| Term | Definition |
|---|
| Ghrelin | this is secreted by parietal cells in the fundus of teh stomach, expecially when the stomach is empty |
| Peptide YY (PYY) | this is a member of a family of hormones related to neuropeptides Y |
| Cholecystokinin | is secreted by enteroendocrine cells in the duodenum and jejunum |
| Leptin | \is secreted by adipocytes throughout the body |
| Insulin | is secreted by the pancreatic beta cells |
| Arcuate Nucleus | brain center for appetite regulation |
| Neuropeptide Y | a potent appetite stimulant |
| Melanocortin | which inhibits eating |
| Hunger Contractions | begin soon after the stomach is emptied and increase in intensity over a period of hours |
| Kilocalorie | in biochemistry |
| Fuel | is oxidized solely or primarily to extract energy from it |
| Nutrient | is any ingested chemical that is used for growth, repair or maintenance of the body |
| Macronutrients | they must be consumed in relatively large quantities |
| Micronutrients | only small quatities are required |
| Recommended Daily Allowances (RDAs) | is a liberal but safe estimate of the daily intake that would meet the nutrtional needs of most healthy people |
| Essential Nutrients | it is essential that they be included in the diet |
| hypoglycemia | deficiency of blood glucose |
| Water-soluble Fiber | found in oats, beans, peas, carrots, brown rice, and fruits |
| Water-insoluble Fibers | apparently have no effect on cholesterol or LDLs |
| Glucose-sparing and Protein-sparing Effects | as long as enough fat is available to meet the energy needs of the tissues, protein is not catabolized for fuel and glucose is spared for consumption by cells that cannot use fat, such as neurons |
| Essential Fatty Acids | are those we cannot synthesize and there fore must obtain from the diet |
| Lipoproteins | tiny droplets with a core of cholesterol and triglycerides and a coating of proteins and phopholipids |
| lipoprotein Lipase | that hydrolyzes triglycerides into monoglycerides and free fatty acids |
| Essential Amino Acids | that we cannot synthesize: isoleucine, leucine, lysine, methionine, phenylalnine, threonine, tryptophan and valine |
| Inessential Amino Acids | not because the body doesn not require them buy because it can syntesize its own when the diet does not supply them |
| Complete Proteins | are those that rpobide all of the essential amino acids in the necessary proportions for human tissue growth, maintance and nitrogen balance |
| Incomplete Proteins | lack one or more essential amino acids |
| Net Protein Utilization | the percent of the amino acids in a protein that the human body uses |
| Nitrogen Balance | is a state in which the rate of nitrogen ingestion equals the rate of excretion |
| Positive Nitrogen Balance | indicates that body proteins are being broken down and used a sfuel |
| Water-soluble Vitamins | are absorbed with water from the small intestine, dissolve freely in the body fluids, and are quickly excreted by the kidneys |
| Fat-soluble Vitamins | are incorporated into lipid micelles in the small intestine and absorbed with dietary lipids |
| Hypervitaminosis | (vitamin excesses) also causes disease |
| Glycolysis | which splits a glucose molecule into two molecules of pyruvic acid |
| Anaerobic Fermentation | which occurs in the absence of oxygen and reduces pyruvic acid to lactic acid |
| Aerobic Respiration | which occurs in the presence of oxygen and oxidizes pyruvic acid to carbon dioxide and water |
| Body Weight | remains stable if energy intake and output are equal |
| Body Weight seems to have a Hoeostatic | set point |
| Combination of Environmental and Hereditary factors | 30 - 50% of variation between individuals is due to heredity with the rest being eating and exercise habits |
| Phosphorylation | the enzyme hexokinase transfers an inorganic phophate group (Pi) from ATP to glucose, producing glucose 6-phophate (G6P) |
| Pyruvic Acid | 3 carbon (C3) molecules |
| Priming | G6P is rearranged (isomerized) to form fructose 6-phophate, which is phophorylated again to form frutose1, 6-diphophate |
