UNIT 1: Nutrition Flashcards
Common elements in food
Carbon (C) Hydrogen (H) Oxygen (O) Nitrogen (N) Phosphorus (P) Sulphur (S)
Elements in foods as dissolved salts
Sodium (Na) Magnesium (Mg) Calcium (Ca) Potassium (K) Chlorine (Cl)
Trace elements
Iron (Fe)
Copper (Cu)
Zinc (Zn)
Biomolecules
Chemicals found in and produced by living organisms Carbohydrates Lipids Proteins Vitamins
Carbohydrates
C,H,O: Cx(H20)y Monosaccharides Disaccharides Polysaccharide (CH20)n
Monosaccharides
Glucose [C6H12O6] - a reducing sugar and formed by the breakdown of glycogen.
Fructose [C6H12O6] - a reducing sugar and found in many fruits.
Galactose [C6H12O6] - a reducing sugar and formed by the breakdown of lactose.
Disaccharides
Maltose (a reducing sugar) - found in germinating seeds e.g. barley.
- glucose + glucose = maltose [C12H22O11] +H2O.
Sucrose (NOT a reducing sugar) - table sugar.
- glucose + fructose = sucrose [C12H22O11] +H2O.
Lactose (a reducing sugar) -found in milk.
- glucose + galactose = lactose [C12H22O11] +H2O
Polysaccharides
Starch (amylose) - plants store glucose as starch e.g. potatoes, bananas.
-Long chains and some branching of glucose molecules making it easy to digest.
Cellulose (fibre / roughage) - found in cell walls and stems of plants e.g. celery.
- composed of many glucose molecules bonded together in long chains making it difficult to digest.
Glycogen - animals store glucose as glycogen in liver and muscles.
- more branched than starch
Structural & metabolic role of carbohydrates
Structural: (cellulose) component of cell walls, keeps plants upright
Metabolic role: (energy) mono-, di-, and polysaccharides are metabolized to release energy
Lipids
C,H and O but have fewer O atoms than carbohydrates.
- triglycerides & phospholipids
- food sources: butter, oils, margarine, cream, olives, animal fat
Triglycerides
one molecule of glycerol linked to three fatty acid molecules
- fats: solid at room temperature
- oils: liquid at room temperature
Phospholipids
one fatty acid replaced by a phosphate
Structural & metabolic roles of lipids
Structural role: - Phospholipids: component of cell membranes of all living things.
- Triglycerides: form adipose tissue that surrounds important internal organs and acts as a shock absorber
Metabolic role: - energy: triglycerides are stored by organisms as a source of energy.
Proteins
C,H,O and N
Sulfur and phosphorus also present in some proteins
2 main categories:
1. fibrous proteins: little or no folding e.g. protein found in hair, skin, nails.
2. globular proteins - lots of folding e.g. protein hormones, enzymes, antibodies.
Structural & metabolic role of proteins
Structural role:
- skin, hair, nails contain keratin.
- muscle composed of actin and myosin.
- bone, ligaments and tendons contain collagen.
Metabolic role:
- enzymes, antibodies, and some hormones are proteins
Vitamins
- complex organic substances needed only in small amounts.
- share no common chemical characteristics - all chemically unique.
A,D,E &K = fat soluble
B&C = water soluble
Structural & metabolic role of vitamins
structural role:
- vitamins do not have any structural role in living organisms
metabolic role:
- homeostasis and normal metabolism
Vitamin B9
deficiency:
- spina bifida in children
- anaemia in adults
Metabolic role:
- formation of red blood cells
Sources;
- spinach, egg yolk, sunflower seeds
Vitamin D (calciferol)
Deficiency: - rickets in children -osteomalacia in adults metabolic role: -absorption of calcium in the digestive system sources: - sunlight, eggs, milk
Water
- makes up 70-95% of cell mass.
- it is an excellent solvent in which all biochemical reactions occur.
- it participates in chemical reactions e.g. photosynthesis, respiration, digestion, hydrolysis & condensation reactions .
- carries substances around the body of animals and plants.
- carries substances into and out of cells.
- good absorber of heat energy
Anabolism
the building up of large biomolecules from smaller biomolecules using energy e.g. photosynthesis, proteinsynthesis.
Catabolism
the breaking down of large biomolecules into smaller biomolecules with the release of energy e.g. respiration, digestion
Food
Provides the nutrients needed for organisms to get their energy and the materials they require to live
