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41 Cards in this Set
- Front
- Back
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nutrients are oxidized and transformed to ATP, the chemical energy form used by cells
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A nutrient is a substance in food the body uses to promote normal growth, maintenance, and repair.
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Three of the nutrients are carbohydrates, lipids and proteins. are major nutrients that make up the bulk of what we eat. The fourth and fifth categories vitamins and minerals through quality crucial for health, are required in only minute amounts.
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A balance of food is neccessary
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Health Eating pyramid; six major food groups, subdividing some of them further. Emphasizes eating whole-grain foods and lots of fruits and vegetables and recommends substituting plant oils for animal fats and restring red meats, sweets, and starchy foods
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My plate; food guide with a completely new symbol; a round dinner plate , it shows food categories in proportion in sections of the plate rather than as segments of pyramid
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Essential nutrients; atleast 45-50 molecules, cannot be made fast enough to meet the bodys need so our diet must provide them
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Carbohydrates; all the carbohydrates we ingest are derived from plants. Uses in the body; the monosaccharide glucose is the carbohydrate molecules ultimately used as fuel by body cells to produce ATP. They also use fats as energy source. Any glucose in excess of what is needed for ATP synthesis is converted to glycogen or fat and stored for later use
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Lipids; the most abundant dietary lipids are triglycerides also called neutral fats. We eat saturated fats in animals products such as meat and dairy foods. Fats are digested to monoglycerides and fatty acids and then reconverted to triglycerides for transport in the lymph.
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Linoleic acid; a fatty acid component of lecithin. Linoleic acid an omega 6 fatty acid is an essential fatty acid that must be ingested. Linolenic acid, an omega 3 fatty acid may also be essential. vegetables oils contain both of these
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fat Uses in the body; fats help the body absorb fat soluble vitamins; triglycerides are the major energy fuel of hepatocytes and skeletal muscle; phospholipids are an integral component of myelin sheaths and cellular membranes; fatty deposits in adipose tissue provide 1. a protective tissue around body organs
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cont. 2. an insulating layer beneath the skin and 3. an easy to store concentrated source of energy fuel; prostaglandins regulatory molecules formed from linoleic acid via arachidonic acid paly a role in smooth muscle contraction control of blood pressure, and inflammation
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Fat substitutes; the oldest fat substitute is air( beaten into a product to make it fluffly), others are starches and gums and milk whey protein. these products are metabolized and provide calories. Olestra a fat-based product made from cottonseeds, is not metabolized because it is not digested or absorbed. the ones not absorbed tend cause gas or diarrhea and may interfere with absorption of fat soluble drugs, vit, and beta carotene, and vit A
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Proteins; animal products contain the highest quality proteins; in other words those with the greatest amount and best ratios of essential amino acids. in eggs milk fish and most meats are complete proteins that meet all the bodys amino acids requirement for tissue maintenance and growth.
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Legumes beans and peas nuts and cereals are protein rich. but their protein are nutrionally incomplete because they are low in one or more of essential amino acids.
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Uses of proteins in the body; all amino acids needed to make a particular protein must be present in a cell at the same time and in sufficient amounts. essential amino acids cannot be stored they are oxidized for energy or converted to carbohydrates or fats
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Adequacy of caloric intake. Nitrogen balance. rate of protein synthesis equals the rate of protein breakdown and loss a homeostatic state called nitrogen balance, when the amount of nitrogen ingested in proteins equals the amount excreted in urine and feces.
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the body is in positive nitrogen balance when the amount of protein incorporated into tissue is greater than the amount being broken down and used for energy
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Negative nitrogen balance protein break down for energy exceeds the amount of protein being incorporated into tissues. during physical and emotional stress
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hormonal controls, anabolic hormones accelerate protein synthesis and growth.
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nutritionist recommend a daily intake of 0.8 g per kilogram of body weight. the amount of protein a person needs reflect his or her age size metabolic rate and state of nitrogen balance.
