remains stable if energy intake and output are equal
is regulated in part by several GUT-BRAIN PEPTIDES that act as chemical signals from the gastrointestinal tract to the brain
a hormone secreted by an empty stomach that sends signals to the brain when a person is hungry.
neuropeptide secreted in the small bowel and colon; signals appetite suppression
creats a feel of satiety and terminate eating
Hormone produced by the pancreas that is released when stimulated by elevated glucose levels. This hormone decreases blood sugar levels by accelerating the transport of glucose into the body cells where it is oxidized for energy or converted to glycogen or fat for storage., adiposity signal, informs the brain of how much adipose tissue one has, and regulate long term food intake, energy consumption and food intake
secreted by fat cells; signals brain to increase metabolism and decrease hunger
in the hypothalamus, responds to gut-brain peptides by secreting the appetite stimulant neuropeptide Y or the appetite suppressant melanocortin
neurotransmitter found in several brain areas, most notably the hypothalamus, that stimulates eating behavior and reduces metabolism, promoting positive energy balance and weight gain
type of chemical that promotes satiety in the hypothalamus, signals decreased eating
ocur in the stomach, motivates eating, and chewing and swallowing alone produce a degree of very short term reduction of hunger.
stimulates a craving for carbohydrates
stimulates a craving for fats
stimulates a craving for proteins
dietary calories (kilocalories)
come predominately from carbohydrates, fat and proteins.
Foods that have a high proportion of calories with little or no nutritional value
ingested chemicals that provide material for growth, repair, and maintenance to the body. dietary substances that never become part of the body's tissues (for ex. fiber) are not considered nutrients but are never the less important components of a health diet. some nutrients (water, minerals,vitamins) require no digestion and yield no calories
A chemical substance that an organism must obtain in relatively large amounts : water, carbohydrates, lipids, proteins
An element that an organism needs in very small amounts :minerals and vitamins
substances the body requires for normal growth and health but cannot manufacture in sufficient amounts: they must be obtained in the diet.
are used as fuel and as structural components of many biologic molecules
carbohydrates fuels in the body
are blood glucose and liver and muscle glycogen. the balance between stored glycogen and glucose is regulated by insulin and glucagon
the most quantitatively significant digestible dietary carbohydrate, but significant quantities of lactose, sucrose, ad fructose are ingested, especially in processed food with added sweeteners.
included cellulose, pectin, gums, and lignin. promotes intestinal motility, and water soluble fiber (pectin) lower the levels of blood cholesterol and harmful low density lipoproteins (LDL)
contains most of the body's stored energy. Being less oxidized than carbohydrates, they contain more than twice as many calories per gram as carbohydrates do. being hydrophobic, they serve as an energy-storage medium that is relatively free of water bulk. it's use for fuel, spares glucose and proteins for other tissues or other purposes.
the molecules that form much of the cell membrane
specialized lipid that is used in cell membranes and making hormones
any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body
modified fatty acids that function in intracellular communication, Lipids that exert complex control over many bodily systems, mainly in inflammation or immunity, and as messengers in the central nervous system.
essential fatty acids
Linoleic acid, linolenic acid and arachidonic acid, fats needed by the body that must be consumed in the diet because the human body cannot manufacture them
protien and fat clusters that transport fats in the blood
Lipoproteins that transport recently ingested dietary fats in the lymph and blood are called _______.
very low density lipoproteins (VLDLs)
produced by the liver, transport lipids from the liver to the adipose tissue for storage
low-density lipoproteins (LDLs)
reminders of very low-density lipoproteins after the trigycerides have been removed; transport cholestrol from liver to body cells for use in cell membrane repair and the production of steroid hormones and bile salts
high density lipoproteins (HDLs)
GOOD cholesterol, they transport excess cholesterol to liver for disposal
high LDL levels
indicates a heightened risk of cardiovascular disease
high HDL levels
beneficial to cardiovascular health
is typically made up of 12-15% protein, which plays a wider variety of of structural and physiological roles than any other class of biological molecule
the nutritional value of a protein
depends on wether it provides the right proportions of the various amino acids, especially the 8 essential amino acids
Proteins containing all the 8 essential amino acids; found only in soy and animal foods (meats and dairy products) in the proportions needed by the human body. the body makes more efficient use of animal proteins than of plant proteins.
