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A&P - Ch 24
Nutrition, Metabolism, and Body Temp Regulation
| Question | Answer |
|---|---|
| organic molecule that stores and releases chemical energy for use in body cells | ATP |
| how energy value of food is measured; amount of heat energy needed to raise body temp of 1kg of water 1degree C | kilocalories |
| chemical substances taken in via the diet that are used for energy and cell building | nutrients |
| carbohydrates, lipids, & proteins | major nutrients |
| vitamins, minerals, & water | other nutrients |
| chemicals that must be obtained from outside sources because they cannot be made fast enough to meet needs of body | essential nutrients |
| except for lactose & negligible amounts of glycogen in meats all carbs ingested are | derived from plants |
| monosaccharides & disaccharides come from | fruits, sugar can, sugar beets, honey & milk |
| polysaccharide, plentiful in most veges; not digested by humans but provides roughage | cellulose |
| insoluble fiber | roughage |
| increases bulk of stool & facilitates defecation | insoluble fiber |
| reduces blood cholesterol levels; pectin found in apples & citrus fruits | soluble fiber |
| glucose is principal __ __ | blood sugar |
| carbohydrate molecule ultimately used as fuel by body cells to produce ATP; monosaccharide | glucose |
| yield of fructose & galactose, during carbohydrate digestion, are | converted to glucose by liver before entering general circulation |
| RBCs & neurons rely __ __ on glucose for their energy needs | almost entirely |
| small amounts of __ __ are used to synthesize nucleic acids | pentose sugars |
| variety of sugars are attached to externally facing plasma membrane __ & __ | proteins; lipids |
| 100 grams of carbs/day is presumed to be __ __ needed to maintain adequate blood glucose levels | smallest amount |
| 130 g/day of carbs, based on amount needed to fuel brain not total amount needed to supply all daily activities | recommended dietary allowance |
| 45-65% of one's total calorie intake with emphasis on complex carbohydrates is the recommended carb intake to | maintain overall health |
| when less than 50 g/day, of carbs, is consumed | tissue proteins & fats are used for energy fuel |
| most abundant dietary lipid | triglycerides |
| triglycerides aka | neutral fats or triacylglycerols |
| fats found in meat & dairy foods | saturated |
| fats found in seeds, nuts, olive/vege oils | unsaturated |
| fats are digested to monoglycerides or all the way to | fatty acids & glycerol |
| once fats are digested into fatty acids & glycerol they are __ to triglycerides for transportation in lymph | reconverted |
| egg yolk, meats, organ meats, shellfish, milk products are | major sources of cholesterol |
| liver produces about 85% of __ __ regardless of dietary intake | blood cholesterol |
| liver __ synthesize linoleic acid | cannot |
| fatty acid component of lecithin; omega-6 fatty acid; essential fatty acid that must be ingested; found in vegetable oils | linoleic acid |
| any of a group of phospholipids found in egg yolks & plasma membrane of plant & animal cells | lecithin |
| bread, cereal, crackers, flour, pasta, nuts, rice, potatoes are all considered | complex carbohydrates |
| carbonated drinks, candy, fruit, ice cream, pudding, young/immature vegetables | simple carbohydrates |
| eggs, milk, milk products, meat (incl. fish, poultry, pork, beef, lamb) are considered | complete proteins |
| legumes (incl. soybeans, lima beans, kidney beans, lentils) nuts & seeds, grains & cereals, & vegetables are considered | incomplete proteins |
| dietary fats are essential because they help body absorb __ __ | fat-soluble vitamins |
| dietary fats are essential because triglycerides are major energy fuel of __ & __ __ | hepatocytes; skeletal muscles |
| dietary fats are essential because phospholipids are integral component of | myelin sheaths & cellular membranes |
| fatty deposits in adipose tissue provide __ __ around body organs | protective cushion |
| fatty deposits in adipose tissue provide __ __ beneath skin | insulating layer |
| fatty deposits in adipose tissue provide easy-to-store __ __ of energy fuel | concentrated source |
| cholesterol is __ __ for energy | not used |
| regulatory molecule formed from linoleic acid via arachidonic acid, which play role in smooth muscle contraction, control of BP, & inflammation | prostaglandins |
| cholesterol is __ component of plasma membranes | stabilizing |
| cholesterol is __ from which bile salts, steroid hormones & other essential molecules are formed | precursor |
| should represent 30% or less of total daily fat intake | fats |
| should be limited to 10% or less of total daily fat intake | saturated fats |
| should be no more than 300 mg | daily cholesterol intake |
| should be less than 200 mg/dl | total blood cholesterol |
| contain highest-quality proteins, those with greatest amount & best ratios of essential amino acids | animal products |
| complete proteins meet all of the body's __ __ requirements for tissue maintenance & growth | amino acid |
| incomplete proteins are nutritionally incomplete because they are low in one or more of the | essential amino acids |
| important structural material of body in skin protein | keratin |
| important structural material of body in CT protein | collagen |
| important structural material of body in muscle protein | elastin |
| enzymes & some hormones that regulate variety of body functions are | functional proteins |
| all amino acids needed to make particular protein must be present in cell at same time & in same amounts; if one missing protein cannot be made | all-or-none rule |
| because essential amino acids cannot be stored those not used immediately to build proteins are | oxidized for energy or converted to carbs/fats |
| for optimal protein synthesis diet must supply sufficient carb/fat calories for ATP production; when doesn't dietary & tissue proteins used for energy | adequacy of caloric intake |
| homeostatic state; rate of protein synthesis equals rate of protein breakdown & loss | nitrogen balance |
| body is in nitrogen balance when amount of nitrogen ingested in proteins | equals amount excreted in urine & feces |
