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Biochemistry Flashcards

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4742041281Amino acids found in eukaryotes areL-amino acids0
4742043887Glycine is the onlyachiral amino acid1
4742047845Nonpolar amino acidsglycine, alanine, valine, leucine, isoleucine, methionine, proline2
4742064005Aromatic amino acidstryptophan, phenylalanine, tyrosine3
4742069498Polar side chain (non-aromatic) amino acidsSerine, threonine, asparagine, glutamine, cysteine4
4742070550Negatively charged side chain amino acidsAspartic acid and glutamic acid5
4742071787Positively charged side chain amino acidsArginine, lysine, histidine (nitrogen on side chain is protonated at physiological pH)6
4742086051pKapH at which half of the molecules of that species are deprotonated - at pH less than the pKa, a majority of the species will be protonated7
4742094374zwitterion- species with a positive and negative charge on it, cancelling out most amino acids at physiological pH - have a positive charge (amino group in acidic form) - and a negative charge (carboxyl group in basic form)8
4742105815Isoelectric pointpH at which a particular molecule carries no net charge - for AA with a neutral side group the pI is equal to the average of the two pKa values9
4742140963Peptide bond formationexample of a condensation or dehyrdation reaction b/c water is formed - C of one AA's COOH group forms a bond with N of another AA's NH3 group10
4742144850Peptides are read fromthe N-terminus to the C-terminus11
4742156352Primary and secondary structurePrimary structure: linear arrangement of amino acids Secondary structure: local structure of neighboring amino acids (B-sheets or alpha helices) - due to hydrogen bonding12
4742161524proline is often not foundin the middle of alpha helices or beta sheets - or if so it introduces a turn or kink13
4742171020Tertiary structure- folding of the protein due to hydrophobic interactions, hydrogen bonds, disulfide bonds, ionic, covalent bonds, van der waals forces14
4742175702Quaternary structure- how a polypeptide interacts with another polypeptide - not found in all proteins - immunoglobulins have 4 subunits15
4742209577Conjugated proteinsproteins with covalently attached molecules - the attached molecule is called a prosthetic group, and may be a metal ion, vitamin, lipid, carbohydrate, or nucleic acid16
4742317174Cofactors vs coenzymes- cofactors are inorganic molecules (mainly minerals) - coenzymes are organic molecules mainly the water soluble vitamins (not A,D, E, and K) - induce a conformational change in the enzyme that promotes its activity - tightly bound cofactors/coenzymes necessary for enzyme function are termed prosthetic groups17
4742351998Cooperativity and cooperative enzymes- displays a sigmoidal curve (michaelis-Menten) because of the change in activity with substrate binding Cooperative enzymes: have multiple subunits and multiple active sites - subunits may exist in a Tense (T) state: low-affinity - or a Relaxed (R) state: high affinity - one subunit changing states can affect other subunits to do the same - ex. hemoglobin18
4742369457Cooperativityrefers to the interactions b/w subunits in a multisubunit enzyme or protein. The binding of substrate to one subunit induces a change in the other subunits from the T (tense) state to the R (relaxed) state, which encourages binding of substrate to the other subunits. In the reverse direction, the unbinding of substrate from one subunit induces a change from R to T in the remaining subunits, promoting unbinding of substrate from the remaining subunits19
4742376402Enzyme activity does what with temperaturetends to double in activity for every 10 degree increase in temperature until it reaches its optimum temp20
4742478493Collagen- trihelical fiber - makes up extracellular matrix of connective tissue - important in providing strength and flexibility21
4742480644Elastin- another important part of extracellular matrix of connective tissues - primary role = stretch and recoil22
4742483868Keratins- intermediate filament proteins found in epithelial cells - contribute to the mechanical integrity of the cell - primary protein of hair and nails23