the balance between the amount of nitrogen taken in (to the soil or the body) and the amount given off (lost or excreted)
positive nitrogen balance
a situation in which protein intake exceeds what is excreted, such as during periods of tissue growth, recovery from illness, and pregnancy
negative nitrogen balance
typical in fasting and malnutrition, Results in muscle wasting and decreased physical energy for movement and work.
inorganic substances acquired from the soil by way of plants. calcium and phosphorus are the body's most abundant minerals, sodium is close third. several are present in relatively small quantities but are vitally important.
small organic molecules that are not used for energy, but are necessary to metabolism. they help regulate body processes, often working with enzymes(coenzymes) antioxidants, components of visual pigments
Absorbed through the intestinal tract with the helps of fats. Vitamins ADEK.
C,B; found in fruits and veggies; need to have daily
Vit C: (scurvy). Vit B: B1 thiamine = beri beri, B2 riboflavin, B3 - niacin - pellagra, B12 - cobalamine - pernicious anemia. 3) Ulron - plummer-vinson syndrome. 4) Vit K - gingival bleeding - coagulopathy
a disorder caused by the intake of too many vitamins
a coenzyme that can accept an electron and acts as an electron carrier in the electron transport chain (carries high energy hydrogen to be released in the electron transport chain)
a coenzyme, that acts as a hydrogen acceptor in dehydrogenation reactions (carries high energy hydrogen to be released in the electron transport chain)
a metabolic process that breaks down carbohydrates and sugars through a series of reactions to either pyruvic acid or lactic acid and release energy for the body in the form of 2 ATP per glucose.
occurs in the absence of oxygen and reduces pyruvic acid to lactic acid, the primary purpose of this is to regenerate NAD+, which is needed to keep glycolysis running and producing ATP.
the process in which pyruvic acid is broken down to make a large amount of ATP; the part of respiration that is carried out in the presence of oxygen, end products are co2, and h20, occurs in the mitochondria
because their controlling enzymes are in the fluid of the mitochondrial matrix, first principal group of reactions in aerobic respirations, co2 released here primary source of co2 in breath
citric acid cycle
Krebs Cycle, the second major stage in cellular respiration., Completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide
the final reactions of aerobic respiration. their controlling enzymes are bound to the membrane of the mitochondrial cristae, enzymes and other electrons carriers here transport electrons from NADH and FADH2 to oxygen, producing water as an end product. source of most metabolic water, the energy from there transfers drive the proton pumps
An active transport protein in a cel membrane that uses ATP to transport hydrogen ions out of a cell against their concentration gradient, generating a mitochondrial membrane potential
ATP is formed in the mitochondria and chloroplast. protons are pumped across the membrane resisting negative charge. they go back through a protein channel through ATP synthase
up to 38 ATP
glycolysis and aerobic respiration collectively produce _________________ per glucose, with the number varying slightly from one tissue type to another.
the conversion of glucose to glycogen when the glucose in the blood exceeds the demand
the hydrolysis of glycogen to release glucose.
formation of new glucose from amino acids produced by the breakdown of proteins, mainly those in muscle tissue cells; also the conversion to glucose of fatty acids produced by the breakdown of fats stored in adipose tissue cells
Lipids containing a glycerol molecule attached to three fatty acid chains; chemical form in which most fats exist in food and in the body
cells that primarily compose adipose tissue, specialized in storing energy as fat.
triglyceride synthesis resulting from nutrients that are not readily needed; occurs when blood glucose is high
the hydrolysis of fat; the decomposition of fats
fatty acids are degraded by a process of ________. oxidation of a typical fatty acid can yield 129 ATP-much more than glucose oxidation
Arise from incomplete oxidation of fatty acids during fasting or diabetes mellitus
presence of an abnormal amount of ketone bodies in the blood and urine indicating an abnormal utilization of carbohydrates as seen in uncontrolled diabetes and starvation
proteins turn over at an average rate of about _____, with especially high turnover in the intestinal mucosa.
amino acid pool
the supply of amino acids derived from either food proteins or body proteins that collect in the cells and circulating blood and stand ready to be incorporated in proteins and other compounds or used for energy
process involved in amino acid catabolism, excess a-acids get sent to liver, the liver tears them apart in NH2 and C2H20, NH2's have potential to form NH3 (ammonia) which is toxic, the liver takes the NH2's and packages them into a molecule of urea, urea is less toxic and can dissolve into H2), getting urea out is job of the kidneys
carbohydrate, lipid, and protein metabolism
non-digestive functions carries out by the liver , though it is mainly associated with the digestive tract.
