WE HAVE all heard the saying, You are what you eat. This

Transcription

1 Proper Nutrition WE AVE all ear te saying, You are wat you eat. Tis prase refers to te relationsip between a boy s overall ealt an te kins of foo eaten. For proper ealt, te boy must take in te proper nutrients, or substances necessary for te functioning of an organism. Nutrition can be tougt of as te process in wic organisms eat foo an use it for growt an te replacement of boy tissues. Objective: Explain wy proper nutrition is important for all organisms. Key Terms: aesion amino acis capillarity carboyrates catalysts coesion eficient isaccarie DNA enzyme fat-soluble vitamins fatty acis yrogenation inorganic lipase lipis macrominerals minerals monosaccarie nucleic aci nutrients nutrition organic polar polysaccarie RNA saturate fatty acis sterois trace elements triglyceries unsaturate fatty acis vitamins water water-soluble vitamins wax E-unit: Proper Nutrition Page 1 AgELibrary.com

2 Te Importance of Nutrition Organisms ave tree basic nees for survival. Selter protects tem from te extremes of te environment. Water is necessary for te variety of cemical reactions tat occur witin teir boies. Foo provies te energy tat teir boies nee to live, grow, an reprouce. Witout proper nutrition, organisms experience stress tat inibits natural functions. Slow growt, low reprouctive success, an poor ealt in general coul be signs of poor nutrition. On te oter an, proper nutrition as a variety of positive effects on animals an plants. Some of tese are an increase ability to igest an use foo, more weigt gain in a sorter time, an increase tolerance of averse conitions. Six essential nutrients are require for te ealty an prouctive functioning of an organism. Tey inclue water, minerals, vitamins, proteins, carboyrates, an lipis. FIGURE 1. Proper nutrition is important to te growt an general ealt of all organisms. (ourtesy, USDA) WATER Water, a molecule mae up of two yrogen atoms an one oxygen atom, is te most essential of all te nutrients. Water is require by every muscle, tissue, an cell of te boy to carry out basic functions. Water is a polar compoun, meaning it as bot positive an negative attraction sites, or poles. Because of tis quality, water molecules easily bon to eac oter to form te various states of water. More tan 75 percent of te muscles an internal tissues of animals are mae up of water. Water is te most abunant inorganic substance in te boy. An inorganic substance is one compose of noncarbon-base materials foun in te eart, suc as minerals. An organic compoun, on te oter an, contains molecules erive from living tings, suc as plants or animals. Water is responsible for suc activities as elping break own foo, regulating boy fluis an temperature, an proviing internal pressure in plants to keep cells rigi. Te cemical properties of water also ai in te effectiveness of water to carry out various functions. Since water is a polar compoun, it exibits te FIGURE 2. Water is essential for all life on Eart. (ourtesy, USDA) E-unit: Proper Nutrition Page 2 AgELibrary.com

