Microorganisms Fifth Grade Science

Standard: S5L4 Students will relate how microorganisms benefit or harm larger organisms. A. Identify beneficial and harmful microorganisms and explain why they are beneficial and harmful.

Microorganisms Living things that can only be seen with microscopes Single-celled or Multi-celled Some are helpful and some are harmful

Examples of Microorganisms Amoebas: Single-celled animals Live in oceans, ponds, moist soil, inside you Some cause diseases Breathe oxygen, eat by surrounding food and bacteria and sweeping it into membrane

Examples of Microorganisms Bacteria: single-celled organisms Discovered in 1600s when microscope was discovered Billions of bacteria can be found in a handful of soil Live everywhere from Artic to bottom of ocean Do not have a nucleus

Examples of Microorganisms Algae: either single or multi-celled Type of plant, but do not have cell walls Have chloroplasts to make their food Live in water and other moist places Produce most of the oxygen we breathe…more than trees

Similarities of single and multi-celled organisms They all eat They all must get rid of waste They reproduce, make more of themselves

Differences of single and multi-celled organisms Some singles have a nucleus, some do not Some singles have chloroplasts but do not have stiff cell walls

Harmful Microorganisms Food: cooking kills bacteria, food left out for 2 hours can start to grow bacteria (Salmonella and E. coli) Skin: staph bacteria can cause pimples or infections Viruses: living cells grow, change, and multiply Fungus: don’t move, eat living and dead organisms nearby (mold, yeasts, mushrooms, ringworm) Algae: red tides in ocean can poison fish

Helpful Microorganisms Algae in ocean provides us with oxygen Plankton are food for fish which is food for us Fungi helps land plants take nutrients from soil Bacteria turns milk into yogurt and cheese Yeast makes bread, rolls, and cakes rise Bacteria helps us digest food Medicines (penicillin from mold, streptomycin from bacteria) Clean up (harmful wastes, decaying plants and animals)

How can mold be helpful? A. It grows on bread and other food. B. It helps dead plants decay. C. It is a kind of fungus. D. It grows on wheat plants.

Which statement is false? A. Microorganisms can cause diseases. B. Microorganisms cure disease. C. Some microorganisms are eaten. D. Microorganisms are rare.

Why are bacteria grouped with microorganisms? A. both are diseases B. both cure diseases C. both are single celled. D. both are harmful.

How can you avoid touching microorganisms? A. Make sure your meat is well cooked. B. Wash your hands many times each day. C. Do not touch any soil. D. You cannot avoid touching microorganisms.

Name one reason why microorganisms are helpful.

Name one reason why microorganisms are harmful.