Do Now Q1. Mammals need food for energy. Give two other reasons why food is needed. Q2. Explain why having a bowl of cereal in the morning is better than having a can of energy drink. Q3. Explain why eating lots of vegetables is very important to prevent constipation.
Why Nutrients are needed • Mammals are made up of many cells and those cells need nutrients for: • Energy– for all the chemical reactions which take place in the cells • Growth– make more cells • Repair– replace damaged cells
On your exercise book: • Write down seven foods containing high amounts of carbohydrates • Write down five foods containing high amounts of lipids • Write down five foods containing high amounts of proteins
The three classes of foodthat mammals consume to obtain nutrients are: • Carbohydrates • Lipids • Proteins
Carbohydrates • Carbohydrates are starch and cellulose. • Starch is a very very long molecule, made of many tiny units called glucose molecules. Glucose is commonly known as sugar. • Cellulose is also a very long molecule made of glucose molecules but it cannot be digested!
Arrange these foods in order of increasing amount of energy. • A banana • A slice of pepperoni pizza • A large cookie (Cookie Time) • A cup of milk • A slice of bread • A BigMac burger from McDonalds • A scoop of chips from Fish n’ Chips
Circle five foods on the list that have the highest amount of energy. Circle (in a different colour) five foods on the list that have the lowest amount of energy.
Lipids Lipids are fats and oils, made up of glycerol and fatty acids. Lipids have three times more energy than carbohydrates, but are much harder to break down.
Proteins Protein molecules are made up of many amino acids. Proteins contain little amount of energy but they are needed for growth and repairing of the body, as they are the building blocks of cells.
The body also needs… • Vitamins & Minerals • Water
Name: Beriberi Symtoms Stomach troubles Muscle paralysis Death Cause Lack of Vitamin D
Name: Scurvy Symtoms The gums and nose bleed Internal bleeding may also occur Cause Lack of Vitamin C
Name: Rickets Symtoms Bones become very soft and bent Cause Lack of Vitamin D Lack of Calcium