Nutrition
The way in which an organism obtains and uses food
Function of food
Source of energy, to make chemicals needed for metabolic reactions, growth and repair
Metabolism
The sum of all the chemical reactions in an organism
Continuity of life
Next generation of the same living thing
6 common elements
Carbon (C), hydrogen (H), oxygen (O), nitrogen (N), phosphorus (P), sulphur (S)
5 elements present in dissolved salts
Sodium (Na) magnesium (Mg) chlorine (Cl) potassium (K) calcium (Ca)
3 trace elements
Iron (Fe) copper (Cu) zinc (Zn)
Biomolecules/biochemicals
Are chemicals that are made inside a living thing
Carbohydrates
Carbon hydrogen oxygen Cx(H2H12O)y Twice as much hydrogen C6H12O6
Monosaccharides
Single sugar unit Sweet to taste Soluble in water
GLUCOSE
Organisms get energy from this Found in fruit sweets chocolate Made in photosynthesis
Fructose
Found in fruits
Disaccharides
Sweet to taste Soluble in water Two monosaccharides joined together
Sucrose (table sugar)
Glycose+fructose
Maltose
Glucose + glucose
Lactose (milk)
Glucose +galactose
Polysaccharides
Insoluble in water Not sweet to taste Many monosaccharides joined together
Starch
Stored in plants Long chain of glucose Easily digested (glucose molecules joined together in a straight line) Rice potatoes flour
Cellulose
Not easily digested due to cross bonding Used as a fibre in diet Very strong cell walls
Glycogen
Stored by animals in the liver and muscles
Structural role carbs
Used to form plant cell walls
Metabolic role carbs
Energy store in all plants (starch) Broken down in respiration to release energy (glucose) Energy is used to carry out other metabolic reactions
Lipids
Carbon hydrogen oxygen Very little oxygen Fats solid at room temperature Lipids liquid at room temperature
Triglyceride
One molecule of glycerol Three fatty acids
Phospholipids
Fat like substance where one of the fatty acids is replaced by a phosphate
Sources of lipids
Butter cod liver oil cream fat on meat olives
Structural role lipids
Stores energy twice as much energy than carbohydrate Heat insulation Protection of organs Cell membranes
Metabolic role lipids
Broken Down in respiration to release energy Energy is used to carry out other metabolic reactions
Proteins
Carbon hydrogen nitrogen sulphur phosphorus
Structure of protein
20 amino acids Peptide : Bond between acids Less than 20 amino acids Polypeptide: less than 200 amino acids Protein: more than 200 amino acids
Fibrous proteins
Little or no folding Form long fibres Strong and tough Keratin in nails myosin in muscles
Globular proteins
Lots of folding Form rounded shapes Enzymes anti bodies hormones
Sources of protein
Meat fish eggs nuts peas
Structural role protein
Fibrous proteins eg keratin in nails
Metabolic role protein
Used as enzymes to control metabolic reactions Anti bodies are used to fight infections Hormones are used to regulate body reactions
Vitamins
Carbon based Needed only in tiny amounts Body cannot make
Water soluble vitamin
Vitamin C Ascorbic acid Soluble in water
Sources of vit C
Veg fresh fruit eg oranges
Metabolic role of vit C
Formation of connecting tissue eg skin gums Growth and maintenance of bones and teeth Immune system Help wounds heal
Deficiency of vit C
Scurvy Bleeding gums Loose teeth Poor healing of skin
Fat soluble vitamin
Vit D Most common = vit D2 (calciferol)
Sources of vit D
Liver milk egg yolk fish oil sunlight
Metabolic role of vit D
Helps absorb calcium Needed for healthy teeth and bone formation
Deficiency of vit D
Rickets in children Osteomalacia in adults Weak deformed bones Break easily
Water
Makes up most of cytoplasm in cells Found in tissue flood which surround all body cells Plasma, liquid part of blood Good solvent Allows chemical reactions to take place Can move in and out through cell membranes Good absorber or heat
Anabolic reactions
Energy is taken in and smaller molecules are converted to larger molecules eg photosynthesis
Catabolic reactions
Energy is released when larger molecules are broken down into smaller molecules eg respiration