wth MR, hepatosplenomegaly, foam cells in bone marrow, cherry red spots, and neuro deficits - death by 3 years of age is common
|
Niemann-Pick
|
|
|
what is the mechanism of cipro?
|
inhibits DNA gyrase (prokaryotic topoisomerase II) essential for DNA replication
|
|
|
what is the mechanism of statins?
|
HMG-CoA reductase inhibitors
|
|
|
this syndrome is characterized by MR, nervous system malformations, rocker-bottom feet, polydactyly, and cleft lip and palate
|
Trisomy 13/Patau syndrome
|
|
|
where does the clinically important degradation of ethanol to acetaldehyde occur in humans?
|
peroxisomes and SER (P450)
|
|
|
where is acetaldehyde oxidized to acetate?
|
mitochondria
|
|
|
what is the defect in von Gierke's?
|
glucose-6-phosphatase
|
|
|
what is Smith-Lemli-Opitz syndrome?
|
recessive genetic disease - first single-gene disease to be associated with multiple malformations
|
|
|
microcephaly, MR, hypotonia, incomplete development of genitalia, high forehead, pyloric stenosis, syndactyly of 2nd and 3rd toes are characteristic of what syndrome?
|
Smith-Lemli-Opitz
|
|
|
what technique is used to identify a specific protein that may be present in very small concentrations in a complex protein mixture?
|
Western blotting
|
|
|
what technique utilizes DNA-RNA hybridization to determine the size and abundance of RNA for a specific gene?
|
Northern blotting
|
|
|
what technique utilizes DNA-DNA hybridization?
|
Southern blotting
|
|
|
what technique involves DNA-protein interactions?
|
Southwestern blotting - a protein sample is subjected to electrophoresis, transferred to a filter, and exposed to labeled DNA
|
|
|
following treatment of ALL, patients often have a high level of what? how do you treat them?
|
urate (secondary to breakdown of nucleic acids) - Rx: allopurinol to decrease plasma urate levels (inhibition of xanthine oxidase)
|
|
|
what is the best technique for determining whether a gene is expresed in a particular cell type?
|
Northern blot
|
|
|
what is the most common technique used to screen for cystic fibrosis?
|
PCR
|
|
|
what is the primary source of ketones in diabetic ketoacidosis?
|
free fatty acid breakdown
|
|
|
severe neonatal jaundice, elevated indirect bilirubin, and exchange blood transfusion suggest what?
|
hemolysis
|
|
|
increased levels of 2,3 BPG, 3-PG, 2-PG, and PEP correspond with what type of hemolytic anemia?
|
one induced by pyruvate kinase deficiency
|
|
|
perifollicular hemorrhages, fragmentation of hairs, purpura, ecchymoses, splinter hemorrhages, and hemorrhages into muscle are characteristic of what?
|
vitamin C deficiency
|
|
|
nearly 90% of cases of hereditary nonpolyposis colorectal cancer are linked to mutations in what?
|
mismatch repair genes - e.g. hMLH1 & hMSH2
|
|
|
hypolglycemia with hypoketosis after fasting suggests what? accumulation of organic dicarboxylic acids suggests what?
|
a block in fatty acid oxidation - fatty acyl CoA dehydrogenase deficiency: most commonly medium chain acyl CoA dehydrogenase (MCAD) deficiency
|
|
|
dementia, ataxia, ophthalmoplegia?
|
wernicke encephalopathy
|
|
|
in what people does wernicke encephalopathy typically develop? what is it a result of?
|
alcoholics; thiamine deficiency
|
|
|
what are the four major enzymes requiring thiamine pyrophosphate?
|
pyruvate dehydrogenase, alpha-ketoglutarate deydrogenase, branched-chain ketoacid dehydrogenase, transketolase
|
|
|
a child with ketotic hypoglycemia following a period of fasting most likely has a defect in what?
|
gluconeogenesis (or pathway providing substrates for gluconeogenesis)
|
|
|
under fasting conditions, what is the primary substrate for gluconeogenesis?
