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Drugs Flashcards iGCSE Biology

Drugs Flashcards iGCSE Biology

iGCSE Biology Flashcards – All Topics

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[h] Drugs Flashcards iGCSE CIE Biology

[q] Alcohol

[a]

  • Alcohol is a powerful depressant drug.
    • Lowers the rate of nervous impulses by blocking synapses.
    • Addictive
      • Causes the release of neurotransmitters such as dopamine into synapses in the reward pathway which causes a ‘high’.
  • Addiction and withdrawal symptoms:
    • Vomiting
    • Slow reaction time
      • Drunk driving
    • Reduced self control
      • More aggressive
    • Impaired balance and muscle control
    • Sleepiness/Unconsciousness
    • Liver Damage/Cirrhosis
      • Less effective at detoxification
    • Brain damage
 

[q] Anabolic steroids as a sport-performance drug

[a]

  • Anabolic steroids: A group of hormones known as steroids which stimulate anabolic reactions to occur in the body (meaning the synthesis of large molecules from smaller ones)
  • They affect protein metabolism, increasing muscle development and reducing body fat. 
    • Increases muscle mass, helps athletes train harder and for longer periods of time, and can increase aggression which can give an edge when competing
  • Side effects: 
    • increases risk of heart disease
    • increases risk of liver damage
    • increases risk of kidney damage
    • affect the menstrual cycle in women
    • decreases the ability of the immune system to destroy pathogens
 

[q] What is a Drug?

[a] Any substance taken into the body that modifies or affects chemical reactions in the body is called a Drug.

 

[q] Heroin

[a]

  • Heroin is a powerful depressant drug.
    • Lowers the rate of nervous impulses by blocking synapses.
    • Addictive
      • Causes the release of neurotransmitters such as dopamine into synapses in the reward pathway which causes a ‘high’.
    • Reduces pain and slows down breathing
  • Addiction and withdrawal symptoms:
    • Highly addictive
      • May turn to crime to get money for expensive heroin.
    • Anxiety, Muscle aches, Sweating, Abdominal cramping, Diarrhoea, Nausea, Vomiting.
 

[q] How does Heroin Affect the Nervous System?

[a]

  1. Heroin is converted into morphine;
  2. Morphine diffuses into synapse;
  3. Morphine binds to endorphin receptors.
    • Morphine is complementary to endorphin receptor;
  4. Heroin blocks neurotransmitter entering receptor site;
  5. Morphine (Heroin) stimulates release of dopamine.
    • Effect: Reduced pain perception/Mood/Hunger sensation.
  • Taking heroin can reduce the production of natural endorphins and other neurotransmitters,
    • Thus repeated use leads to the need for greater and greater amounts in order to get the same feelings.
 

[q] Testosterone as a sport-performance drug

[a]

  • Made in the testes of males
  • Promotes protein synthesis and growth of muscle tissue
    • Leads to increased muscle and bone mass. 
  • Makes people more aggressive
 

[q] Tobacco & The Gas Exchange System

[a]

  • Smoking causes chronic obstructive lung disease, coronary heart disease and increased risks of several different types of cancer, including lung cancer
  • Chemicals in cigarettes include:
    • Tar
      • Carcinogenic
      • Tar sticks to alveoli / cilia;
        • Produce more mucus;
          • making prone to (the common cold) respiratory infections;
        • Reduced gas exchange;
    • Nicotine
      • Addictive
      • Stimulant
      • Damages the circulatory system
        • Nicotine narrows blood vessels so will put more strain on the circulatory system and increase blood pressure
      • Narrow blood vessels are more likely to become clogged with fat, including cholesterol – if this happens in the coronary artery, this causes coronary heart disease
      • This means the heart muscle cells do not get sufficient oxygen and so less aerobic respiration takes place
      • To compensate the cells respire anaerobically, producing lactic acid which cannot be removed (due to lack of blood supply)
      • This creates a low pH environment in the cells causing enzymes to denature and eventually heart muscle cells will die
      • If enough die this can cause a heart attack
    • Carbon monoxide
      • Binds with  haemoglobin permanently to form carboxyhaemoglobin
        • Reduced oxygen transported to heart muscle.
      • Increases the risk of coronary heart disease and strokes
    • Smoke Particles
      • Smoke particles reach the alveoli and get stuck.
      • White blood cells are triggered.
        • Phagocytes try to remove the smoke particles by phagocytosis, damaging the alveolar walls.
      • Increased risk of asthma, and Chronic Obstructive Pulmonary Disease (COPD)
      • It causes the surface area of the lungs to decrease and thus decreases the efficiency of obtaining oxygen.
      • The person is said to have emphysema.
        • A person with emphysema is forced to be less active to such an extent that they may not have the energy to even walk.
 

[q] Why don’t antibiotics affect virus?

[a]

  • Idea that viruses have no target for antibiotics / owtte; 
  • Antibiotics stop enzymes working;
    • Viruses have no metabolism;
      • Allow: viruses do not have ribosomes
  • Antibiotics stop cell wall growth;
    • Viruses have no cell wall;
 

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