4742485018Actin- makes up microfilaments and thin filaments in myofibrils - most abundant protein in eukaryotes - have a positive side and a negative side24
4742486658Tubulin- makes up microtubules - provide structure, chromosome separation during mitosis, and intracellular transport with kinesin and dynein - has polarity like actin (negative end near nucleus)25
4742490171Myosin- primary motor protein that interacts with actin - thick filament in myofibril - crucial for sarcomere contraction26
4742492455Kinesin vs dynein- motor proteins associated with microtubules Kinesins: anterograde transport Dynein: retrograde transport27
4742499264Cell adhesion moleculesCadherins: group of glycoproteins that mediate calcium-dependent cell adhesion - two cells of the same or similar type adhered using calcium Integrins: important for binding to and communication with ECM, cellular signalling (important for clot formation) - once cell to proteins in the extracellular matrix Selectins: bind to carbohydrate molecules that project from other cell surfaces - one cell to carbohydrates, usually on the surface of other cells28
47425172333 possibilities for a when antibodies bind antigens1) neutralization of pathogen or toxin 2) opsonization - marking for destruction 3) agglutination - creating insoluble antigen-antibody complex that can be phagocytized and digested29
4742563176In electrophoresis anions move toward the ______ and cations move toward the _______cations move toward the cathode (negative charge) and anions move toward the anode (positive charge)30
4742565559SDS page Isoelectric focusingSDS page: separates protein on mass alone (SDS denatures proteins and covers them in negative charge) Isoelectric focusing: separates proteins based on their isoelectric point using a gel with the pH spectrum and an electric field, a cathode (negative charge) at the basic end of the gel will bring positively charged proteins to their pI where they will become unprotonated - opposite happens at the other end31
4742603522Bradford protein assay- Coomassie blue die is used to measure the concentration of protein - dye changes colours as it gives up protons to the protein the different colour can be measured with a spectrophotometer and compared to a known curve of protein concentration32
4742961020Enantiomersnonsuperimposable mirror images of each other - any molecule that contains a chiral carbon (4 different groups attached) and no internal planes of symmetry has an enantiomer - a compound can have only one enantiomer33
4742976241diastereomers vs epimersDiastereomers: two sugars that are in the same family that are not identical and are not mirror images of each other Epimers: a special type of diastereomers that differ in configuration at exactly one chiral center34
4742996414Alpha or beta anomersalpha anomer: -OH group of C-1 is trans to the -CH2OH Beta anomer: -OH group of C-1 is cis to the -CH2OH35
4743003056Anomeric carbonthe new chiral center formed in ring closure; it was the carbon containing the carbonyl in the straight-chain form36
4743040087Sucrose, lactose, maltoseSucrose: glucose and fructose Lactose: galactose and glucose Maltose: glucose and glucose37
4743042706Cellulose, starches, glycogenCellulose: main structural component of plant cell walls and is the main source of fiber in the human diet, made up of beta-D-glucose molecules linked by beta-1,4 glycosidic bonds Starches: main energy source for plants, glucose linked by alpha-1,6 glycosidic bonds (amylose - non branching) (amylopectin - branching) Glycogen: main energy source in animals, highly branched38
4744824759beta and alpha amylaseBeta amylase: cleaves amylose at the reducing end of the polymer to yield maltose alpha amylase: cleaves randomly along the chain to yield shorter polysaccharide chains39
4744826898glycogen phosphorylasefunctions by cleaving glucose from the nonreducing end of the glycogen branch and phosphorylating it, thereby producing glucose 1-phosphate40
4744797845Mutorationinterconversion b/w anomers of a compound41
4744801560Tautomerizationa rearrangement of bonds - ketose sugars undergo tautomerization to undergo keto-enol shifts, which forms an aldose, which then allows them to act as reducing sugars42