|
alanine (derived from muscle protein)
|
|
|
in a child with ketotic hypoglycemia, if alanine rapidly increases blood glucose, what is the likely defect?
|
defect in protein catabolism (rules out defect in gluconeogenesis)
|
|
|
what LOD score is required to establish linkage between two loci?
|
3.00 or higher
|
|
|
what LOD score is required to rule out linkage between two loci?
|
-2.00 or less
|
|
|
what two red cell enzyme deficiencies are characterized clinically by long 'normal' periods interspersed with episodes of hemolytic anemia triggered by infections and oxidant drug injury?
|
pyruvate kinase deficiency and G6PD deficiency
|
|
|
primers in PCR must pair up with what?
|
the 3' sequences of the two strands (sequence of left primer is identical to that of top strand and sequence of right primer is identical to bottom strand written 5'to 3')
|
|
|
alopecia is related to deficiency of what vitamin?
|
vitamin A
|
|
|
what begins the HMP shunt?
|
conversion of glucose-6-phosphate to 6-phosphogluconate
|
|
|
what pathway increases the ratio of NADPH/NADP+?
|
HMP shunt
|
|
|
proteins destined to be secreted are synthesized where?
|
on ribosomes associated with RER
|
|
|
proteins destined for the cytosol and several organelles are synthesized on what?
|
'free' ribosomes
|
|
|
what are the characteristics of abetalipoproteinemia?
|
rare AR disorder characterized by very low levels of serum cholesterol and triglyceride
|
|
|
what is absent in abetalipoproteinemia?
|
ApoB-containing lipoproteins (chylomicrons, VLDL, LDL)
|
|
|
what enzyme is closely related to the role of folate in lowering the risk of CV disease?
|
homocysteine methyltransferase
|
|
|
what does cyanide inhibit?
|
cytochrome oxidase - causes loss of all ATP production associated with oxidative phosphorylation
|
|
|
on what chromosome is the Wilms tumor suppressor gene located?
|
chromosome 11
|
|
|
a higher Km means a lower what?
|
affinity
|
|
|
liver and steroidogenic tissues have a scavenger receptor that recognizes HDL and mediates transfer of cholesterol into these tissues - what is it called?
|
SR-B1
|
|
|
triad of ophthalmoplegia, ataxia, and global confusion?
|
Wernicke encephalopathy - requires immediate administration of B1/thiamine
|
|
|
where is ribosomal RNA manufactured?
|
nucleolus
|
|
|
ingestion of alcohol and what else can exacerbate hyperuricemia/gout?
|
nucleic acids - foods rich in DNA (caviar) or RNA (liver pate and sweetbreads (pancreas)) are sources of purines
|
|
|
what is MELAS?
|
mitochondrial encephalomyopaty, lactic acidosis, and stroke-like episodes
|
|
|
what is seen on muscle biopsy in patients with MELAS?
|
ragged red muscle fibers and disrupted mitochondria
|
|
|
what high-energy compound is formed when succinate thiokinase catalyzes the cleavage of the succinl-CoA thoiester bond?
|
GTP
|
|
|
what is the energy source used in protein synthesis (formation of activated elongation factor to which tRNA binds & in transfer of elongating chain from P to A site in ribosome)
|
GTP
|
|
|
proteins that fail to achieve normal tertiary and quaternary structures are retained where?
|
RER
|
|
|
vitamin B12 deficiency causes an increase in what in urine?
|
methylmalonate (due to low activity of methylmalonyl CoA mutase)
|
|
|
1 gram of protein or carbs produces how many kcal of energy?
|
about 4
|
|
|
one gram of fat produces how many kcal of energy?
|
9
|
|
|
deletion of two nucleotides will lead to what type of mutation?
