Cell Transport Review
Facilitated diffusion across a biological membrane requires _______ and moves a substance ________ its concentration gradient.
Transport proteins; down
True/False: Fatty acid tails are hydrophobic.
True.
What occurs in a hypertonic solution?
Water leaves the cell.
The fluid mosaic model describes the plasma membrane as consisting of...
A phospholipid bilayer embedded with proteins attached to carbohydrates that can "float" among the lipids.
Membrane phospholipids form...
A strong barrier between the cell and its surroundings.
What type of transport requires ATP?
Active Transport.
Which of the following processes could result in the net movement of a substance into a cell, if the substance is more concentrated in the cell that its surroundings?
Active Transport.
What best describes the general direction of diffusion across a membrane of a cell when the relative concentration of carbon dioxide is higher inside the cell.
Carbon dioxide would diffuse out of the cell.
When physicians perform an organ transplant, they choose a donor whose tissues match those of the recipient as closely as possible. Which of the following cell components are being matched?
Cell-surface carbohydrates.
True/False: Diffusion occurs when particles spread from areas where they are less concentrated to where they are more concentrated.
False.
________ _________ help maintain homeostasis.
Feedback mechanisms.
A balloon is filled with a solution of 20% sucrose and 80% water. This solution is immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the *beaker* is ___________ to the solution in the balloon.
Hypertonic
In a hypotonic solution, an animal cell may...
Lyse (go through cytolysis)
White blood cells are more resistance to lysis than red blood cells. When looking at a sample of blood for WBCs what could you do to reduce interference from RBCs?
Mix the blood with a hypotonic solution, which will cause the RBCs to lyse.
Small, nonpolar, hydrophobic molecules such as fatty acids can easily...
Pass through a membrane's lipid bilayer.
Oxygen crosses a plasma membrane by...
Passive Transport.
Diffusion does not require the cell to expend any ATP. Therefore, diffusion is considered a type of __________ transport.
Passive.
Most of the functions of the cell membrane are performed by...
Proteins.
What will happen to the concentration of O2 if there are more O2 molecules present outside of the cell?
The concentration of O2 molecules will increase inside the cell.
Plasma membranes are selectively permeable. This means...
The plasma membrane allows some substances to enter or leave the cell more easily than others.
You are adrift in the Atlantic Ocean, and, being thirsty, drink the surrounding seawater. As a result...
You dehydrate yourself.