3 principle of coesion, te boning of two water molecules to eac oter. Te yrogen in water as a positive carge, wile te oxygen as a negative carge. Water as a net carge of zero; but because of ow te water molecule is structure, te molecule as one sligtly positive pole an one sligtly negative pole. Tis allows water molecules to bon to eac oter very easily. Tis can be seen if a small amount of water is poure on a smoot surface. Te water tens to form pules or roplets on te surface because te molecules are boning, or sticking togeter. Tis polarity of water also increases te amount of eat it takes to break te water molecule apart. A large amount of eat is neee to break te molecular bons an cause te water to boil. Tis is goo news for all water-base organisms, suc as umans. Oterwise, a small amount of eat, even tat from te sun, woul cause our water molecules to break apart an boil us! Because of te polarity of water, it likes to bon not only to oter water molecules but to oter substances as well. Aesion is te boning of one type of molecule to anoter type of substance or molecule. You ave probably ear tis term before wen you use aesive tape. Tape is known as an aesive because it causes two ifferent types of materials to aere, or stick, to eac oter. Water bons easily to most oter substances, especially if te oter substances are also polar compouns. Take, for example, wat appens wen you was your car. Wen you finis, water is still clinging to te surfaces of your veicle (just waiting to make all tose water spots)! If te roplets are small enoug, tey will aere, or stick, to te molecules on te surface of te car. A spot-free rinse at te carwas covers your veicle wit a temporary liqui surface tat oes not allow water to aere. Terefore, water slies off te car surface before te roplets can ry an leave spots. ave you ever seen a magician levitate an assistant, seeming to FIGURE 3. Water can aere to nearly any surface, incluing te nonstick coating tat prevents foos from sticking to tis frying pan. efy gravity? We know tat tis levitation is an illusion, but water can actually move against gravity an pull itself upwar. apillarity is te ability of a liqui to move upwar against te force of gravity because of te liqui s molecular attraction to te surrouning surface. Di you ever woner ow water travels from te soil all te way to te top of a tall tree? Using coesion an aesion, water can move up te small xylem cells in te plant, beginning in te roots an ening in te leaves. To explain tis better, tink of a glass cyliner. Te water insie te cyliner will bon to te glass surface ue to aesion. At te same time, coesion E-unit: Proper Nutrition Page 3 AgELibrary.com

4 between water molecules will pull more water up te cyliner. Te smaller te cyliner, te smaller te amount of water tat gravity is acting upon, causing te liqui to rise farter. MINERALS Along wit water, minerals are also necessary for proper growt of plants an animals. Inorganic compouns foun in rocks, soil, an water, among oter places, are known as minerals. Several minerals ave been ientifie as essential elements for proper life an growt. If any one of tese elements is eficient, or lacking in te neee amount, an organism can experience serious, sometimes ealy, results. Te mineral elements ave been ivie into two general groups, macrominerals an trace elements. Macrominerals are tose elements tat are neee in larger quantities in te boy. Tere are six macrominerals: calcium, posporus, magnesium, soium, potassium, an clorie. Because most minerals are neee in very small amounts, larger quantities may mean only a few milligrams! Trace elements, often calle microminerals, are tose minerals tat are neee in very small quantities but are just as important to growt an survival. Tere are nine trace elements: cromium, copper, fluorie, ioie, iron, manganese, molybenum, selenium, an zinc. Sickness an isease can commonly be te result of low mineral amounts in te iet. Do you ever take a mineral supplement? ances are tat most of us o not eat enoug foo wit te proper minerals. ave you ever felt exauste or run own? Feelings of tireness can sometimes be attribute to low iron levels. Not enoug magnesium can result in muscle tremors an saking. Got milk? Low levels of calcium, a mineral commonly foun in airy proucts, can lea to osteoporosis (brittle bone isease) an to poor teet, skin, an fingernails. FIGURE 4. Salt blocks are a common way for livestock proucers to fee minerals to teir animals. VITAMINS Vitamins are similar to minerals in tat tey are neee in small amounts an are important for te proper functioning an growt of an organism. Vitamins are complex compouns, generally consisting of carbon, yrogen, oxygen, an nitrogen molecules. Vitamins often serve as catalysts, compouns tat cause oter cemical reactions to occur. Tink of your- E-unit: Proper Nutrition Page 4 AgELibrary.com

