Since Toxicity has been described as a cascade of events initiated by exposure to a harmful chemical, let's see if we can apply that to real life terminology, not just Textbook definition. Post a real-life example of Toxicity based in this definition, describe What is the toxic chemical, how it will effect a number of events in the body or in cells, what the possible end results to exposure at different levels might be. Address why we might use molecular and cellular techniques like testing out your toxic chemical on cell culture tissue in a petry dish, and how this could be helpful to us in figuring out levels of toxicity.

Brief example (which does not go into nearly enough detail, but is sufficient for you guys to get the idea) which you may NOT use for your example in the posts. Example is cigarette smoking. The smoking of cigarettes directly exposes several tissues such as the lining of the mouth and nasal cavities, the throat, the lungs, etc to MANY chemicals, such as nicotine, tar, formaldehyde, and nitrosamies just to name a few. Chemicals such as formaldehyde are carcinogens. These carcinogens are toxic chemicals that don't themself cause the cancers to portions of the body, but are the instigating chemical of inital exposure. The body in combination with other chemicals the body is exposed to will process the formaldehyde, generating a secondary carcinogen which may be capable of altering DNA structure or even altering a portion of our genetic code inside a single cell. This alteration can be a simple event which makes cells grow uncontrolled by the body they are within and twice to 20X as rapidly as normal, no longer under the control of that body they exist within.

Now obviously more detail should be provided about the chemicals, their toxicity, and the physiological cascades they might cause, but this should give you some idea as to where to start.