Chapter 25 - Nutrition, Metabolism, And Temperature Regulation

Front 1

Nutrition

Back 1

the process by which certain components of food are obtained and used by the body;
process includes digestion, absorption, transportation, and cell metabolism

Front 2

Nutrients

Back 2

chemicals taken into the body that are used to produce energy, provide building blocks for new molecules, or function in other chemical reactions;
divided into six basic groups: carbohydrates, proteins, lipids, vitamins, minerals, water

Front 3

Essential nutrients

Back 3

nutrients that must be ingested because the body cannot manufacture them or is unable to manufacture adequate amounts of them

Front 4

Carbohydrates

Back 4

include monosaccharides, disaccharides, and polysaccharides; usually come from ingested plant material;
glucose and fructose are the most common in diet;

Front 5

Complex carbohydrates

Back 5

polysaccharides such as glycogen, starch, and cellulose;
starch is found in plants, glycogen is foud in the muscles and liver of animals

Front 6

Triglycerides

Back 6

lipids consisting of three fatty acids attached to a glycerol molecule;
often referred to as fats or oils;
make up about 95% of lipids in the diet

Front 7

Saturated fats

Back 7

triglycerides that have only single covalent bonds between the carbon atoms of their fatty acids;
found in the fats of meats and dairy products

Front 8

Unsaturated fats

Back 8

triglycerides that have one or more double covalent bonds between the carbon atoms of their fatty acids;
olive and peanut oils (monounsaturated), and fish, sunflower, corn oil (polyunsaturated)

Front 9

Lecithin

Back 9

a lipid that is composed of cholesterol and phospholipid;
found in high conc. in egg yolks and liver, as well as whole milk, cheese, butter, and meats

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Proteins

Back 10

chains of amino acids;
constructed of 20 different amino acids;

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Essential amino acids

Back 11

amino acids that must be contained in the diet;
histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine

Front 12

Nonessential amino acids

Back 12

amino acids that the body can synthesize from other materials

Front 13

Differentiate between complete protein and incomplete protein foods.

Back 13

complete protein foods contain adequate amounts of all essential amino acids, incomplete proteins do not

Front 14

Nitrogen balance

Back 14

the nitrogen content of ingested protein is equal to the nitrogen excreted in urine and feces

Front 15

Essential fatty acids

Back 15

fatty acids that the body cannot synthesize and must be obtained through the diet; for example, linoleic acid

Front 16

Vitamins

Back 16

organic molecules that exist in minute quantities in food and are essential to normal metabolism;
vitamin means life-giving chemical

Front 17

Essential vitamins

Back 17

vitamins that cannot be produced by the body and must be obtained through the diet

Front 18

Provitamin

Back 18

a part of a vitamin that can be assembled or modified by the body into a functional vitamin; for example beta carotene can be modified by the body to form vitamin A

Front 19

List three provitamins found in the body.

Back 19

Beta carotene to vitamin A
7-dehydrocholesterol to vitamin D
Tryptophan to niacin

Front 20

Coenzymes

Back 20

molecules that combine with enzymes to make the enzyme functional;
many vitamins function as coenzymes

Front 21

Fat-soluble vitamins

Back 21

vitamins that dissolve in lipids; can be stored in the body, and thus may reach a toxic level;
vitamins A, D, E, & K

Front 22

Water soluble vitamins

Back 22

vitamins that dissolve in water; remain in the body only for a short time before excreted in the urine;
vitamins B, C, most others

Front 23

Recommended Dietary Allowances (RDAs)

Back 23

the nutrient intakes sufficient to meet the needs of nearly all people in certain age and gender groups

Front 24

Minerals

Back 24

inorganic nutrients that are necessary for normal metabolic functions; constitute 4-5% of total body weight and form componenents of coenzymes, a few vitamins, hemoglobin, and other organic molecules;
important in establishing resting membrane potentials and generating action potentials, adding mechanical strength to bones and teeth, act as buffers or regulators of osmotic pressure

Front 25

Metabolism

Back 25

the total of all the chemical reactions that occur in the body;
consists of anabolism and catabolism

Front 26

Anabolism

Back 26

the energy-requiring process by which small molecules are joined to form larger molecules

Front 27

Catabolism

Back 27

the energy-releasing process by which large molecules are broken down into smalled molecules;
begins during the process of digestion and is concluded within individual cells

Front 28

Glycolysis

Back 28

a series of chemical reactions in the cytosol that results in the breakdown of glucose into two pyruvic acid molecules;
divided into four phases, input of ATP, sugar cleavage, NADH production, and ATP and pyruvic acid production