| when amount of protein incorporated into tissue is greater than amount being broken down & used for energy | positive nitrogen balance |
| positive nitrogen balance is found in | growing children & pregnant women |
| positive nitrogen balance also occurs when | tissues are being repaired, following illness/injury |
| protein breakdown for energy exceeds amount of protein being incorporated into tissues | negative nitrogen balance |
| negative nitrogen balance occurs during | physical & emotional stress (i.e. infection, injury, or burns) |
| negative nitrogen balance occurs when __ or __ of dietary protein is poor | quality; quantity |
| negative nitrogen balance can occur during __ | starvation |
| hormones that accelerate protein synthesis & growth | anabolic hormones |
| effects of anabolic hormones __ __ throughout life | vary continually |
| stimulates tissue growth during childhood & conserves protein in adults | pituitary growth hormone |
| trigger growth spurts of adolescence | sex hormones |
| hormones released during stress; enhance protein breakdown & conversion of amino acids to glucose | adrenal glucocorticoids |
| supply essential amino acids; furnish raw material for making nonessential amino acids & various nonprotein nitrogen-containing substances | dietary proteins |
| reflects his/her age, size, metabolic rate, & current state of nitrogen balance | amount of protein a person needs |
| nutritionists recommend __ __ __ of 0.8 g per kg of body weight | daily protein intake |
| organic compounds required by body in minute amounts; not used for energy & do not serve as building blocks, but are crucial in helping body use nutrients that do | vitamins |
| nonprotein substance associated with and activating an enzyme, typically a vitamin | coenzyme |
| most vitamins __ __ coenzymes | function as |
| act as coenzymes in oxidation of glucose for energy | B vitamins |
| most vitamins are not | made in the body |
| vitamin D, small amounts of B vitamins & vitamin K | are made in the body |
| synthesized by intestinal bacteria | vitamin K |
| body can convert beta-carotene into | vitamin A |
| beta-carotene, and substances like it, are call | provitamins |
| no one food contains | all the required vitamins |
| B-complex vitamins & vitamin C are | water-soluble vitamins |
| in order to be absorbed, vitamin B12 must bind to __ __ in stomach secretions | intrinsic factor |
| vitamins A, D, E, & K bind to ingested lipids & are absorbed along with their digestion products | fat-soluble vitamins |
| anything that interferes with fat absorption also interferes with | absorption of fat-soluble vitamins |
| with exception of __ __, fat soluble-vitamins are stored in the body | vitamin K |
| vitamins C, E, & A & mineral selenium are __ that neutralize tissue-damaging free radicals | antioxidants |
| inorganic chemical compounds found in nature; salts | minerals |
| calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium & trace amounts of about a dozen other minerals are | required in moderate amounts in the body |
| sum total of chemical reactions occurring in body cells | metabolism |
| energy-requiring building phase of metabolism in which simpler substances are combined to form more complex substances | anabolism |
| process in which living cells break down substances into simpler substances | catabolism |
| metabolic processes in which ATP is produced | cellular respiration |
| chemical reaction in which a phosphate molecule is added to a molecule | phosphorylation |
| phosphorylation __ the molecule to change in a way that increases it activity, produces motion, or does work | primes |
| essential for oxygen binding to hemoglobin | iron |
| harden bone & teeth | calcium, phosphorus & magnesium salts |
| necessary for thyroid hormone synthesis | iodine |
| major electrolytes in the blood | sodium & chloride |
| digestion in GI tract; absorbed nutrients are then transported in blood to tissue cells | stage 1 in processing of energy-containing nutrients |
| during stage 2 of processing of energy-containing nutrients, which occurs in tissue cells, newly delivered nutrients can be built into lipids, proteins, & glycogen by | anabolic pathways |
| during stage 2 of processing of energy-containing nutrients, which occurs in tissue cells, newly delivered nutrients can be broken down by __ __ to pyruvic acid & acetyl CoA in cell cytoplasm | catabolic pathways |
| major catabolic pathway of stage 2 of processing of energy-containing nutrients is | glycolysis |
| catabolic breakdown (in mitochondria) of intermediates into | CO2, water, & ATP |
| primary function of cellular respiration is to | generate ATP |
| gain of oxygen or loss of hydrogen | oxidation |
| whichever way oxidation occurs the oxidized substance always __ __ as they more to a substance that more strongly attracts them | loses electrons |
| reaction that couples oxidation of one substance with reduction of another substance | oxidation-reduction (redox) reactions |
| oxidized substances lose energy & reduced substances gain energy as energy-rich electrons are transferred from one substance to the next | key of redox reactions |
| enzymes that catalyze the transfer of oxygen in oxidation-reduction reactions | oxidases |
| catalyze redox reactions in which hydrogen are removed | dehydrogenases |
| C6H12O6 + 6O2 arrow 6H2O + 6CO2 + 38 ATP + heat | oxidation of glucose |
| glycolysis, Krebs cycle, & electron transport chain-oxidative phosphorylation | catabolic pathways of glucose |
| process of ATP synthesis during which an inorganic phosphate group is attached to ADP; occurs via electron transport chain within mitochondria | oxidative phosphorylation |
| occurs in cytosol of cells; series of 10 chemical steps by which glucose is converted to 2 pyruvic acid molecules | glycolysis |
| glycolysis is a(n) __ pathway | anaerobic |
| glycolysis does not use | oxygen |
| glycolysis occurs whether or not | oxygen is present |
| phase 1 of glycolysis | sugar activation |
| phase 2 of glycolysis | sugar cleavage |
| phase 3 of glycolysis | sugar oxidation & ATP formation |
