Organisation in animals

• Blood vessels


  The structure of each blood vessel relates to its function
• Vessel types


  • Artery
  • Vein
  • Capillary
• Artery


  • Carries blood away from the heart under high pressure
  • Has thick, muscular, and elastic walls
  • Has a small lumen
• Vein


  • Carries blood to the heart under low pressure
  • Has thin walls
  • Has a relatively large lumen
  • Often has valves
• Capillary


  • Connects arteries and veins
  • Has a one-cell-thick wall
  • Has a very narrow lumen
  • Provides a short diffusion distance for substances to move between the blood and tissues
• The heart


  • The organ that pumps blood around your body
  • Made from cardiac muscle tissue
  • Supplied with oxygen by the coronary artery
• Heart rate


  • Controlled by a group of cells in the right atrium that generate electrical impulses, acting as a pacemaker
  • Artificial pacemakers can be used to control irregular heartbeats
• Stem cells


  • More specialised cell types
  • No genetic variation, so, for example, an entire cloned crop could be destroyed by a disease
• Key terms


  • alveoli
  • amylase
  • aorta
  • artery
  • atrium
  • bronchi
  • coronary artery
  • double circulatory system
  • lipase
  • protease
  • pulmonary artery
  • pulmonary vein
  • vena cava
• Active transport


  Movement of particles against a concentration gradient-from a dilute solution to a more concentrated solution - using energy from respiration
• Required practical skills
• Food tests


  • Ethanol test for lipids (fats)-colour change from colourless to cloudy white if present
  • Benedict's test for sugars-colour change from blue to red if present
  • Iodine test for starch (carbohydrates)-colour change from brown to blue-black if present
  • Biuret reagent test for protein- colour change from blue to purple if present
• You need to be able to identify and describe the correct method, and results, for each test
• A student wanted to test a sample for the presence of protein using Biuret reagent. Write a risk assessment for this activity.
• General safety practices in labs

  • Wear goggles to protect your eyes
  • Wash hands at the end of the practical
  • Clear up any spills quickly
  • Do not eat any of the food
• Risks in the practical

  • Biuret reagent-irritant
  • Glass can break
  • Pipette can poke you in the eyes
• How to prevent risks

  1. Wash hands after touching Biuret reagent, and if it is ingested or it gets into the eyes inform a teacher immediately

  2. If glass is broken inform a teacher immediately

  3. Point pipettes downwards
• A student picked up solution A and added it to a sample of food. Solution A was blue and turned purple after adding it to the food.
• Benedict's test for sugar requires the solution to be heated. One way to do this is by heating the test tube in a beaker of water using a Bunsen burner.
• When testing a sample for protein in a test tube, a student found that the top of the sample tested positive whereas the bottom did not.