|
frame-shift
|
|
|
children with this disease are generally healthy for the first two years but develop progressive hepatosplenomegaly with accumulation of glucocerebroside in macrophages
|
Gaucher's
|
|
|
flaring of the distal femur is common in this disease - may be described as having an Erlenmeyer flask appearance
|
Gaucher's
|
|
|
what binds to receptors with zinc finger motifs?
|
steroid hormones
|
|
|
what amino acid can partially take the place of niacin?
|
tryptophan - about 2% can be converted to quinolinate, which can then be used in place of niacin in NAD synthesis
|
|
|
if misfolded proteins accumulate in large quantities, where will they be found?
|
ER
|
|
|
weakness accompanied by difficulty in relaxation that is most pronounced in hands and feet; cataracts, testicular atrophy, heart disease, dementia, baldness?
|
myotonic dystrophy
|
|
|
the affected gene in myotonic dystrophy is located on what chromosome? how is it inherited?
|
19; autosomal dominant
|
|
|
the DNA polymerase used in PCR is highly resistant to what?
|
heat - comes from bacteria that grow in hot springs
|
|
|
during intense exercise, in what form will carbons derived from glucose enter the TCA cycle?
|
acetyl-CoA
|
|
|
what syndrome is due to a defect in copper transporting P-type ATPase?
|
Ehlers-Danlos
|
|
|
this contributes to hyperlipidemia in type I diabetes (and thus the risk for lipid deposition in the retina)
|
overactive hormone-sensitive lipase
|
|
|
dideoxycytidine (an antiviral) works by preventing what?
|
formation of a phosphodiester bond during viral DNA synthesis
|
|
|
how is Leber hereditary optic neuropathy inherited?
|
mitochondrial
|
|
|
about 20% of patients with 13q syndrome develope what?
|
retinoblastoma
|
|
|
what is the deficiency in fructose intolerance?
|
aldolase B
|
|
|
what accumulates in fructose intolerance, and what is the result?
|
fructose-1-phosphate accumulates, causing a decrease in available phosphate, which results in inhibition of glycogenolysis and gluconeogenesis
|
|
|
what are the symptoms of fructose intolerance?
|
hypoglycemia, jaundice, cirrhosis, vomiting
|
|
|
what is the treatment for fructose intolerance?
|
decrease intake of both fructose and sucrose (glucose + fructose)
|
|
|
what is the defect in essential fructosuria?
|
defect in fructokinase - benign, asymptomatic condition
|
|
|
what are the symptoms of essential fructosuria?
|
fructose appears in blood and urine
|
|
|
what is absent in galactosemia? what is the mode of inheritance?
|
absence of galactose-1-phosphate uridyltransferase; autosmal recessive
|
|
|
how is damage caused in galactosemia?
|
accumulation of toxic substances (including galactitol) rather than absence of an essential compound
|
|
|
what are the symptoms of galactosemia?
|
cataracts, hepatosplenomegaly, MR
|
|
|
what is the treatment for galactosemia?
|
exclude galactose and lactose (glucose + galactose) from diet
|
|
|
what does galactokinase deficiency cause?
|
galactosemia & galactosuria; galactitol accumulation if galactose is present in diet
|
|
|
what is decreased in PKU?
|
phenylaline hydroxlase or tetrahydrobiopterin cofactor
|
|
|
this disorder is characterized by excess pheylketones in urine (phenylacetate, phenyllactate, phenylpyruvate)
|
PKU
|
|
|
how is PKU inherited; what is the approximate incidence
|
autosomal-recessive; 1:10,000
|
|
|
what are the findings in PKU?
|
MR, growth retardation, fair skin, eczema, musty body odor
|
|
|
what is the treatment for PKU?
|
decrease phenylaline and increase tyrosine in diet
|
|
|
this is a congenital deficiency of homogenistic acid oxidase in the degradative pathway of tyrosine
|
alkaptonuria
|
|
|
what disease is characterized by urine that turns black on standing? what causes this?
|
alkaptonuria; alkapton bodies, connective tissue is also dark
|
|
|
although alkaptonuria is considered benign, it may be associated iwth this debilitating symptom
|
arthralgias
|
|
|
congenital deficiency of tyrosinase results in what?