| Cleavage | the lysis part of glycolysis occurs when fructose 1, 6-diphophate splits into two 3-carbon molecules |
| Oxidation | each PGAL molecule is then oxidized by removing a pair of hydrogen atoms |
| Dephosphorylation | phosphate groups are taken from the glycolysis intermediates and transferred to ADP, phophorylating it to ATP |
| Matrix Reactions | because their controlling enzymes are in the fluid of the mitochondrial matrix |
| Membrane Reactions | their controlling enzymes are bound to the membrane of the mitochondrial cristae |
| Proton Pump | that removes H+ from the mitochodrial matrix and pumps it into the space between the inner and outer mitochodrial membranes |
| Chemiosmotic Mechanism | which suggests the "push" created by the electrochemical H+ gradient |
| Efficiency | a ratio of energy output to input |
| Glycogenesis | teh synthesis of glycogen, is stimulated by insulin |
| Glycogenolysis | the hydrolysis of glycogen, releases glucose between meals when new glucose is not being ingested |
| Lipogenesis | synthesizing fats from other types of molecules |
| Lypolysis | breaking down fat for fuel |
| Beta-oxidation | which removes two carbon atoms at a time |
| Ketogenesis | two acetyl groups are condensed to form acetoacetic acid and some of this is further converted to B-hydroxybutyric acid and acetone |
| Amino Acid Pool | that cells can draw upon to make new proteins |
| Deamination | the removal of an amino group |
| Amination | the addition of -NH2; |
| Transamination | the transfer of -NH2 from one molecule to another |
| Absorptive (fed) State | lasts about 4 hours during and after a meal. |
| Postabsorptive (fastin) State | prevails in the late mornign, late afternnon and overnight |
| Metabolic Rate | means the amount of energy liberated in the body per unit of time, expressed in such terms as kcal/hr or kcal/day |
| Calorimeter | a closed chamber with water filled walls that absorb the heat given off by the body |
| Basal Metabolic Rate BMR | is a baseline or standard of comparison that minimizes teh effects of such variables |
| Total Metabolic Rate (TMR) | is the sum of BMR and energh expenditure for voluntary activities, especially muscular contractions |
| Hypothermia | an excessively low body temperature, can cause metabolism to slow down to the point that it cannot sustain life |
| Hyperthermia | an excessively high temperature, can disrupt the coordination of metabolic pathways and also lead to death |
| Thermoregulation | the balance between heat production and loss, is a critically important aspect of homeostasis |
| Core Temperature | the temperature of organs in the cranial, thoracic, and abdominal cavities |
| Shell Temperature | is the temperature closer to the surface, especially skin and oral temperature |
| Radiation | heat means molecular motion |
| Conduction | as the molecules of our tissues vibrate with heat energy, they collide with other molecules and transfer kinetic energy to them |
| Convection | the motion of fluid due to uneven heating |
| Evaporation | the cohesion of water molecules hampers their vibratory movement in response to heat input |
| Forced Convection | accelerates heat removal |
| Heat-losing Center | a nucleus still farther anterior in the hypothalamus |
| Heat-promoting Center | a more posterior nucleus |
| Nonshivering Thermogenesis | is a more long-term mechanism for generating heat , used especially in the colder seasons of the year |
| Behavioral Thermoregulation | behaviors that raise or lower the body's heat gains and losses |
| Heat Cramps | are painful muscle spasms that result from excessive electrolyte loss in the sweat |
| Heat Exhaustion | results from more severe water and electrolyte loss and is characterized by hypotension, dizziness, vomiting and sometimes fainting |
| Heatstrake | sunstroke |
| Appetite and satiety are contolled by | hypothalamus |