| fate of __ __, during glycolysis, depends in availability of oxygen | pyruvic acid |
| if O2 not available, during glycolysis, pyruvic acid is | converted to lactic acid |
| if O2 available, during glycolysis, pyruvic acid | enters aerobic pathways of Krebs cycle & electron transport chain |
| aerobic metabolic pathway occurring within mitochondria, in which food metabolites are oxidized & CO_2 is liberated, & coenzymes are reduced | Krebs cycle |
| Krebs cycle also called | citric acid cycle |
| glycogen formation when glucose supplies exceed need for ATP synthesis | glycogenesis |
| glycogenesis mostly occurs in | liver & skeletal muscles |
| glycogen breakdown in response to low blood glucose | glycogenolysis |
| glucose formation from noncarbohydrate (glycerol & amino acid) molecules when dietary sources & stores are depleted | gluconeogenesis |
| gluconeogenesis occurs mainly in liver & protects | brain against effects of hypoglycemia |
| energy yield from __ __ is twice that from glucose or protein catabolism | fat catabolism |
| digested fats are transported in lymph as | chylomicrons |
| chylomicrons are __ in plasma by enzymes into fatty acids and glycerol which are taken up by cells | hydrolyzed |
| only triglycerides are routinely | oxidized for energy |
| metabolite enters glycolytic pathway | glycerol pathway |
| takes place in mitochondria; produces acetyl CoA- enter the Krebs cycle | beta oxidation of fatty acids |
| glycerol & fatty acids not needed for energy are stored as triglycerides( mostly in subcutaneous tissues) | lipogenesis |
| in lipogenesis, when cellular ATP & glucose levels are high glucose is | stored as triglycerides |
| when carbohydrates are deficient breakdown of stored fats to glycerol & fatty acids provides fuel for aerobic respiration | lipolysis |
| when carbohydrates are severely deficient lipolysis results in | accumulation of acetyl CoAgets converted to ketone bodies in liver |
| when dietary protein is in excess of that needed for anabolic processes, amino acids are | oxidized for energy or converted into fat |
| results in pyruvic acid & carbohydrate intermediates- enter the Krebs cycle | oxidation of Amino Acids |
| during oxidation of Amino Acids, amine group is removed as toxic ammonia which is converted by liver to | urea & excreted by kidney |
| requires a complete set of amino acids so essential amino acids must be provided in diet | protein synthesis |
| dynamic state in which organic molecules are continuously broken down and rebuilt | catabolic-anabolic steady state |
| during catabolic-anabolic steady state, body nutrient pools of amino acids carbohydrates & fats are | interconvertible |
| used for protein synthesis, gluconeogenesis & supply of energy (after being converted to a carbohydrate intermediates) | amino acid pool |
| are easily interconverted through key intermediates | carbohydrate & fat pools |
| during and shortly after eating, nutrient absorption into blood has occurred | absorptive (fed) state |
| excess metabolites will be transformed into fat when | anabolism exceeds catabolism |
| when the GI tract is empty- energy sources are supplied by breakdown of reserves | postabsorptive (fasting) state |
| Krebs cycle is key pathway in __ __, of metabolism of energy-containing nutrients | Stage 3 |
| cellular respiration consists of __ of Stage 2 (metabolism of energy-containing nutrients) and __ __ of Stage 3 | glycolysis; all events |
| generating ATP is __ __ of cellular respiration | primary function |
| cellular respiration traps some of chemical energy of original food molecules in its | own high-energy bonds |
| many reactions that take place within cells are __ reactions | oxidation |
| hydrogen in __, so its lone electron usually spends time orbiting other atoms of molecule | electropositive |
| oxygen is very __, so when oxygen binds with other atoms shared electrons spend more time in oxygen's vicinity | electron-hungry |
| all oxidation of food fuels involves step-by-step removal of pairs of __ atoms from substrate molecules | hydrogen |
| result of oxidation of food fuels, where there is step-by-step removal of pairs of hydrogen atoms from substrate molecules, eventually leaves only | carbon dioxide CO2 |
| in oxidation of food fuels, __ __ is final electron acceptor | molecular oxygen |
| in oxidation of food fuels, molecular oxygen combines with removed hydrogen atoms at very __ of process, to form __ | end; water |
| whenever one substance is oxidized, another substance is | reduced |
| as food fuels oxidized, their energy is transferred from one molecule to another, and ultimately to __ to form __ __ | ADP; energy-rich ATP |
| redox reactions are __ by enzymes | catalyzed |
| enzymes require help of __ __, typically derived from one of B vitamins | specific coenzymes |
| enzymes that catalyze removal of hydrogen atoms to oxidize substance cannot | accept the hydrogen |
| coenzymes act as __ __, becoming reduced each time substrate is oxidized | hydrogen acceptors |
| occurs when high-energy phosphate groups are transferred directly from phosphorylated substrates to ADP | substrate-level phosphorylation |
| substrate-level phosphorylation occurs because high-energy bonds attaching phosphate groups to substrates are | even more unstable than those in ATP |
| ATP is synthesized via substrate-level phosphorylation, once during __ and once during each turn of __ __ | glycolysis; Krebs cycle |
| enzymes catalyzing substrate-level phosphorylation are located in __ & __ __ inside mitochondria | cytosol; watery matrix |
| oxidative phosphorylation releases most of energy that is eventually | captured in ATP bonds during cellular respiration |
| oxidative phosphorylation is carried out by __ __ __ forming part of inner mitochondrial membrane | electron transport proteins |
| couple movement of substances across membranes to chemical reactions | chemiosmotic processes |
| oxidation of food fuels is __ part of chemiosmotic | chemi |
| chemi part of chemiosmotic is used to __ __ across inner mitochondrial membrane into intermembrane space | pump protons (H+) |
| chemiosmotic processes create __ __ __ for protons across mitochondrial membrane | steep concentration gradient |