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vitamins; =life, are potent organic compounds needed in minute amounts for growth and good health. they are not used for energy and do not serve as building blocks they help the body use those nutrients that do.
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w/o vitamins all the carbohydrates proteins and fats we eat would be useless
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Coenzymes, most vitamin fx as this, or parts of coenzymes which act with an enzyme to accomplish a particular chemical task. some are not made in body and need to be ingested in food or supplements. a balance diet is the best way to ensure full vitamin complement
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vit are either water soluble or fat soluble
water soluble vitamins- b complex vit and vit C are absorbed along with water from the gastrointestinal tract. |
Fat soluble vit (A, D, E, K) bind to ingested lipids and are absorbed along with their digestion products.
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Minerals; (calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium) and trace amounts of about a dozen others. they ensure a smoothly fx body
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metabolism; biochemical rx, substances are constantly built up and torn down. cells use energy to extract energy to drive their activities.
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metabolic processes are either anabolic or catabolic; anabolism all rx that build larger molecules or structures from small ones such as the bonding together of amino acids to build proteins
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catabolism, all processes that break down complex structures to simpler ones
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in the group of catabolic rx collectively called cellular respiration, food fuels,particulary glucose, are broken down in cells and some of the energy released is captured to form atp the cells energy currency
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atp is never hydrolyzed directly instead enzymes shift its high energy phosphate groups to other molecules which are then said to be phosphorylated. it primes a molecule to change in a way that increases its activity produces motion or does work.
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The primary fx of cellular respiration which consists of glycolysis o stage 2 and all events of stage 3 is to generate ATP which traps some of the chemical energy of the original food molecules in its own high-energy bonds. The body can also store energy in fuels, such as glycogen and fats and mobilize these stores later to produce ATP for cellular use
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Many of the rx that take place within cells are oxidation reaxtion. oxidation was originally defined as the combination of oxygen with other elements.
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Oxidation is the gain of oxygen or the loss of hydrogen. oxidize substances always lose or gain electrons as they move toward a substance more strongly attracts them.
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FIG 24.12 Page 924
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Glycogenesis
glucose --->Glycogen (insulin) When high ATP levels begin to turn off glycolysis glucose molecules are combined long chains to form glycogen the animal carbohydrate storage product. |
Glycogenolysis
Glucose---->Glycogen (glucogon) when blood glucose levels drop glycogen lysis occurs. |
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Gluconeogenesis- sugar from non-carbohydrates CHO
the process of forming new glucose from noncarbohydrate molecueles occurs in the liver |
Oxidation of Glycerol and fatty acids; routinely oxidized for energy.
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beta oxidation; the initial phase of fatty acid oxidation, occurs in the mitochondria.
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Lipogenesis; occurs when cellular ATP and glucose levels are high.
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Lipolysis the breakdown of stored fats in glycerol and fatty acids is essentially lipogenesis in reverse. the fatty acids and glycerol are released to the blood helping to ensure that body organs have cont. access to fat fuels for aerobic respiration
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Ketogenesis; the liver converts acetylcoA molecules to ketone bodies; or ketones which are released into the blood. ketone bodies include acetoacetic acid b hydroxybutyric acid and acetone.
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because most ketone bodies are organic acids, ketosis leads to metabolic acidosis.
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deaminated-urea is created; their amine group must be removed
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complete set of amino acids must be present for protein synthesis is to take place so the diert must provide all essential amino acids
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Fig 24.18 page 931
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Fig 24.20 page 934
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cholesterol it serves as the structural basis of bile salts, steroid hormones and vit D and is major component of plasma membranes
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triglycerides and cholesterol are insoluble in water they do not circulate free in the blood. they are transported to and from tissue cells bound to small lipid-protein complexes called lipoproteins.
