Viruses, bacteria and fungi love your body and want to take it over.
Microorganisms
Before we start, its important to know some disease like, arthritis, heart conditions and diabetes can’t be spread to other people.
However diseases which can be passed on are called infectious diseases. These diseases can be passed from one person to another.
Organisms which cause disease are called pathogen.
Infectious diseases are caused by micro-organisms (MOs) which attack our bodies.
When they enter your body, the first thing the do is reproduce. Bacteria will reproduce through binary fission. Every 20 minutes the bacteria split. 2 - 4 - 8 - 16 etc.
While Viruses will use your own cells as viral baby factories.
Bacteria will produce dangerous toxins, which hurt near by cells. Viruses will take over healthy cells and use them to create other viruses until the cell bursts.
Since they are so simple, their replication rate is very high. With in minutes you could have billions of bacteria in your body
The reason they reproduce so rapidly in your body is because you are an ideal environment for them.
Your body provides Warmth, moisture, nutrients and shelter.
MOs are incredibly small. A bacteria is 1 - 5 µm, while a virus is 20-300 nm.
A nanometer is one millionth of a millimetre. (Scroll over the image)
With every breath you take, billions of MOs get into your body.
Quick Questions
1. What is an infectious disease?
2. What are 3 types of pathogens?
3. How do bacteria and viruses reproduce?
Short answer Questions
1. How do a bacterial cells cause damage to your body?
2. How do viruses cause damage to your body?
3. What is it about the human body which makes it an ideal location for pathogens.
4. Create a Ven-Diagram, comparing Bacteria, Viruses and Fungi.
5. Even though billions of MOs enter your body every time you breath, you don’t die. Briefly explain why this is.
6. Explain why someone can’t catch heart disease.
7. Using the following words create a small paragraph.
