Biology, 6: Animal nutrition

• A balanced diet is a diet including all nutrients needed by our cells and tissues.
• Mechanical digestion is the breakdown of food into smaller pieces without chemical change to food molecules
• Chemical digestion is the breakdown of large, insoluble molecules into small, soluble molecules, making it easier to be absorbd.
• What are the essential nutrients?

  Protein, carbohydrates, fats, vitamins & minerals, water, and fibre.
• Proteins are broken down to make amino acids

  It is needed to form other proteins needed by cells, e.g. enzymes.
• What is the function and sources of protein?

  Function: Growth and repair

  Source: Eggs, milk, meat, nuts
• Carbohydrates are broken down to simple sugars which is used in respiration

  It releases energy in our cells, allowing for life processes to take place.
• What is the function and sources of carbohydrates?

  Function: Source of energy

  Sources: Rice, potato, pasta, bread
• Fats are deposited in many parts of the body

  It helps maintain body temperature

  It is a store of energy to supply molecules for respiration
• What is the function and sources of fats?

  Function: Insulation, energy storage

  Sources: Meats, nuts, oily fish
• Vitamins and minerals are needed in small amounts for correct body functionings
• What is the function and sources of vitamins & minerals?

  Function: Needed in small amounts of maintain health

  Sources: Fruits, vegetables
• Water is needed for chemical reactions to take place, ist is continuously lost through excretion and sweating.
• Fibre provides bulk to food for intestine to push food through easier.
• What is the function and sources of fibre?

  Function: Helps with peristalsis, prevents constipation

  Sources: Leafy greens, brown rice
• What is the function and source of vitamin C

  Function: Healthy skin, teeth & gum, keeps lining of blood vessels healthy

  Sources: Citrus, green veggies, potatoes
• What is a deficiency of vitamin C?

  Scurvy- bleeding gums
• What is the function and sources of vitamin D?


  Function: Strong bones and teeth

  Sources: Fish, egg, liver, cheese
• What is the deficiency of vitamin D?

  Rickets- softening of the bone
• What is the function and sources of calcium?

  Function: Strong teeth and bones, clotting of blood

  Sources: Milk, eggs
• What is the deficiency of calcium?

  Rickets- softening of bones
• What is the function and sources of iron?

  Function: Makes haemoglobin in RBC

  Source: Red meat, liver, kidneys
• What is the deficiency of iron?

  Anemia- becomes tired and short of breath easily
• Kwashiorkor is a diet with little protein
• Kwashiorkor’s is common in children who are breast-fed, then weaned after another baby’s birth
• Kwashiorkor leads to:

  • Swelling of the feet and abdomen
  • Wasting muscle
  • Thinning hair
  • Loss of teeth
  • Damaged liver
• Marasmus is a diet low in carbohydrates, fats, and protein
• Marasmus leads to:

  • Being short for age group
  • Wasted appearance due to low body fat and muscle
  • Fatal with dehydration
  • Can lead to heart problems and infections
• How do diets vary on age?

  Children have higher proportion of protein in diet for growth

  Amount of energy needed increases from birth to adulthood, then decreases
• How do diets vary on activity levels

  More active == more energy needed for movement

  Because muscles are contracting more and respiring faster
• How do diets vary on pregnancy

  Energy need increases to support foetus growth

  Extra calcium and iron is needed
• How do diets vary on breastfeeding

  Energy need increase because needs to produce breast milk

  Esp calcium
• Malnutrition is diet that is too high in energy content
• Malnutrition can lead to obesity
• If substance needed is too low, malnutrition can lead to deficiency

  Too little fiber can lead to food moving slowly through the alimentary canal, increasing risk of bowel cancer
• Starvation is too little energy provided by diet
• In starvation, body breaks down its energy store to produce substance needed for respiration

  This can damage heart muscles and the immune system
• Ingestion is the taking in of food and drink into the body
• Digestion is the breaking down of large food molecules into smaller water-soluble molecules via mechanical and chemical processes
• Absorption is the movement of digested food through wall of intestine into blood