5 self jogging at a normal pace. If suenly you foun yourself being case by a bear, you woul probably pick up te pace! Te bear woul be like a catalyst, causing a efinite reaction in your running spee. Vitamins o not provie any energy for te boy; tey simply elp te boy carry out its functions more efficiently. Vitamins can elp your bloo clot quickly, your bones form correctly, an your cells reprouce effectively (all important if you get caugt by tat bear)! Vitamins can also elp organisms prouce milk an prevent some nervous system isorers. Tere are a vast number of vitamins to coose from wen you walk own te isle at your local parmacy. Generally, vitamins can be classifie into two categories. Water-soluble vitamins must be consume anew eac ay, as te vitamins are able to be issolve in water, an any excess will be excrete from te boy. Examples of water-soluble vitamins are vitamins an B. Fat-soluble vitamins are issolve by fat an are store in te boy for future use. Examples of fat-soluble vitamins are vitamins A, D, E, an K. Vitamins, like minerals, are essential but neee in small amounts. Take vitamin, for example. Te recommene aily intake of vitamin is 60 milligrams (a milligram is 1 / 1,000 of a gram). Because vitamin is water soluble, any excess will be excrete from te boy (altoug toxicity can occur wit large oses). More is not always better in te case of vitamins. Large oses of vitamins can be toxic to an organism. Most livestock animals o not receive te proper vitamins tey nee in teir fee an must terefore ave vitamin supplements ae to teir rations to give tem ealty iets. FIGURE 5. Tere are numerous coices wen looking at vitamins at te local parmacy. FIGURE 6. Vitamin, commonly foun in citrus fruit, is essential for ealty living. (ourtesy, USDA) E-unit: Proper Nutrition Page 5 AgELibrary.com

6 PROTEIN Nearly everyting we eat or grow as protein as part of its structure. air-care proucts boast protein fortifie sampoos to strengten your air. Atletes sometimes rink protein sakes to elp rebuil muscles after exercising. Next to carboyrates, protein is te most common nutrient substance foun in plant material. Protein is largely foun in te sees of most plants an is essential for te biological functions of bot te plants an umans. Most of us ave been injure at some point in our lives. Proteins elpe us an continue to elp us repair our injuries an to grow. Of our cells, 3 to 5 percent must be repaire an rebuilt every ay. Protein is also te main component of our genetic coe, wic passes on information from an iniviual to its offspring. Proteins are forme by te joining of many single molecular units, known as monomers, into amino acis. Te creation of amino acis involves te joining of a central carbon atom to oter atoms. Tere are 20 known amino acis essential to uman life an growt. Our boies can prouce 11 of te 20, but te oter 9 must be consume in te foo we eat or in ietary supplements, like vitamins. Wen two amino acis bon, te resulting compoun is a ipeptie. Wen more tan two amino acis bon, te resulting compoun is a polypeptie. Proteins are forme by te linking of two or more polypepties. From tis progression, you can clearly see wy protein is truly te builing block of life! Proteins, owever elpful tey seem, woul be useless in our boies witout te presence of enzymes. An enzyme works as a catalyst to reuce te amount of energy neee for a cemical reaction to occur. Enzymes are essential in our boies to elp igest, or break own, te proteins we consume into usable energy. Witout enzymes, pro- FIGURE 7. Sees, suc as tese beans, can be a major source of protein from plant material. (ourtesy, Agricultural Researc Service, USDA) Protein ain Amino acis Peptie bons FIGURE 8. Proteins are mae of cains of amino acis joine by peptie bons. E-unit: Proper Nutrition Page 6 AgELibrary.com

7 teins woul be unable to be igeste an pass troug our systems witout muc benefit to us. One of te most important functions of protein is te formation of nucleic acis. Nucleic acis are organic molecules foun in te nucleus of a cell tat contain genetic information. Tere are two main nucleic acis, DNA an RNA, wic are essential to all life on Eart. DNA (eoxyribonucleic aci) is a large molecule built from te boning of te four nucleoties aenine, tymine, guanine, an cytosine. Troug te arrangement of ifferent protein groups, a DNA molecule coes all te genetic an ereitary information for an organism. RNA (ribo- Stran Stran Gene Fraction base T base A Stran Deoxyribose Pospate p Base Aenine ytosine Guanine Tymine A G T yrogen Bon p p p T G G A p p p p T A p base base Stran Stran FIGURE 9. DNA molecules store an transfer ereity information from one generation to te next. E-unit: Proper Nutrition Page 7 AgELibrary.com

