Exam 5: Cell Membrane Structure and Function

Phospholipids spontaneously form a bilayer in an aqueous solution. Why do the heads of the phospholipids point out and the tails point toward one another?

The net movement of molecules from a high concentration to a low concentration is BEST described by which of the following?

To say that a cell is "selectively permeable" means:

After a dye diffuses uniformly throughout a glass of water, the dye molecules are no longer moving. True or False?

Cystic fibrosis is a genetic disease that leads to the production of excessive, thick mucus in the respiratory tract, causing frequent and serious respiratory infections. The defect is due to the production of a faulty membrane protein for the transport of the chloride ion. The protein exists in membranes, but it doesn't function normally. Based on this scenario, what is occurring at the molecular level in a person with cystic fibrosis?

Suppose a bag made of a selectively permeable membrane was filled with a 5% solution of glucose and sealed. What would happen if the bag was placed in pure water or in a 10% glucose solution?

The main lipids found in cell membranes are:

Some of the most important molecules that are embedded within the bilayer membrane of a cell, such as the molecules that allow for transport and cell recognition, are:

Which of the following occurs as an enzyme produced by a cell is secreted from the cell?

Which of the following groups includes carrier and channel proteins?

Protein channels that provide passage for hormones and nutrients between animal cells are termed:

Active transport requires all of the following EXCEPT:

Suppose you have two glucose solutions separated by a selectively permeable membrane. If there is a concentration gradient of glucose across the membrane, then one of the solutions cannot be:

Imagine an artificial cell made with a selectively permeable membrane that allows water to pass through but does not allow sugar to pass. If you fill this cell with a 1% sugar solution and then you place the cell in a 2% sugar solution, what happens?

More than half a century ago, two cell biologists published details of their research involving isolated membrane vesicles from chloroplasts. Normally, the fluid inside these vesicles is near neutral. In an experiment, these membrane vesicles were soaked in an acidic solution (pH 4)until the inside of the vesicle also became pH 4. Based on the details provided in this scenario, by what mechanism could hydrogen ions have crossed the vesicle membrane, and what do you think happened at the molecular level?

Which of the following is an energy-requiring mode of transport that brings substances into a cell?

The process in which white blood cells engulf bacteria is termed:

Compare and contrast the intercellular junctions that allow communication between plant and animal cells.

Distinguish among the three types of endocytosis: pinocytosis, receptor-mediated endocytosis, and phagocytosis.

The major lipids in biological membranes are called ________.