| Other Factors in Appetite Control | inflating the stomach with balloon inhibits hunger, amino and fatty acids stimulate release of CCK from small intestine (appetite suppressant), neuropeptide Y from hypothalamus is an appetite stimulant (it may be inhibited by leptin from "full" fat cells), different neurotransmitters stimulate desire for different kinds of food -- carboyhydrates, fats or protein |
| One Calorie | is amount of heat that will raise the temperature of 1 g of water 1 degree C. (1,000 calories is a kilocalorie in biochemistry) |
| Fat contain about | 9 kcal/g when oxidized |
| Carbohydrates and proteins contain about | 4 kcal/g |
| When a substance is used for fuel | it is oxidized solely or primarily to make ATP |
| Nutrients | are any ingested chemical used for growth, repair or maintenace -- water, carbohydrates, lipids, proteins, minerals, vitamins |
| Macronutrients | must be consume in large amounts -- proteins, fats and carbohydrates |
| Micronutrients | are needed only in small amounts |
| Recommended Daily Allowances (RDA) | is safe estimate of daily intake that meets standard needs (minimums) |
| Essential Nutrients | are those the body can not synthesize- minerals, vitamins, 8 amino acids and 1-3 fatty acids must be consumed in the diet |
| Carbohydrates | in 3 places in the body - muscle and liver glycogena and blood glucose |
| Neurons and RBCs | depend on glucose almost exclusively |
| Fat is Oxidized | when glycogen and glucose levels are low (if incompletely oxidized produces ketone bodies and acidosis) |
| Sugars do serve as | Structural components |
| Blood Glucose | is carefully regulated through the actions of insulin and glucagon |
| Carbohydrates RDA | 175 g/day |
| Dietary Carbohydrates come in 3 forms | monosaccharides, disaccharides, polysaccharides |
| Monosaccharides | glucose, galactose and fructose, arising from digestion of starch and disaccharides, normal blood sugar concentration ranges 70 to 110 mg/dL |
| Disaccharides | table sugar (sucrose) |
| Polysaccharides | starch, glycogen and cellulose |
| Nearly all dietary carbohydrates come from | plants |
| Dietary Fiber | all fibrous animal or plant material that resist digestion- cellulose, pectin, gums and lignins |
| Fiber is important to the diet | RDA is 30 g/day |
| insoluble Fiber | absorbs water in the intestines and thus softens the stool and gives it bulk speeding teh transit time |
| Pectin | is a water-soluble fiber found in oats, beans, carrots, fruits and brown rice and reduces blood cholesterol and LDL levels |
| Cellulose, himicellulose and lignin | are water-insoluble fibers having no effect upon cholesterol |
| Lipids | average adult male is 15% fat; female 25% fat, represents body's stored energy |
| Hydrophobic | contains almost no water, contains twic as much energy per gram and is thus more compact storage form |
| Fat-soluble Vitamins | A,D,E and K depend on dietary fat for their absorption by the intestine |
| Phopholipids and Cholesterol | are structural components of plasma membranes and myelin |
| Cholesterol | is precursor of steriods, bile salts and vitamin D |
| Fatty Acids | are precursors of prostaglandins and other eicosanoids |
| Lipids should be less than | 30% of daily calorie intake- typical american gets 40-50% of calories from fat |
| Most Fatty Acids | can be synthesized by the body |
| Essential Fatty Acids | are those that must be consumed (linoleic, linolenic and arachidonic acids must be consumed) |
| Saturated Fats | are of animal origin-- meat, egg yolks and dairy products |
| Unsaturated Fats | are found in nuts, seeds and most vegetable oils |
| Cholesterol | is found in egg yolks, cream, shellfish, organ meats and other meats |
| Lipids | are transported in the blood as lipoporteins (keeps it suspended in plasma) |
| Lipoproteins | are categorized into 4 groups by their density: more protein means more dense |
| Lipoproteins Types | chylomicrons, high-density (HDLs), low-density (LDLs), very low-density (VLDLs) |