| during chemiosmotic processes, H+ flows back across membrane through membrane channel called | ATP synthase |
| during chemiosmotic processes, when H+ flows back across membrane, some of gradient energy is | captured & used to attach phosphate groups to ADP |
| are eventually turned into glucose | all food carbohydrates |
| glucose enters tissue cells by | facilitated diffusion |
| facilitated diffusion of glucose into tissue cells is greatly enhanced by | insulin |
| upon entry into cell glucose is immediately phosphorylated into | glucose-6-phosphate |
| because most body cells lack enzymes needed to reverse immediate phosphorylation of glucose, upon entry into tissue cells, it | effectively traps glucose inside of cells |
| the only body cells that have enzymes needed to reverse immediate phosphorylation of glucose, upon entry into tissue cells, are | intestinal mucosa cells, kidney tubules cells, & liver cells |
| catabolic & anabolic pathways for carbs | all begin with glucose-6-phosphate |
| glucose is pivotal fuel molecule in __ pathways | ATP-producing |
| exclusive function of electron transport chain is | use of oxygen |
| carries out final catabolic reactions that occur on mitochondrial cristae | electron transport chain |
| when more glucose available than can be oxidized, rising intracellular ATP concentrations eventually inhibit glucose catabolism and | begin process that stores glucose as glycogen/fat |
| accounts for 80-85% of stored energy | fat |
| an important energy source for skeletal muscles that have depleted their own glycogen reserves | liver glycogen |
| fatty acid metabolites; strong organic acids | ketones |
| adrenal cortex, ovaries, & testes use cholesterol to | synthesize their steroid hormones |
| protein synthesis occurs on | ribosomes |
| protein anabolism reflects __ __ at each stage of life | hormonal balance |
| during absorptive state anabolism __ catabolism | exceeds |
| absorbed monosaccharides are delivered directly | to the liver |
| once absorbed monosaccharides are delivered to liver, __ & __ are converted to glucose | fructose; galactose |
| glycogen formed in liver is | stored there |
| most fat synthesized in liver is packaged with proteins as | very low density lipoproteins (VLDLs) |
| very low density lipoproteins (VLDLs) are released to blood to be picked up for | storage by adipose tissues |
| not sequestered by liver enters body cells to be metabolized for energy | bloodborne glucose |
| any excess of bloodborne glucose is stored in __ __ as glycogen or in __ cells as fat | skeletal muscles; adipose |
| enzyme that catalyzes fat hydrolysis & is active in capillaries of muscle & fat tissues | lipoprotein lipase |
| use triglycerides as primary energy source | adipose, skeletal & cardiac muscle, & liver cells |
| most fatty acids & glycerol enter adipose tissue to be __ to triglycerides & stored | reconverted |
| liver __ some amino acids to make them keto acids | deaminates |
| keto acids may be used for __ __ in Krebs cycle, or may be converted to __ __ stores | ATP synthesis; liver fat |
| liver uses some amino acids to | synthesize plasma proteins |
| plasma proteins synthesized from amino acids by liver include | albumin, clotting proteins, & transport proteins |
| most amino acids traveling through liver remain in blood to be | used by other cells for protein synthesis |
| hormone that enhances carrier-mediated diffusion of glucose into tissue cells, thus lowering blood glucose levels | insulin |
| insulin directs essentially all events of | absorptive state |
| rising blood glucose levels after carb-containing meal act as __ __ that prods beta cells of pancreatic islets to secrete more insulin | humoral stimulus |
| glucose-induced stimulation of insulin release (by pancreatic islets) is enhanced by GI tract hormone | glucose-dependent insulinotropic peptide (GIP) |
| glucose-induced stimulation of insulin release (by pancreatic islets) is enhanced by __ stimulation | parasympathetic |
| 2nd important stimulus for insulin release is | elevated amino acid levels in blood |
| enhances carrier-mediated facilitated diffusion of glucose | translocation of glucose transporter (GLUT-4) |
| brain & liver cells take up glucose whether or not | insulin is present |
| once glucose enters tissue cells, insulin __ glucose oxidation for energy & __ it conversion to glycogen | enhances; stimulates |
| insulin revs up __ __ of amino acids into cells | active transport |
| insulin __ protein synthesis | promotes |
| insulin __ liver export of glucose | inhibits |
| insulin inhibits virtually all liver enzymes that | promote gluconeogenesis |
| insulin is __ hormone | hypoglycemic |
| insulin sweeps glucose out of blood into tissue cells, in turn | lowering glucose levels |
| consequence of inadequate insulin production or abnormal insulin receptors | diabetes mellitus |
| net synthesis of fat, glycogen, & protein ends & catabolism of these substance begins to occur | postabsorptive state |
| primary goal of postabsorptive state is to | maintain blood glucose levels between meals |
| postabsorptive state promotes | use of fats for energy |
| postabsorptive state spares glucose | for brain |
| liver's glycogen stores are __ __ of glucose reserves used in postabsorptive state | 1st line |
| in postabsorptive state, liver's glycogen stores can maintain blood sugars levels for about | 4 hours |
| in postabsorptive state, 2nd line of glucose reserves tapped into are | glycogenolysis in skeletal muscles |
| before liver glycogen is exhausted, in postabsorptive state, glycogenolysis begins in | skeletal muscles |
| glucose produces by glycogenolysis in skeletal muscles, in postabsorptive state, is not released into blood because | skeletal muscles does not enzymes needed to dephosphorylate glucose |
| during glycogenolysis in skeletal muscles, in postabsorptive state, glucose is __ __ to pyruvic acid | partly oxidized |
| skeletal muscle contributes to blood glucose homeostasis | indirectly via liver mechanisms |
| during lipolysis in adipose tissues & liver, glycerol is used for | gluconeogenesis in the liver |
