Tutor profile: Tristan L.

You are running an experiment where you are manipulating the amount of a drug given to rats to help lower blood pressure. One group of rats get a placebo pill with no drug, another group gets a pill with 10 milligrams of drug, and a third group gets a pill with 50 milligrams of drug. After treatment the rats blood pressure is measured and recorded. In this experiment what is the independent variable and what is the dependent variable?

The independent variable is the thing you manipulate or change in an experiment and dependent variable is what you measure. So since you are manipulating the amount of drug and measuring the blood pressure, the independent variable is the drug and the dependent variable is the blood pressure.

You are studying an unknown animal cell under the microscope. You observed the cell undergo division twice and note that the number of labeled chromosomes in the four cells is half that in the original cell. What process did you just observe? Explain why.

I just observed meiosis. Animal cells usually divide through mitosis or meiosis. After mitosis the cell has created two copies of itself with the same number of chromosomes. After meiosis a cell has split twice and creates four copies each with half the original number of chromosomes. Since the cell I observed has half the number of chromosomes I observed meiosis and not two rounds of mitosis.

If there is a blood clot in the right middle cerebral artery what loss of motor function would you expect and why?

You would expect paralysis on the left side of the body. The right middle cerebral artery supplies blood flow to the right motor cortex which controls voluntary motor movement of the left side of the body. So a blood clot would damage those neurons and result in inability to move on the left side, or left hemiparesis.