germs

1. Germs can be categorized in to 4 types:
Bacteria. Bacteria are single-celled organisms, which can reproduce very quickly. ...
Viruses. Viruses are simpler than bacteria in structure and usually not even really considered a living organism. ...
Fungi. ...
Protozoa.
2. What prompted this question is a label on hand sanitiser saying it kills 99.999% of germs, so I'm trying to work outhow many germs there are out there and how many it can't kill!
3. Somewhere, something incredible is waiting to be known.
Carl Sagan
4.
Thinker
GO IN DEPTH
AAAS/Subaru SB&F Prize for Excellence in Science Books
See the Collection
lessons
April Pulley Sayre: Science Explorer ›
An Egg Is Quiet ›
tools
Stars Beneath Your Bed: The Surprising Story of Dust ›
The Amateur Naturalist ›
/Black History Month
See the Collection
lessons
Images of Science ›
African Americans in Science ›
tools
Science Update: Spotlight on African American Scientists ›
collections
Martin Luther King Day Teaching Resources ›
Material Marvels ›
videos
Conversations with a Scientist: John Dabiri ›
/
Changing Lifestyles & Heart Health

This lesson focuses on how changes in diet andlifestyle from prehistoric to modern times have had an impact on heart health.
See the Lesson
Science NetLinks
Top of Form

Search
Bottom of Form
Lessons
Tools
Collections
Afterschool
Science News
What's a Germ?

Introduction
This sheet contains information about the four main types of germs.

What do germs, also called microbes, have to do with humans? Humans (and plants) are a placefor germs to live. Think of it this way: humans need certain things to live, like oxygen, food, and water. If you take a human out of this safe, earthly environment and sent him or her to say, the moon, without food, water, and oxygen, he or she would not survive. Germs also need a certain environment in order to survive. And to some germs, the best place to be is inside the human body. Othersthrive on our skin, or even just inside our mouths. Germs look for what they need to live.

One important thing to remember is that not all microbes are bad. Many are good and they help our bodies stay in balance. The bad ones, though, can make us sick. The four main types of germs are bacteria, viruses, fungi, and protozoa.
Bacteria
Bacteria are single-celled creatures that live just abouteverywhere on earth. You name it in the air, in soil, in water, and yes, in and on humans. In these places, their homes, they find nutrients to survive.

Bacteria are so small that you cannot see them unless you use a microscope. Just to give you an idea of how small they are, imagine a teaspoon with a BILLION little creatures on it. Those creatures would be bacteria. That means that one bacteriumis even smaller than a grain of salt, or the tip of a pin! If you could get a look at different types of bacteria, you would find out that they come in all shapes. Some are shaped like balls, others commas, while others are long and thin like a stick. Some bacteria have longish hairs covering their bodies, which they use like arms to wave around in order to move about.

How could bacteriapossibly be good? They are many types of good bacteria, including those that live in your intestines and actually help digest your food. One the other hand, there are several types of bad bacteria, including those that cause sore throats or infect a cut.
Viruses
Viruses need a host to survive. While bacteria can grow and reproduce on their own if they have enough food, viruses need to be INSIDE thecell of a living plant or animal (including humans), or even inside a bacterium!

What is the goal of a virus? Once a virus finds the perfect host, the goal is to reproduce and spread. Imagine that a virus makes a home in the cells that make up your blood. Then, it can hitch a ride just about anywhere in the body, and spread itself around. Some viruses will make a home inside a cell and grow...