I/GCSE Biology - Defence against diseases

It's important to memorize how immune system of human body work in I/GCSE Biology!! 🤪

Ensure you understand what immunity is in I/GCSE Biology

• Acts like a "Bubble boy"
• Bacteria and Viruses release toxins (poisonous chemicals) and they make you ill
• Bacteria and Viruses prevent cells from working properly
• For example: Headache, fever, feeling sick (symptoms)

Bacteria VS Viruses

• Bacteria inside you multiply every 20 min
• Viruses multiply inside cells by entering them, using the chemicals inside there to multiply. New Viruses bursts out of cell to invade another – damages / destroys cell

In I/GCSE Biology, mechanism of immune system is commonly asked in exam.

Do you remember which 3 types of blood cells you have learnt in I/GCSE Biology?

White blood cells (WBC) – specialised cells that defend your body against pathogens

• Some WBC ingest ➡️ take into the cell any pathogen, once inside the WBC releases enzymes to digest and destroy pathogen
• Other WBC release antibodies (chemicals)
• Certain type of antibody ➡️ can only destroy certain type of pathogen

• Step 1 – Viruses gets inside body
• Step 2 – WBC make antibodies and memory cells
• Step 3 – antibodies attack Viruses and kill it
• Step 4 – if Viruses enters body again then memory cells know what kind of antibody to make

WBC produce antitoxins ➡️ chemicals which prevent toxins made by pathogens poisoning

• Unlikely to develop disease again once WBC destroyed pathogen
• Why ➡️ next time pathogen comes, WBC release the antibody and destroy the pathogen before you can get affected

References:

1. "Immunity", https://www.gutmicrobiotaforhealth.com/wp-content/uploads/2018/10/Science_immunity_resilience.jpg
2. "Phagocytes And Lymphocytes Bbc Bitesize", https://lh3.googleusercontent.com/R01Zb7yIvEE5Mzyk4aQuxQwQCyMnaCB13SaH428vdILGg36uwh-23jQBKD__lOAgHw7G8_QdMZLZoyhuWsv64xiqYPpGCRSprQs264hpHc3tz5_NnPFYzS-TYu7u0fFCqlM2jCc4
3. "Immune system", https://biology-igcse.weebly.com/uploads/1/5/0/7/15070316/2990245_orig.png

And we're done with this topic! Well Done!

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Drafted by Alyssa (Biology)