When a solute moves down its concentration gradient across a non-permeable barrier, the process is known as __________.

Plasma membrane channels are classified as which of the following?

Cryptosporidium is a genus of gastrointestinal parasite that infects the intestinal epithelium of mammals. Cryptosporidium is water-borne, and is an apicomplexan parasite. This phylum also includes Plasmodium, Babesia, and Toxoplasma.

Apicomplexans are unique due to their apicoplast, an apical organelle that helps penetrate mammalian epithelium. In the case of cryptosporidium, there is an interaction between the surface proteins of mammalian epithelial tissue and those of the apical portion of the cryptosporidium infective stage, or oocyst. A scientist is conducting an experiment to test the hypothesis that the oocyst secretes a peptide compound that neutralizes intestinal defense cells. These defense cells are resident in the intestinal epithelium, and defend the tissue by phagocytizing the oocysts.

She sets up the following experiment:

As the neutralizing compound was believed to be secreted by the oocyst, the scientist collected oocysts onto growth media. The oocysts were grown among intestinal epithelial cells, and then the media was collected. The media was then added to another plate where Toxoplasma gondii was growing with intestinal epithelial cells. A second plate of Toxoplasma gondii was grown with the same type of intestinal epithelium, but no oocyst-sourced media was added.

The apicoplast that defines the phylum Apicomplexa is a membrane bound organelle. Which of the following is true of membrane-bound organelles?

I. They are only present in eukaryotes

II. They are bound by a single phospholipid layer

III. They do not have membrane-associated proteins attached

Which is not a difference between prokaryotic and eukaryotic cells?

Which of the following is true regarding plasma membrane channels?

Which of the following is generally permeable to the cell membrane?

The sodium-potassium pump helps to maintain electrolyte gradients through use of ATP. Which of the following best describes this type of transport?

Which of the following molecules would not require a transport protein to cross the cellular plasma membrane?

Which of the following are true about a cell's phospholipid bilayer?

Assume that there are thirty sodium ions outside the cell and twenty potassium ions inside the cell. What will happen after one cycle of the sodium-potassium pump?