| when fasting is prolonged & glycogen/fat stores are nearly exhausted | tissue proteins become major source of blood glucose |
| during catabolism of cellular proteins, cellular amino acids are __ & converted to glucose in liver | deaminated |
| during fasting for several weeks, __ also carry out gluconeogenesis & contribute as much glucose to blood as liver | kidneys |
| during prolonged fasting/starvation, __ __ are 1st to be catabolized | muscle proteins |
| determines time a person can survive without food | amount of fat body contains |
| increased use of noncarbohydrate fuel molecules, especially triglycerides, to conserve glucose | glucose sparing |
| as body progresses from absorptive to post absorptive state all other organs, besides __, switch to fatty acids as major energy source | brain |
| during transition phase, from absorptive to post absorptive state, __ begins in adipose tissues & released __ __ are picked up by tissue cells & oxidized for energy | lipolysis; fatty acids |
| important trigger for initiating postabsorptive events is | dampening of insulin release |
| dampening of insulin release occurs as blood glucose levels __ | drop |
| as insulin levels drop, during postabsorptive state, all __ __ responses are inhibited as well | insulin-dependent cellular |
| can improve body's use of insulin, during postabsorptive state | drinking moderate amounts of beer, wine, or gin |
| stimulate alpha cells of pancreatic islets to release glucagon | declining glucose levels |
| hormone formed by alpha cells of pancreatic islets; raises glucose level of blood | glucagon |
| glucagon is __ of insulin | antagonist |
| during postabsorptive state glucagon is considered __ __ | hyperglycemic hormone |
| term used to describe hormones such as glucagon that elevate blood glucose level | hyperglycemic |
| targets of glucagon are | liver & adipose tissue |
| during postabsorptive state, they respond to glucagon by accelerating glycogenolysis & gluconeogenesis | hepatocytes in liver |
| during postabsorptive state, in response to glucagon they mobilize lipolysis & release fatty acids & glycerol to blood | adipose cells |
| during postabsorptive state, glucagon __ blood energy sources by __ both glucose & fatty acid levels | restores; enhancing |
| during postabsorptive state, certain hormonal controls combined with persistent low glucose levels or prolonged fasting, most fat that is mobilized is | converted to ketone bodies |
| glucagon release is __ after next meal or whenever blood glucose levels rise & insulin secretion begins again | inhibited |
| insulin & thyroxine stimulate | glucose uptake by cells |
| insulin & growth hormone stimulate | acid uptake by cells |
| insulin & thyroxine stimulate __ __ for energy | glucose catabolism |
| hormone that stimulates glycogenesis, lipogenesis, & fat storage | insulin |
| insulin inhibits | gluconeogenesis |
| insulin, growth hormone, thyroxine, & testosterone stimulate | anabolic protein synthesis |
| glucagon & epinephrine stimulate | glycogenolysis |
| glucagon, epinephrine, growth hormone, thyroxine, & cortisol stimulate | lipolysis & fat mobilization |
| glucagon, epinephrine, growth hormone, & cortisol __ gluconeogenesis | stimulate |
| cortisol stimulate __ __ breakdown | catabolic protein |
| both insulin & glucagon release are strongly stimulated by | rising amino acid levels in blood |
| when high-protein low carb meal is eaten stimulus for insulin release is strong, & if not counterbalanced may cause | damage to brain by abrupt onset of hypoglycemia |
| when high-protein low carb meal is eaten, simultaneous release of glucagon __ effects of insulin | modulates |
| when high-protein low carb meal is eaten, simultaneous release of glucagon helps __ blood glucose levels | stabilize |
| plays crucial role in supplying food quickly when blood glucose levels drop suddenly | sympathetic nervous system |
| well supplied by sympathetic nerve fibers | adipose tissues |
| epinephrine released by adrenal medulla in response to sympathetic activation acts on | liver, skeletal muscles, & adipose tissues |
| when acting together, sympathetic nerve stimulation & release of epinephrine from its activation | mobilize fat & promote glycogenolysis |
| enhanced by prolonged fasting or rapid declines in blood glucose levels; exerts important anti-insulin effects | growth hormone |
| growth hormone reduces ability of insulin to promote | glucose uptake in fat & muscle |
| function of carbohydrate metabolism in liver, important in maintaining blood glucose homeostasis, is to convert | galactose & fructose to glucose |
| in carbohydrate metabolism, it store glucose as glycogen when blood glucose levels are high & in response to hormonal controls performs glycogenolysis & releases into blood called | glucose buffer function |
| a function of carbohydrate metabolism in liver is | gluconeogenesis: conversion of amino acids & glycerol to glucose when glycogen stores are exhausted & blood glucose levels are falling |
| a function of carbohydrate metabolism in liver is conversion of glucose to | fats for storage |
| function of fat metabolism in liver, primary site of | beta oxidation |
| beta oxidation is | breakdown of fatty acids to acetyl CoA |
| function of fat metabolism in liver, converts excess acetyl CoA to | ketone bodies for release to tissue cells |
| function of fat metabolism in liver, is | fat storage |
| function of fat metabolism in liver, forms __ for transport of fatty acids, fats, & cholesterol to & from tissues | lipoproteins |
| function of fat metabolism in liver, synthesis of cholesterol from __ __ in order to catabolize cholesterol to __ __ which are excreted in bile | acetyl CoA; bile salts |
| without liver metabolism of protein many __ __ would not be made | clotting proteins |
| without lever metabolism of protein __ would not be disposed from the body | ammonia |
| important function of liver, metabolism of protein __ amino acids | deaminates |
| required for amino acid conversion to glucose or use for ATP synthesis; takes place in liver | deamination of amino acids |
| through metabolism of protein by liver, ammonia is removed from body | in urea |
| inability to form urea in liver results in | accumulation of ammonia in blood |
