Organisms - Biology

• Gas exchange

  The process of taking in oxygen and giving out carbon dioxide
• Gas exchange

  • Occurs in the respiratory system
  • The proportions of gases in the air we inhale and exhale changes due to using oxygen in respiration and producing carbon dioxide
• Breathing in (inhale)

  1. Muscles between the ribs contract

  2. Ribs are pulled up and out

  3. Diaphragm contracts and flattens

  4. Volume of the chest increases

  5. Pressure inside the chest decreases

  6. Air rushes into the lungs
• Breathing out (exhale)

  1. Muscles between ribs relax

  2. Ribs are pulled in and down

  3. Diaphragm relaxes and moves up

  4. Volume in the chest decreases

  5. Pressure inside the chest increases

  6. Air is forced out of the lungs
• Enzyme

  Biological catalyst that speeds up the digestion of nutrients
• Enzymes

  • Each enzyme is specific to each nutrient
  • The way the enzyme and nutrient bind with each other is called a lock and key model
• Carbohydrases

  Break carbohydrates down into simple sugars
• Proteases

  Break proteins down into amino acids
• Lipase

  Breaks lipids (fats) down into fatty acids and glycerol
• Balanced diet

  Eating the right amount of nutrients for your body to function
• Deficiency

  Not eating enough of a nutrient, leading to an unbalanced diet
• Nutrients and their roles

  • Carbohydrates - main source of energy
  • Lipids - fats and oils provide energy
  • Proteins - growth and repair of cells and tissues
  • Vitamins and minerals - essential in small amounts to keep you healthy
  • Water - needed in all cells and body fluids
  • Fibre - provides bulk to food to keep it moving through the gut
• Parts of the digestive system

  • Mouth
  • Salivary gland
  • Oesophagus
  • Stomach
  • Liver
  • Pancreas
  • Small intestine
  • Large intestine
  • Rectum
  • Anus
• Drugs

  Chemicals that affect the way our body works
• Medicinal drugs

  Used in medicine, they benefit health
• Recreational drugs

  Taken by people for enjoyment, normally have no health benefits and can be harmful
• Drug addiction

  When your body gets so used to a drug, it feels it cannot cope without it
• Withdrawal symptoms

  Experienced if someone who has an addiction stops taking the drug
• Carbon Dioxide Process

  Alveolus

  Bronchiole

  Bronchus

  Trachea

  Nose/Mouth
• Short Term Effects of Alcohol


  Heart rate and blood pressure increase

  Core body temperature decreases

  Reflexes become sluggish

  Brain activities slow down
• Long Term Effects of Alcohol


  Cancer

  Cirrhosis
• Smoking includes


  Tar - A sticky black material that collects in the lungs. It irritates and narrows the airways. Contains cancer cells.

  Nicotine - Addictive drug that is a stimulant

  Carbon monoxide - A poisonous gas that stops the blood carrying as much oxygen as needed
• Smoking causes


  Bronchitis - When pathogens and bacteria are in the mucus

  Lung Cancer - Lungs don't work as well

  Emphysema - Structure of alveoli changes and surface area decreases
• Cirrhosis 


  The liver can become scarred and less effective at removing toxins