Chapter 3

• Levels of organization in the body

  • Cells
  • Tissues
  • Organs
  • Organ systems
  • Organisms
• Cells


  • Made up of organelles like nucleus, cell membrane, cytoplasm, mitochondria, ribosomes
• Tissue


  Similar cells working together to achieve a particular function
• Organ

  Bunch of tissues working together to achieve a particular function
• Organ system


  Organs that work together for a particular function
• Organism


  Any living thing comprised of many organ systems
• Organ systems

  • Digestive system
  • Cardiovascular system
• Digestion


  1. Mouth

  2. Esophagus

  3. Stomach

  4. Liver

  5. Small intestine

  6. Large intestine
• Saliva


  Contains digestive enzyme amylase that breaks down carbohydrates
• Hydrochloric acid


  Helps break down food in the stomach
• Bile


  Produced by the liver, helps break down fats and neutralize stomach acid
• Small intestine


  Where most absorption of nutrients takes place
• Large intestine


  Processes waste and passes it out through the anus
• Gallbladder


  Stores bile produced by the liver
• Protease


  Enzyme that breaks down proteins into amino acids
• Amylase


  Enzyme that breaks down carbohydrates into glucose
• Lipase


  Enzyme that breaks down lipids into fatty acids and glycerol
• Food tests


  1. Biuret solution for proteins

  2. Iodine for carbohydrates/starch

  3. Benedict's solution for simple sugars

  4. Ethanol and water for lipids
• Lock and key mechanism

  Enzyme active site binds to specific substrate, changing its shape to facilitate catalysis
• Enzyme


  Biological catalyst that speeds up reactions without being consumed
• Enzyme activity


  Depends on optimum temperature and pH
• Enzymes can become denatured at extreme temperatures or pH, changing their active site shape