4 hours during & after a meal. Nutrients are being absorbed and then immediately used or stored.
absorptive state is regulated mainly by____________, which promotes glucose uptake and oxidation, glycogenesis, and lipogenesis, promotes protein synthesis, and inhibits gluconeogenesis.
Stomach and intestine are empty. Stored fuel molecules are used for energy., glucose metabolism reaches a steady state (overnight fast) -fatty acids derived from lipolysis are used as fule by many cells
postabsorptive state is regulated by many hormons_____________ promote lypolysis, and glycogenolysis,
cortisol and glucagon
raised blood glucose by antagonizing insulin
is the amount of energy released in the body in a given time, such as kcal/day. it varies according to the metabolic state and physical and mental and hormonal conditions.
basal metabolic rate
the rate at which heat is produced by an individual in a resting state
total metabolic rate
a higher non-resting state that takes into account muscular activity
average basal metabolic rate. low level of physical activity increases the daily energy need to about 2500/day, hard physical exercise can increase it tot as much as 500 kcal/day, rate also varies according to age, sex, mental statte, strss, health or illness.
the homeostatic balance of body temperature, excessive high or low body temp can be fatal
Condition that occurs when body temperature exceeds 104 F, or 40 F, rectally
condition in which body temperature is below normal, usually below 95 F (35 C) and often in the range of 78 to 95 F (26 to 35 C)
the temperature of the deep tissues of the body (e.g., thorax, abdominal cavity); relatively constant at 37.2°C-37.6°C (98.6°F) can be estimated from anal temperature
is temperature closer to the the surface (oral cavity and skin) - adult varies normally from 36.6°C-36.0°C (97.9 - 98.6 F) can be estimated from oral temperature
is generated mainly by exogenic chemical reactions, especially in the brain, heart and liver, and endocrine glands at rest and in the skeletal muscles during activity.
how the body loses heat
radiation, conduction, and evaporation
the hypothalamic thermostat
monitors blood temperature and receives signals from the peripheral thermoreceptors in the skin
monitors skin temp in body and sends info to hypo
to rid the body of excess heat, the thermostat send signals to a hypothalamic___________, which triggers cutaneous vasodilation and sweating.
to generate and retain heat, the thermostat sends signals to a hypothalamic____________, which triggers shivering and cutaneous vasoconstriction.
primarly in neonates(babies); they cannot shiver, limited amount of vascular brown tissue, present at birth,thyroid hormone causes the increased metabolic rate to produce heat instead of ATP. releases heat from organic fuels
Body temperature regulated through behavioral means like adding or removing clothing, moving to the shade or the sun.
muscle spasms that result from a loss of large amounts of salt and water through perspiration, one of the effects of hyperthermia
a condition marked by dizziness and nausea and weakness caused by depletion of body fluids and electrolytes, one of the effects of hyperthermia
caused by prolonged exposure to high temperatures. is is a medical emergency. the body is unable to eliminate the excess heat, and internal body temp. rises to/over 106 degrees, often progresses to fatal mulitorgan dysfunction.
