Biology

• Breathing


  Mechanical process of getting oxygen into the lungs and releasing carbon dioxide out of the lungs, allowing gas exchange to take place
• Respiration


  Process that releases energy by breaking down food molecules (glucose) in living cells
• Respiration


  1. Oxidation of food

  2. Biochemical process

  3. Occurs at cellular level

  4. ATP is produced
• Breathing


  • Biophysical process that occurs at organ level when breathing takes place
  • ATP is utilized for various purposes such as muscle contraction, active transport, building large molecules, cell division
• Aerobic respiration


  Breaking down of glucose completely by the action of oxygen, producing more energy
• Anaerobic respiration


  Breaking down of glucose without using oxygen, producing less energy
• Alveoli


  • Folded to increase surface area
  • Dense network of blood capillaries
  • Walls are one cell thick
  • Walls are moist
• Ventilation


  Moving air in and out of the lungs due to pressure difference
• Inhalation


  1. Ribs move outward and upward

  2. External intercostal muscles contract

  3. Internal intercostal muscles relax

  4. Diaphragm flattens

  5. Volume of chest increases

  6. Pressure decreases

  7. Air enters lungs
• Exhalation


  1. Ribs move inward and downward

  2. External intercostal muscles relax

  3. Internal intercostal muscles contract

  4. Diaphragm curves

  5. Volume of chest decreases

  6. Pressure increases

  7. Air leaves lungs
• The digestive system breaks down complex food into nutrients such as proteins, fats and carbohydrates
• Parts of the digestive system

  • Mouth
  • Esophagus
  • Stomach
  • Small intestine
  • Pancreas
  • Liver
  • Large intestine
  • Rectum
• Different types of food have different energy values
• Humans require more energy as they grow older to perform daily tasks
• Sound can travel only through a medium which creates vibrations spreading through the air, forming sound waves
• When an object is moved, the particles around it start moving too
• Lack of proper nutrition can lead to deficiency diseases like kwashiorkor, night blindness, scurvy, anemia
• Roots


  • Hold plants in place
  • Absorb water and minerals from the ground
• Stems


  • Transport water and minerals from roots to leaves
  • Transport food from leaves to other parts of the plant
• Leaves


  • Provide space and conditions for photosynthesis
  • Contain adaptations like larger size to maximize light absorption
• Photosynthesis


  Vital process in plants that uses chlorophyll and light energy to convert carbon dioxide and water into glucose and oxygen
• Photosynthesis takes place in plant cells in small organelles called chloroplasts, which contain the green pigment chlorophyll