| Chylomicrons | are formed in the absorptive cells of teh small intestine, passes into the lymphatic system and into the blood, capillary surface enzymes hydrolyze the triglycerides, fatty acids and glycerol enter the fat cells to be resynthesized into triglycerides for storage, chylomicron remnant is degraded by liver |
| VLDLs | produced by the liver, transport lipids to the adipose tissue for storage |
| Desirable to maintain high levels of HDL | since it indicates cholesterol is being removed from the arteries |
| Desirable to maintain a low LDL concentration | signifies high rate of cholesterol deposition in arteries (smoking, saturated fats, coffee and stress increase LDLs) |
| Desirable to maintain total plasma cholesterol concentration of 200 mg/dL or less | most cholesterol is internally synthesized, but dietary restriction may lower blood cholesterol levels (vigorous exercise lowers blood cholesterol) |
| Proteins | c12-15% of body mass - mostly inskeletal muscles |
| Functions of Proteins | muscle contraction, ciliary and flagellar motility, structural role in all cell membranes (channels, pumps, etc...), fibrous proteins (collagen, elastin and keratin) globular proteins include antibodies, hormones, hemoglobin, enzymes, etc..., plasma proteins maintain blood osmolarity and viscosity |
| RDA | is 44-60 g/day depending on age and sex |
| Nutritional Value of a Protein | depends whether it supplies amino acids in the proportions needed- essential amino acids can not be synthesized |
| Cells do not store surplus | when a protein is to be synthesized, all the necessary amino acids must be present |
| Complete Proteins | supply all amino acids in right amounts |
| Nitrogen Balance | requires the rate of nitrogen (protein) ingestion equals the rate of excretion |
| Positive Nitrogen Balance | occurs in growing children since they ingest more than they excrete |
| Negative Nitrogen Balance | occurs if body proteins are being broken down for fuel (muscle atrophy) |
| Glucocorticoids | promote protein catabolism in states of stress |
| Calcium and phosphorus | make up the bones and teeth |
| Phosphorus | is part of many structural compounds |
| Calcium, Iron, Magnesium and Manganese | function as cofactors for enzymes |
| Iron | is essential for hemoglobin and myoglobin |
| Chlorine | is component of stomach acid (HCl) |
| Mineral Salts | function as electrolytes and govern teh function of nerve and muscle cells, regulating the distribution of water in the body |
| Vitamins | body synthesizes some vitamins from precursors (A,D, etc...) |
| Water-soluble Vitamins | are absorbed with water from the small intestine and are not stored (C and B) |
| C Promotes | hemoglobin and collagen synthesis |
| B Vitamins | are coenzymes or parts of coenzymes |
| Fat-soluble | are absorbed with dietary lipids- A is a component of teh visual pigments and important to epithelium, D promotes calcium absorption and bone minerlization, K is essential for prothrombin synthesis and clotting, E is an antioxidant |
| Dietary Carbohydrate | is burned as fuel within a few hours of absorption (glucose catabolism) C6H12O6 + 6O2 -> 6CO2 + 6H2) |
| Purpose of Carbohydrates Metabolism | is to transfer energy from glucose to ATP |
| Common Pathway of Carbohydrate Metabolism | through which fats and amino acids are also oxidized as fuel |
| Glucose Catabolism | must occur as a series of steps where small amounts of energy are transferred to ATP with the rest released as heat |
| Three Major Pathways | Clycolysis, anaerobic fermentation, aerobic respiration |
| Clycolysis | splits a glucose molecule into 2 pyruvic acids molecules |
| Anaerobic Fermentation | (in the absence of O2) reduces pyruvic acid to lactic acid |
| Aerobic Repiration | (in the presence of O2) - oxidizes pyruvic acid to CO2 and H2O |
| Enzymes | remove electrons a hydrogen atoms during glucose catabolism |
| NAD+ | (nicoinamide adenine dinucleotide), derived from niacin (B vitamin), NAD+ +2H -> NADH + H+ |
| FAD | (flavin adenine dinucleotide), derived from riboflavin FAD + 2H -> FADH2 |
| Coenzymes | are reduced and temporary carriers of teh energy |
