Grade 11 biology NUTRITION Why Nutrients Nutrients are
Grade 11 biology NUTRITION
Why Nutrients? �Nutrients are atoms and molecules needed by the body (has a useful function when taken up by the body) found in the foods that we eat �We require nutrients to get energy, support physiological functions and to provide raw materials for growth and reproduce �Nutrients are to a living organism like fuel, oil, and coolant are to an automobile engine - it will not function without them. Can you name some nutrients that we intake?
Types of Nutrients Carbohydrate Lipid Vitamins Minerals Protein
What are Nutrients �Nutrients contain: a) energy (glucose, some amino acids, fatty acids) a) structural materials (amino acids, minerals, lipids) a) functional materials (vitamins, minerals, water)
Three Categories �Macronutrients ~ needed in large amounts Carbohydrates Fats/lipids Proteins �Micronutrients ~ small amounts Vitamins and minerals �Special Nutrient Water- involved in most chemical reactions in the body
Necessary vs. Essential �Necessary Can be made by the body if lacking in diet Ex. The body can convert some amino acids that make up protein into other amino acids or carbohydrates �Essential Cannot be supplied by the body Must be made from nutrients supplied by an external source Ex. Vitamin C must be obtained from fruits and vegetables About 40 essential nutrients
MACRONUTRIENTS Role: a) Structural -provide substances needed by body to manufacture new cells for growth and replace old/damaged cells or tissue b) Energy -needed by body to carry out cellular processes (cellular respiration (ATP)) -physical and mental activity
1) Carbohydrates • Organic compounds made of Carbon, Hydrogen and Oxygen • Cn. H 2 n. On Example C 6 H 12 O 6 Glucose
Carbohydrate
Simple Carbohydrates: Monosaccharides and disaccharides �MONO: • simplest mono = 1 saccharide = sweet • glucose, fructose, galactose, ribose • quick source of energy because they do not have to be digested (can be used directly)
Simple Carbohydrates: Monosaccharides and disaccharides �Disacc: di = 2 “double sugars” � � � -glucose + fructose = sucrose -glucose + galactose = lactose (“milk sugar”) -glucose + glucose = maltose (“malt sugar” from germinating grain) �(the suffix -ose denotes simple carbohydrates)
Complex Carbohydrates: Polysaccharides �poly = 3 or more monosaccharides linked together examples: starch (plants), cellulose (plants), glycogen (animals), chitin
Starch: �-chemical bonds weak �-easily broken down by animals �-1000 glucose units (storage in plants)
Glycogen: �Storage form of glucose �short term storage in animals storage if excess amounts of carbohydrate are ingested �stored in liver and muscle or converted to fat �Part of regulating glucose levels in the blood
Cellulose: �-found in cell walls of plants �-works as roughage in your diet (indigestible bulk) (ex. celery) �-cows (cud chewing animals) can break down cellulose
Chitin �Polysaccharide of glucose �Found in the cell walls of fungi, the exoskeletons of arthropods such as crustaceans (e. g. , crabs, lobsters and shrimps) and insects
2) Lipids
2) Lipids and Fats Not soluble in water structural backbone is glycerol (three-carbon chain) second energy source after carbs energy used in endurance used to maintain body temperature protects organs some fat is a healthy component of our daily diet There are 4 main categories
I) Fatty Acids: �long chain of C atoms linked together, end with – COOH (carboxyl) �not soluble in water �Saturated animal fats and butter high levels of saturated fatty acids (solid at room temp. ) �monounsaturated (one point of unsaturation) Canola oil and Cashews are both about 58% monounsaturated fat. �polyunsaturated – linoleic acid (essential for humans) found in plant oils can be stored in fatty tissues liquid at room temp
II) Glycerides: glycerol + fatty acid �monoglycerides – one fatty acid molecule attached to a glycerol molecule �diglycerides – two fatty acid molecules attached to a glycerol molecule �triglycerides – three fatty acid molecules attached to a glycerol molecule Produced when fat is digested Vegetable oils and animal fats contain mostly triglycerides
III) Phospholipids: diglyceride +phosphate �part of all cell membranes �two fatty acids (hydrophobic) 1. 2. + phosphate containing group (hydrophilic) Phosphate head 2. Glycerol backbone 3. Fatty acid tails 1. 3.
