Single-Celled Organisms

• Humans are made up of millions of tiny cells (multi-celled organisms).

• Microorganisms are made up of only ONE cell (single-celled organisms) 1.Single-celled organisms are simple life forms

 Include: bacteria, protists and others.  They move, find food, grow, and make new organisms. 2. Bacteria are one-celled organisms that do NOT have a nucleus.  The material that is usually in a nucleus can be found all over the cytoplasm instead.  More bacteria on earth than any other living thing  Some bacteria are helpful, and some are harmful.  One handful of soil can contain billions of bacteria. 3. Protists are a kind of single-celled organism.

 They live everywhere including pond water, saltwater, animals, and humans  Amoebas have a cell membrane, cytoplasm, and a nucleus  They move by: changing their shape. 4. Algae are plant-like organisms that

 Live in water, moist places, and under rocks  Among the oldest things on earth!  Algae have a cell membrane, cytoplasm, nucleus, and chloroplast.  Algae produce most of the oxygen that you breathe! 5. How do single-celled organisms move?

 Tail-like parts called flagella  Hair like structures called cilia  Paramecium also use their cilia to get food Multi-Celled Organisms Multi-celled organism is made of up of more than one cell.  Plants, animals and other living things.  Made up of different kinds of cells that have certain jobs to do.  Muscle cells, white blood cells, and nerve cells  For example: the cells that make up your heart work together to move oxygen and blood to other cells throughout your body. How the body works: Cells

www.educationdiscovery.com Harmful Microorganisms A microorganism is a living thing that is too small to be seen without a microscope.

• Microorganisms live everywhere on Earth. • Soil, air and water o Bacteria make up the largest group of microorganisms o Fungi, algae, protozoa (amoebas and paramecium) Harmful Microorganisms Bacteria

www.educationdiscovery.com Harmful Microorganisms

• Some harmful bacteria such as Salmonella or E. Coli can make you sick.  Harmful bacteria can be found in:  Raw chicken and other meat, raw eggs and other foods • A virus also causes disease.  smaller than bacteria • NOT a living thing.  Viruses cause diseases, and they change as they reproduce  Examples: Colds, flu, and chicken pox.  Medicine that kills one virus cannot kill another virus. • Fungi is another harmful microorganism

 Causes diseases in plants and infections in people.  Example: athletes foot, make food spoil (bread mold)  Fungus rots food and wood We could NOT live without Microorganisms.

 E-coli helps your body digest, or break down, the food you eat. o Ex. Bacteria helps cows digest grass; termites could not digest the wood they chew without bacteria. Humans use microorganisms to make certain foods. o Turn milk into cheese and yogurt. o Yeast to make dough rise • Bacteria and fungi are decomposers  Without it, Earth would be covered with a layer of dead plants and animals. Algae are the main producers.  Source of food and energy for living things.  Puts oxygen into the air for animals to breathe. Algae

www.educationdiscovery.com Protozoa are helpful too.

 They are food for animals that live in water.

 Help remove harmful wastes from sewage at water treatment plants. Living with Microorganisms

 Wash your hands after cooking.

 Antibiotics: medicines that cure diseases caused by bacteria. o Kill harmful bacteria, but can kill helpful bacteria too. o Eating yogurt can help put back the helpful bacteria.