4744803717Anomerizationrefers to ring closure of a monosaccharide, creating an anomeric carbon (can than turn into a hemiacetal or hemiketal)43
4744891463Fully saturated fatty acidshave only single bonds - carbon is considered saturated when it is bound to four other atoms - have greater van der waals forces and are more often to be a solid at room temperature44
4744894494Unsaturated fatty acidsform one or more double bonds - double bonds introduce kinks into the fatty acid chain, which makes it difficult for them to stack and solidify - more often liquid room temp, ex. olive oil45
4744918648Glycosphingolipids, cerebrosides vs globosidesGlycosphingolipids: sphingolipids with head groups composed of sugars bound by glycosidic linkages Cerebrosides: have a single sugar Globosides: have two or more46
4744974538Terpenesodiferous steroid precursors made from isoprene, a five-carbon molecule - one terpene unit (monoterpene) contains two isoprene units47
4744975901Steroidscontain three cyclohexane rings and one cyclopentane ring - oxidation state and functional group may vary48
4744977825Prostaglandinsautocrine and paracrine hormones that regulate cAMP levels. They have powerful effects on muscle contraction, body temperature, the sleep-wake cycle, and wain49
4744986636Vitamin A (carotene)is metabolized in retinal for vision and retinoic acid for gene expression in epithelial development50
4744987569Vitamin D (cholecalciferol)metabolized to calcitriol in the kidneys and regulates calcium and phosphorus homeostasis in the intestines (increasing calcium and phosphate absorption), promoting bone formation - deficiency - rickets51
4744990686Vitamin E (tocopherols)act as biological antioxidants. Their aromatic rings destroy free radicals, preventing oxidative damage52
4744992186Vitamine K (phylloquinone and menaquinones)is important for formation of prothrombin a clotting factor. It performs posttranslational modifications on a number of proteins, creating calcium-binding sites53
4745018165Saponificationis the ester hydrolysis of triacylglycerols using a strong base - making free fatty acids - aka soup - usually use lye - soaps act as surfactant (lower surface tension at the surface of a liquid)54
4745077580More saturated fatty acids make for a ______ fluid solutionmake for a less fluid solution55
4745096279Nucleoside vs NucleotideNucleoside: composed of five-carbon sugar (pentose) bound to a nitrogen base and are formed by covalently linking the base to C-1' Nucleotides: formed when one or more phosphate groups are attached to C-5' of a nucleoside56
4745105519DNA backbonealternating sugar and phosphate - always read 5' to 3' - 3' end has free C-3' -OH group 5' end has C-5' phosphate group or -OH group57
4745109954PyrimidinesCytosine, thymine, uracil (CUT the Pye)58
4745111158PurinesAdenine, and guanine (PUre As Gold) - two rings59
4745497745Nuclesosometwo of H2A, H2B, H3A, H4A histones with 147 bp of DNA wrapped aroudn60
4745507899Heterochromatin vs EuchromatinHeterochromatin: condensed DNA, transcriptionally inactive Euchromatin: uncondensed DNA, transcriptionally active61
4745526516Helicase, DNA topoisomerase II (gyrase)Helicase: unwinds DNA Topoisomerase II: cuts DNA and relieves tension caused by twisting62
4745531318DNA polymerasesread the DNA in the 3' to 5' direction and synthase the complimentary strand in the 5' to 3' direction63
4747030925Monocistronic vs polycistronicMonocistronic: in eukaryotes, each mRNA translates into only one protein Polycistronic: in prokaryotes, each mRNA that can be translated into different proteins based on where translation begins64
4747037543Amino acids attach to which end of a tRNA molecule3' hydroxyl end65
4747040359start and stop codonsstart: AUG - methionine Stop: UAA, UAG, UGA66
4747043485The genetic code is degenerate b/cmore than one codon can specify a single amino acid ex. AAU, AAC both for Asparagine67
4747045417Missense mutationone AA substitutes for another - nonsense mutation: a premature stop codon due to a mutation68