| protein metabolism by liver, forms most __ proteins | plasma |
| if protein metabolism by liver does not take place plasma protein depletion causes | rapid mitosis of hepatocytes & actual growth of liver |
| plasma proteins not formed by liver | gamma globulins, some hormones & some enzymes |
| intraconversion of nonessential amino acids | transamination |
| transamination is liver function brought about by | protein metabolism |
| liver functions to store 1-2 year supply of | vitamin A |
| liver functions to store sizable amounts (1-4 months' supply) of | vitamin D & B12 |
| liver functions to store __, stored as ferritin until needed | iron |
| liver releases iron to blood as | blood levels drop |
| biotransformation function of liver includes metabolism of __ & __ by performing synthetic reactions yielding inactive products for excretion by kidneys | alcohol; drugs |
| biotransformation function of liver includes metabolism of alcohol & drugs by performing __ __ that may result in products which are more active, changed in activity, or less active | nonsynthetic reactions |
| the only thing that can do liver's work | is a hepatocyte |
| serves as structural basis of bile salts, steroid hormones, & vitamin D as a major component of plasma membranes | cholesterol |
| cholesterol is part of __ __ molecule that helps direct embryonic development | key signaling |
| about 15% of __ cholesterol comes from diet | blood |
| 85% of blood cholesterol is made from __ __ by liver | acetyl CoA |
| intestinal cells also make __ from acetyl CoA | cholesterol |
| because triglycerides & cholesterol are insoluble in water they do not | circulate freely in blood |
| triglycerides & cholesterol are transported to & from tissue cells bound to small __ __ | lipid-protein complexes |
| solubilize hydrophobic lipids, & protein part contains signals that regular lipid entry & exit at specific target cells | lipoproteins |
| in lipoproteins, relative __ __ varies considerably | fat-protein composition |
| contain triglycerides, phospholipids, & cholesterol | all lipoproteins |
| the higher the % of lipid in lipoproteins, to __ its density | lower |
| greater the proportion of protein in lipoproteins, the __ its density | higher |
| class of lipoproteins that transport triglycerides from intestine & liver to adipose & muscle tissues; they contain primarily triglycerides w/some cholesteryl esters | very-low-density lipoprotein (VLDL) |
| class of plasma lipoproteins that transport cholesterol to extrahepatic tissues; high serum levels have been correlated w/premature coronary heart disease | low-density lipoprotein (LDL) |
| class of plasma lipoproteins that promote transport of cholesterol from extrahepatic tissue to liver for excretion in bile; serum levels have been negatively correlated w/premature coronary heart disease | high-density lipoprotein (HDL) |
| liver is __ source of VLDLs | primary |
| once triglycerides are unloaded from liver to peripheral tissues VLDL residues are | converted to LDLs |
| LDLs are considered | cholesterol-rich |
| transport cholesterol to peripheral (non-liver) tissues making it available to tissue cells for membrane/hormone synthesis & for storage for use later | role of LDLs |
| LDLs also regulate __ __ in tissue cells | cholesterol synthesis |
| docking of LDL to LDL receptor triggers __ __ of entire particle | receptor-mediated endocytosis |
| HDLs are particularly rich in | phospholipids & cholesterol |
| major function of __ is to scoop up & transport excess cholesterol from peripheral tissues to liver | HDLs |
| liver make __ __ of HDL particles & then ejects them into bloodstream in collapsed form | protein envelopes |
| once in blood incomplete HDL particles __ __ __ picked up from tissue cells & pulled from artery walls | fills with cholesterol |
| HDL also provides __ organs with raw their material of cholesterol | steroid-producing |
| organs like ovaries & adrenal glands have ability to __ __ cholesterol from HDL particles without engulfing them | selectively remove |
| transport absorbed lipids from GI tract; separate class from lipoproteins; have lowest density of all | chylomicrons |
| chylomicrons come from | intestines |
| VLDLs & LDLs are made | by liver |
| HDLs are returned | to liver |
| are thought to protect against heart attack (good cholesterol) | high levels of HDL |
| increase the risk of heart attack (bad cholesterol) | high levels of LDL |
| partially adjusted amount of cholesterol produced by liver according to amount of cholesterol in diet | negative feedback loop |
| high cholesterol intake inhibits | cholesterol production by liver |
| liver produces __ __ of cholesterol even when dietary intake is high | basal amount |
| saturated fatty acids __ __ synthesis of cholesterol | stimulate liver |
| saturated fatty acids inhibit __ of liver cholesterol from body | excretion |
| unsaturated fatty acids enhance __ of cholesterol & its __ to biles salts | excretion; catabolism |
| unsaturated fatty acids reduce | total cholesterol levels |
| unsaturated __ fatty acids lower proportions of saturated fats & cholesterol | omega-3 |
| healthy oils that have been hardened by hydrogenation to make them more solid; cause serum changes worse than those cause by saturated fats | trans fats |
| spark greater increase in LDLs & greater reductions in HDLs, producing unhealthiest ratio of total cholesterol to HDL | trans fatty acids |
| energy liberated during food oxidation | energy intake |
| sum of energy lost as heat (60%), as work (driven by ATP), and as fat or glycogen storage | energy output |
| nearly all energy derived from food stuffs is | eventually converted to heat |
| heat is lost during | every cellular activity |
| cells cannot use it to do work, it warms the tissues and blood | heat energy |
| heat energy helps maintain __ __ temperature | homeostatic body |
| heat energy allows __ __ to occur efficiently | metabolic reactions |
| important part of energy equation only during periods of growth & net fat deposit | energy storage |
| when energy intake/output are balanced | body weight remains stable |
| nuclei in __ regulate hunger & satiety | hypothalamus |
