topic 2 bio

• What do we call connected similar cells?

  Tissue
• What do tissues form in the body?

  Organs
• What do organs work together to form?

  Organ systems
• What does the digestive system do?

  Breaks down food into nutrients
• What substance in the stomach helps break down food?

  Acid
• What do bile and enzymes do in the small intestine?

  Break down food further
• Where is bile made?

  Liver
• What is the function of bile?

  Neutralizes stomach acid and emulsifies fats
• What do enzymes do?

  Act as biological catalysts
• What enzyme breaks down starch?

  Amylase
• Where is amylase found?

  Small intestine and saliva
• What is the specificity of enzymes?

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

  Carbohydrates
• What do proteases break down?

  Proteins into amino acids
• What do lipases break down?

  Fats into glycerol and fatty acids
• What principle explains enzyme specificity?

  Lock and key principle
• What happens when a substrate binds to an enzyme?

  A complex is formed
• What is required for the substrate to fit the enzyme's active site?

  The right shape
• How does temperature affect enzyme activity?

  Increases until denaturation occurs
• What is the optimum temperature for enzyme activity?

  Best temperature for activity
• How does pH affect enzyme activity?

  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 starch is broken down.
  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?

  Turns cloudy
• What is the role of the respiratory system?

  Facilitates breathing and gas exchange
• What is the difference between breathing and respiration?

  Breathing provides oxygen for respiration
• What is the pathway of air during breathing?

  Trachea, bronchi, bronchioles, alveoli
• What happens in the alveoli?

  Gas exchange occurs
• How does oxygen travel in the blood?

  Binds to hemoglobin in red blood cells
• What happens to carbon dioxide produced from respiration?

  Dissolves in plasma and is exhaled
• What is the heart's role in the circulatory system?

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

  Double circulatory system
• How does deoxygenated blood enter the heart?

  Through the vena cava
• What prevents backflow of blood in the heart?

  Valves
• What happens to blood after it is oxygenated in the lungs?

  Returns to the heart via pulmonary vein
• Why does the left ventricle have thicker walls?

  Pumps blood to the whole body
• What generates electrical pulses in the heart?

  A group of cells near the right atrium
• What is an artificial pacemaker used for?

  To regulate heartbeats