4747076171RNA polymerase II reads in the3' to 5' direction, so that it forms RNA in the 5' to 3' direction during transcription69
4747080167Post transcriptional hnRNA processing1) splicing: get rid of introns 2) 5' methyl-7-Guanylate cap 3) 3' Polyadenylation70
4747087263Main promotor of trancriptionTATA box: thymine, adenine rich sequenced bound by TATA binding protein - ~ 25 BP upstream (-25) of transcription initiation site71
4747088585RNA pol I, II, and IIIRNA pol I: rRNA RNA pol II: mRNA & snRNA RNA pol III: tRNA (and 5S rRNA)72
4747099734Eukaryote ribosomes vs prokaryote ribosomesEukaryotes: 80S, made up 60S (5S, 5.8S, 28S) & 40S (18S) subunits Prokaryotes: 70S, made up of 50S (5S and 23 S) and 30S (16S)73
4747106992Shine-Dalgarno sequenceprokaryotes translation initiation site74
4747112250peptidyl transferaseenzyme in the large ribosomal subunit that facilitates the formation of a peptide bond, transferring the polypeptide in the E site onto the AA in the A site - uses GTP75
4747123872Operon (prokaryote gene regulation)cluster of genes transcribed as a single mRNA - very common in prokaryotes - can be - inducible (positive control):inducer removes repressor and transcription can proceed - repressible (negative control): transcription proceeds until corepressor binds repressor then bind DNA preventing transcription76
4747137471Operatorsite where repressor can bind preventing transcription of Operon77
4747177442Trp operonwhen tryptophan is present in high concentrations it acts as a corepressor - thus cell transcription of proteins used in creating tryptophan78
4747179992lac operoninduced by the presence of lactose (when glucose is low) and induces genes for lactose metabolism79
4747143161Transcription factors (eukaryote gene regulation)have two domains: activation domain and DNA-binding domain - bind DNA motif or response element and RNA pol to alter transcription80
4747151918Acetylationhistone acetylases acetylate lysine residues making them less positive and decrease their affinity to histones, therefore opening up the DNA for transcription - deacetylation = opposite81
4747155424DNA methylationsilences gene activity via chromatin remodelling - heterochromatin is much more methylated82
4747194901Sense coding strand and antisensesense coding strand is identical to the mRNA transcript - antisense is the one transcribed83
4747204962Peptide bonds are what kind of linkagesamide linkages84
4747264752Cholesterolincreases cell membrane fluidity85
4747267415Transmembrane proteins vs embedded proteinstransmembrane proteins actually traverse the membrane embedded proteins are only associated with one side of the membrane86
4747270784Gap junctions are made of6 connexin molecules which form a connexon - a hydrophilic pore that connects adjacent cells87
4747274768Desmosomesbind adjacent cells by anchoring to their cytoskeletons - interactions b/w intermediate filaments Hemidesmosomes: attach cell to underlying membranes (ECM)88
4747320345Colligative propertya physical property of solutions that is dependent on the concentration of dissolved particles, but not on the chemical identity of those dissolved particles ex. osmosis, freezing point depression, boiling point elevation, and vapour pressure depression89
4747330725Osmotic pressurea sucking force, water will move toward the compartment with the greatest osmotic pressure90
4747391552GLUT 2low-affinity glucose transporter found in hepatocytes and pancreatic cells - captures excess glucose passing through portal vein from intestine after a meal - in pancreas serves as an indicator for insulin release - if blood glucose concentrations are high, glucose will enter beta-islet cells and with glucokinase cause insulin release - km ~ 15mM91
4747399326GLUT 4in adipose and muscle - insulin causes additional GLUT 4 movement to the membrane - km ~5 mM (which is the normal glucose level in the blood) therefore when more glucose in blood, need more transporters to increase glucose intake92
4747416449Red blood cells only method of acquiring energyglycolysis b/c they lack mitochondria93
4749565337Glycolysis takes place inthe cytoplasm94