IV) Sterols: �Occur naturally in plants, animals and fungi �ex. cholesterol structurally important part of bile – digests fat �-ring structures
3)Proteins �Un-branched polymers of amino acids �Amino acids are joined together to form proteins Protein made up of many a. a
3) Proteins �Are fundamental to life and are made up of amino acids (most abundant organic compound in body) �Roles: �-structural (muscles, skin, hair, nails) �-enzymes �-hormones �-receptors �-membrane channels
Amino Acids �digestive process breaks up protein into amino acids (a. a). �a. a. are temporarily stored in blood �a. a. are linked to form proteins for a particular function �all a. a. ’s must be present for proteins to be built �unusable a. a. ’s excreted in urine
Amino Acids � -of the 20 a. a. 8 must be obtained in the diet essential � -essential are: methionine tryptophan leucine valine threonine isoleucine lysine phenylalanine � -complete protein – food that contains all essential a. a. (ex. meat, fish, eggs, dairy) � -incomplete protein – lacks one or more of essential a. a. (ex. plant foods – flour, rice cereals, beans, peas, nuts) � -making complete from incomplete: � rice protein + soybean protein soybean + rice protein (lysine missing) (methionine missing) (complete protein)
MICRONUTRIENTS �Characteristics – required in small amounts - cannot be used as an energy source - each have a unique role in the body’s metabolism �Can be classified into two categories: - Vitamins and Minerals
Vitamins �Organic �C, H, O, N, and small amounts of other elements �most are coenzymes (join to enzymes to ensure that certain biological reactions take place properly
Two Major groups of Vitamins �Fat Soluble: A, D, E, K found in fats and oils you eat stored in liver and fatty tissue cannot be excreted (over time break down as they are used up by the body) not needed on a daily basis can be toxic in large quantities (vitamin supplements may be dangerous)
Rickets �Caused by a lack of vitamin D or calcium � Bones become so weak that they bend when they have to support the body’s weight.
�Water Soluble: B, C B complex of 8 � (B 1, B 2, B 6, B 12, B 13, B 15, B 17, Biotin) � act as coenzymes not stored in body for long excess excreted in urine daily intake recommended too large of a dose may put a strain on kidneys
Scurvy � Lack of vitamin C � Gums bleed easily around teeth � Capillaries under skin break spontaneously (causing pinpoint hemorrhages)
Minerals �Inorganic chemical elements �Roles: -forms structural part of bone -structural parts of hormones & enzymes -controls water balance of cells -control acid-base (p. H) of blood -involved in the transmission of nerve impulses
Major and Trace Minerals �Major – required in large amounts: Calcium, Phosphorus, Chlorine, Potassium, Magnesium, Sodium, Sulfur (ex. Calcium + phosphorus = tooth and bone formation) Sodium used for muscle contraction �Trace – required in small amounts: Cobalt, Iodine, Selenium, Copper, Iron, Silicon, Chromium, Molybednum, Tin, Manganese, Nickel, Fluorine, Zinc, Vanadium (ex. Iron = found in hemoglobin)
Goiter �Iodine is an integral part of two hormones released by the thyroid gland (regulate body temp. , metabolic rate, growth, etc. ) �With iodine deficiency, thyroid hormone declines �If deficiency persists, cells of the thyroid gland enlarge so as to trap as much iodine as possible �Sometimes the gland enlarges until it makes a visible lump in the neck
WATER � A special nutrient (does not directly supply energy) � A body’s need for water is second in importance only to its need for oxygen � Adult body weight is approx 55 -60% water � Water is needed for chemical reactions in the body, part of a cells cytoplasm, to digest food, eliminate waste, keep skin and organs hydrated, and as a medium for all body fluids including blood, lymph, digestive juices, urine and perspiration
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