| Glycolytic Steps | Step 1- phosphorylation, step 2 and 3- priming, step 4- cleavage, Step 5- oxidation, steps 6 and 7- dephosphorylation, 4 ATP produced |
| Step 1= Phosphorylation | glucose that just entered cell has phophate added to it, prevents glucose from leaving |
| Step 4= Cleavage | modified glucose molecule is split into 2 three-carbon molecules, PGAL (glyceraldehyde 3-phosphate) |
| Step 5= oxidation | removes a pair of hydrogen atoms picked up by coenzymes NAD+ |
| Steps 6 and 7= dephosphorylation | (phosphate groups are transferred to ADP to form ATP) |
| 4 ATP produced, but | 2 were used in steps 1 and 3 |
| Anaerobic Fermentation | fate of pyruvic acid depends on whether or not oxygen is available |
| In an exercising muscle | demand for ATP> oxygen supply so ATP is produced by glycolysis |
| Glycolysis | can not continue once supply of coenzyme NAD+ is gone |
| NADH donates | a pair of electrons to pyruvic acid which reduces it to lactic acid --restoring NAD+ |
| Lactic Acid Travels | to the liver to be oxidized back to pyruvic when O2 is available (oxygen debt), then stored as glycogen or released as glucose |
| Fermentation | is wasteful and not favored by brain or heart |
| Aerobic Respiration | most ATP is generated in the mitochondria, requiring oxyen as teh final electron acceptro |
| Principal Steps | Matrix Reactions, membrane reactions |
| Matrix Reactions | occurring in fluids of mitochondria |
| Membrane Reactions | whose enzymes are bound to the mitochondrial membrane |
| Three steps to | prepare pyruvic acid to enter citric acid cycle |
| Aerobic Respiration known as | formation of acetyl-coenzymes A |
| Matrix Reactions | steps 12 through 21 called the citiric acid cycle (also called the kreb's cycle or tricarboxylic acid (TCA)cycle) |
| Carbon Atoms of the Glucose | have all been carried away as CO2 and exhaled |
| The energy has been lost as heat or stored in the: | 2 ATP, the 8 reduced NADH and 2 FADH2 molecules of teh matrix reactions and 2 NADH from glycolysis |
| Citric Acid Cycle | is also a source of substances for the synthesis of fats and nonessential amino acids |
| Membrane Reactions | purpose is to oxidize NADH and FADH2, transfer their energy to ATP and regenerate them |
| Reactions | carried out by series of compounds attached to inner mitochondrial membrane called electron transport chain |
| Hydrogen atoms from NADH and FADH2 are | split apart |
| Protons released into matrix and electrons | passed along the transport chain with energy being released in small amounts |
| Final Electron Acceptor is | oxygen: accepts 2 electrons and 2 H+ to form a water molecule |
| NADH Releases | its electron pairs as hydrogen atoms to the electron-transport system-generates enough energy to synthesize 3 ATP molecules per electron pair |
| FADH2 Releases | its electron pairs oa little further along the elctron-transport system- generates enough energy to synthesize 2 ATP |
| Energy Balance Sheet | from complete aerobic oxidation of glucose to CO2 and H2O produces 38 ATP per glucose molecules (efficiency rating of 40% --0 rest is body heat) |
| Glycogen Metabolism | ATP is quickly used after it is formed -- it is not a storage molecule - extra glucose will not be oxidized, it will be stored |
| Glycogenesis | synthesis of glycogen, stimulated by insulin (average adult contains 450 g) |
| Glycogenolysis | breakdown of glycogen into glycose, stimulated by glucagon and epinephrine |
| Gluconeogenesis | synthesis of glucose from noncarbohydrates, such as fats and amino acids |
| Triglycerides | are stored in adipocytes |
| Lipogenesis | synthesizing fat from other sources |
| Lipolysis | breaking down fat for fuel |
| Glycerol | is converted to PGAL and enters glycolysis |
| Fatty Acids | are broken down 2 carbons at a time to produce acetyl-6A (process is beta oxidation) |
| Fatty Acids are Catabolized | in the mitochondrial matrix by beta-oxidation (2 carbons removed at a time) -- the resulting acetyl group can be turned into actyl-CoA and fed into citric acid cycle |
