Nutrition in humans

• What does a balanced diet include?

  CarbohydratesProteinsLipidsVitaminsMinerals WaterFibre
• The sources and functions of carbohydrates?

  Pasta, rice, and sugar They provide energy
• The sources and functions of lipids?

  Butter and oily fishThey provide energy, act as an energy store and provide insulation
• What are the sources and functions of proteins?

  Meat and fish Needed for growth and repair of tissue, and to provide energy in emergencies
• What is a source and function of vitamin A?

  Liver and carrots Helps to improve vision and keep your skin and hair healthy
• What is a source and unction of vitamin C?

  Fruits like oranges and strawberries Needed to prevent scurvy
• What is a source and function of vitamin D?

  Eggs Needed for calcium absorption
• What is a source and function of calcium?

  Milk and cheese Needed to make bones and teeth
• What is a source and function of iron?

  Red meat Needed to make haemoglobin for healthy blood
• What is a source and function of water?


  Found in foods and drinks Just about every bodily function relies on water
• What is a source and function of dietary fibre?

  Whole meal bread and fruit Aids the movement of food through the gut
• How do energy requirements vary with activity levels?

  Active people need more energy than people who sit all day
• How do energy requirements vary with age?

  Children and teenagers need more energy than older people because they need energy to grow and they're generally more active
• How do energy requirements vary with pregnancy?

  Pregnant women need more energy than other women because they've got to provide the energy their babies need to develop
• Describe the function of the mouth?


  Salivary glands in the mouth produce amylase enzyme in the saliva Teeth break down the food
• Describe the function of the oesophagus?


  The muscular tube that connects the mouth and stomach
• Describe the function of the liver?


  Where the bile is produced
• Describe the function of the gall bladder?


  Where bile is stored
• Describe the function of the large intestine?


  Where excess water is absorbed from the food
• Describe the function of the rectum?


  Where the faeces are stored
• Describe the function of the stomach?


  It pummels the food with its muscular wallIt produces the protease enzyme, pepsinIt produces hydrochloric acid to kill bacteria and to give the optimum PH for the protease enzyme to work
• Describe the function of the pancreas?


  Produces protease, amylase, and lipase and release them into the small intestine
• Describe the function of the small intestine?

  Produces protease, amylase and lipase to complete digestion This is where the nutrients are absorbed out of the alimentary canal into the body
• How is food moved through the gut by peristalsis?

  There's muscular tissue all the way down the alimentary canal It squeezes balls of food through your gutThe squeezing action which is waves of circular muscular contractions is called peristalsis
• What's the digestion of starch to maltose?

  Amylase converts starch into maltose
• What's the digestion of maltose to glucose


  Maltase converts maltose into glucose
• What's the digestion of protein into amino acids?

  Protease converts proteins into amino acids
• What's the digestion of lipids into glycerol and fatty acids?

  Lipase converts lipids into glycerol and fatty acids
• Where is bile produced and stored?

  Produced in the liver and stored in the gallbladder
• What does bile do?

  It neutralises stomach acid and emulsifies lipids
• How is the small intestine adapted for absorption including the structure of villus?

  The small intestine is very long so there's time to break down and absorb all the food before it reaches the end It has a big surface area because it's covered in millions of villiVilli has a single permeable layer of surface cells, good blood supply to assist quick absorption
• Practical: Describe an experiment to investigate the energy content in a food sample


  You need a food that'll burn easily Weigh a small amount of the food and skewer it on a mounted needle Add a set volume of water to a boiling tube to measure the amount of energy that's released when food is burnt Measure the temperature of the water then set fire to the food using a Bunsen burner flame Hold the burning food under the boiling tube until it goes out, then relight the food and hold it under the tube and keep doing this until the food wont catch fire againMeasure the temperature of the water Energy in food= mass of water x temperature change in water x 4.2