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Osmosis.
Horace Hill
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What is cell membrane permeability?
It is the ability of the membrane to allow ions and/or particles to cross.
Which particles-starch or Lugol's-were able to cross the model cell membrane?
The particles that were able to cross the model cell membrane was the Lugol's solution.
What is pore protein?
integral protein that embedded to the plasma membrane. Allow small substances to cross the plasma membrane.
Are the salt particles able to cross the membrane?
If you are referring to osmosis, the salt doesn't cross the membrane, water does. Water will move into the salt water to attempt to dilute it to create homeostatsis, or equal concentrations on each side of the membrane.
What structures allow small particles to cross the cell membrane?
Small particles can cross the cell membrane through simple diffusion, facilitated diffusion, or active transport. In simple diffusion, particles move from an area of high concentration to low concentration without the need for energy. Facilitated diffusion involves the use of protein channels or carriers to aid in the movement of particles. Active transport requires energy and transport proteins to move particles against their concentration gradient.
Do protein channels allow small charged molecule to cross the cell membrane?
Yes
Why is the tonicity of a solution important?
TONICITY describes the degree to which a solution can exert an osmotic pressure on a membrane. Particles which can freely cross a membrane do NOT affect tonicity. This is because they will freely move in order to achieve equilibrium. Therefore, tonicity is dictated by the particles than can't cross the membrane (such as proteins, which are usually too large to cross, or highly charged particles). Non-permeable particles will therefore force water to cross the membrane towards them in order to achieve equilibrium - they can therefore be said to exert an osmotic pressure on the membrane.Solutions can be HYPERTONIC (i.e. the surrounding solution contains a larger concentration of these non-permeable particles than inside the cell, causing water to LEAVE the cell) or HYPOTONIC (i.e. the opposite, where water moves INTO the cell). They can also be ISOTONIC (there is equilibrium of the non-permeable particles, so no water moves).There is a very important distinction between tonicity and OSMOLARITY: osmolarity ALSO takes into account the particles that CAN cross the membrane (the permeable ones). So a solution could be both HYPEROSMOLAR and ISOTONIC at the same time - one set of particles will be able to freely cross the membrane, so there will no net change in cell volume.
What helps to allow materials to cross the plasma membrane?
Integral proteins - proteins which span the width of the membrane. This can be things such as channels and pumps.
Is an ability of a plasma membrane to allow some substance to cross across the membrane more easily than others?
selective permabiltiy
What is meant when a system has reach equilibrium?
when the substance can cross the cell membrane, its particles will tend to move toward the area where it is less concetrated
How easy or hard is it for polar molecules to pass through the cell membrane?
Polar molecules are effectively charged molecules. It's hard for them to cross the cell membrane because the membrane is comprised of an uncharged phospholipid bilayer. Charged molecules tend to have specific protein channels that allow them to cross the membrane.
What properties of carbon dioxide and oxygen allow them to easily cross a membrane?
i believe its their small size-- low atomic weight.