4749569312Rate limiting enzymes of 1) glycolysis: 2) fermentation: 3) glycogenesis: 4) glycogenolysis: 5) gluconeogenesis: 6) Pentose phosphate pathway:1) glycolysis: Phosphofructokinase-1 2) fermentation: lactate dehydrogenase 3) glycogenesis: glycogen synthase 4) glycogenolysis: glycogen phosphorylase 5) gluconeogenesis: fructose-1,6-bisphosphatase 6) Pentose phosphate pathway: glucose-6-phosphate deydrogenase95
4749580386Hexokinase and GlucokinaseHexokinase: present in all tissues, low km, inhibited by glucose-6-phosphate Glucokinase: present in liver and pancreatic beta-islet cells, high km, induced by insulin in hepatocytes - both use ATP and phosphorylate glucose to glucose-6-phosphate, which prevents it from leaving the cell96
4749589928Phosphofructokinase 1 (PFK-1)- rate limiting enzyme & main control point in glycolysis - converts fructose-6-phosphate to 1,6-BP and uses ATP - inhibited by: ATP, citrate, and glucagon (indirectly) - activated by: AMP, F2,6-BP PFK-2: activated by insulin, turns a small amount of F-6-P into F-2,6-BP which activated PFK-1 - inhibited by: glucagon - therefore inhibits PFK-197
4749608501Substrate level phosphorylationplacing an inorganic phosphate (Pi) onto ADP to form ATP - does not require oxygen98
4749621615Irreversible enzymes of glycolysis1) glucokinase or hexokinase 2) PFK-1 3) pyruvate kinase99
4749624598Adaption to high altitude (low pO2) involves- increase respiration - increased oxygen affinity for hemeglobin (initial) - increased rate of glycolysis - increased [2,3-BPG] in RBC (over 12-24 hour period) - normalized oxygen affinity for hemeglobin restored by the increased levels of 2,3-BPG - increased hemeglobin (over days to weeks)100
4749700431Fructose metabolismfructokinase converts to fructose-1-phosphate - aldolase B converts to glyceraldehyde and DHAP - both these are downstream from the rate limiting step of glycolysis (PFK-1), therefore high-fructose drinks supply a quick source of energy to both anaerobic and aerobic cells101
4749736043Glucogenic amino acidsall except leucine and lysine102
4749751076Insulin will _______ fructose 2,6-BP and _________ gluconeogenesis Glucagon will _______ F2,6-BP and ________ gluconeogenesisInsulin will increase F2,6-BP and inhibit gluconeogenesis Glucagon will lower F2,6-BP and stimulate gluconeogenesis103
4749755968Acetyl-CoA ______ pyruvate dehydrogenase and _______ pyruvate carboxylaseAcetyl-CoA inhibits pyruvate dehydrogenase ane stimulates pyruvate carboxylase - shift from burning pyruvate in citric acid cycle to creating new glucose molecules for rest of body - Acetyl-CoA is crucial to gluconeogenesis - the Acetyl-CoA comes from fatty acid oxidation104
4749758063Cori cycleRBC's convert glucose to lactate - lactate is delivered to the liver where it is turned into pyruvate then used for gluconeogenesis - which supplies glucose for the RBCs105
4749765032Gluconeogenic specific enzymes and what they replacepyruvate carboxylase - pyruvate kinase Phosphoenolpyruvate carboxykinase - pyruvate kinase Frucose-2,6-bisphosphatase - Phosphofructokinase 1 Glucose-6-phosphatase - glucokinase106
4749784306Two major metabolic products of the pentose phosphate pathwayNADPH and ribose-5-phosphate107
4753242861Glycolysis yields how many molecules of ATP per glucose2 ATP per glucose108
4753253009Pyruvate is _________ transported into the mitochondria after glycolysis and is oxidized and decarboxylated by pyruvate dehydrogenase complex to from _______actively transported to from Acetyl-CoA109
4753258849Pyruvate dehydrogenase complexes 5 enzymes1) Pyruvate dehydrogenase: oxidizes pyruvate and yields CO2. Mg2+ required, TPP coenzyme 2) Dihydropropyl transacetylase: lipoic acid accepts 2 carbon molecule from TPP and oxidizes it to yield an Acetyl group, Acetyl-CoA is formed 3) dihydrolipoyl dehydrogenase: FAD used to reoxidize lipoic acid, FAD reduced to FADH2, NAD+ is reduced to NADHf 4) pyruvate dehydrogenase kinase 5) Dehydrogenase phosphatase110
4753329874Citric Acid cycle rate limiting stem and enzymeD-Isocitrate to alpha-ketoglutarate - Isocitrate dehydrogenase111
4753344350Synthase vs synthetaseSynthetases: use ATP in the reaction Synthases: do not use ATP112
