1. Microorganisms
Fifth Grade Science

2. 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.

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

4. 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

5. 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

6. 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

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

8. 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

9. 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

10. 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)

11. 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.

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

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

14. 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.

15. Name one reason why microorganisms are helpful.

16. Name one reason why microorganisms are harmful.