1. Cells What do you remember about cells?

2. What is an organism made of? Single-celled organisms are just one cell. What does unicellular mean? Examples include the paramecium, amoeba, and euglena.

3. What is an organism made of? Multi-cellular organisms are made of many cells. What does multi- mean? Examples include sponges, insects, worms, fish, amphibians, reptiles, birds, and mammals.

4. How do organisms make more organisms? A unicellular organism can divide into two new organisms. The new ones are exactly like the original. Multicellular organisms have many ways to reproduce. –Some produce exact copies of themselves. –Others require two individuals who produce offspring with similar but not exact characteristics.

5. Why do the cells in multicellular organisms divide? Growth –Adults have more cells than babies. –Growing does not make bigger cells. Repair –Damage to cells on the inside or outside makes cells die. –They must be replaced by new cells. Reproduction –Egg and sperm cells must have half the genetic information (DNA) of the original cell. –When an egg and sperm join, the new organism will have the correct amount of DNA.

6. How are cells organized to form an organism? Similar cells are grouped as tissues. In animals, muscle cells → muscle tissue In plants, leaf cells → leaf tissue Tissues are grouped into organs. In animals, some muscle tissue is grouped into muscles and other muscle tissue is grouped to form a heart. In plants, several kinds of leaf tissue forms a leaf. Several organs form a system. Several systems form the organism.

7. What do cells do for the organism? All cells must change food molecules into energy to do their work, get rid of waste products, and divide to make new cells. How is this like what organisms must do?

8. What do cells do for the organism? Plant and animal cells are specialized to do specific jobs such as Making proteins or other molecules Changing simple molecules into glucose during photosynthesis Storing energy Taking in or releasing water Sensing the surroundings How is this like what organisms do?

9. How are the structures or shapes of cells related to their functions? Plant cells have cell walls that support the cells. Leaf cells have chloroplasts to capture light energy for photosynthesis. Nerve cells in animals are long and thin. They carry chemical and electrical messages to the brain. Muscle cells in animals relax and contract. What other examples can you think of?