8 nucleic aci) is a smaller molecule forme from sections of DNA. Te purpose of RNA is to store information for te manufacture of proteins tat will be use for boy functions. Unlike DNA, wic is foun only in te cell nucleus, RNA is foun in bot te nucleus an te cytoplasm of a cell. ow o I know weter tere is enoug protein in my iet? you ask. ances are if you are eating well-balance meals, you are consuming te proper amount of aily protein. Meats, airy proucts, eggs, beans, an nuts are all great sources of protein in our iets. For our livestock, to wic protein is just as important, soybeans, peanuts, an cottonsee are a few examples of goo sources of protein. Most livestock proucers, owever, fee teir animals preformulate protein supplements tat meet te aily requirements of teir animals instea of feeing raw soybeans or peanuts. FIGURE 10. Many premixe livestock fees are alreay supplemente wit protein. ARBOYDRATES arboyrates are organic compouns, usually starces an sugars, wic are te primary sources of energy for an organism. Americans typically consume nearly alf teir calorie intake from carboyrates, wile Asians an Africans may consume closer to fourt-fifts, because of te amount an type of foo tey eat. Examples of foos tat are ric sources of carboyrates are rice, corn, potatoes, an weat. arboyrates are compose of carbon, yrogen, an oxygen. Te number of carbon atoms in a particular carboyrate may vary from te number in anoter carboyrate, but tere are always two yrogen atoms an one oxygen atom in eac molecule. Tis 2:1 ratio of yrogen to oxygen is te same ratio present in a common water molecule. Tere are tree main types of carboyrates: monosaccaries, isaccaries, an polysaccaries. All tree are simple sugar compouns tat vary only by te number of molecules in eac structure. Look at te prefix of eac wor (mono-, i-, an poly-) to get a int as to ow many molecules will make up te final carboyrate. Monosaccaries are simple, single-molecule sugars tat contain te ratio of one carbon atom : two yrogen atoms : one oxygen atom. Some common monosaccaries are glucose, E-unit: Proper Nutrition Page 8 AgELibrary.com

9 fructose, an galactose. All tree of tese monosaccaries ave a cemical formula of 6 12 O 6 but are structure in ifferent ways. ompouns of tis type are calle isomers. Take a moment an tink about te tree monosaccaries just liste. an you tink of were eac of tese coul be foun? Te main purpose of potosyntesis is to prouce foo for plants, an te foo create is known as glucose. We, as well as oter animals, benefit from glucose wen we eat te stem, roots, sees, an leaves of a plant. Fructose is a very sweet-tasting monosaccarie foun in fruit, wile galactose is a monosaccarie foun in milk. Wen two monosaccaries, or single-molecule sugars, join, tey form a isaccarie, or ouble-sugar molecule. Lactose, a milk sugar, is forme from te combination of bot glucose an galactose. Maltose is create wen two glucose molecules combine. Sucrose, or wat we commonly know as sugar, is actually te joining of fructose an glucose. Sucrose is commonly foun in plants tat we arvest an use for teir sweet taste, suc as sugar cane an sugar beets. ELP WANTED ON TE JOB AREER ONNETION: Foo Scientist Witout foo scientists, many of our favorite foos woul simply not exist. Foo scientists ream up new foos an new combinations of ingreients to give us ifferent flavors, textures, an smells from our foo. In aition to te creation of new foos, tey also work to ensure tat our foo supply is safe from contaminants tat coul arm consumers. Foo scientists use a vast amount of scientific knowlege in teir aily routines. emistry, biology, microbiology, an pysics all play roles in te eucation of foo scientists. Tese scientists may work inepenently, for companies or corporations, or for te government. Tey evelop an refine preservation, processing, packaging, an prouction tecniques to be use in te foo inustry. Tey also make sure tat all foo proucts are meeting regulations an guielines for quality, safety, an waste management uring prouction. A foo scientist works in a laboratory to evelop new foos or cange te caracteristics of existing foo proucts. (ourtesy, Agricultural Researc Service, USDA) One aspect of te agriculture inustry tat employs foo scientists is researc in te uses of soybeans. Scientists are continually eveloping new ways to increase te protein content of oter foos by using soybeans. Sometimes, foo scientists may even evelop nonfoo items from foo sources, as in te case of soy ink from soybeans! Foo scientists nee a bacelor s egree in foo science or relate fiel, wit most people going on to receive teir master s or octorate egree. E-unit: Proper Nutrition Page 9 AgELibrary.com