|
albinism - inability to synthesize melanin from tyrosine
|
|
|
albinism may be caused by 2 deficiencies - what are they?
|
1. deficiency of tyrosinase or 2. defective tyrosine trasnporters
|
|
|
what may be the cause of albinism?
|
lack of migration of neural crest cells
|
|
|
what becomes essential in homocystinuria?
|
cysteine
|
|
|
cystathionine synthesis deficiency is a form of what?
|
homocystinuria
|
|
|
what is the treatment for cystathionine deficiency?
|
decrease Met and increase Cys in diet
|
|
|
decreased affinity of cystathionine synthase for pyriodoxal phosphate is a form of what?
|
homocystinuria
|
|
|
what is the treament for decreased affinity of cystahionine synthase for pyriodoxal phosphate?
|
increase vitamin B6 in diet
|
|
|
what are potential symptoms of homocystinuria?
|
MR, osteoporosis, tall stature, kyphosis, lens subluxation (downward and inward), and atheroscleorsis (stroke and MI)
|
|
|
how common is cystinuria?
|
1:7000
|
|
|
what is cystinuria?
|
inherited defect of renal tubular AA transporter for cystine, ornithine, lysine, arginine (COLA)
|
|
|
how do you treat cystinuria?
|
acetazolamide to alkalinize urine
|
|
|
what is a potential complication of cystinuria?
|
cystine kidney stones
|
|
|
what is the defect in maple syrup urine disease?
|
blocked degradation of branched amino acids due to decreased alpha-ketoacid dehydrogenase
|
|
|
what are the branched AA's?
|
Ile, Val, Leu (I Love Vermont)
|
|
|
what happens in maple syrup urine disease?
|
increased alpha-ketoacids in the blood, especially Leu -- causes severe CNS defects, MR, and death
|
|
|
a deficiency in what enzyme can cause SCID?
|
adenosine deaminase
|
|
|
what was the first disease to be treated by experimental gene therapy?
|
adenosine deaminase deficiency
|
|
|
what is absent in Lesch-Nyan syndrome?
|
HGPRTase, which converts hypoxanthine to inosine monophosphate (IMP) and guanine to guanosine monophosphate (GMP)
|
|
|
how is Lesch-Nyan inherited
|
X-linked recessive
|
|
|
retardation, self-mutilation, aggression, hyperuricemia, gout, and choreoathetosis are findings in what syndrome?
|
Lesch-Nyan
|
|
|
this syndrome is marked by a purine salvage problem
|
Lesch-Nyan
|
|
|
in this syndrome, excess ATP and dATP imbalances nucleotide pool via feedback inhibition of ribonucleotide reductase, which prevents DNA synthesis and thus decreases lymphocyte count
|
adenosine deaminase deficiency
|
|
|
what gycogen storage disease is due to a deficiency in glucose-6-phosphatase? what type is it?
|
Von Gierke's; type I
|
|
|
severe fasting hypoglycemia, marked increase of glycogen in liver, hepatomegaly, and increased blood lactate are characteristic of what glycogen storage disease?
|
Von Gierke's
|
|
|
what is the deficiency in Pompe's disease? what type is it?
|
lysosomal alpha-1,4 glucosidase deficiency; type II
|
|
|
what glycogen storage disease is marked by cardiomegaly and systemic findings, leading to early cardiac death?
|
Pompe's - Pompe's trashes the Pump (heart, liver, and muscle)
|
|
|
what is the deficiency in Cori's disease?
|
debranching enzyme alpha-1,6-glucosidase; type III
|
|
|
this glycogen storage disease is a milder form of type I with normal blood lactate levels
|
Cori's disease; type III
|
|
|
what is the deficiency in McArdle's disease?
|
skeletal muscle glycogen phosphorylase; type V
|
|
|
painful cramps and myoglobinuria during exercise are characteristic of what glycogen storage disease?
