All the organelles in a cell work together to help the cell and the whole organism function. Some diseases are caused by the failure of one type of organelle. Read the description below of an example of this type of disease. Joe’s cells can’t convert food energy effectively into energy they can use. As a result, he gets extremely tired, has weak legs, and can’t breathe well. Joe swims every day to keep his body as strong as possible. Which organelle is affected by Joe's disease?

Dr. Lopez studies the cells of oak trees that grow on steep hills. He is learning how the trees can support themselves and get enough food. The trees have very different needs than animals. Describe two structures found in plant cells but not in animal cells. How do these structures help plant cells to meet a plant’s needs?

Mad cow disease is caused by deformed proteins called prions. The disease is spread when meat from an infected cow is eaten. Prions can make normal proteins deform into more prions. After a few years, the brain of an infected person or cow looks like a sponge full of holes. Are prions considered organisms?

The ghost plant is white with a single stalk. The ghost plant is a parasite that feeds on the roots of plants. The roots of a ghost plant join with the root-like structures of a fungi and trick fungi into obtaining food from the roots of trees under the ground.  Ghost plant cells have all the usual plant organelles, except the __________ are not needed to transform energy.

A virus can reproduce only inside a cell. Once inside, the virus causes the cell to make many new copies of the virus. In an animal, which part of the cell is responsible for keeping viruses out?

Before a new medicine is approved, scientists study the effects the medicine has on different parts of the body. Often, a medicine is tested on mice before it is tested on humans. All the cells in the illustration below came from the same mouse.

If all of these cells are mouse cells, why do they look so different from each other?