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Lectures 15-20AgricultureAgriculture – science, art, and practice of cultivatin the soil, producing crops and raising livestockIn the WorldArtificial selection (domesticated plants) and Cultivated plantsFood and fiber that sustains the entire population of the planet is produced on just 3% of planet’s land.OriginsPeople were foragers first, and gradually transitioned to sedentary agricultural lifestyle1) The Fertile Crescent (14,000 years ago)Wheat, barley, pea, lentilGoat, sheep, dog2) The Far East (8,000 years ago)Rice, millet, broomcorn, rapeseed, hempCattle, pigs, dogs, poultry3) New World (12,000 – 10,000 years ago)Beans, corn, tomato, peanut, chili peppers, squash, potato, cacaoAgriculture in the US16% of US land is used as crop land; 34% for pasture and grazing4 major crops planted on 80% crop land (corn, wheat, soybeans, hay)Veggies, fruits, and nuts are produced on 7% of crop land. Cotton is 4%NutritionCarbohydratesMacronutrient; (4 Cal/gram)MonosaccharaidesBuilding block of carbs – GLUCOSEMetabolized during cellular respiration to produce energyFructose, galactoseDisaccharides2 monosaccharaidesSucrose (Glucose + Fructose = sucrose)Lactose, maltoseNo nutritional value, only caloriesPolysaccharidesHundreds of thousands of individual sugar unitsCOMPLEX CARBOHYDRATESSTARCH – long glucose chain found stores in plants (potato, wheat, rice, etc.). Broken down by enzymes in salivaGlycogen – storage form of glucose in human bodyExcess glucose – fatFIBERPolysaccharide derived from plants. Comes from cellulose. Not digestible, but provides bulk.Dietary fiber can beSoluble – oat, reduces cholesterol levels and risk of heart diseaseInsoluble – fruit, bran, veggies. Absorbs water, prevents constipation and may prevent certain cancer (colorectal)ProteinsLarge complex molecules that form many functions. Made of 20 amino acidsAid with structure, support, digestion, hormones, transport, storage, muscle movement, antibodiesSources: meat, fish, cheese, milk, egg, bean, corn, soybeanEssential Amino AcidsCells in human body can make 11 of 20 amino acidsThe 9 they cant make are essential amino acids, and must come from diet. Can’t be stored in body, must constantly be in dietComplete proteinsContain all essential amino acidsProteins from animal sources are completeProteins from plant sources are incompleteFats: 9 cal/gramHydrophilic head; hydrophobic tailFunctions: energy storage, insulation, hormones, structuralTriglycerides: Glycerol + 3 fatty acids3 Essential fatty acids – found in vegetable oilSaturated – Carbon atoms joined by single bond. Solid at room temperature (butter, lard, beef fat)Unsaturated – carbon-carbon bonds are double bonds. Liquid at room temperature: corn oil, olive oil, safflower oil. Lower cholesterol levelsCholesterolSubcategory of lipids called steroidsImportant for making cell membranes ad human hormonesAnimal products (eggs, butter, meat, cheese) high cholesterolBAD cholesterol – LDL Low density lipoproteinGOOD cholesterol – HDL High density lipoproteinVitamins:Fat SolubleAImportant in formation of vision pigmentsHelps maintain smooth, healthy skinBone and tooth developmentAnimal sources: liverPlant sources: yellow, orange, and dark green fruits and veggiesLACK OF VITAMIN A – night blindness, dry/scaly skin, infections, lack of bone growthDWater SolubleB (Vitamin B Comlpex)8 vitamins, all water solubleMost act as coenzymes, help in food breakdown and release of energyLACK OF VITAMIN B – fatigue, weakness, depression, dermatitis, anemiaGood sources – meat, fish, chicken, whole grains, seeds, nuts, legumesCSynthesis of collagen (connective tissue of cells). Found in bones, teeth, cartilageGood antioxidant that helps in absorption of ironLACK OF VITAMIN C – scurvy, bleeding gums, hemorrhages in skin, fatigue, brittle bones and maybe deathMinerals: 17 required by bodyIronTrace mineral (needed in smaller amounts)Component of hemoglobin (molecule that carries oxygen in red blood cells)Deficiency – Anemia; too much = toxicSources – liver, shellfish, fish, poultryPlant sources – dark green, leafy vegetables, dried fruits, legumes (bean), whole rains, breads and cerealsCalciumMost abundant mineral in body; found in bones and teethDeficiency causes osteoporosisSources: milk, dairy, green leafy veggies, seeds, nutsIodineTrace mineralRequired for formation of thyroid hormones that regulate cell metabolismDeficiency – goiter – swelling of thyroid glandIodized salt best source of iodineFood pyramid, calories and food labelsCalories – Dietary guidelines use KCalories (energy needed to raise 1000 grams of water (1 liter) 1 degree Celcius)Humans require 1200-3200 calories per dayCereals:Grasses - MONOCOTSGrasses are monocots – herbaceous, parallel leaf venation, flower parts in 3’s, scattered vascular bundles, fibrous roots.Importance to HumansGrasses include the grains, the single most important food group in the world.Edible grains of cultivated grasses are called cerealsCereals are the major suppliers of calories for human nutrition (wheat, corn and rice)Advantage of cereal grains: dry seeds can be stored for yearsGrains are a concentrated food sourceGeneral Features of GrassesFlowers are adapted to wind pollinationFlowers are small, inconspicuous and manyAnthers are large and produce lots of pollenStigmas are double and large, to catch pollenGrass FruitGrasses have simple, dry fruits that do NOT open at maturityCaryopsis: seed coat is fused to the ovary wall (corn, wheat, rice)Grain parts include:1. Endosperm - (3n) large cells filled with starch grains; supplies food to germinating seedling2. Embryo (or germ) - young plant (2n); also known as the germ: rich in oils, proteins, vitamins.3. Bran - consists of outer layers of old fruit wall, seed coat and aleurone layer. Aleurone layer secretes enzymes that digest the stored starch in the endosperm; aleurone is rich in protein and vitaminsWhole-grain foods are more nutritious: germ and bran are still thereOrigin, features of:Wheat (Triticum)Most widely cultivated grainAdapted to cool dry climateOrigin: wild wheat species found in the Near East crossed, forming polyploid species used todayWheat TypesDurum wheat (Triticum durum) is used to make pasta like spaghetti, macaroni and noodlesBread wheat (Triticum aestivum) – has high gluten contentGluten is the protein that gives bread elasticity.Together with a leavening agent (like yeast or baking soda + sugar) is added to

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UMD BSCI 124 - Exam III Study Guide

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