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the higher the percentage of lipid in the lipoprotein the higher the density. Very low density lipoproteins (VLDLS), low density lipoproteins (LDLs) and high density lipoproteins (HDLs) . Chylomicrons which transports absorbed lipids from the GI tract are a separate class and have the lowest density of all
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the liver is primary source of VLDLs which transport triglycerides from the liver to peripheral tissues, mostly to adipose tissues
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LDLs transport cholesterol to peripheral tissues making it available tissue cells to synthesize membranes or hormones and to store it for later use.
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Major fx of HDLs rich in phospholipids and proteins is to scoop up and transport excess cholesterol from peripheral tissues to the liver where it is broken down and becomes part of bile.
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Energy balance; energy intake =energy output
energy intake is the energy liberated during food oxidation (undigested foods are part of the equation bc they contribute no energy. Energy output includes energy 1. immediate lost as heat 2. used to do work driven by ATP 3.stored as fat or glycogen. |
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official medical measure of obesity and body fatness is the body mass index an index of a persons weight relative to height.
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the NPY/AgRP group of ARC releases neuropeptide Y (NPY) and agouti-related peptides, which collectively enhance appetite by stimulating the orexin releasing second order neurons of the LHA
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LEPTIN; a key component of the long term controls of feeding behavior is the hormone leptin; secreted by adipopse cels in respone to an increase in body fat mass leptin indicates the bodys total energy stores in fat tissue
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Metabolic rate; is the total heat produced by all the chemical rx and mechanical work of the body.
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measured by directly method; person enters a chamber called a calorimeter and water circulating around the chamber absorbs heat liberated by the body. indirect method; uses a respirometer to measure oxygen consumption which is directly proportional to heat production
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Basal metabolic rate reflects the energy the body needs to perform only its most essential activities, such as breathing and maintaining resting levels of organ fx
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several factors influence BMR including body surface area, age, gender, body temperature, stress, and the hormone thyroxine
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thyroxine produced by thyroid gland is probably the most important hormonal factor in determining BMR.
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Total metabolic rate; is the rate of kilocalorie consumption needed to fuel all ongoing activities -involuntary and voluntary. BMR accounts for a surprisingly large part of TMR.
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Mechanism of heat exchange;
radiation; is the loss of heat in the form of infrared waves . any object that is warmer than objects in its environment |
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conduction; hand experiment on table. transfers heat from a warmer object to a cooler one when the two are in direct contact with each other.
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convection; the process that occurs because warm air expands and rises and cool air being denser falls.
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evaporation; the fourth mechanism by which the body loses heat is evaporation. water evaporates bc its molecules absorb heat from the environment and become energetic enough.
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heat of vaporization; heat absorbed by water during evaporation
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insensible water loss, unnoticeable water loss occurring.
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Role of hypothalamus; the main integrating center for thermoregulation
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heat promoting mechanism. constriction of cutaneous blood vessels, shivering, increase of metabolic rate. enhanced thyroxine release.
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heat loss mechanism; dilation of cutaneous blood vessels, enhanced sweating,
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fever; controlled hyperthermia occurs from infections
pyrogens "fire starters" the "chills" sign of body temperature rising |
chemical messengers called cryogens (vasopressin and others) prevent fever from becoming excessive and reset the thermostat to a lower or normal level sweating begins and skin becomes flushed and warm
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what are the six major nutrients?
carbohydrates, proteins, fats, water, minerals and vitamins |
why is it important to include cellulose in a healthy diet even though we do not digest it?
cellulose provides fiber which helps in elimination |
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how does the body use triglycerides? Cholesterol?
triglycerides are used for ATP synthesis, body insulation and protective padding and to help the body absorb fat soluble vitamins. cholesterol is the basis of our steroid hormones and bile salts and stabilizes cellular membranes |
john eats nothing but baked bean sandwhiches is he getting all the essential amino acids he needs in this restricted diets?
beans legumes and grains wheat neither is a complete one but they provide essential amino acids |
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vitamins are not used for energy fuels. what are they used for?
vitamins serve as the basis for coenzymes which work with enzymes to accomplish metabolic reactions |
done
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