| Excess acetyl Groups | can be metabolized by liver during ketagenesis -- the products are called ketone bodies |
| If body Rapidly Oxidizing fats | ketones build up leading to ketoacidosis |
| Some Cells can use acetoacetic acid for | their principal fuel (cardiac and renal crotex cells) |
| Protein Metabolism - as fuel- | first must be deaminated (removal of NH2) - - what remains is converted to pyruvic acid, acetyl-CoA or part of citric acid cycle |
| When Shortage of Amino Acids | the reverse occurs for protein synthesis |
| The NH2 become | ammonia (NH3) which is toxic and which the liver converts to urea (excreted in urine) |
| Nutrtional Absorptive State | lasts about 4 hours during and after a meal (time of nutrient absorption and use for energy needs), regulated by insulin secreted in response to elevated blood glucose and amino acid levels and teh hormones gastrin, secretin and cholecystokinin |
| Postabsorptive State | homeostasis of blood glucose levels critical to brain- when stomach and small intestine are empty and stored fuels are used, regulated by sympathetic nervous system and glucagon, sympathoadrenal effects- adipose, liver cells and muscle cells are richly innervated and respond to epinephrine from adrenal medulla |
| Metabolic Rate | amount of energy used int he body in a given period of time (kcal/hr or kcal/day)- measured indirectly by oxygen consumption |
| Basal Metabolic Rate (BMR) | relaxed, awake, fasting, room comfortable temperature, adult male BMR is 2000 kcal/day (slightly less female) |
| Factors Affecting total MR | pregnancy, anxiety, fever, eating, thyroid hormones and depression |
| Homeostasis requires | heat loss match heat gain |
| Hypothermia | is excessively lo body temperature |
| Hyperthermia | is excessively high body temperature |
| Thermoregulation | is the ability to balance heat production and heat loss |
| Normal Body Temperature | varies about 1.8 degrees F. in a 24 hour cycle- low in morning and high in late afternnon |
| Core Body Temperature | is temperature of organs in cranial, thoracic and abdominal cavities- adult varies normally from 99.0 - 99.7 degrees F |
| Shell Temperature | is temperature closer to the the surface (oral cavity and skin) - adult varies normally from 97.9 - 98.6 degrees F |
| Heat Production | most comes from energy- releasing chemical reactions such as nutrient oxidation and ATP use, most from brain, heart, liver, endocrine and muscles, exercise greatly increase heat production in muscle |
| Radiation | is loss of body heat to the objects around us |
| Conduction | is loss of body heat to the air which when warmed rises to be replaced by cooler air (carrying heat away by convection) |
| Evaporative | heat loss is heat loss as sweat evaporates |
| Hypothalamic Thermostat | monitors the temperature of teh blood and skin thermoreceptors |
| Signals heat-losing center in hypothalamus | cutaneous vasodilation promotes heat loss, triggers sweating |
| Signals heat- promoting center in hypothalamus | causes cutaneous vasoconstriction, stimulates arrector pili muscles to make hair stand on end, shivering thermogenesis- muscle contraction, nonshivering thermogenesis- increase thyroid hormone and increase BMR |
| Behavioral Thermoregulation | get out of sun or remove heavy clothing |
| Fever | normal protective mechanism that elevates BMR which produces more heat elevating the BMR, etc. |
| Hyperthermia | is exposure to excessive heat |
| Heat Cramps | are muscle spasm due to electrolyte imbalance from excessive sweating |
| Heat Exhaustion | severe electrolyte imbalance producing fainting, dizziness, hypotension |
| Heat Stroke | body temperature rises dangerously high and may cause coma, convulsions and death |
| Hypothermia | is exposure to excess cold- as core body temperature decrease, BMR decrease causing a further body temperature decrease, etc. (fatal if body temperature decrease 75 F |
Combine with other sets
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