|
McArdle's
|
|
|
what is the deficient enzyme in Fabry's disease, and what substate is accumulated?
|
alpha-galactosidase A; ceramide trihexoside (fAbry)
|
|
|
Fabry's disease and Hunter's syndrome are inherited in what manner?
|
X-linked recessive (Fabry the Hunter aims for the X)
|
|
|
peripheral neuropathy of the hands and feet, angiokeratomas, CV/renal disease are characteristic of what lysosomal storage disease?
|
Fabry's disease
|
|
|
hepatosplenomegaly, aseptic necrosis of femur, bone crises are characteristic of what lysosomal storage disease?
|
Gaucher's (AR)
|
|
|
what is the deficient enzyme in Gaucher's disease? what substrate accumulates?
|
beta-glucocerebrosidase; glucocerebroside
|
|
|
what is the deficient enzyme in Niemann-Pick disease? what subtrate accumulates?
|
sphingomyelinase; sphingomyelin (AR) (no man picks his nose with his sphinger)
|
|
|
progressive neurodegeneration, hepatosplenomegaly, cherry-red spot on macula are characteristic of what lysosomal storage disease?
|
Niemann-Pick
|
|
|
hexosaminidase A is deficient and GM2 ganglioside accumulates in what lysosomal storage disease?
|
Tay-Sachs (Tay SaX lacks heXosaminidase)
|
|
|
this lysosomal storage disease is characterized by progressive neurodegeneration, developmental delay, cherry-red spot, lysozymes with onion skin
|
Tay-Sachs
|
|
|
what enzyme is deficient in Krabbe's disease? what accumulates?
|
beta-galctosidase; galactocerebroside
|
|
|
name 3 characteristics of Krabbe's disease
|
peripheral neuropathy, developmental delay, optic atrophy
|
|
|
this lysosomal storage disease is marked by central and peripheral demyelination with ataxia, dementia
|
metachromatic leukodystrophy
|
|
|
in this lysosomal storage disease, arylsulfatse A is deficient and cerebroside sulfate accumulates
|
metachromatic leukodystrophy
|
|
|
developmental delay, gargoylism, airway obstruction, corneal clouding, hepatosplenomegaly are characteristic of what lysosomal storage disease?
|
Hurler's syndrome
|
|
|
alpha-L-iduronidase is deficient and heparan sulfate, dermatan sulfate accumulate in which lysosomal storage disease?
|
Hurler's syndrome (alpha-L-iduronidase - HurLer's)
|
|
|
the symptoms of this lysosomal storage disease are similar to Hurler's, but there is aggressive behavior and no corneal clouding
|
Hunter's (you have to see and be aggressive if you are a hunter)
|
|
|
in what syndrome is there a deficiency of iduronate sulfatase and accumulation of heparan sulfate/dermatan sulfate?
|
Hunter's (X-linked recessive)
|
|
|
what do the defectve LDL receptors in familial hypercholesterolemia recognize?
|
apo-B 100 protein (cotransported with cholesterol esters in LDL)
|
|
|
what pathway is altered in achondroplasia?
|
cell signaling (FGFR3)
|
|
|
what condition clinically resembles pellagra?
|
Hartnup's disease (diarrhea, dementia, dermatitis)
|
|
|
what is the underlying defect in Hartnup's disease?
|
defect in epithelial transport of neutral AA's, including tryptophan, which can act as a precursor of niacin - poor dietary absorption of AA's & excess AA secretion into urine
|
|
|
normal child at birth who begins to suffer from diminished responsiveness, deafness, blindness, loss of neuro function, seizures?
|
Tay-Sachs - death by 4/5
|
|
|
a defect in what enzyme would yield chylomicrons in plasma?
|
lipoprotein lipase
|
|
|
severe memory deficit with confabulation in an alcoholic?
|
thiamine deficiency
|
|
|
type of gall stones in patient with sickle cell?
