KNES 191B Lecture Notes - Lecture 3: Cell Membrane, Facilitated Diffusion, Osmosis
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Question 1
Plasma membranes are selectively permeable. This means that
A. | glucose cannot enter the cell. | |
B. | the plasma membrane allows some substances to enter or leave a cell more easily than others. | |
C. | plasma membranes must be very thick. |
Question 2
Oxygen molecules O2 crosse a plasma membrane by
A. | passive transport | |
B. | osmosis | |
C. | active transport |
Question 3
Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient.
A. energy and channel proteins; against (up) | ||
B. transport proteins that make channels ; down | ||
C. energy ; down |
Question 4
When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will
A. move to the side with lower water concentration | ||
B. | move to the side with higher water concentration | |
C. | move to the side with lower solute concentration |
Question 5
Kinetic energy differs from chemical energy in that
A. | chemical energy is a particular form of kinetic energy. | |
B. | kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules. | |
C. | kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement. |
Question 6
When a cell uses chemical energy to perform work, it uses the energy released from a(n) ________ reaction to drive a(n) ________ reaction.
A. | exergonic; endergonic | |
B. | endergonic; exergonic | |
C. | spontaneous; exergonic |
Question 7
When an enzyme catalyzes a reaction
A. it raises the activation energy of the reaction. | ||
B. it lowers the activation energy of the reaction. | ||
C. it is used once and discarded. |
Question 8
Which of the following statements regarding enzyme function is false?
A. An enzyme's function depends on its three-dimensional shape. | ||
B. Enzymes are very specific for their substrates. | ||
C. Enzymes are used up when they catalyze a chemical reaction so must be synthesized for each new chemical reaction |