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All ionic molecules and all large fat molecules.
What can get in (without help) is water and dissolved gases.
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∙ 15y ago
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How do you large molecules and ions pass through the cell membrane?
Recently had a homework on the cell membrane, i do know that larger molecules that cant fit through the polar heads into the cell (like gases can...and small molecules?!) can get through only if they qualify the shape fitting of the channel protein- the one that reaches all the way from the outside to the inside of the membrane. hope this helps
What two factors of a molecule determine whether or not cross the membrane?
size and shape. cell membranes are selectively permeable, so only some molecules can get through. (i.e. water can go through, but starch cant) Polarity and size.
When does all motion of molecules stop?
When the temperature reached absolute zero (0 Kelvin or -273 Celsius), all molecular motion ceases.
Which two factors of the molecule determine whether or not it can cross the membrane?
size and shape. cell membranes are selectively permeable, so only some molecules can get through. (i.e. water can go through, but starch cant) Polarity and size.
What are membranes that only allow certain molecules to pass through them and keep others out?
This is because the cell membrane is a partially permeable membrane, hence allowing the smaller molecules to enter it and larger molecules to be out. For example, protein is too large to enter the cell. So, it is broken down by the enzymes in our stomach into amino acids, which are small enough to enter the holes into the membrane. A way to remember this is to remember that oversized people cant enter the house because the door is too small, hence keeping him/her away.
What part of the membrane would help a large protein molecule enter the cell?
Globular Proteins
Why cant polar molecules and ions diffuse across the cell membrane?
Ions cannot diffuse through a phospholipid bilayer because they are not able to dissolve in lipids, hence the phosphoLIPID bilayer . Also, since they have an electrical charge, they are repelled by the membrane.
Why cant big molecules pass through wall guts?
The cell walls of the intestinal cells do not allow the passage of large molecules through them; in addition, the tight junctions between the cells blocks the transfer of large molecules through the interstitial space.
What does seminpermeable membrane do?
semi permeable membrane is semi-permeable or not completely permeable...it allows particles of a certain shap or size flow through but other shapes that are large or snaller cant fit through.
Why cant water simply diffuse through the phospholipid bilayer?
Because there is a hydrophobic core in the phospholipid bilayer, it may be difficult for water molecules to pass through the membrane. Therefore, there are proteins that aid this process called aquaporins.
Name the 2 ways that materials can pass through the cell membrane?
The two ways that materials can pass through the cell membrane are active transport and passive transport. In active transport the molecules cannot pass freely across the membrane and have to be carried across in ways that require energy. In passive transport the molecules can pass freely across the membrane in ways that do not take any energy.
How many types of atoms and molecules are found in cells?
Atoms are the same. In fact mostly light but molecules are very very large. So large that you cant write most of their symbol on the page