|
calcium bilirubinate
|
|
|
B-complex deficiencies often result in what?
|
dermatitis, glossitis, diarrhea
|
|
|
thiamine: TPP
|
vitamin B1
|
|
|
riboflavin: FAD, FMN
|
vitamin B2
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niacin: NAD+
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vitamin B3
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pantothenate: CoA
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vitamin B5
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pyridoxine: PP
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vitamin B6
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cobalamin
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vitamin B12
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this vitamin is a constituent of visual pigments
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vitamin A/retiol
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deficiency in this vitamin can lead to night blindness, dry skin, and impaired immune response
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vitamin A
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excess of this vitamin can cause arthralgias, fatigues, headaches, skin changes, sore throat, allopecia
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vitamin A
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deficiency of this vitamin is seen in beriberi and Wernicke-Korsakoff syndrome; seen in alcoholism and malnutrition
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vitamin B1
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which beriberi is associated with polyneuritis, muscle wasting?
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dry
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which beriberi is associated with high-output cardiac failure (dilated cardiomyopathy) and edema?
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wet
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in thiamine pyrophosphate, this vitamin serves as a cofactor for oxidative decarboxylation of alpha-keto acids (pyruvate, alpha-ketoglutarate) and as a cofactor for transketolase in the HMP shunt
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vitamin B1
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deficiency of this vitamin leads to angular stomatitis, cheilosis, corneal vascularization
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vitamin B2 (the 2 C's)
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this vitamin serves as a cofactor in oxidation and reduction (e.g. FADH2)
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vitamin B2 (FAD and FMN are derived from riboFlavin (B2=2 ATP))
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what are the symptoms of pellagra/vitamin B3 deficiency?
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3 D's: diarrhea, dermatitis, dementia (also beefy glossitis)
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Hartnup disease (increased tryptophan absorption), malignant carcinoid syndrome (increased tryptophan metabolism), and INH (decreased vit. B6) can all cause what vitamin deficiency?
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pellagra (vitamin B3/niacin)
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which vitamin is derived from tryptophan using vitamin B6 and is a constituent of NAD+ and NADP+?
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vitamin B3/niacin (NAD derived from Niacin; B3 = 3 ATP)
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deficiency of this vitamin can cause dermatitis, enteritis, alopecia, and adrenal insufficiency
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vitamin B5 (pantothenate)
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this vitamin is a constituent of CoA (a cofactor for acyl transfers) and component of fatty acid synthase
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vitamin B5 (pantothen-A is in Co-A)
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deficiency of this vitamin can cause convulsions, hyperirritability (deficiency inducible by INH and oral contraceptives), and peripheral neuropathy
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vitamin B6 (pyridoxine)
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this vitamin is converted to pyridoxal phosphate, a cofactor used in transamination (e.g. ALT, AST), decarboxylation, and heme synthesis
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vitamin B6 (pyridoxine)
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deficiency of this vitamin can cause macrocytic, megabloblastic anemia; neurologic symptoms (optic neuropathy, subacute combined degeneration, paresthesia); and glossitis
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vitamin B12 (cobalamin)
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where is vitamin B12 found?
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only in animal products
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this vitamin serves as a cofactor for homocysteine methylation (transfers CH3 groups as methylcobalammin) and methylmalonyl-CoA handling
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vitamin B12
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where is vitamin B12 stored?
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primarily in the liver; synthesized only by microorganisms
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what might the abnormal myelin seen in B12 deficiency be due to?
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decreased methionine or increased methylmalonic acid (from metabolism of accumulated methylmalonyl CoA)
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what is the most common vitamin deficiency in the U.S.?
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folic acid
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deficiency of this vitamin can cause a macrocytic, megaloblastic anemia often without neurologic symptoms
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folic acid
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this vitamin serves as a coenzyme 1-carbon transfer & is involved in methylation reactions; it is important for the synthesis of nitrogenous bases in DNA and RNA
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folic acid
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what is the folic acid precursor in bacteria? what kind of drugs are analogs of it?