| vagus nerve delivers neural signals from __ __ to hypothalamus | digestive tract |
| rising blood levels of glucose, amino acids, fatty acids send signals to | brain indicating fullness |
| chemoreceptors respond to | hormones, like glucose, insulin, etc. |
| released from fat cells; suppress hunger | insulin & leptin |
| glucagon stimulates __ | hunger |
| body temperature & psychological factors increase or inhibits __, to a lesser degree | eating |
| reflects energy body needs to perform its most essential activities; such as breathing & resting level of organ function; ‘the cost of living’ | basal metabolic rate (BMR) |
| energy body needs to fuel all ongoing activities | total metabolic rate (TMR) |
| hormone released by fat cells that signals satiety | leptin |
| involves neural signals from GI tract, blood levels of nutrients, & GI tract hormones; target hypothalamic centers via solitary tract/nucleus of brain stem | short-term regulation of appetite & feeding behaviors |
| activation stretch receptors ultimately inhibits appetite, because GI Tract distention sends signals along vagus nerve afferents that suppresses appetite-enhancing/hunger center | long-term regulation of appetite & feeding behaviors |
| rising blood glucose, elevated blood levels of amino acids, & blood concentration of fatty acids are all | nutrient signals that indicate fullness or satiety |
| during fasting & hypoglycemia the activation of glucose receptors in brain that ultimately depress eating are | absent resulting in hunger & turn-on of food-seeking behaviors |
| larger the amount of fatty acids in blood, the greater the | inhibition of eating behavior |
| insulin & cholecystokinin (CCK) are __ __ released during food absorption, & act as satiety signals to depress hunger | gut hormones |
| glucagon & epinephrine levels __ during fasting | rise |
| powerful appetite stimulant, produced by stomach; trigger for meal initiation; levels peak just before mealtime, troughs after meals | Ghrelin (Ghr) |
| the hormone leptin is __ __ of long-term control of feeding behavior | key component |
| leptin is secreted exclusively by adipose cells in response to a(n) | increase in body fat mass |
| leptin serves as an indicator of | body's total energy stores in fat tissue |
| energy expended by the body per unit time; total heat produced by all chemical reactions & mechanical work of body | metabolic rate |
| device used for measuring quantities of heat generated by friction, chemical reaction, or the human body | calorimeter |
| calorimeter is considered __ __ of measurement of metabolic rate | direct method |
| used to measure oxygen consumption, which is directly proportional to heat production | respirometer |
| respirometer is considered __ __ of measurement of metabolic rate | indirect method |
| metabolic rate is measured when a person is in | postabsorptive state (at least 12hrs w/out food) |
| most important hormonal factor in determining BMR is the amount of | thyroxine released by thyroid gland |
| direct effect of thyroxine on most body cells, except brain cells, is to | increase O2 consumption & heat production |
| thyroxine increases O2 consumption & heat production by accelerating use of ATP to operate | sodium-potassium pump |
| results in slowed metabolism, obesity, & diminishes thought processes | hypothyroidism |
| catabolize stored fats & tissue proteins, weight loss despite food intake, bones weaken & muscles begin to atrophy | hyperthyroidism |
| BMR account for __ __ of TMR | large part |
| skeletal muscle activity causes most dramatic | short-term changes in TMR |
| food ingestion induces __ __ in TMR | rapid increase |
| rapid increase in TMR from food ingestion, is an effect called | food-induced thermogenesis |
| food-induced thermogenesis is greatest when | proteins are ingested |
| as ratio of body surface area to volume __, BMR increases | increases |
| 2 people of same weight __ will have more BMR | taller |
| BMR decreases with | age |
| BMR increases with | temperature or stress |
| BMR in males is | higher |
| __ hormone increases BMR | thyroid |
| reflects balance btwn heat production & heat loss | body temperature |
| liver, heart, brain, & endocrine organs generate most heat when | body at rest |
| heat production from skeletal muscles increases 30-40 times that of rest of body | during exercise |
| 37°C (98.6°F) | normal body temperature |
| occurs at 37°C (98.6°F) | optimal enzyme activity |
| beta oxidation results in | fatty acid chains being broken down |
| glycolysis results in | pyruvic acid |
| Krebs cycle initial metabolite is | citric acid |
| oxidative phosphorylation requires | ATP synthase at end |
| comprised of simple sugars; used as major fuel source for cellular respiration | carbohydrate |
| comprised of amino acids; used to build structural components of cells as well as functional components (enzymes) | protein |
| comprised of fatty acids & glycerol; should be 20%-35% of caloric intake | lipids |
| comprised of electrolytes; important as cofactors | minerals |
| small organic molecules; important as coenzymes; fat-soluble forms are A, D, E, and K | vitamins |
| carbohydrates | provide primary source of fuel for ATP synthesis |
| lipids | act as an accessory fuel; component of membranes |
| proteins | important structural material (keratin, collagen, etc.) and functional material (enzymes, etc.) |
| vitamins | most function as coenzymes; not used as structural components |
| minerals | incorporation into some body structures; used in conjunction with enzymes |
| water | solvent for chemical reactions in body |
| vitamin A required for | synthesis of photoreceptor pigments in vision; integrity of skin, mucosae, & normal bone; tooth development |
| vitamin E | primarily an antioxidant preventing oxidative damage to cell membranes & atherosclerosis |
| vitamin D | enhances absorption of calcium; works in conjunction with hormones regulating calcium blood levels |
| vitamin K | essential for formation of clotting proteins; intermediate in electron transport; participates in oxidative phosphorylation |
