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107 Cards in this Set
- Front
- Back
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What are some functions of carbohydrates?
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- energy stores, fuels, metabolic intermediates
- components of nucleic acids and many proteins & lipids - structural elements in cell walls - mediate cell-cell recognition |
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What are enantiomers?
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mirror images
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What are stereoisomers?
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same chemical formula and bonding sequence
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What are two structures that are mirror images called?
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enantiomers
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What are two structures with the same chemical formula and bonding sequence called?
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stereoisomers
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What are the simplest sugars called?
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trioses
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Which carbon determines whether a sugar is D or L?
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most distal from aldehyde carbon
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What are epimers?
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diastereomers with a different configuration at one asymmetric carbon
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What are structures that differ in configuration at one asymmetric carbon called?
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epimers
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What forms a hemiacetal?
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alcohol + aldehyde
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What forms a hemiketal?
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alcohol + ketone
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What is formed by an alcohol and aldehyde?
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hemiacetal
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What is formed by an alcohol and ketone?
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hemiketal
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How is an α-anomer differ from a β-anomer?
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α-anomer has -OH on opposite side of ring from -CH2OH at chiral carbon
β-anomer has -OH on same side of ring as -CH2OH at chiral carbon |
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Is the α-anomer or β-anomer of glucopyranose more common?
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β-anomer (63%)
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Are the axial or equatorial substituents more crowded?
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axial
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What kind of bonds are used to join monosaccharides to alcohols or amines?
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glycosidic bonds
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What kind of bonds prevent interconversion of α-anomers and β-anomers?
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glycosidic bonds
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What is the basis for diagnosing blood glucose levels in diabetics?
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covalent bonding of glucose to hemoglobin (HbA1c)
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What kind of functional groups can reducing sugars use to covalently bind proteins?
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aldehyde or ketone
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True or False: Glucopyranose is a reducing sugar?
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True
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True or False: Glucopyranose is a nonreducing sugar?
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False
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True or False: Glucopyranoside is a reducing sugar?
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False
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True or False: Glucopyranoside is a nonreducing sugar?
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True
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What is the largest source of calories (45%) for most people?
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carbohydrates
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What are the components of starch?
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amylose and amylopectin
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How much saliva is secreted by the salivary glands each day?
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1 L
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What does saliva contain?
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mucin and α-amylase
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What does α-amylase hydolyze and what does it produce?
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hydrolyzes internal α-1,4 bonds between glucosyl residues within amylopectin, amylose, and glycogen
produces dextrins |
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What kind of enzyme is α-amylase classified as?
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endoglycosidase
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What does the pancreas secrete?
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bicarbonate to neutralize stomach acid
amylase to continue starch digestion |
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What is the function of lactase?
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splits β-1,4 bond between glucose and galactose
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What is the function of maltase?
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splits α-1,4 bond between 2 glucoses
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Adult level of lactase is about what percentage of the infant level?
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10%
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Which ethnic group is late onset lactase deficiency most prevalent in?
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Asians
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Which ethnic group is late onset lactase deficiency least prevalent in?
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Dutch
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In lactose intolerance, what do colonic bacteria convert lactose to?
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lactic acid, methane gas, and hydrogen gas
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What are three ways to cope with lactose intolerance?
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avoid dairy products
use lactose-free milk take lactase pills |
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Which foods are a good source of food for gut bacteria?
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beans and legumes
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How is dietary fiber digested?
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bacteria in the gut digest some fiber to give fatty acids, methane, hydrogen, and carbon dioxide gases
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True or False: Galactose is transported across the cell membrane by the same transporters as glucose.
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True
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What happens in Na+-dependent glucose transport?
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glucose moves into cell against its concentration gradient by moving with Na+ using its concentration gradient
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True or False: Glucose transporters are only found on the serosal side of a cell.
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False
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Which glucose transporters are found in all mammalian tissues and are responsible for basal glucose uptake?
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GLUT1 and GLUT3
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Which glucose transporter is located in the small intestine and actually functions primarily as a fructose transporter?
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GLUT5
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Which glucose transporter plays a role in regulation of insulin in the liver and removes excess glucose from blood?
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GLUT2
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Which glucose transporter can be increased in quantity with endurance training?
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GLUT4
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Where is GLUT1 located?
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all mammalian tissues
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Where is GLUT2 located?
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liver and pancreatic β cells
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Where is GLUT3 located?
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all mammalian tissues
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Where is GLUT4 located?
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muscle and fat cells
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Where is GLUT5 located?
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small intestine
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What is the structure of a proteoglycan?
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protein core with attached glycosaminoglycans (95%)
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What are some functions of proteoglycans?
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joint lubricants
structural components in connective tissue mediators of cell adhesion to matrix storage of growth factors |
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What diseases can result from an inability to degrade glycosaminoglycans?
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mucopolysaccharidoses
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What causes mucopolysaccharidoses?
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inability to degrade glycosaminoglycans
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What are five important proteoglycans?
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chondroitin 6-sulfate
dermatan sulfate heparin hyaluronate keratan sulfate |
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What does heparin consist of?
