B2 - organisation

• What is a tissue?


  A group of cells that perform a specific function
• Explain what is meant by the term "organ system"?

  Group of organs working together
• Why can enzymes be described as biological catalysts?

  They speed up reactions
• Why do enzymes only catalyse 1 reaction?

  Different enzymes have different active sites
• What does it mean when an enzyme is "denatured"?

  It loses its shape and function
• Describe how you could investigate the effect of pH on the rate of amylase activity?

  Record the time taken for amylase to break down starch and increase the temperature each time
• List 3 places where amylase is made in the human body?

  Salivary glands

  Pancreas

  Small intestine
• What is the role of lipase?

  Break down and digest fats
• Where is bile stored?

  Gallbladder
• Name the solution that you would use to test for lipids?

  Sudan III
• Name the tubes that split off the trachea?

  Bronchi
• Explain the role of the alveoli play in gas exchange?

  It has a large surface area and is thin

  This means oxygen and carbon dioxide can exchange quickly
• Explain why the circulatory system in humans is described as a "double circulatory system"?

  The heart pumps the blood twice
• Why does the heart have valves?

  To prevent the backflow of blood
• Name the 4 chambers of the heart?

  Left atrium, left ventricle, right atrium, right ventricle
• How is the resting heart rate controlled in a healthy heart?

  The nervous system
• How are arteries adapted to carry the blood away from the heart?

  They have thick muscular walls and are strong
• Why do red blood cells not have a nucleus?

  It allows them to carry more oxygen around the body
• Give 2 advantages of statins?

  Lower cholesterol, reduce risk of heart disease
• Give 2 disadvantages of statins?

  Muscle pain, liver damage
• What is the difference between biological and mechanical replacement heart valves?

  Mechanical valves are usually made from carbon and metal

  Biological valves are made from pig or cow tissue. This has to be treated to make sure it's not rejected by the body
• What is a non-communicable disease?

  A disease/medical condition that cannot be spread between people

  Example - heart disease
• Give an example of where different types of disease might interact in the body?

  The reaction of the immune system to pathogens could trigger allergic reactions
• What is meant by a risk factor of a disease?


  A characteristic/behaviour that increases the likelihood of developing a disease
• Which type of tumour is cancerous?

  Malignant
• List the tissues that make up a leaf?

  Epidermis

  Mesophyll

  Vascular tissue

  
• Explain how the structure of the upper epidermal tissue in a leaf is related to its function?

  The upper surface is covered in a waxy, waterproof cuticle which serves to reduce water loss from the leaf
• What is the function of phloem?

  Transportation
• What is transpiration?

  The process by which plants release water vapour into the atmosphere through their leaves
• List the 4 main things that affect transpiration?

  Humidity

  Temperature

  Wind

  Light
• How could you measure the rate of transpiration?

  A potometer
• Name the cell that helps open and close stomata?

  Guard cells