Unicellular and Multicellular Organisms

Unicellular Organisms

• Most are microscopic• Examples: Amoeba, Paramecia, E. Coli• Perform the same tasks as multicellular

organisms • They move, eat, reproduce and expel waste.

THE AMOEBA

                                                                                                                                                               

          

Binary Fission (cell division)

                    

PARAMECIA

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.

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.

Question to Consider

• Why do you think small cells are more efficient than large cells?

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.

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.

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.

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.

CELL DIVISION

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.