Exam 5: Cell Membranes and Signaling

The LDL receptor is an integral membrane protein that crosses the plasma membrane,with portions of the protein extending both outside and into the interior of the cell.The amino acid side chains (R groups)in the region of the protein that crosses the membrane are most likely

One reason cancer therapy often fails is that the targeted cells become resistant to the drugs that are supposed to kill them.Which of the following is the most likely mechanism of this resistance?

Adenosine is the normal _______ for its membrane receptor.

Which type of membrane protein would likely be most easily removed in a laboratory experiment?

Which of the following is an example of passive transport?

A selectively permeable membrane ensures that

You are doing a summer internship in a cell biology lab.Your supervisor asks you to change the medium on some cells she is growing.You do so and then examine the cells under a microscope.To your dismay,you can't find any cells and see only what looks like cell debris.What most likely happened to your cells and why?

G proteins do not bind to

How does a protein kinase cascade amplify an intercellular signal?

Houseplants adapted to indoor temperatures may die if they are left outdoors,because in a cold environment their

Which statement does not correctly describe the processes by which materials are taken up by the cell?

Osmosis is a specific form of

Which of the following bind(s)to the acetylcholine receptor?

The difference between osmosis and diffusion is that

The existence of a concentration gradient of glucose across a membrane means that

The plasma membranes of winter wheat are able to remain fluid when it is extremely cold by

The signals that bind to receptors on nearby cells are known as

A benefit of the many steps involved in a protein kinase cascade is that they allow for

If a hospital patient is mistakenly given an IV of pure water instead of a saline solution that is isotonic to blood,the patient's red blood cells will

Many signal transduction pathways cause