HELP!!!!!!! I need help with my science homework!!! i do NOT get it at all!!!?

Question

i'm so confused for my hw...it might look easy, but science is so hard for me. okay. heres what it says on my worksheet.

*imagine an individual cell in your body carrying on respiration.
1. what does the cell need? How does these materials reach the cell?
2. What does the cell give off? How do these materials leave, first from the cell and then from the body?
3. How do substances get into and out of the cell?
4. Why does he cell carry on respiration? Why is this process so important?
5. Many parts of the body are either directly or indirectly involved with respiration. How do each of the following parts of the body contribute to respiration at the level of individual cells: teeth, heart, skin, kidneys, lungs, salivary glands, thyroid glands, brain, capillaries, pancreas, and stomach

HELP!

Answer 1

1. glucose, oxygen

2. CO2, water. The wastes leave the cell by diffusion, carried to the lungs by the blood circulation, and leave the body from the lungs.

3. Glucose enters the cell by facilitated diffusion. Oxygen by simple diffusion.

4. Aerobic respiration produces 36 ATP's for each glucose oxidised, whereas only 2 ATP's are produced by anaerobic respiration. Anaerobic respiration can support only unicellular organisms.

5. Teeth, stomach, pancreas, etc. for digesting food to produce glucose. Lungs for taking in oxygen and removing CO2. The heart for blood circulation. Kidneys for removing nitrogen waste and water. Etc., etc.

Answer 2

1. The cell needs food and air(particularly oxygen) These materials reach the cells by different means. For example, the blood vessels containing the blood in the lungs carry nutrients and oxygen to different parts of the body. This way, each cell in the body receives equal amounts of nutrients and oxygen needed by the body.
2. The cell gives off waste materials. Inside the cell, the waste materials are engulfed by a special membranous fluid. Through the process of exocytosis, the waste materials are expelled from the body. Then, through the blood vessels carrying waste materials, the waste materials are expelled from the body through exhalation.
3. Substances get in and out of the cell through different processes. There is bulk transport, endocytosis, osmosis and other more complex processes which is very long to enumerate. Then only process I know which allow substances to get out of the cell is exocytosis.
4. First, the air, containing oxygen enters the lungs. Minute blood vessels, called capillaries, carry the oxygen directly to the cells. Through this process the cell carries on respiration. After using the oxygen, it is converted to carbon dioxide and expelled from the cell. This process is very important because it enables the cell to continue living. It is one of the most important process carried on by the cell.
5. Oh my god! This is quite long. I cannot remember the others! Sorry, but I cannot enumerate it all to you. For more information, go to http://en.wikipedia.org/wiki/Cellular_respiration and http://biology.clc.uc.edu/Courses/bio104/cellresp.htm
That's all!!!!