Exam 5: Cell Membrane Structure and Function

ISO membranes are inside- out membrane vesicles used by researchers in membrane studies. As a molecule diffuses into the vesicle, it will encounter the layers of the membrane in the following order

If the radius of one cell were twice as large as the radius of another cell, how much higher or lower would its surface- area- to- volume ratio be?

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?

What is active transport?

In reference to diffusion, passive really means

According to the fluid mosaic model of cell membranes, which of the following is a TRUE statement about membrane phospholipids?

Recognition proteins, such as those embedded on the surface of red blood cells, are composed of

Imagine that beaker A has a 10% sucrose solution, and beaker B has an 8% sucrose solution. This means that

Glucose is a six- carbon sugar that diffuses slowly through artificial phospholipid bilayers. The cells lining the small intestine, however, rapidly move large quantities of glucose from the glucose- rich food into their glucose- poor cytoplasm. Given this information, which transport mechanism is most probably functioning in the intestinal cells?

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

The secretion of excess water via a contractile vesicle of a Paramecium cell is an example of

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

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

is used by white blood cells to consume large particles such as bacteria.

What happens when diffusion moves molecules across the plasma membrane?

A freshwater protozoan, such as Paramecium, tends to because it lives in a environment.

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 electrical signal for a muscle to contract passes rapidly from one cell to the next via

The rate of facilitated diffusion of a molecule across a membrane will increase as the concentration gradient of the molecule across the membrane increases to a certain point. Eventually, an increase in the concentration of the molecule will not cause any further increase in facilitated diffusion. Thus, there is a maximal rate of facilitated diffusion. This is because

Carbon dioxide crosses the plasma membrane by simple diffusion. The rate at which carbon dioxide enters the cell is determined by the