inessential amino acids
the body does not require them because it can syntesize its own when the diet does not supply them
a metabolic process that breaks down carbohydrates and sugars through a series of reactions to either pyruvic acid or lactic acid and release energy for the body in the form of ATP
occurs in the absence of oxygen and reduces pyruvic acid to lactic acid
which occurs in the presence of oxygen and oxidizes pyruvic acid to carbon dioxide and water
3 pathways to glucose catabolism
glycolysis, anaerobic fermentation, aerobic respiration
the direct transfer of heat from one substance to another substance that it is touching
the transfer of thermal energy by infrared rays
process by which water changes from a liquid into an atmospheric gas carries away heat
the transfer of thermal energy by the circulation or movement of a liquid or gas
metabolism of fatty acids by removing a series of 2-carbon units to form acetyl coa, occurs when fats are used instead of sugars to produce ATP
producton of ketone bodies such as from acetyl-coa
(adenosine triphosphate) main energy source that cells use for most of their work
circular pathway in which lactic acid produced by glycolysis in skeletal muscle is carried to liver cells, where it si back to converted back to glucose and stored as liver glycogen
what free fatty acids are converted into in the liver
The transfer of a phosphate group to a molecule
removal of an amine group of an amino acid to form a keto acid, ammonia and nadh
electron transport chain
series of electron carriers in the inner mitochondrial membrane, they receiver electrons from the fadh2 and the nadh, using the electrons in the formation of ATP and water
citric acid cycle
series of chemical reactions in which citric acid id converted into oxaloacetic acid, carbon dioxide is formed, and energy is released, the oxaloacetic acid can combin ewith the acetly-coa to from citric acid and restart the cycle. the energy released is used to form nadh, fadh and APT
3 Stages of Cell Respiration (in order)
1. Glycolysis 2. Kreb's Cycle 3. Electron Transport System (ETS)
How is glucose changed in glycolysis?
Split by enzymes into to parts called Pyruvate (each with 3 Carbons)
At the end of Glycolysis, what do you have?
1. 2 charged ATP 2. 2 Pyruvate NO WASTE!!
1st step in Kreb's Cycle
Pyruvate (3-C molecule) breaks down into Acetyl CoA (2-C Molecule). Extra C's and O's are released as waste (CO2), H's stored on NAD creating NADH
Acetyl CoA bonds to _____ forming_____
Oxaloacetate , Citric Acid
In Krebs, During "magic" enzyme reactions, what happens to the original Acetyl CoA that is now part of the Citric Acid
All the C's and O's are stripped away and are released as waste, the H's are stored on NAD, now NADH
In Krebs, What happens to the rest of what was citric acid (at the end)?
it is now back to just Oxaloacetate and is reused again with a new Acetyl CoA
Why is Kreb's Cycle a Cycle?
Why is Kreb's Cycle a Cycle?
What happens to NADH in ETS?
the hydrogen is dumped off the NADH. The NAD goes back to Krebs Cycle and the H splits into an electron and a proton
What are the products of Kreb's?
1. NADH 2. 2 More ATP 3. CO2 (WASTE)
How is energy produced in ETS?
There are little turbine shaped proteins (ATP SYNTHASE) in the special pores, as the p+ go through the pores, the turbines turn and create ATP
What is produced in ETS?
1. 34 Charged ATP 2. Water (waste)
Total Amount of ATP created in Cell Respiration
38 Molecules ATP (per molecule Glucose)
During the citric acid cycle, citrate is progressively decomposed back to what?
fats, proteins, and carbohydrates
What can all by used by cellular respiration to make ATP?
What are digested into amino acids, which then deaminated, and can enter into respiration at several sites?
glycerol and fatty acids
What is yielded by by the digestion of fats?
Oxidative phosphorylation produces how many ATP per NADH that's oxidized?
2 pyruvate, 2 CoA, and 2 NAD+
What are the inputs to the oxidation of pyruvate to acetyl CoA?
2 acetyl CoA, 2 CO2, and 2 NADH + 2H+
What are the outputs of the oxidation of pyruvate to acetyl CoA?
glucose, 2 ATP, 2 NAD+, 4 ADP + (P)i
What are the inputs of glycolysis?
2 acetyl CoA, 2 ADP + (P)i, 6 NAD+, and 2 FAD
2 acetyl CoA, 2 ADP + (P)i, 6 NAD+, and 2 FAD What are the inputs of the citric acid cycle
2 CoA, 4 CO2, 2 ATP, 6 NADH + 6H+, and 2 FADH2
What are the outputs of the citric acid cycle?
10 NADH + H+, 2 FADH2, H+ + O2, and 34 ADP + (P)i
What are the inputs of oxidative phosphorylation?
10 NAD+, 2 FAD, H2O, 34 ATP
What are the outputs of oxidative phosphorylation?
2 pyruvate and 2 NADH
What is the input of fermentation (doesn't include the input of glycolyis)
2 ATP, 2 NAD+, 2 ethanol and 2 CO2 or 2 lactate
What are the outputs of fermentation?