TOPIC 2 - ORGANISATION

• Give an example of diffusion in the human body.

  An example of diffusion within the human body is the exchange of Oxygen and Carbon Dixoide in the lungs.
• What is a tissue?

  A tissue is a group of cells working together to carry out a job.
• What are the two important functions of the pancreas? [2]

  - Secreting hormones to control the blood glucose concentration - Controling some enzymes that digest food
• What is an organ system?

  An organ system is a group of organs that all work together to preform specific functions. Examples of Organ Systems could be: - Digestive System - Circulatory System - Endocrine System
• What is an organism?


  An organism is a collective of organ systems working together.
• What is the purpose of the digestive system?

  The purpose of the digestive system is to break down large insoluble molecules into small soluble molecules so your body can absorb and use these molecules.
• What are enzymes?

  Enzymes are biological catalysts which speed up the reaction without being used up.
• Where is the food mostly digested in the digestive system? [2]

  - Stomach - Small intestine
• What do enzymes do?

  Enzymes help break down large insoluble food molecules into smaller, soluble ones.
• Where do the small soluble food molecules get absorbed?

  The small soluble food molecules get abosrbed in the small intestine into your bloodsteam. One there, they get transported in the bloodstream around your body.
• How is the small intestine adapted to absorb a large quantity of small, soluble food molecules? [4]

  - Large surface area as it's covered in villi's and microvilli's. - Good blood supply - One cell thick walls giving it a short diffusion distance to the blood vessels As a result this greatly increases diffusion and active transport from the small intestine to the blood.
• What happens to the remaining undigested food in your small intestine?

  The remaining undigested food in your small intestine is squeezed out by the muscular walls of the small intestine into the large intestine. This is where water is absorbed from the undigested food into your blood. The material left forms faeces.
• How is the liver associated with the digestive system?

  The liver carries out many different functions within your body. However, the function that is most closely linked to the digestive system is the production of bile, which helps in digestion of lipids.
• What is bile?


  Bile is an alkaline. It neautralises the hydrochloric acid in the stomach and makes the conditions alkaline. The enzymes in the small intestine work best in these alkaline conditions. It also emulsifies fats. Because of this it gives a much bigger surface area of fat for the enzyme lipase to work on which as a result make its digestion faster.
• What chemical element do Carbohydrates contain?

  Carbon, Hydrogen, and Oxygen.
• What is the written element of Glucose?

  C6H12O6
• What are all carbohydrates made up of?

  All carbohydrates are made up of units of sugars.
• What will carbohydrates break down into when you eat them?

  They will break down into glucose, that will be used in cellular respiration to provide energy for metabolic reactions in your cells.
• What type of sugar is Glucose and Sucrose?

  Simple sugars.
• What are lipids?


  Lipids are fats (solids) and oils (liquids). They are the most efficient energy store in your body and an important source of energy in your diet.
• What elements make up lipids?

  Carbon, Hyrogen and Oxygen.
• Are lipids insoluble in water?

  Yes.
• What molecules are lipids made up of?

  Lipids are made up of 3 molecules of fatty acids joined to a molecule of glycerol. (The Glycerol is always the same however the fatty acids may vary)
• What are proteins used for?

  Proteins are for building up the cells and tissues of your body, as well as the basis of all your enzymes.
• What element is protein made up of?

  Carbon, Hydrogen, Oxygen and Nitrogen.
• What happens when an enzyme is exposed to a high temperature or the extremes of pH?

  The enzyme will denature.
• What are the 3 digestive enzymes called?

  Protease, Lipase, Carbohydrase
• Where is Amylase produced? [2]

  - Salivary glands - Pancreas
• What does Amylase do?

  Amylase is a carbohydrase that breaks down starch into maltose (sugar).
• Where is protease produced?

  Protease is produced in the stomach, pancreas and small intestine.
• What does protease do?

  It breaks down proteins into amino acids.
• Where is Lipase produced?

  Lipase is produced in the pancreas and small intestine.
• What does lipase do?

  It breaks down lipids into fatty acids and glycerol.
• What is blood?


  Blood is a tissue.
• What is blood made up of?

  It is made up of a liquid called plasma, which contains RBC, WBC and platelets.
• What does plasma transport?


  Chemical substances around the body (products of digestion, hormones, antibodies, urea and carbon dioxide)
• What do red blood cell contain?

  Contain haemoglobin, which binds to oxygen to transport it from the lungs to the tissues and cells, which need it for respiration.
• What adaptations do red blood cell have? [3]

  - Do not contain a nucleus - Are very small - Shaped like biconcave discks giving them a large surace area that oxygen can quickly diffuse into.
• What do white blood cells do?

  Help protect the body against infection
• What are platelets?

  They are fragments of cells, which collect at wounds and trigger blood clotting.