Exam 7: Cell Membranes, Transport, and Communication

Imagine two solutions separated by a selectively permeable membrane that is impermeable to glucose. On one side of the membrane, solution A contains 10 percent glucose and on the other side, solution B contains 25 percent glucose. Which of the following is true?

Active carrier proteins are not found in the same cells as passive carrier proteins.

A concentration ____________________ is said to exist when a molecule is more abundant in one area than it is in another.

Cells suspended in a hypertonic solution will lose water.

Hydrophilic signaling molecules interact with cells by interacting with cell surface ____________________.

Signaling molecules can affect a cell from the outside by interacting with specific receptors that are located

To coordinate the functions of specialized cells, those cells must be able to

Tight junctions prevent the movement of the extracellular matrix between cells.

The concentration of glucose inside of a cell is higher than the concentration outside of that cell, yet glucose continues to enter the cell. This is an example of

Muscle cells require high concentrations of calcium to function properly. As a result, these cells use ____________________ transport to move calcium from areas of low concentration outside the cell into the cytoplasm.

Active carrier proteins can transfer molecules into areas of higher concentration.

The various connections between cells including cell junctions and signaling molecules allow the cells in a multicellular organism to "talk" to each other, a principle known as cell-to-cell ____________________.

You observe a vesicle moving toward the plasma membrane from the inside of a cell. Once it reaches and fuses with the plasma membrane, you will most likely see an example of

Osmoregulation refers to balancing water concentrations in organisms and cells.

People are often warned to watch their blood cholesterol level to be sure it does not become too high. In fact, some people do not eat any cholesterol-containing foods at all. Even though we associate elevated cholesterol levels with a risk of heart attack and stroke, why does the body make some cholesterol even if none is eaten?

Receptors in target cells can be located in the plasma membrane, the cytosol, or the ____________________.

Channel proteins provide a means for large ____________________ [hydrophobic or hydrophilic] molecules to move across the plasma membrane.

The passive movement of water across a selectively permeable membrane is called ____________________.

Cells in the liver typically acquire cholesterol by receptor-mediated ____________________.

Elevated cholesterol and LDL (the particles that transport cholesterol)have been strongly associated with vascular disease; what process(es)lead to the elevated levels?