ORGANISATION

• What do we call connected similar cells?

  Tissue
• What do tissues form in the body?

  Organs
• What system do organs work together in?

  Organ system
• What does the digestive system do?

  Breaks down food into nutrients
• What role does acid in the stomach play?

  Breaks down food
• What do bile and enzymes do in the small intestine?

  Break down food further
• Where is bile made and stored?

  Made in the liver, stored in gallbladder
• What is the function of bile?

  Neutralizes stomach acid and emulsifies fats
• What are enzymes?

  Biological catalysts
• What does amylase break down?

  Starch into glucose
• Where is amylase found?

  In saliva and small intestine
• What is the specificity of enzymes?

  They only break down certain molecules
• What do carbohydrases break down?

  Carbohydrates into simple sugars
• What do proteases break down?

  Proteins into amino acids
• What do lipases break down?

  Fats into glycerol and fatty acids
• What principle do enzymes operate on?

  Lock and key principle
• What happens when a substrate binds to an enzyme's active site?

  They form a complex
• What is required for the substrate to fit the enzyme's active site?

  The right shape
• What happens to enzyme activity as temperature increases?

  It increases until denaturation occurs
• What does it mean when an enzyme is denatured?

  Its active site changes shape
• What is the optimum temperature for enzyme activity?

  The best temperature for activity
• How does pH affect enzyme activity?

  It can denature enzymes at extremes
• What is the practical method to test enzyme activity with starch?

  1. Mix amylase with starch at different temperatures or pH.
  2. Time the reaction.
  3. Use iodine to test for starch presence.
  4. Record the time until iodine stays orange.
  5. Plot times against pH or temperature.
  6. Identify optimum conditions.
• What color does iodine turn in the presence of starch?

  Black
• What color does Benedict's solution turn in the presence of sugars?

  Orange
• What color does Biuret's reagent turn in the presence of proteins?

  Purple
• What happens to cold ethanol in the presence of lipids?

  It turns cloudy
• What is the role of the respiratory system?

  Breathing and gas exchange
• How does air move through the respiratory system?

  Down the trachea into bronchi and alveoli
• What happens in the alveoli?

  Gas exchange occurs
• What is the function of hemoglobin?

  Binds oxygen in red blood cells
• How is carbon dioxide exhaled?

  It diffuses from blood into lungs
• What is the heart's role in the circulatory system?

  It pumps blood throughout the body
• What type of circulatory system do humans have?

  Double circulatory system
• How many times does blood enter the heart in a double circulatory system?

  Twice
• What vein carries deoxygenated blood to the heart?

  Vena cava
• What prevents backflow of blood in the heart?

  Valves
• What happens to deoxygenated blood in the heart?

  It goes to the lungs for oxygenation
• What is the function of the left ventricle?

  Pumps blood to the whole body
• Why does the left side of the heart have thicker walls?

  It pumps blood to the entire body