10 O O O O O O O O O O O O Galactose Glucose (6 12 O6) (6 12 O6) O O O O O O Fructose (6 12 O6) FIGURE 11. Tese tree monosaccaries ave te same molecular formula (te same number an type of atoms), but eac as a ifferent structural formula because te atoms are arrange ifferently. O O O O O O O O O O O O Fructose (6 12 O6) Glucose (6 12 O6) Sucrose (12 22 O11) FIGURE 12. emical structure of a isaccarie. E-unit: Proper Nutrition u Page 10 u AgELibrary.com opyrigt 2006 by AERT, Inc. Reprouction by subscription only

11 Sometimes, more tan two monosaccaries will join, forming wat is known as a polysaccarie. Tree common polysaccaries are starc, cellulose, an glycogen. Wen plants complete potosyntesis an create glucose, a monosaccarie, tey form long cains of glucose into starces tat are store for an energy supply later. We as umans also benefit from starces. Tis is wy we arvest certain plants potatoes, corn, an rice, for example wen te levels of starces being store are igest. Witout plants, te amount of carboyrates in our iets woul be severely lacking. ellulose is also a cain of glucose molecules tat are joine ifferently tan starc molecules. ellulose makes up muc of plant cell walls an as support an structure to plants. umans an all nonruminant animals are unable to igest cellulose. Goo examples of cellulose are te veins in a stalk of celery. We may be able to cew tem into small pieces, but our igestive system cannot issolve an use tem, passing tem out wit our waste. A ruminant animal, suc as a cow, as specialize bacteria in te rumen compartment of its stomac tat can break own cellulose, allowing te animal to benefit from grasses an oter plants. As we eat foo sources tat contain glucose, we are sure to ingest glycogen, te storage form FIGURE 13. attle are ruminant animals. Tus, tey can igest cellulose, a polysaccarie. (ourtesy, Agricultural Researc Service, USDA) of glucose in our boies. All animals, incluing umans, store energy for later use, just as plants o. Glycogen is commonly foun in muscle tissue an can be use for energy if oter sources namely, our fat supplies begin to run low. Tis is wy extreme ieting can estroy muscle mass an amage internal organs. LIPIDS All living organisms, incluing plants an animals, require lipis to carry out basic life functions. Lipis are fatty compouns mae up of carbon, yrogen, an oxygen. Lipis are not water soluble. Tis means tey cannot be issolve in water. Tere are many uses of lipis, incluing storing energy for later use, aing bulk or flavor to our foo, aing insulation to our boies, an being part of various oter cemical reactions. Lipis are commonly ae to livestock fee to improve te flavor, palatability, an texture, as well as te energy levels gaine from te fee. As mentione earlier in tis E-unit, some vitamins are fat soluble. Lipis are terefore require to carry an store tese vitamins for later use. Vitamins A, D, E, an K are fat-, or lipi-, soluble vitamins. E-unit: Proper Nutrition Page 11 AgELibrary.com

