Cell Transport and Facilitated Diffusion

Question 1

T/F: All channel proteins are gated and require a signal from the body to open or close.

Accepted Answer

FALSE

Question 2

T/F: Transport proteins shield polar molecules from the hydrophobic core of a plasma membrane.

Accepted Answer

TRUE

Question 3

What part of a cell's plasma membrane would slow or block the entry of charged/polar molecules?

Accepted Answer

hydrophobic core

Question 4

Which type of transport protein can change shape to move target molecules through the membrane?

Accepted Answer

carrier proteins

Question 5

T/F: Materials with stronger concentration gradients result in faster diffusion.

Accepted Answer

TRUE

Question 6

At about what rate do carrier proteins facilitate the diffusion of molecules?

Accepted Answer

1,000 per second

Question 7

T/F: Channel & carrier proteins are typically selective for only 1 to a few types of molecules.

Accepted Answer

TRUE

Question 8

Which type of transport proteins span the membrane & make a hydrophillic tunnel for molecules?

Accepted Answer

channel proteins

Question 9

In this type of diffusion, molecules diffuse with the assistance of membrane proteins:

Accepted Answer

facilitated diffusion

Question 10

At what rate do typical channel proteins facilitate the diffusion of molecules?

Accepted Answer

tens of millions per second

Question 11

Which type of channel protein allows water to cross the membrane very quickly?

Accepted Answer

aquaporins

Question 12

Which of the following ions does NOT require facilitated diffusion to pass through a membrane?

Accepted Answer

ethanol

Question 13

Why are channel proteins able to move molecules across the plasma membrane at a faster rate?

Accepted Answer

they do not need to change shape and reset

Question 14

What term describes a substance's tendency to move from a high to a low area of concentration?

Accepted Answer

diffusion

Question 15

In general, which type of transport protein moves molecules more quickly across the membrane?

Accepted Answer

channel proteins

Question 16

What is known as a region of space where a substance's concentration changes?

Accepted Answer

concentration gradient

Questions 16