Download Cell Defense Build a membrane: The membrane of the cell is

Cell Defense
Build a membrane:
The membrane of the cell is selectively permeable meaning that only some substances are allowed to
enter and leave the cell. The membrane is organized into a lipid bilayer. Each layer is made up of
macromolecules called phospholipids (a phosphate head and 2 fatty acid tails).
The heads are hydrophilic or water­loving.
The tails are hydrophobic or water­fearing.
What role does cholesterol play in the cell membrane?
a. They provides structure for the membrane
b. They provides a channel for large and/or charged molecules to pass through
c. They provides additional energy for the membrane
d. They adds decoration to make the cell more attractive
Why were CO₂ and O₂ molecules allowed to pass through the membrane?
a. They are polar.
c. They are nonpolar
b. They are small and nonpolar
d. They are fast moving
Why were the sugar molecules not allowed to pass through the membrane?
a. They are large and polar.
c. They are small and nonpolar.
b. They are small and polar.
d. They are slow moving.
What structures in the membrane allows for large and charged molecules to pass through it?
a. phospholipids
c. protein channels
b. carbohydrates
d. cholesterol
Movement of molecules from HIGH concentration to LOW concentration through the use of a protein
channel is called…
a. simple diffusion
c. osmosis
b. facilitated diffusion
d. active transport
Which of the following is necessary in order for active transport to take place?
a. a protein channel
c. ATP or energy
b. All of these
d. Particle movement from LOW to HIGH concentration
Diffusion Challenge:
Add additional molecules to the right side of the membrane to establish dynamic equilibrium.
If the concentration of oxygen in a body tissue cell is 5% and the concentration of oxygen in the blood
surrounding the cell is 10%, which direction will oxygen diffuse?
a. Oxygen will diffuse INTO the body tissue cell.
b. Oxygen will diffuse OUT OF the body tissue cell and INTO the blood.
c. Oxygen will not diffuse. It is already in dynamic equilibrium.
d. Oxygen only diffuses in video games, not in real life.
Energy and Transport Challenge:
If the sugar concentration in a cell is 3% and the concentration in the cell’s environment is 5%, how
can the cell obtain more sugar? Hint: Sugar is polar and does not pass through the phospholipid
bilayer easily.
a. Sugar can diffuse straight through the phospholipid bilayer.
b. Sugar can undergo facilitated diffusion through a channel protein and no energy is required.
c. The cell CANNOT obtain any more sugar. It is doomed.
d. The cell must use active transport to pump the sugar in. Energy is required.
If the sugar concentration in a cell is 4% and the concentration in the cell’s environment is 2%, how
can the cell obtain MORE sugar?
a. Sugar can diffuse straight through the phospholipid bilayer.
b. Sugar can undergo facilitated diffusion through a channel protein and no energy is required.
c. The cell CANNOT obtain any more sugar. It is doomed.
d. The cell must use active transport to pump the sugar in. Energy is required.
Osmosis:
Use arrows to indicate which direction water will flow in the image below.
Hypertonic = _High__ in solute.
Hypotonic = _Low_____ in solute.
Isotonic = _Equal_______ in solute.
If a cell is placed in HYPERTONIC solution, what will happen?
a. The cell will lose water to its environment because water will travel out of the cell due to
osmosis.
b. The cel will gain water because water will travel into the cell due to osmosis
c. The cell will remain the same because the cells are not affected by solutions.
d. The cell will explode.