Chapter 5 Test
Facilitated diffusion across biological membrane requires ___(1)____ and moves a substance ___(2) its concentration gradient.
1. energy and transport proteins 2. down
Which of the following statements regarding active transport is false?
Active transport is driven by the concentration gradient
A child is brought to the hospital with a fever of 107 degrees F. Doctors immediately order an ice bath to lower the child's temperature. Which of the following statements offer the most logical explanation for this action?
Elevated body temperatures may denature proteins. This would interfere with the cell's abilities to catalyze various reactions
In the lab, you use a special balloon that is permeable to water, but not sucrose, to make an artificial cell. The balloon is filled with a solution of 20% sucrose and 80% water and immersed in a beaker containing a solution of 40% sucrose and 60% water. Which of the following will occur?
Water will leave the balloon
Which of the following substances could be a cofactor?
a zinc atom
Substrate binds to an enzyme's ____ site?
active
Which of the following processes can move a solute against its concentration gradient?
active transport
A plant cell in a hypertonic solution___.
becomes turgid because of an inflow of water
After the reverse osmosis system has been operating for 30 minutes, the solution in Tank A would ___.
by hypertonic to tank B
Heating inactivated enzymes by_____.
changing the enzyme's three dimensional shape
How does inhibition of an enzyme-catalyzed reaction by a competitive inibior differ from inhibition by a noncompetitive inhibitor?
competitive inhibitors bind to the active site of the enzyme;noncompetitive inhibitors bind to a different site
Inhibition of an enzyme is irreversible when____.
covalent bonds form between inhibitor and enzyme
Which of the following statements regarding diffusion is false?
diffusion occurs when particles spread from areas where they are less concentrate to areas where they are more concentrated
The fluid mosaic model describes the plasma membrane as consisting of_____.
diverse proteins embedded in a phospholipid bilayer
Phagocytosis is to drinking as pinocytosis is to_____.
eating
Which of the following statements regarding enzymes is true?
enzymes are inorgainc
Which of the following statements regarding enzyme function is false?
enzymes are used up when the catalyze a chemical reaction, so must be synthesized for each new chemical reaction
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____.
exhibit a net movement to the side with lower free water concentration
Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion?
exocytosis
In the lab, you use a special balloon that is permeable to water to make an artificial cell. The balloon is filled with a solution of 20% sucrose and 80% water and immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the balloon is ______ relative to the solution in the beaker.
hypertonic
A cell that neither gains nor loses water when it is immersed in a solution must be____.
isotonic to its environment
When an enzyme catalyze a reaction_____.
it lowers the activation energy of the reactant
In a hypertonic solution, an animal cell will_____.
lyse
Which of the following statements regarding membrane protein function is false?
membrane proteins transfer genetic information to the cytoplasm
White blood cells are more resistant to lysis than red blood cells. When looking at a sample of blood of white blood cells, what could you do to reduce interference from red blood cells?
mix the blood in an isotonic solution and allow the white blood cells to float to the top
Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of ____.
passive transport
Oxygen crosses a plasma membrane by_____.
passive transport
The process of a white blood cell engulfing a bacterium is_____.
phagocytosis
Most of a cell's enzymes are___.
proteins
Most of the functions of a cell membrane, including transport and enzymatic functions, are performed by____.
proteins
The molecules responsible for membrane transport are___.
proteins
All cells are enclosed by a plasma membrane that is similar in ____ and _____.
structure and function
Which of the following statements is true among all types of passive transport?
the concentration gradient is the driving force
Osmosis can be defined as____.
the diffusion of water
Plasma membranes are selectively permeable. This means that______.
the plasma membrane allows some substances to enter or leave a cell more easily than others
Which of the following statements regarding membrane is false?
the plasma membrane id the control center of the cell
The active site of an enzyme is_____.
the region of a product that attaches to a substrate
Which of the following statements regarding is a typical feature of an ATP-driven active transport mechanism?
the solute moves against the concentrated gradient
You are adrift in the Atlantic ocean, and, being thirsty, drink the surrounding seawater. As a result ____.
you dehydrate yourself