12 Now tat we unerstan wat a lipi is, we soul focus on wat a lipi oes. Tree main types of lipis are foun in plants an animals: triglyceries, wax, an sterois. Triglyceries are lipis compose of tree fatty-aci molecules an one glycerol molecule. Glycerol is an alcool molecule tat provies te framework for various types of triglyceries to form substances we commonly know as oils or fats. Wen we eat triglyceries, our boies use a substance calle a lipase,an enzyme tat breaks own lipis, cutting te triglyceries into smaller cains of molecules. Our boies can ten restructure tese broken cains into te appropriate form for use or storage. If a triglycerie is in a liqui state at room temperature, it is calle an oil. Oils are commonly foun store in te sees of plants, suc as soybeans, canola, an peanuts. Triglyceries tat are in a soli state at room temperature are known as fats. Fats are commonly foun covering organs an muscle tissues in animals. Wax is anoter common form of lipi tat is actually a long fatty aci connecte to a long alcool cain. Because of te structure of wax, it is igly waterproof an is often foun as a coating on leaves to elp conserve water an reflect te rays of te sun. Wax is a soli at room temperature but canges to a liqui wen subjecte to eat. Wen te eat is remove, te wax cools an returns to a soli state basically uncange. Our final group of lipis to iscuss is sterois. Sterois are lipis tat inclue colesterol an cortisone an are foun in ormones, nerve tissues, an plant poisons. Sterois ave te ability to cause canges or cemical reactions to occur. FIGURE 14. A layer of fat cover is easily seen in tis poto of a sie of meat. Te fat layer is mae of lipis. (ourtesy, Agricultural Researc Service, USDA) FIGURE 15. Oils are triglyceries in a liqui state at room temperature. E-unit: Proper Nutrition Page 12 AgELibrary.com

13 Sterois are essential for te functioning of our boies; owever, te aition of artificial sterois to our boies can be angerous. Lipis in Our Diet All lipis are create wen a molecule of glycerol, an alcool, is linke to any number of fatty acis, or long cains of carbon molecules joine to an aci molecule. Some examples of fatty acis are lauric aci, butyric aci, an caproic aci. Our boies ave te ability to prouce some fatty acis tat can be use in te creation of lipis. owever, oter fatty acis, known as essential fatty acis, are not prouce in our boies an must be consume in our aily intake of foo. Terefore, a iet tat as no fat may soun appealing to someone trying to lose weigt, but it is actually very amaging to te boy. UNDER INVESTIGATION LAB ONNETION: Testing for arboyrates, Fats, an Proteins uman beings, an most living organisms for tat matter, require six essential nutrients for proper growt an ealt. Water can usually be reaily foun an is normally not eficient in our iets. Te oter five (minerals, vitamins, proteins, carboyrates, an lipis) are sometimes overlooke in our aily iets. Tis can lea to serious ealt concerns. Foo scientists, along wit plant scientists an breeers, ave foun tat plants can provie many of te essential nutrients in our iet. From te carboyrate storage cells in te roots to te protein-packe sees in te fruit, plants are proucing tese essential nutrients in great quantities. But sometimes quantity oes not equal quality. Scientists are now canging te nutrient content of various plant proucts to meet an ever-canging eman for nutritious foo an balance livestock fee. From corn to soybeans, scientists are altering te amounts of nutrients wit tecniques as complex as DNA manipulation an as simple as selective breeing. owever complex or simple te process of nutrient altering may be, it still must begin wit a base knowlege of wat nutrients are Testing for carboyrates, fats, an proteins is a common activity in most foo science laboratories. alreay present an in wat quantities tese nutrients are present in te plant material. A laboratory experiment can be conucte to test foos for carboyrates, fats, an proteins. Te instructor will provie specific instructions. A variety of foos soul be teste. Ten, te foos can be compare base on te presence of sugar, starc, fats, an proteins. E-unit: Proper Nutrition Page 13 AgELibrary.com