| vitamin C | important in formation of connective tissues; antioxidant; conversion of tryptophan to serotonin; conversion of cholesterol to bile salts |
| vitamin B1 (thiamine) | acts as coenzyme in carbohydrate metabolism; required to transform pyruvic acid to acetyl CoA; oxidation of alcohol |
| vitamin B2 (riboflavin) | acts as hydrogen acceptor in electron transport (FAD and FMN); component of amino-acid oxidases |
| niacin | acts as hydrogen acceptor in electron transport (NAD) during glycolysis & Krebs cycle; inhibits cholesterol synthesis; peripheral vasodilator |
| folic acid | basis of coenzymes in formation of certain amino acids, choline, DNA, RBCs, & normal neural tube development in embryo |
| vitamin B12 | functions as coenzyme in all cells; acts in synthesis of DNA; essential for erythrocyte division during RBC production |
| food sources of calcium | milk, milk products, leafy green vegetables, egg yolk, shellfish |
| food sources of sulfur | meat, milk, eggs, legumes |
| food sources of potassium | avocados, dried apricots, meat, fish, fowl, cereals, bananas |
| food sources of sodium | cured meats, sauerkraut, cheese |
| food sources of magnesium | milk, dairy products, whole grain cereals, nuts, legumes, leafy green vegetables |
| food sources of phosphorus | diets rich in proteins; milk, eggs meat, fish, poultry, legumes, nuts, whole grains |
| two molecules of pyruvic acid and two NADH + H+ | products of glycolysis |
| five carbon dioxide molecules and ten molecules of reduced coenzymes (NADH + H+ and FADH2) | products of Krebs cycle |
| 36 ATP and 12 H2O molecules | products of electron transport chain & oxidative phosphorylation |
| major means for conserving heat is | vasoconstriction of cutaneous blood vessels |
| in glycolysis, glucose must be activated with the use of | 2 ATP molecules |
| most vitamins function as coenzymes in the body; coenzymes help | catalyze chemical reactions |
| one function of vitamin A is to | form visual pigments |
| are derived from vitamin A | retinol in the rods and cones |
| thyroxine is hormone responsible for | setting the basal metabolic rate |
| site of electron transport is | mitochondrial inner membrane (cristae) |
| inner membrane of the mitochondrion contains | integral proteins necessary for electron transport |
| coenzyme reduced in both glycolysis and the Krebs cycle | NAD |
| element is considered a trace mineral | chromium |
| lipoprotein contains high levels of cholesterol | LDL |
| LDL is | nearly 1/2 cholesterol |
| nutritionally incomplete protein lacks | one of the essential amino acids needed by the body |
| most of the ATP produced during cellular respiration is produced by | oxidative phosphorylation during electron transport |
| mobilize glucose reserves by glycogenolysis | function of the liver during the post-absorptive state |
| insulin is hormone that controls essentially all | events of the absorptive state |
| factor that makes it harder for an obese person to lose weight | increase in alpha receptors (the kind that favor fat accumulation) in fat cells |
| BMR is | amount of energy the body needs to maintain life |
| shivering is | physiological response to hypothermia |
| prolonged high protein intake can lead to | loss of bone mass |
| beta-carotene is | considered a provitamin |
| fat-soluble vitamin, which is eliminated by the kidney and, therefore is not stored in the body | vitamin K |
| two molecules of pyruvic acid, two molecules of NAD+, and a net gain of two ATP is | final product of glycolysis |
| cyanide acts as a poison by | interfering with the flow of electrons in the electron transport chain |
| blood glucose is maintained by gluconeogenesis when | fasting for several weeks |
| low-density lipoprotein would contain | high lipid content |
| role of high-density lipoproteins is to | transport excessive cholesterol from peripheral tissue to the liver, where it is broken down and becomes part of bile |
| official medical measurement of obesity is | body mass index |
| leptin acts to suppress appetite by | inhibiting neuropeptide Y, which is the most-powerful known appetite stimulant |
| in a redox reaction coenzymes | accept hydrogen |
| ascorbic acid (vitamin C) is | an antioxidant |
| fermentation occurs when | oxygen is NOT available |
| in glycolysis, glucose is initially cleaved into | two, three-carbon groups |
| in order for amino acids to be converted into lipids, | they must be deaminated |
| oxidative phosphorylation is coupled to | chemiosmosis |
| electron transport causes a chemiosmotic gradient, which causes | oxidative phosphorylation of ADP to ATP |
| before lipids can be metabolized | fatty acids must undergo beta oxidation to be converted into two-carbon acetic acid fragments |
| gluconeogenesis is | formation of glucose from noncarbohydrate precursors |
| major function of HDL is to | transport excess cholesterol from peripheral tissues to the liver |
| calcium is | a mineral |
| glucose is exclusive energy source for | neurons |
| cholesterol serves as | precursor to hormones and maintains the fluidity of the plasma membrane |
| protein is used to | build enzymes |
| vitamins can function | as coenzymes |
| person who is starving is likely to exhibit | negative nitrogen balance |
| if consumed in large quantities | fat-soluble vitamins can be toxic |
| Krebs cycle generates | rich supply of the reduced coenzymes, NADH and FADH2 |
| final electron acceptor in the electron transport chain is | O2 |
| glycogenesis | formation of glycogen to store glucose |
| glycogenolysis | cleavage of glycogen to release glucose |
| gluconeogenesis | process of forming new glucose from noncarbohydrate molecules |
| beta oxidation | starts phase of fatty acid breakdown |
| lipogenesis | triglyceride synthesis |
| as proteins are broken down for energy __ is generated; the liver then converts this potentially toxic intermediate into __ | ammonia; urea |
| in the absorptive state insulin serves as | regulatory hormone |
| in the postabsorptive state glycogen is | broken down to release glucose |
| leptin is considered | long-term regulator of food intake |
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lfrancois
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