Food - Leaving Cert Flashcards
Biomolecule
Organic chemical produced and found only within living organisms
Metabolism
The sum of all chemical reactions in an organism
Types of metabolism
Anabolic
Catabolic
Anabolic
Energy is required to convert smaller molecules into larger molecules
eg photosynthesis, protein synthesis
Catabolic
Energy released to convert larger molecules into smaller molecules
eh respiration, digestion
Why do we need food
Energy source for respiration
Growth and repair of cells
Chemical elements found in food
C, H , O , N , P , S Salts of: Na, Mg, Cl, K, Ca Traces of: Fe, Cu, Zn
Biomolecule types
Carbs
Lipids
Proteins
Vitamins
Carbohydrates general formula and ratio
Cx(H2O)y
X=Y Y=6
Ratio: 2:1 (2hydrogen 1oxygen)
Carbohydrates structural role
Cellulose(poly) found in plant cell walls
Chitin(poly) found in fungal cell walls
Carbohydrates metabolic role
Glucose(mono) broken down to release energy in respiration
Glucose stored as glycogen in animal muscle after respiration
Starch (poly) stores glucose after photosynthesis
Monosaccharide
1 single sugar unit
eg glucose, fructose
Source- fruit
Disaccharide
Two sugar molecules joined
eg sucrose, lactose, maltose
Source- table sugar, milk
Polysaccharide
Many sugar molecules joined
eg starch, cellulose
Source- bread, pasta, cereal
Lipids types
Triglycerides (3 fatty acids one glycerol)
Phospholipids (one fatty acid replaced by a phosphate group) (major component of cell membranes)
Lipids general structural components
Fatty acids and glycerol
Examples of lipids
Fats- solid at room temp
Oils- liquid at room temp
Steroids (cholesterol and some sex hormones)
Structural role of lipids
In cells: phospholipids are major component of cell membranes
In an organism: energy store, protection of organs, heat insulation
Metabolic role of lipids
Release energy in respiration
Protein shapes
Fibrous - no folding eg keratin in hair and nails
Globular - lots of folding eg albumin in egg white, enzymes
Structural role of proteins
Keratin in skin and hair
Myosin in muscles
Metabolic role of proteins
All enzymes are proteins -> biological catalysts that control photosynthesis and respiration
Hormones regulate body functions eg insulin regulates blood sugar levels
Vitamins
Needed in small amounts
Cannot be made by the body
Vitamin C
Water soluble Chemical name: ascorbic acid source: citrus fruits,green veg deficiency: scurvy symptoms: soft bleeding gums
Vitamin C functions
Build connective tissue
Maintain bones and teeth
Good immune system function
Vitamin D
Fat soluble
Chemical name: calciferol
Source: dairy, fish liver oils, egg yolk
Deficiency: tickets in children, osteomalacia in adults
Symptoms: bones lose calcium and break easily
Vitamin D Functions
Needed to absorb calcium from food
To form bone
Minerals
Inorganic
Needed in small amounts
Plants absorb minerals through their roots
Animals get minerals through food
Plant minerals
Calcium - to form middle lamella (cell wall) between cells
Magnesium - to form part of chlorophyll
Animal minerals
Calcium- forms bones and teeth
Iron- forms part of haemoglobin
Water
Cells and body fluid are made of 70% water in animals and 90% in plants
Uses of water
Universal solvent that transports substances in blood or in plants, allows substances to move through membranes
Where all metabolic reactions take place, component of cytoplasm, controls shape of cell by osmosis
Is a reactant/product in chemical reactions, source of oxygen produced in photosynthesis
