Organisation Biology

• What are cells described as in living organisms?

  Cells are the basic building blocks of all living organisms
• What do we call a group of cells with similar structure and function?

  Tissue
• What is an organ?

  An organ is a group of tissues performing specific functions
• What is the term for a group of organs performing a specific function?

  Organ system
• What is the highest level of organization in living things?

  Organism
• What are enzymes made of?

  Enzymes are protein molecules
• Where are enzymes typically found?

  Enzymes are found in cells
• What is the active site of an enzyme?

  The active site is the part of the enzyme that binds to the substrate
• How do enzymes function as biological catalysts?

  Enzymes speed up reactions in the body and can be reused
• What model is used to explain how enzymes work?

  The lock and key model
• What does it mean for an enzyme to be specific to one type of substrate?

  Each enzyme fits only one type of substrate molecule
• How can we measure the rate of enzyme-controlled reactions?

  By measuring gas production, color change, or pH change
• What is metabolism?

  Metabolism includes reactions that build up and break down molecules
• What happens to enzyme activity as temperature increases?

  Initially, the reaction rate increases until the optimum temperature is reached
• What is the optimum temperature for many living things?

  About 37 degrees Centigrade
• What occurs to an enzyme when the temperature is too high?

  The enzyme denatures and the active site changes shape
• How does pH affect enzyme activity?

  Enzymes work best at their optimum pH
• What is the test for starch?

  The iodine test
• What color change indicates the presence of starch in the iodine test?

  From orange to blue-black
• What is the test for protein?

  The biuret test
• What is the test for lipids?

  The ethanol test
• What color indicates the presence of protein in the biuret test?

  Lilac
• What is the test for sugars?

  The Benedict's test
• What color change indicates the presence of sugars in the Benedict's test?

  From blue to brick red
• What indicates the presence of lipids in the ethanol test?

  A cloudy white emulsion
• What is the function of bile in lipid digestion?

  Bile neutralizes stomach acid and emulsifies fats
• What is the role of the gallbladder in digestion?

  The gallbladder stores bile
• What is the structure of arteries?

  Arteries have a thick muscle layer and a narrow lumen
• What is the function of valves in the heart?

  Valves prevent the backflow of blood
• What is the structure of capillaries?

  Capillaries have very thin walls that are one cell thick
• Why are capillaries important for diffusion?

  Thin walls allow for a short diffusion distance
• What is the role of the pacemaker in the heart?

  The pacemaker controls the resting heart rate
• What are the key components of the human digestive system?

  • Mouth
  • Esophagus
  • Stomach
  • Pancreas
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
  • Liver
  • Gallbladder
• What are the main types of enzymes involved in digestion and their functions?

  • Carbohydrase: breaks down carbohydrates
  • Amylase: a type of carbohydrase that breaks down starch
  • Protease: breaks down proteins into amino acids
  • Lipase: breaks down lipids into glycerol and fatty acids
• What is the process of emulsification in lipid digestion?

  • Bile is produced by the liver
  • Bile is stored in the gallbladder
  • Bile emulsifies large lipid droplets into smaller droplets
  • Increases surface area for lipase action
• What are the steps of the food tests for starch, protein, lipids, and sugars?

  1. Starch: Add iodine, color change from orange to blue-black
  2. Protein: Add biuret solution, color change to lilac
  3. Lipids: Add ethanol, then water, cloudy white emulsion indicates lipid
  4. Sugars: Add Benedict's reagent, heat, color change from blue to brick red
• What are the main features of the heart and circulation system?

  • Oxygenated and deoxygenated blood are kept separate
  • The heart has four valves to prevent backflow
  • The pacemaker regulates heart rate
  • Blood is pumped to the body and lungs in a double circulatory system
• What are the structural differences between arteries and capillaries?

  • Arteries: Thick muscle layer, narrow lumen, withstand high pressure
  • Capillaries: Very thin walls (one cell thick), allow for diffusion
• What is the significance of the surface area to volume ratio in lipid digestion?

  • Larger surface area allows lipase enzymes to work more effectively
  • Emulsification increases the surface area of lipid droplets
• What are the roles of the liver and gallbladder in digestion?

  • Liver: Produces bile
  • Gallbladder: Stores bile and releases it into the small intestine