Cell Block Security
Explain what is meant by "selective permeability."
Some things can move through, while others cannot move through a membrane.
What is the special name for the diffusion of water?
Osmosis
What is the term for the solution around a cell if the solution and the inside of the cell have the same concentration of solutes (such as salts, sugars, etc).
Isotonic
What energy molecule is necessary for any type of active transport to function?
ATP -or- adenosine triphosphate
Give any example of how homeostasis is maintained by the plasma membrane.
Control what enters/exits; Regulate water; Regulate ions; ATP powered pumps; Communicating with hormones; Removing waste; Nutrient uptake; Structural integrity & Fluidity
What do the terms "Hydrophilic" and "Hydrophobic" mean?
Water loving (mixes with water) and water fearing (doesn't mix with water)
Ions like sodium and potassium cannot freely diffuse through a membrane. They need help from a channel protein. What is the term for that type of diffusion.
Facilitated Diffusion
Sometimes, the concentration of solutes outside a cell is higher or lower than the inside of a cell. What are the two terms we use to describe these conditions? (need both)
Hypertonic; Hypotonic
How are oxygen and carbon dioxide able to move through the membranes of the lungs (alveoli) and red blood cells?
High to low concentration; Simple Diffusion; More on one side than the other.
Name any two components/parts of the plasma membrane. (Need two)
What are the two parts of the "bilayer" in the plasma membrane? (Need both)
Hydrophilic (polar) heads and hydrophobic (nonpolar) tails -or- glycerol head and two fatty acid tails.
In the term "Dynamic Equilibrium" what do each of the words mean? (Dynamic and Equilibrium)
Equilibrium means equal concentrations; Dynamic means still moving.
What happens to a red blood cell if placed into a hypotonic solution, such as distilled water?
It will expand, and possibly burst open.
What does it mean to pump solutes "against the concentration gradient"?
Move solutes from where there aren't as many, into an area where there are already many. Lower concentration into a higher concentration of solutes.
What are the terms for moving large particles, or large amounts of materials, into or out of the cell through the membrane? (Need both)
Endocytosis and Exocytosis
List at least three jobs or functions of the proteins in the cell membrane.
Enzymes (metabolism); transport of substances; identification; attachment; receptors, structural support
In order for simple diffusion of a solute through a membrane to occur, what two conditions must be met? (Need both)
Higher concentration on one side; membrane is permeable to the solute.
What might happen to a plant cell if it is exposed to a hypertonic water solution, such as salty water?
Shrink, wilt, die.
In a nerve cell, the Na+/K+ Pump moves sodium which direction and potassium which direction?
Sodium (Na+) out; Potassium (K+) in
What component of the membrane keeps the phospholipids together when the temperature increases, and also keeps phospholipids separated when the temperature decreases?
Cholesterol
List the names of at least three different types of membrane proteins.
Na/K Pump; Na/Glucose cotransporter; sodium and/or potassium leakage channel; voltage gated sodium and/or potassium channel; aquaporin
Name at least two things that will change the rate/speed of diffusion of a solute through a membrane. (need two)
Temperature (heat increases; cold decreases); Concentration difference (high difference goes faster); Size of the pores in the membrane (larger pores diffuse faster); Time (more time means more diffusion); Size of the solute (smaller solutes move faster); Others if reasonable.
A freshwater fish is placed into a saltwater tank. What direction will the majority of the water move?
Out of the fish -or- Into the saltwater tank.
Diffusion and Facilitated diffusion will not be affected; Active transport will be inhibited/stopped.
What are the three different names of the structure surrounding all cells? (Need three)
Phospholipid Bilayer; Plasma Membrane; Cell Membrane