Biology HL
4
Chapters
553
Notes
Theme A - Unity & diversity
Theme B - Form & Function
Theme C - Interaction & Interdependence
Theme D - Continuity & Change
Biology HL
Theme A - Unity & diversity
Unlocking Virus Evolution Mysteries!
510 words
3 mins read
Last edited on 5th Nov 2024
Table of content
Why are viruses the speedsters of evolution? 📌
- 🏁 Short Generation Time: Humans have a generation time of about 25 years. Imagine waiting 25 years for a new iPhone! Viruses, on the other hand, can reproduce in under an hour. This means more generations and more chances for change.
- 🎲 High Mutation Rates: Think of mutations like typos when you're texting. We all make them! Viruses, especially RNA ones like coronaviruses, make a lot of typos when copying their genetic code. No auto-correct here!
- 💪 Intense Natural Selection: The human body is like a fortress with guards (antibodies) that detect and eliminate intruders (viruses). But if a virus wears a different hat (changes its antigens), it can sneak past. This "survival of the sneakiest" means rapid evolution.
Influenza vs. human immune system 🤧 vs. 🛡️
- What it is: The flu virus is like a secret agent with 8 different ID cards (RNA molecules). And just like in spy movies, sometimes these agents swap IDs, resulting in a new virus strain.
- The Costume Trick: Influenza has two proteins (haemagglutinin and neuraminidase) that act as disguises. If they change, the virus can go undetected. Spanish flu = H1N1 disguise, Hong Kong flu = H3N2 disguise.
- Why yearly vaccines? Due to this quick change in disguise, we need new flu vaccines every year.
HIV - the master of mutation 🎭
- Mutation Machine: HIV uses a tool called reverse transcriptase which is, unfortunately, not very accurate. Plus, our own body's enzyme (cytidine deaminase) can cause the virus to mutate more.
- Hide & Seek with Immune System: Most mutations harm HIV, but some help it hide better, making it hard for our immune system to catch.
- Drug Resistance: HIV is like that kid in class who always has a new trick up their sleeve. It can become resistant to drugs, so doctors use a combo of treatments.
Unlock the Full Content! 
Dive deeper and gain exclusive access to premium files of Biology HL. Subscribe now and get closer to that 45 🌟
Biology HL
Theme A - Unity & diversity
Unlocking Virus Evolution Mysteries!
510 words
3 mins read
Last edited on 5th Nov 2024
Table of content
Why are viruses the speedsters of evolution? 📌
- 🏁 Short Generation Time: Humans have a generation time of about 25 years. Imagine waiting 25 years for a new iPhone! Viruses, on the other hand, can reproduce in under an hour. This means more generations and more chances for change.
- 🎲 High Mutation Rates: Think of mutations like typos when you're texting. We all make them! Viruses, especially RNA ones like coronaviruses, make a lot of typos when copying their genetic code. No auto-correct here!
- 💪 Intense Natural Selection: The human body is like a fortress with guards (antibodies) that detect and eliminate intruders (viruses). But if a virus wears a different hat (changes its antigens), it can sneak past. This "survival of the sneakiest" means rapid evolution.
Influenza vs. human immune system 🤧 vs. 🛡️
- What it is: The flu virus is like a secret agent with 8 different ID cards (RNA molecules). And just like in spy movies, sometimes these agents swap IDs, resulting in a new virus strain.
- The Costume Trick: Influenza has two proteins (haemagglutinin and neuraminidase) that act as disguises. If they change, the virus can go undetected. Spanish flu = H1N1 disguise, Hong Kong flu = H3N2 disguise.
- Why yearly vaccines? Due to this quick change in disguise, we need new flu vaccines every year.
HIV - the master of mutation 🎭
- Mutation Machine: HIV uses a tool called reverse transcriptase which is, unfortunately, not very accurate. Plus, our own body's enzyme (cytidine deaminase) can cause the virus to mutate more.
- Hide & Seek with Immune System: Most mutations harm HIV, but some help it hide better, making it hard for our immune system to catch.
- Drug Resistance: HIV is like that kid in class who always has a new trick up their sleeve. It can become resistant to drugs, so doctors use a combo of treatments.
Unlock the Full Content!
Dive deeper and gain exclusive access to premium files of Biology HL. Subscribe now and get closer to that 45 🌟