Water Some Review, Some New Food Science Ms. McGrath

Water – A Summary

Water – A Summary

Water – A Summary

Water – A Summary

Water – A Summary

Water – A Summary

What Does Water Do? Carries nutrients and wastes Helps for the structure of many large molecules Participates in metabolism Solvent for minerals, vitamins, amino acids, glucose, and other small molecules Lubricates joints Shock absorber inside eyes, spinal cord, and amniotic sac Regulates body temperature (sweating to cool the body) Maintains blood volume (plasma)

The Water Molecule H2O – held together by covalent bonds The two hydrogen atoms share electrons with one oxygen atom, creating chemical stability for all There is an uneven sharing of the electrons (oxygen atoms pulls the electrons towards itself) causing water molecules to be slightly polar (having a slightly positive end and a slightly negative end)

The Water Molecule

Water – A Solvent Water is a good solvent because it is a polar molecule. It will dissolve polar solutes easily. Remember that “like dissolves like” and water makes an excellent solvent for the chemical reactions to occur in your body.

Water Balance Balance between water intake and excretion ~ 60% adult body weight Can only survive a few days without water Can survive much longer without food

Water - Dehydration Reduces body water Excess losses Inadequate intake Symptoms rapidly progress Thirst Weakness Exhaustion & delirium Death from heart attack (electrolyte imbalance)

Water - Intoxication Rare condition seen with Excess intake Kidney disorders Humans don’t store water well, over intake may cause excess water on the lungs and brain. Symptoms include: headache, muscular weakness, confusion, loss of appetite, convulsions, death

Water - Sources Nearly all foods contain water Fruits and Vegetables – up to 95% water Meats and Cheese – up to 50% water Free form of water Removed easily from food – ex. Orange juice

For your notes What is metabolism? What is anabolism? What is catabolism? What does DRI stand for? What does DRI mean? What is osmosis?