Saturday, February 27, 2016Saturday, February 27, 2016Saturday, February 27, 2016Saturday, February 27, 2016

 Teenager food pyramid

  Macro: provide the body with energy  Ex. protein, lipids (fats), carbohydrates  Micro: provide the body with small amounts of chemicals needed in biochemical reactions ex. vitamins Sec Human Nutrition What is the difference between macronutrients & micronutrients?

  Kilocalories  1 kcal = amount of energy needed to raise 1 kg of H 2 O by 1 o C  Kilocalories are known as Calories to consumers.  1 kcal = 1 Calorie  So… The number of Calories in a food indicates how much energy the food provides. Which units do we use to measure energy from macronutrients?

 1.Carbohydrates : C,H,O in a 1:2:1 ratio a.Basic unit is the monosaccharide (single ring) b.Sugars: a.Simple carbs that are absorbed by the body quickly c.Starches: a.Complex carbs that provide the body with steadier, long lasting energy d.Carb Energy a.Most carbs provide the body with 4kcal per gram 3 major groups of macronutrients.

 Simple Sugars-quick energy

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  Complex Starches- longer lasting energy

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  Basic unit = amino acids  4kcal per gram Proteins

  20 different amino acids arrange in numerous ways to make proteins.  Protein structure and function depend on this arrangement. Amino Acids

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  The human body can make (20 )many of the amino acids.  The remaining amino acids (8) are obtained from food.  essential amino acids = amino acids that must be obtained from food. Where do we get our Amino Acids

  Basic unit is the Lipid  3 fatty acids attached to glycerol  9kcal per gram  -saturated fat-usually solids at room temp; Worse for your health ex. butter/lard -unsaturated fat-usually liquids at room temp ex. oils Fats

  Phospholipid Bilayer of Your Cells Lipid Functions

  Energy Storage Lipid Functions

  Vitamins & Minerals  Do not provide energy directly  Obtained from fruits, veggies, & breads  Play key roles in biochemical reactions responsible for:  releasing energy  structural formation Micronutrients

  Adult nutritional requirements  kcal per day  500 million people worldwide are nutritionally deficient (if they receive less than 90% of their energy needs)  13 million people die of starvation each year  Causes: stunted growth, low mental development Undernourishment -are not meeting their energy needs

 World Hunger

  Lack of a specific type of nutrient  Examples:  Kwashiorkor (lack protein)  Scurvy (lack Vit. C)  Beri beri (lack Vit. B1)  Rickets (Lack Vit. D)  Goiter (Lack iodine) Malnutrition

  Food supplies worldwide are increasing.  More food available per person  Why are so many people starving.  Food increases are in countries that already produced enough food  Long drought, lack of money, and civil war/political stability make it difficult for the neediest countries to improve food production. World Food Supply

 1.Green Revolution : 1960’s Developments of new strains of wheat & rice These crops had more response to fertilizers and irrigation Crops were resistant to disease, grew faster, survived in a variety of climates Modern farming methods and machinery increased efficiency Greater crop yields Increase gains, decreases price!! Food Production and Economics

  Intended to help underfed nations feed themselves  However, farmers in developing nations:  do not have an adequate water supply to maintain the new crops  Do not have money to buy fertilizers  Do not own modern machinery  Side effect of Green Revolution:  Huge crop yields in developed nations drive down prices, resulting in poorer farmers receiving lower profit for their crops. Green Revolution (cont)

  crops grown for purpose of selling  MAIN POINT  Poor farmers in developing nations can’t sell crops to other poor people in their own country  These farmers choose crops that can be exported Cash Crops

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  Oceans can provide approximately 100 million metric tons of food per year without damaging marine biomes.  Currently, over 90 million metric tons per year are harvested Food from the Water

  Aquaculture : commercially grown food in controlled water environment  Reduces the overfishing of oceans  Produces over 21 million metric tons of food  Fish, clams, oysters Aquaculture

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  Historically, Preparing soil, planting seeds, and maintaining crops were done by hand  Industrialized Agriculture (mid-20 th Century)  Equipment powered by fossil fuels replaced human- powered tools Modern Farming Techniques.

  Able to feed 5 people in 1850 per farmer; now able to feed 78 people after industrialized agriculture Industrialized agriculture’s positive impact on food production

  Requires a large amount of energy, pesticides, and fertilizers Industrial agriculture’s negative impact on environment?

  Pesticides kill most pests, but a small portion of the pest population is genetically resistant and will survive.  These resistant pests are able to reproduce, passing on the gene that is resistant to pesticides.  Result: more resistant individuals within the population. Pesticide Resistance

  Homozygous Dominant: TT  Heterozygous: Tt  Homozygous Recessive: tt Revisiting Mendelian Genetics

  Grow 1 or 2 crops that get highest prices  Problems:  No genetic diversity  Vulnerable to disease  soil becomes depleted of nutrients Ex. cereal crops-deplete soil of phosphorus -potatoes- take away phosphorus & calcium -fertilizers are used to combat the problem but pesticide resistance occurs & fertilizers can hurt the ground water -can also lead to erosion; so less yield of crops occur What is monoculture farming? Does this have a positive or negative impact on environment?

  Driven by economics and international trade  Negative Results  Soil erosion  Deforestation  Hunger  War  Desertification Modern Agriculture

 1.Crop Rotation : changing your crops on a regular cycle a.Prevents soil from becoming depleted of nutrients b.Prevents the need for nitrogen-based fertilizers 3 main components of Sustainable Agriculture

 ss Nitrogen Fixing Legumes

  Wind and Flowing Water are main agents of erosion  When topsoil is eroded, organic and mineral nutrients are lost.  This is bad news for farmers. 2. Erosion

  Cover Crops  Non food crops planted between growing seasons.  Drip irrigation  Delivers small quantities of water directly to roots of plants  No drain off  Reduce tillage  Process of turning the soil so that lower layers are brought to the surface.  Excessive tillage causes erosion. Reducing Erosion

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  IPM: integrated pest management  Alternative to pesticides  Use natural predators to control pest populations  Bats, lady bugs, wasps, viruses, bacteria 3. Pest Management

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