A prokaryote is a unicellular organism that lacks a membrane-bound nucleus. Bacteria are prokaryotes that fall into two major categories: the Kingdom Eubacteria and the Kingdom Archaebacteria. Eubacteria are common types that occur all around us, usually they are on surfaces and in the soil. You can only find Archaebacteria in extreme environments, like hot sulfur springs. Archaebacteria are thought to be some of the oldest life forms on earth. Most bacteria don't make their own food. That means they must rely on other organisms to provide them with food. These bacteria break down, or decompose, other living things to obtain energy.
When most people hear the word bacteria, they think of something that is bad for you. In fact, very few bacteria cause illnesses. Some bacteria actually help you! Bacteria are used to make food, such as cheese and yogurt, and they can also help us break down harmful substances in the environment. Scientists created a type of bacteria that could gobble up oil from oil spills. Some bacteria live inside the guts of animals and help them to digest food.
Unfortunately, there are many types of bacteria that can make us ill. Salmonella bacteria can cause food poisoning, and certain types of bacteria are responsible for other infections. You might have had some experience with Streptococcus, the bacteria that causes strep throat.
The instructions below describe a typical prokaryote cell, though many bacteria come in different shapes, and sizes and not all contain some of the features described.
- The cell wall protects the cell and gives it shape. It is the outermost layer on the image. Color the cell wall purple.
- On the inside of the cell wall is the cell membrane. Its job is to regulate what comes in and out of the cell. Color the cell membrane pink.
- The surface of some bacteria cells is covered in pilus, which help the cell stick to surfaces. Color the pilus light green.
- Some bacteria can move within their environment by using structures called flagella, which resemble tails. Color the flagella dark green.
- The watery interior of the cell is called cytoplasm. Color the cytoplasm light blue.
- Throughout the cytoplasm are tiny round structures called ribosomes. Ribosomes make proteins for the cell. Color the ribosomes red.
- Every prokaryote cell has a circular strand of DNA that floats within the cytoplasm. DNA contains the instructions for the cell and controls the cell’s activities. Color the DNA yellow.
- Many prokaryote cells have a small circular loop of DNA called a plasmid. The plasmid is used in sexual reproduction. Color the plasmid orange.
- What bacteria causes strep throat? _________________
- What are the oldest life forms on earth? _________________
- What bacteria is associated with food poisoning? _______________
- What part of the bacteria cell helps it stick to surfaces? __________
- Name two foods that are made with the help of bacteria: _______________________________________
- What does “decompose” mean? _______________________
- What part of the bacteria cell helps it move? _______________
- Where do Archaebacteria live? __________________
- To what kingdom do common bacteria belong? _______________
- What structure controls the cell’s activities? __________
- What is the function of ribosomes? ______________________
- What is the function of the cell membrane? __________________________________________________
- What is the watery environment that the DNA and ribosomes float within? ________________________________________
- Bacteria cells can come in different shapes, some of them even form long chains. Streptococcus is a bacterium that is circular and form chains. The chains can be any number in length. Staphylococcus is a bacterium that is also circular but occurs in clumps. Draw how you would imagine staphylococcus would appear.