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PABA; sulfa drugs and dapsone are PABA analogs
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deficiency of this vitamin is marked by dermatitis & enteritis, and is caused by antibiotic use and ingestion of raw eggs
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biotin (avidin in eggs avidly binds biotin)
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this vitamin is a cofactor for carboxylations:
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biotin
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this vitamin is necessary for hydroxylation of proline and lysine in collagen synthesis
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vitamin C (C Cross-links Collagen)
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this vitamin facilitates iron absorption by keeping iron in Fe2+ reduced state (more absorbable) and is also necessary as a cofactor for dopamine -> NE
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vitamin C
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what form of vitamin D is found in milk?
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D2 = ergocalciferol
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what form of vitamin D is formed in sun-exposed skin?
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D3=colecalciferol
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what is the storage form of vitamin D?
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25-OH D3
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what is the active form of vitamin D?
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1, 25 (OH)2 D3
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deficiency of this vitamin causes rickets in children (bending bones), osteomalacia in adults (soft bones), and hypocalcemic tetany
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vitamin D
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this vitamin increases intestinal absorption of calcium and phosphate
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vitamin D
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excess of this vitamin causes hypercalcemia, loss of apetite, and stupor
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vitamin D
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what disease can be associated with vitamin D excess?
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sarcoidosis - epitheliod macrophages convert vitamin D into its active form
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deficiency of this vitamin is associated with increased fragility of erythrocytes
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vitamin E (E-Erythrocytes)
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deficiency of this vitamin can cause neonatal hemorrhage with increased PT and PTT but normal bleeding time
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vitamin K
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what are the vitamin K dependent clotting factors?
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II, VII, IX, X, proteins C & S
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what drug is a vitamin K antagonist?
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warfarin
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this vitamin catalyzes gamma-carboxylation of glutamic acid residues on various proteins concerned with blood clotting
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vitamin K
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what synthesizes vitamin K?
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intestinal flora - deficiency can occur after prolonged broad-spectrum antibiotic use
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deficiency of this vitamin is associated with delayed wound healing, hypogonadism, decreased adult hair, and may predispose to alcoholic cirrhosis
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zinc
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what is the rate-limiting reagent in ethanol metabolism?
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NAD+
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by what order kinetics does alcohol dehydrogenase operate?
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zero-order
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what does disulfiram inhibit? what accumulates?
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inhibits acetaldehyde dehydrogenase; acetaldehyde accumulates, contributing to hangover symptoms
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what is the result of the increased NADH/NAD+ ratio in the liver that is caused by ethanol metabolism?
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causes diversion of pyruvate to lactate and OAA to malate - inhibits gluconeogenesis and leads to hypoglycemia
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what is responsible for the hepatic fatty change seen in chronic alcoholics?
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increased NADH/NAD+ ratio - shunts away from glycolysis and toward fatty acid synthesis)
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this is protein malnutrition resulting in skin lesions, edema, liver malfunction (fatty change)
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Kwashiorkor (small shild with swollen belly): MEAL (malabsorbtion, edema, anemia, liver (fatty))
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this is protein-calorie malnutrition resulting in tissue wasting
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marasmus
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this type of chromatin is condensed and transcriptionally inactive
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heterochromatin
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this type of chromatin is less condensed and transcriptionally active
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euchromatin
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which type of chromatin ties nucleosomes together in a string (30-nm fiber)?
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H1
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what histones make up the nucleosome core?
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H2A, H2B, H3, H4
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what are the purines, and how many rings do they have?
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A, G; 2 rings
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what are the pyrimidines and how many rings do they have?
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C, T, U; 1 ring (pyramids were CUT)
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which nucleotide has a ketone?
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guanine
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which nuclotide has a methyl?
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thymine (THYmine has a meTHYl)
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deamination of cytosine makes what?
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uracil
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which bond is stronger: G-C or A-T? why?
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G-C is stronger because it has 3 H bonds
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what happens to the melting temperature when you increase the G-C content?
