Unicellular and Multicellular Organisms

1. Unicellular and Multicellular Organisms

2. Unicellular Organisms • Most are microscopic • Examples: Amoeba, Paramecia, E. Coli • Perform the same tasks as multicellular organisms • They move, eat, reproduce and expel waste.

3. THE AMOEBA

4. Binary Fission (cell division) PARAMECIA

5. The Amoeba • Have characteristics of an animal cell • Live in fresh and salt water environments and decaying vegetation sites. • Are predators – they prey on algae and bacteria • Uses osmosis to get water and diffusion to get oxygen and dispose of carbon dioxide.

6. Multicellular Organisms • Rely on a variety of cells to perform cellular functions. These are called “specialized cells”. • Specialized cells perform duties such as digestion or movement. • Example: Eyes, Muscles and Tongue. (what duties do these perform?) • Cells can be compared to small cities. Each one performs a different job/function. They all work together to be efficient. Just like we need specialist doctors, cells need specialist cells.

7. Question to Consider • Why do you think small cells are more efficient than large cells?

8. Cellular Process in Plants and Animals • Materials enter cells through diffusion and osmosis • Cells break down materials and convert them to energy, to transport energy from one place to another, to build protein and send chemical messages. • Cells also expel waste products. The higher number of cells, the more waste that is expelled.

9. Energy • Energy is necessary for digestion, transport, reproduction and repairing damage to cells • In animal cells, the mitochondria are responsible for breaking down carbs and releasing energy. • Specialized cells like liver and muscle cells have more mitochondria than other cells in the animal system. Why do you think this is? • In plant cells, chlorophyll convert energy to sugars using water, carbon dioxide and nutrients.

10. Processing and Transporting Main Cell Parts: Cytoplasm, Endoplasmic Reticulum, Golgi Apparatus, Lysosomes • Materials move through the cytoplasm • The Endoplasmic Reticulum creates protein from the materials and passes them to the Golgi Apparatus • The Golgi apparatus processes the protein and secretes them outside the cell to be used in other places. • Lysosomes break down food and digest waste.

11. Reproduction • Cells have a life span. Amoeba live for approximately 2 days. • Brain cells: 30-50yrs • Red Blood Cells: 120 days • Skin Cells – 20 days • New cells are created through cell division, when one cell splits into two. First the nucleus splits, and then the remainder of the cell. • The two new cells are identical. • In plant cells, the nucleus divides and then a new cell wall is created.

12. CELL DIVISION

13. Do you Get It? • Consider the following question: A unicellular organism is a living thing that meets all of the basic needs with just one cell. A multicellular organism can require up to several trillion cells to do the same thing. Which do you consider to be more advanced? Explain your reasoning.