BSCI124 Exam 3 Guide Lecture 15: Agriculture, Human Nutrition Agriculture Origins of Agriculture: 1. “Fertile Crescent” of Mesopotamia- 14,000 years ago; wheat, barely & lentil 2. Southeast Asia (Thailand)- 8,000 years ago; rice, millet, broomcorn millet, rapeseed, and hemp 3. New World (Mexico)- 10-12,000 years ago; corn, potato, squash Agriculture in the US: ! 1.9 billion acres in US (16% crop land, 34% pasture/grazing) ! 4 major crops: Corn, wheat, soybeans and hay Increase in Agriculture without an increase in land: 1. Improved crops varieties –higher yield 2. Improved agricultural practices 3. Improved pest control – resistant cultivars 4. Tailored fertilization of crops Nutrition Carbohydrates: A. Monosaccharide: basic building block of all carbohydrates; glucose is most important (used in respiration) B. Disaccharide: 2 monos joined together; sucrose (sugar) is most abundant C. Polysaccharide: long chains of glucose; starch (in potato); broken down into glucose by saliva Proteins: ! made up of amino acids (20 different types) ! body produces 11 AA; the 9 it cannot make on its own are the essential amino acids ! Complete proteins – contain all the essential amino acids; complete from animals, incomplete from plants Fats (lipids): ! have glycerol head and fatty acid tail, insoluble in water ! saturated fats- carbon atom joined by a single bond; solid at room temperature (beef fat, butter) ! unsaturated fats- carbon atom joined by a double bond; liquid at room temperature (oil) ! saturated leads to obesity & heart disease; unsaturated lowers cholesterol levels (omega 3) ! cholesterol are important for making cell membranes; animal products contain high cholesterol o LDL is bad, blocks arteries  HDL is good, helps lower LDL Vitamins Vitamin A: (fat soluble) • Formation of vision pigments; maintain smooth, healthy skin; bone and tooth development • Sources: animal (liver) & plant (yellow & orange veg/fruits) • Lack of Vitamin A causes night blindness, dry/scaly skin, infections, lack of bone growth Vitamin B: (water soluble) • There are 8 vitamins; help breakdown food • Deficiency of Vitamin B complex causes: fatigue, weakness, depression, dermatitis, anemia • Good sources of Vitamin B are meat, fish, chicken, whole grains, seeds, nuts, legumes Vitamin C: (water soluble) • important role in the synthesis of collagen (bones, teeth, cartilage) • Lack of Vitamin C causes scurvy: bleeding gums, hemorrhages in skin, fatigue, brittle bones and maybe death • Good sources are citrus fruit (lemon, orange, grapefruit) and other fresh fruits and vegetables Vitamin D: (fat soluble) • regulate calcium and phosphorous levels in normal bone development • can be synthesized on exposure to sunlight • Deficiency can cause bone malformation called rickets Minerals Calcium: • Found in bones & teeth; most abundant mineral in the body; comes from dairy products, spinach & nuts/seeds • Calcium deficiency causes osteoporosis (a degenerative bone disease) Iron: • Functions as a component of hemoglobin, the molecule that carries oxygen in red blood cells • Good plant sources: dark green leafy vegetables, dried fruits, legumes (bean), whole grains, breads and cereals • Good animal sources: liver, shellfish, fish, and poultry Iodine: • required for the formation of the thyroid hormones that regulate cell metabolism • deficiency causes goiter: swelling of the thyroid gland • Iodized salt is the best source of iodine Calories: • amount of energy required to raise 1 gram of water 1 degree C • Food energy measured in kilocaloriesLecture 16: Grasses, Legumes, Starchy Staples Grasses: General Features: • Leaves are linear, form a sheath and have parallel venation • Stems vary: Upright stem is called culm, usually surrounded by sheaths • Blades are secondary stems growing from the base of the main stem • Root system is fibrous: many small roots grow from the crown Features of Grain (wheat): • Endosperm (3n) large cells filled with starch grains; supplies food to germinating seedling • embryo is the young plant (2n) (aka the germ), is rich in oils, proteins & vitamins • bran consists of outer layers of old fruit wall, seed coat and aleurone layer. • Origin: wild wheat species found in Near East formed polypoid species used today Features of Corn: • Origin: Central Mexico • Has a tassle at the end of the stem; has an ear on a lateral branch • The silks coming from the ears are the stigmas of each female Features of Rice: • Origin: southeast Asia • Rice has air chambers on roots and stems to allow aeration of submerged parts • Rice is planted on rice paddies (flooded fields); drained for harvesting when rice is mature Other Important Grains: • Oats- highly nutritious, high protein, many vitamins/minerals, soluble fiber helps lower bad cholesterol • Barley- used mostly for brewing beer and animal feed Legumes: General Features: • Legumes are members of the bean family; examples: peas, beans, peanuts, lentils • Mostly herbaceous; seeds are large Uses: • Legumes are nitrogen fixers- they take nitrogen from the air and turn it into proteins which are consumed by animals Beans: native to Mexico, rich in protein, hundreds of species Peas: originated in Near East; rich in protein Soybean: native to China; used in cooking oil, salad dressings, and mayo Starchy Staples: • General Features: Starch is the most widespread storage form of energy in plants, broken down by saliva • Potato: originated in South America, grows well in high elevations • Sweet Potato: native to Caribbean; requires a tropical climate, not a yam • Plantain: from SE Asia; hybrid cultivator of banana family • Cassava: from Brazil; processed to remove cyanide; used in tapioca • Yam: used as food & source of steroids to make cortisone and medicine • Taro: from SE Asia Lecture 17: Fibers, Herbs & Spices Fibers: 3 definitions • Botanical- long tapering cell; thick wall made of cellulose; found in vascular tissue • Commercial- long & flexible; may be hair/wool or nylon • Nutritional- fiber is a polysaccharide that comes from cellulose; indigestible in food Types of Plant Fibers: • Cotton- from Peru; grows best in humid climates; cotton seeds have 20,000 hairs attached • Flax- from Switzerland; adapted to cold climates; woven to make linen • Hemp- from China;