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increases (b/c more H bonds)
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what is it called when a purine is substituted for a purine or a pyrimidine is substituted for a pyrimidine?
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transItion (Identical type)
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what is it called when a purine is substituted for a pyrimidine or vice versa?
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transVersion (conVersion between types)
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what are some exceptions to the universality of the genetic code?
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mitochonria, archaeobacteria, mycoplasma, some yeasts
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what is a silent mutation
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same amino acid - often base change in 3rd position of codon (tRNA wobble)
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what is a missense mutation?
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changed amino acid (conservative - new aa is similar in chemical structure)
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what is a nonsense mutation?
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change resulting in an early stop codon - stop the nonsense!
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what are the stop codons?
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UGA, UAA, UAG
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what is the mRNA initiation codon and what does it code for in eukaryotes?
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AUG, methionine (AUG inAUGurates protein synthesis
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what does the initial AUG code for in prokaryotes?
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formyl-methionine
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what do DNA topoisomerases do?
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create a nick in the helix to relieve supercoils
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what does primase do?
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makes an RNA primer on which DNA polymerase III can initiate replication
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what does DNA polymerase III do?
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elongates the chain by adding deoxynucleotides to the 3' end until it reaches primer of preceding fragment; 3' -> 5' exonuclease activity proofreads each added nucleotide
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what does DNA polymerase I do?
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degrades RNA primer with 5' to 3' exonuclease
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what does DNA ligase do?
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seals DNA
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in which direction does DNA polymerase synthesis occur?
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5' to 3'
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in which direction does proofreading with exonuclease occur?
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3' to 5'
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after excision repair-specific glycosolase recognizes and removes a damaged base, what does endonuclease do?
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makes a break several bases to the 5' side and removes a short stretch of nucleotidse - the n DNA polymerase fills gap and DNA ligase seals it
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the 5' of the incoming nucleotide bears what?
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the triphosphate/engergy sourse for bond
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DNA, RNA, and protein synthesis all occur in what direction
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5' to 3'
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which is the largest type of RNA?
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mRNA (massive)
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which is the most abundant type of RNA?
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rRNA (rampant)
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whihc is the smallest type of RNA
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tRNA (tiny)
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RNA polymerase I makes what?
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rRNA
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RNA polymerase II makes what?
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mRNA
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what does RNA polymerase III make?
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tRNA
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alpha-amantin, a substance found in death cap mushrooms, inhibits what?
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RNA polymerase II
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this is the site where RNA polymerase and multiple other transcription factors bind to DNA upstram from gene locus
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promoter
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this is a stretch of DNA that alters gene expression by binding transcription factors
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enhancer - may be located close to, far from, or even within (in an intron) teh gene whose expression it regulates
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theis is the site where negative regulators (repressors) bind
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operator
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intervening noncoding segments of DNA are called what?
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introns
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where are introns spliced out of?
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primary mRNA transcripts
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these particles facilitate splicing by binding to primary mRNA transcripts and forming spliceosomes
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snRNPs
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where does RNA processing occur?
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nucleus
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what three events occur in RNA processing after transcription?
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(1) capping on 5' end (7-methyl-G) (2) poly AAAs on 3'end (about 200 As) (3) splicing out of introns
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what do all tRNAs have at the 3' end?
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CCA along with a high percentage of chemically modified bases
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in tRNA, the anticodon end is opposite what?
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the 3' aminoacyl end
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what does a mischarged tRNA do?
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reads the usual codon but inserts wrong amino acid
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what two things are responsible for the accuracy of amino acid selection?
|
aminoacyl-tRNA synthetase and binding of charged tRNA to the codon
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during protein synthesis, in which site does Met sit?
|
in the P site - peptidyl
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during protein synthesis, where does the incoming amino acid bind?
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A site - aminoacyl; hydrolyzes Met's bond to its tRNA while simultaneously forming a peptidyl bond between the 2 amino acids
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