food

food

1. organisms need food for growth and repair

2. food is made up of 14 elements , carbon, hydrogen, oxygen, and the rest are often called minerals

3. carbohydrates

   • monosacharides discharides polysacharrides
   • source: bread, potatoes, rice, flour and sweets
   • made up of carbon, hydrogen and oxygen

4. structure:amino acids, peptides, poly peptides and protein

   • proteins contain the elements carbon, hydrogen ,oxygen and nitrogen
     • sometimes small amounts of sulfur and some may contain small bits of phosphorus
   • sources: meat,fish,eggs,milk
   • proteins
     • metabolic role: proteins are used as ensymyes to control reactions ,they also form antibodies to fight infection. some hormones are protein-based and are used to regulate body reactions
     • test: sodium hydroxide , then copper sulfate (biuret test)
   • help to form structures such as skin, hair, nails, and muscles

5. minerals

   • plants need calcium to hold the cell wall together, and magnesium for chlorophyll
   • animals need calcium for bones and teeth and iron for haemoglobin

6. lipid

   • the molecules of a lipid are made up of a glycerol molecule and 3 fatty acid molecules
     • fats solid at room tempeture
     • oils liquid at room tempeture
     • phospholipids- used to make up cell membrane & is critical for the function of cells

7. vitamins

   • vitamin c
     • water soluble , source:veg,fresh fruit. metabolic role: forms connective tissue ,bones +teeth. helps healing and immune system. deficiency: scurvy(poor skin,bleeding gums,bad teeth
   • vitamin d
     • fat-soluble source:liver,fish oils ,milk, made in skin. metabolic role: helps absorb calcium for teeth and bones. deficiency : rickets in children, osteomalacia in adults

8. food tests:

   • rub a piece of butter(fat) and a drop of water on brown paper. fat is present in butter, brown paper turns translusent
   • starch: brick-red to blue black. (iodine solution)
   • protein: blue-lilac (biuret solution)