14 You ave probably ear of saturate an unsaturate fatty acis but, like most consumers, are unaware of wat makes one fatty aci saturate an one unsaturate. Te terms actually refer to te number of yrogen molecules linke to te fatty acis. Saturate fatty acis are linke to te maximum number of yrogen molecules an are terefore saturate wit yrogen. Unsaturate fatty acis are exactly wat tey soun like, unsaturate wit yrogen molecules. Saturate fatty acis are more likely to appear as solis at room temperature an are present in suc foos as meats, butter, an coconuts. Unsaturate fatty acis are in a liqui form at room temperature an are commonly foun in te oils of fis an plants. Sometimes, a foo proucer wises to ave an unsaturate fatty aci in a soli state at room temperature. For tis to occur, te unsaturate fatty aci must unergo a process calle yrogenation, in wic yrogen molecules are ae to te unsaturate fatty aci to give it te qualities of a saturate fatty aci. Margarine, a substitute for butter, is an example of an unsaturate fatty aci tat as unergone yrogenation to become soli at room temperature. Unlike people of oter countries, we in te Unite States consume quite a bit of fat in our iets. Nearly 50 percent of te calories consume by Americans are in te form of fat. As we sai earlier, some fat in our iets is necessary, but most octors agree tat people soul limit fat calories to about 30 percent of teir total caloric intake. Some meical stuies ave sown tat a ig-fat iet can contribute to a variety of unealty meical conitions, ranging from obesity an ig colesterol to cariovascular isease an eart attacks. FIGURE 16. Margarine, a yrogenate unsaturate fatty aci, is a substitute for butter, a saturate fatty aci. (ourtesy, Agricultural Researc Service, USDA) FIGURE 17. Salas are low-fat alternatives to fast foos. (ourtesy, Agricultural Researc Service, USDA) E-unit: Proper Nutrition Page 14 AgELibrary.com

15 To reuce te amount of fat in our iets, we must monitor our intake of ig-fat foos, suc as fast foos an snack cips. We must also be aware of te amount of saturate fatty acis in a foo prouct. Most foo items, even saturate fat items, are safe to eat as long as we remember tat te key is moeration. Too muc of a goo ting (or someting tat tastes goo) can turn out to be a ba ting! Wat s Your Profile? Intereste in te information presente in tis E-unit? You migt make a great Nutritionist/Dietician! eck out: Looking for someting a little ifferent? Explore your options! Visit: Summary: Proper nutrition is critical to all living organisms because it provies te energy neee for life, growt, an reprouction. Water, te most critical nutrient, is require on a cellular level an allows our most basic processes to be carrie out. Minerals are inorganic compouns neee in various amounts to prevent isease an poor ealt in organisms. Vitamins are compouns tat provie nutrients to te boy for tissue maintenance an growt, among oter processes. Proteins are te builing blocks for amino acis, wic, in turn, are essential to te formation of DNA an life in general. arboyrate, our most abunant nutrient, is responsible for te energy neee to carry out our aily metabolic functions. Lipis are primarily use to store energy until our boies require its breakown an use. ecking Your Knowlege: 1. Wat is nutrition, an wy is it important for a boy to take in nutrients? 2. Wat are te six essential nutrients require for te ealty an prouctive functioning of an organism? 3. ow can water move itself upwar against te force of gravity? 4. Wat is te ifference between water-soluble an fat-soluble vitamins? 5. Wy are enzymes essential to your boy s functioning? 6. List an briefly escribe te tree main types of carboyrates. 7. ow oes wax, a lipi, elp protect leaves uring te summer? E-unit: Proper Nutrition Page 15 AgELibrary.com

16 Expaning Your Knowlege: Bring five ifferent foo items wit nutrition labels to class. Using te nutritional information an te ingreients liste on eac package, sort eac ingreient into one of te six categories of essential nutrients. Use te Internet to classify any unknown aitives. Web Links: USDA Foo an Nutrition Information enter ttp:// U.S. Department of Labor Foo Scientist ttp:// Agricultural areer Profiles ttp:// E-unit: Proper Nutrition Page 16 AgELibrary.com