Front 29

Anaerobic respiration

Back 29

the breakdown of glucose in the absence of oxygen to produce two molecules of lactic acid and two molecules of ATP;
divided into two phases, glycolysis and lactic acid formation

Front 30

Cori cycle

Back 30

the process of converting lactic acid to glucose; conversion takes place in the liver

Front 31

Aerobic respiration

Back 31

the breakdown of glucose in the presence of oxygen to produce carbon dioxide, water, and 38 ATP molecules;
occurs in four stages, glycolysis, acetyl-CoA formation, the citric acid cycle, and the electron-transport chain

Front 32

Citric acid cycle

Back 32

the third stage of aerobic respiration, also called the Kreb's cycle;
three important events occur during the citric acid cycle: ATP production, NADH and FADH2 production, and carbon dioxide production

Front 33

ELectron-transport chain

Back 33

the four phase of aerobic respiration, involves a series of electron carriers in the inner mitochondrial membrane

Front 34

Chemiosmotic model

Back 34

a process in which the chemical formation of ATP is coupled to a diffusion force (H+) similar to osmosis

Front 35

Free fatty acids

Back 35

between meals, triglycerides are broken down in adipose tissue and some of the fatty acids produced during this process get released into the bloodstream;
used by other tissues, esp. skeletal muscles and the liver, as a source of energy

Front 36

Beta-oxidation

Back 36

a series of reactions in which two carbon atoms at a time are removed from the end of a fatty acid chain to form acetyl-CoA;
metabolism of fatty acids occurs through this process

Front 37

Ketogenesis

Back 37

the formation of ketone bodies;
a process that utilizes acetyl-CoA

Front 38

Ketone bodies

Back 38

molecules that are released into the bloodstream, where they travel to other tissues, especially skeletal muscle, where they can be converted back into acetyl-CoA and enter the Kreb's cycle;
examples are acetoacetic acid, beta-hydroxybuytric acid, and acetone;
produced when acetyl-CoA exists in high conc., esp. in liver

Front 39

Transamination

Back 39

a tranfer of an amine group from an amino acid to the keto acid; one step in the synthesis of nonessential amino acids

Front 40

Oxidative deamination

Back 40

an energy producing process in which an amine group is removed from an amino acid, leaving ammonia and a keto acid and NAD+ is reduced to NADH which can then enter the electron transport chain to produce ATP

Front 41

Glycogenesis

Back 41

the production of glycogen;
in the presence of excess glucose, glycogen is formed, esp. in skeletal muscle fibers and the liver

Front 42

Lipogenesis

Back 42

the synthesis of lipids from glucose and amino acids;
this process is carried out only once excess glucose has been converted to a sufficient supply of glycogen

Front 43

Glycogenolysis

Back 43

the breakdown of glycogen into glucose-6-phosphate when glucose is needed

Front 44

Gluconeogenesis

Back 44

in the presence of insufficient liver glycogen levels and when glucose is needed, it can be synthesized from amino acids from proteins and glycerol from triglycerides

Front 45

Absorptive state

Back 45

the period immediately after a meal when nutrients are being absorbed through the intestinal wall into the circulatory and lymphatic systems;
lasts about 4 hours after each meal;
during this state, glucose in the circulation enters the cells to be used as an energy source; excess is stored in the liver as glycogen or additional fatty acid

Front 46

Postabsorptive state

Back 46

a metabolic state during which blood glucose levels are maintained by the conversion of other molecules to glucose, first glycogen from the liver and then fats from adipose tissue, and finally proteins can also be used

Front 47

Metabolic rate

Back 47

the total amount of energy produced and used by the body per unit of time

Front 48

How long does ATP last within the body once produced?
Approximately how much energy is produced per liter of oxygen?

Back 48

less than one minute;
4.8 kcal

Front 49

Basal metabolic rate (BMR)

Back 49

the energy needed to keep the resting body functional;
the metabolic rate calculated in expedned kilocalories per square meter of body surface area per hour;
determined by measuring oxygen consumption of an awake person who is resting and has not eaten for 12 hours

Front 50

Thermic effect of food

Back 50

the energy expenditure during the digestion of food and nutrients

Front 51

Free energy

Back 51

the total amount of energy liberated by the complete catabolism of food;
kcal/mol of food;
about 43% of energy derived from food is used, the remaining is lost as heat

Front 52

Heat

Back 52

thermal energy that is lost and is not available for work

Front 53

Radiation

Back 53

the loss of healt as infrared radiation;
for example, coals in a fire radiate infrared heat energy

Front 54

Conduction

Back 54

the exchange of heat between objects in direct contact with each other

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Convection

Back 55

a transfer of heat between the body and the air or water

Front 56

Evaporation

Back 56

the conversion of water from a liquid to a gaseous form, a process that requires heat