4753354928Please, ah, can I keep selling sex for money, officer? Mneumonic for TCA cylePyruvate, acetyl-CoA, citrate, isocitrate, alpha-ketoglutarate, succinyl CoA, Succinate, fumarate, malate, oxaloacetate113
4753385653Pyruvate dehydrogenase kinase and phosphatasePyruvate dehydrogenase kinase: phosphorylates PDH (pyruvate to Acetyl-CoA) if ATP levels are high, preventing Acetyl-CoA formation Pyruvate dehydrogenase phosphatase: reactivates PDH in response to high ADP levels - PDH also inhibited by high levels of Acetyl-CoA114
4753428445glycolysis and fermentation occurin the cytosol115
4753473361in ETC which complexes pump protons into intermembrane space? Acquire electrons from NADH Acquire electrons from FADH2 have the highest reduction potentialI, III, IV (all except II pump protons, IV is only 2 protons) Complex I acquires electrons from NADH Complex II acquires electrons from FADH2 Highest reduction pot = IV (must be last step)116
4753511791Uncouplersinhibit ATP synthesis without affecting the electron transport chain117
4753522649Pancreatic enzymes responsible for digesting fatspancreatic lipase, colipase, and cholesterol esterase - broken down into cholesterol, 2-monoacylglycerol, free fatty acids, - reform triacylglycerol and cholesteryl esters once absorbed into mucosa118
4753540468Hormone sensitive lipase- hydrolyzes triacylglycerols, yielding fatty acids and glycerol - activated by decrease in insulin levels or increase in EP or cortisol levels - active in adipose tissue119
47535485011) Chylomicrons 2) VLDL 3) IDL (VLDL remnants) 4) LDL 5) HDL1) chylomicrons: transport dietary TAG and cholesterol from intestine to tissues 2) VLDL: transport TAG from liver to tissues 3) IDL: picks up cholesterol from HDL to become LDL, picked up by the liver 4) LDL: delivers cholesterol into cells 5) HDL: picks up cholesterol in blood vessels, delivers cholesterol to liver and steroidogenic tissues, transfers apolipoproteins to other lipoproteins (considered good cholesterol)120
4753586091Alpha carboncarbon 2 of a fatty acid121
4753592884Palmitic acidprimary end product of fatty acid synthesis (16:0)122
4753604963Rate limiting step of fatty acid biosynthesisAcetyl CoA carboxylase123
4753624137Rate limiting enzyme of fatty acid oxidationCarnitine acyltransferase I: transport long-chain fatty acids (14 to 20 carbons) into the mitochondria124
4753644329Alpha-lenolenic acid lenoleic acidalpha-lenolenic acid: 18:3 all-cis-9, 12, 15, an omega-3 fatty acid Lenoleic acid: 18:2 cis,cis-9, 12, and omega-6 fatty acid (omega is the last carbon, number refers to how many carbons the first double bond is away from the omega carbon)125
4753651452excess acetyl-CoA from beta-oxidation of fatty acids is turned intoKetone bodies: transportable forms of Acetyl-CoA, produced in the liver - acetoacetate and 3-hydroxybutyrate126
4753657738Acetyl-CoA cannot be used to produceglucose via gluconeogenesis127
4753659094Ketogenesis and ketolysisKetogenesis: favored by a prolonged fast and occurs in the liver, stimulated by increasing concentrations of acetyl-CoA Ketolysis: favored during prolonged fasting, but is stimulated by low-energy state in muscle and brain tissue and does not occur in the liver128
4753666092Glucogenic Amino acidsall but leucine and lysine - can be turned into glucose via gluconeogenesis129
4753666404Ketogenic amino acidsleucine, lysine, isoleucine, phenylalanine, threonine, tryptophan, and tyrosine - can be converted to acetyl-CoA and ketone bodies130
4753692568LCAT and CETPLCAT: catalyzes the formation of cholesteryl esters for transport with HDL CETP: catalyzes the transition of IDL to LDL by transferring cholesteryl esters from HDL131
4753711872main gluconeogenesis precursorslactate, glycerol (from TAGs), alanine, and glutamine (all glucogenic amino acids, aka not leucine and lysine)132
4755579740Amino acids that are both glucogenic and ketogenicPITTT phenylalanine, Isoleucine, threonine, tyrosine, tryptophan133
4755615110Gluconeogenesis occurs mainly inthe liver and kidneys134
4755677658High energy electron carriers in cytoplasmNADH (glycolysis, fermentation, TCA, ECT), FADH2, NADPH (PPP, lipid biosynthesis, bleach formation, oxidative stress, photosynthesis), ubiquinone (ECT), cytochromes (ECT), and glutathione (oxidative stress)135
