B4

• What is a tissue?

  Similar cells working together
• What is an organ?

  A group of different tissues
• What are enzymes?

  Catalysts produced by living things
• How can you speed up a chemical reaction?

  By using a higher temperature
• What are enzymes made of?

  Large proteins from chains of amino acids
• What conditions do enzymes need to work best?

  Certain temperature and pH level
• What happens if the temperature or pH is wrong for enzymes?

  The enzyme could denature
• What are the main organs of the digestive system?

  • Mouth: produces amylase
  • Stomach: produces protease (pepsin)
  • Liver: produces bile
  • Gall bladder: stores bile
  • Pancreas: produces amylase, protease, lipase
  • Small intestine: absorbs food
  • Large intestine: absorbs water
• What does bile do?

  Neutralizes acids
• What is the Benedict test used for?

  Testing for sugar
• What does iodine solution test for?

  Starch
• What does the Biuret test indicate?

  Presence of proteins
• What does Sudan III test for?

  Lipids
• What color change indicates sugar presence in the Benedict test?

  From blue to green, yellow, or red
• What color change indicates starch presence in the iodine test?

  From brown to black
• What color change indicates protein presence in the Biuret test?

  From blue to pink to purple
• What happens in the Sudan III test if lipids are present?

  Mixture separates into two layers
• What is a capillary?

  The tiniest blood vessel
• How close is every cell to a capillary?

  Within 0.05 mm
• What is the function of capillaries?

  Allows substances to diffuse in and out
• What do arteries do?

  Carry blood away from the heart
• What color is blood in arteries?

  Bright red (full of oxygen)
• What are the characteristics of artery walls?

  Thick walls with muscle and elastic fiber
• What do veins do?

  Carry blood to the heart
• What color is blood in veins?

  Purple-red (low in oxygen)
• What is a key feature of vein walls?

  Thinner walls than arteries
• What do veins have to prevent backflow?

  Valves
• How many chambers does the heart have?

  Four chambers
• Where does blood enter the heart?

  From the atria
• What type of blood enters the heart from the vena cava?

  Deoxygenated blood
• What type of blood does the pulmonary vein carry?

  Oxygenated blood from the lungs
• Where does oxygenated blood go from the aorta?

  Around the body
• What do ventricles do?

  Pump blood out of the heart
• What is bypass surgery used for?

  To replace blocked coronary arteries
• How does blood flow through the heart?

  From veins to atria to ventricles to arteries
• How does deoxygenated blood compare to oxygenated blood?

  Deoxygenated blood is darker
• What are the methods to help the heart?

  • Stents: Open narrowed arteries
  • Bypass surgery: Replace blocked arteries
  • Statins: Lower cholesterol levels
  • Mechanical valves: Long-lasting, need medication
  • Biological valves: Shorter lifespan, no medication
  • Pacemakers: Regulate heart rhythm
  • Artificial heart: Temporary support until transplant
• What is the purpose of a stent?

  To open narrowed arteries
• What do statins do?

  Lower cholesterol levels
• What are mechanical valves made of?

  Titanium and polymers