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alternating D-glucuronic acid and N-acetyl-D-glucosamine residues
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Heparin is isolated from mammalian tissues rich in what kind of cells?
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mast cells
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What can be isolated from mammalian tissues rich in mast cells?
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heparin
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What is the function of heparin?
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acts as anticoagulant by increasing activity of antithrombin to inhibit factor Xa (and thrombin for full length heparin)
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Use of heparin involves the risk of inducing what diseases?
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thrombocytopenia and osteoporosis
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What is aggrecan and what is its function?
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proteoglycan of cartilage that contains keratan sulfate & chondroitin sulfate and functions to cushion compressive forces in joints
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What is caused by proteolytic degradation of aggrecan and collagen of cartilage?
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osteoarthritis
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What causes osteoarthritis?
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proteolytic degradation of aggrecan and collagen
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What is caused by accumulation of glycosaminoglycans and proteoglycans in cells from a defect in lysosomal enzymes?
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mucopolysaccharidoses
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What causes mucopolysaccharidoses?
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defect in lysosomal enzymes leading to accumulation of glycosaminoglycans and proteoglycans in cells
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What are two important mucopolysaccharidoses?
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Hunter and Hurler
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What are three common types of membrane lipids?
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phospholipids
glycolipids cholesterol |
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What are the spherical monolayer structures that spontaneously form from membrane lipids?
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micelles
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What are the spherical bilayer structures that spontaneously form from membrane lipids?
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liposomes
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What are micelles?
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spherical monolayer structures that spontaneously form from membrane lipids
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What are liposomes?
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spherical bilayer structures that spontaneously form from membrane lipids
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Arrange the following in increasing order of membrane permeability: Cl-, Glucose, Glycerol, Indole, K+, Na+, Tryptophan, Water
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Na+, K+, Cl-, Glucose, Tryptophan, Glycerol, Indole, Water
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What are some functions of cell membrane proteins?
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pumps
channels receptors energy transducers enzymes |
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How many transmembrane α-helices does bacteriorhodopsin contain?
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seven
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What do prenylated proteins contain?
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isoprenoid chains attached to cysteine
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What do myristoylated proteins contain?
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myristic acid attached to cysteine
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What do palmitoylated proteins contain?
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palmitic acid attached to cysteine
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How much more viscous are plasma membranes than water?
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100 times
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True or False: Some proteins may diffuse nearly as fast as lipids
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True
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What regulates membrane fluidity?
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unsaturated fatty acids and cholesterol
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True or False: Carbohydrate linked to lipid or protein is always on the inner membrane?
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False
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Does passive-mediated transport lead to a decrease or increase in concentration or charge difference?
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decrease
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Does active transport lead to a decrease or increase in concentration or charge difference?
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increase
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How many transmembrane-spanning helices does erythrocyte glucose transporter contain?
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twelve
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At least how many P-type ATPases are encoded by the human genome?
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seventy
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What is the importance of the Na+/K+ ATPase?
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regulates cell volume
mediates neurotransmission drives active transport |
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What function is the Ca2+-ATPase important for?
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contraction in muscle cells
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What is the purpose of the gastric H+/K+ ATPase?
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lowers pH in stomach to 1.0
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What do all P-type ATPases produce as an intermediate in converting between in- and out-states?
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aspartyl-phosphate
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What are the two pumps that mediate calcium ion transport?
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Ca2+-ATPase
Na+/Ca2+ exchanger |
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Which has a higher affinity for Ca2+: Ca2+-ATPase or Na+/Ca2+ exchanger?
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Ca2+-ATPase
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Which has a lower affinity for Ca2+: Ca2+-ATPase or Na+/Ca2+ exchanger?
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Na+/Ca2+ exchanger
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Which has a higher capacity for transporting Ca2+: Ca2+-ATPase or Na+/Ca2+ exchanger??
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Na+/Ca2+ exchanger
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Which has a lower capacity for transporting Ca2+: Ca2+-ATPase or Na+/Ca2+ exchanger??
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Ca2+-ATPase
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What do cardiotonic steroids do?
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stimulate heart muscle contraction by inhibiting Na+/K+-ATPase pump
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What drugs stimulate heart muscle contraction by inhibiting Na+/K+-ATPase pump?
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cardiotonic steroids
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What is digitalis used to treat?
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congestive heart failure
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What drug is used in treatment of congestive heart failure?
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digitalis
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What is the mechanism by which digitalis works?
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º inhibits Na+/K+ pump to produce high internal [Na+]
º diminished Na+ gradient slows extrusion of Ca2+ by Na+-Ca2+ exchanger º increased internal Ca2+ enhances contraction of heart muscle |
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How many mitochondria are in a liver cell?
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about 1,000
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How many mitochondria are in a red blood cell?
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none
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Where do the TCA cycle and production of ATP take place?
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mitochondria
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True or False: All mitochondrial proteins are encoded by the mitochondrial genome.
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False - nuclear genome encodes some
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How common are diseases caused by mutations in mitochondrial DNA?
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1 in 5,000-10,000
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What does mitochondrial DNA encode mRNA for?
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13 subunits of the complexes involved in oxidative phosphorylation, as well as rRNA and tRNAs
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