4755681917Flavoproteinssubclass of electron carriers that are derived from riboflavin (vitamin B2) - also nucleic acid derivatives (FAD - flavin adenine dinucleotide or FMN flavin mononucleotide)136
4755700510Postprandial state (well-fed state)- greater anabolism than catabolism - insulin is released with increased blood glucose levels - promotes glycogen synthesis in liver and muscle - liver converts excess glucose to fatty acids/ TAGs - promotes TAG synthesis in adipocytes - promotes protein synthesis in muscle137
4755709699Two types of cells insensitive to insulinnervous tissue and RBC's - nervous tissue uses glucose from blood (why its concentration is maintained) unless in prolonged fasting state in which switches to ketones - RBCs only use glucose anaerobically but also kidney tubules, intestinal mucosa, β-cells of pancreas - all these tissues need to take in glucose even when the concentration is low138
4755713959"Fasting state" Counterregulatory hormones (oppose insulin)glucagon, EP, NE, cortisol, and growth hormone liver: glycogenolysis, gluconeogenesis Muscle and adipose: low insulin = release of amino acids and fatty acids (sent to liver for gluconeogenesis)139
4755720442Prolonged fastingfurther elevated EP and glucagon - 24 hours - gluconeogenesis is primary energy source, glycogen stores are depleted - rapid lipolysis = excess acetyl CoA = ketone bodies - after several weeks the brain primarily uses (2/3rds) energy from ketone bodies140
4755736560Insulinpeptide hormone secreted by β-cells of the pancreatic islets of Langerhans - used for effective uptake of glucose in muscle and adipose tissue - increases glycogen synthesis in liver by increasing activity of glucokinase and glycogen synthase (decrease activities of glycogen phosphorylase and glucose-6-phosphatase) - increases amino acid uptake by muscle cells141
4755748043Insulins affect on fat metabolismInsulin increases: - glucose and TAG uptake by adipocytes - lipoprotein lipase activity - which clears VLDL and chylomicrons from the blood - TAG synthesis in liver and adipocytes from acetyl-CoA Insulin decreases: - TAG breakdown in adipose tissue - formation of ketone bodies in the liver142
4755752871Glucagonpeptide hormone secreted by α-cells of the pancreatic islets of Langerhans, primary target is hepatocytes - increased liver glycogenolysis (activates glycogen phosphorylase and inhibits glycogen synthase) - increased liver gluconeogenesis (increases pyruvate carboxylase and PEPCK activity (pyruvate to PEP) - increased liver ketogenesis and decreased lipogenesis - increases lipolysis in liver (activates hormone sensitive lipase) - glucagon is released due to low blood glucose, but also high amino acid concentration (arginine, lysine, histidine esp)143
4755763212Glucagon increasesincreases glycogenolysis, lipolysis, protein catabolism (gluconeogenesis), ureagenesis, ketogenesis, gluconeogenesis144
4755770489Cortisolglucocorticoid (steroid) released from adrenal cortex - increases lipolysis and protein catabolism, - inhibits glucose uptake in most tissues (muscle, lymph, adipose) - increases hepatic output of glucose via gluconeogenesis, particularly from amino acids145
4755776482CatecholaminesEP and NE, released from the adrenal medulla - increase activity of liver and muscle glycogen phosphorylase = more glucose output by liver - increase lipolysis via hormone-sensitive lipase146
4755786971Thyroid hormonesactivity is largely permissive (levels kept ~ constant) Thyroxine (T4) - several hour latency period and can last for several days Triiodothyronine (T3) - produces a more rapid increase in metabolic rate and shorter duration - both increase O2 consumption and heat production (aka raise basal metabolic rate)147
4755931185Ghrelinhormone secreted by the stomach in response to signals of an impending meal (sight, sound, taste, smell) - cause release of orexin148
4755932073Orexin- further increases appetite & involved in alertness & sleep-wake cycle149
4755933637Leptinsecreted by fat cells to decrease appetite by suppressing orexin production150

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