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Why would a substance not be able to pass through a membrane by diffusion?
Wiki User
∙ 7y ago
Water cannot diffuse a plasma membrane because of the fact that the phosphate heads of the phospholipids are hydrophilic, the hydrocarbon tails of the phospholipids are hydrophobic, meaning they repel water. The bilayer phospholipid model of the plasma membrane shows that the phophates face outward on either side of the membrane and the lipid tails are in the middle of the bilayer.
Wiki User
∙ 13y ago
Wiki User
∙ 12y agoBecause water is h20 which is polar molecule and it has unequal charges around the molecules.
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Which substance may enter a cell membrane by simple diffusion?
Water, certain ions, air and glucose molecules.
How does active transport differ from the process of diffusion across a membrane?
Diffusion is the process in which a certain substance achieves equal concentrations in a specific area. Diffusion across a membrane means that the substance is equally distributed between both sides of the membrane, assuming the substance can pass through that membrane (the membrane is permeable to the substance).Active transport is just that, active. It requires energy because it is usually moving substances to a place where they would not naturally move or increases the rate of their disbursing. Active transport can move molecules against a concentration gradient, whereas diffusion cannot.Simply, active transport means that energy is needed to transport the object/molecule while diffusion is a naturally occurring process dependent on the concentration gradients between the membrane.
What are metaphors for 'diffusion'?
Diffusion is the movement of a mineral or nutrient moving across the concentration gradient of a membrane. The closest word to diffusion would probobly be osmosis, which is the movement of water through a membrane.
What is active transport permeable membrane?
"Active" in this context means that energy is required. A substance will flow in a certain direction, through diffusion, without having to provide additional energy. To force the substance in the opposite direction would require energy; the cell has to be "active" to achieve this, and this requires energy.
What substances would be moved across the cell membrane by diffusion?
Smaller particles are more likely to move by diffusion. Fat soluble substances are also more likely to move through diffusion also.
What substances would most likely require a protein to facilitate its diffusion across a cell membrane?
Quick answer: glucose Explanation: Any substance that the membrane selects against requires integral proteins to cross the membrane. B/c the lipid bilayer is selectively permeable, not all substances can pass through it by diffusion or osmosis. However, when the cell requires a substance that it's membrane does not easily allow to pass through, it must enter via the proteins in the membrane. They can either be carrier proteins or protein channels depending on the substance. One example of a substance which requires facilitated diffusion is glucose.
Which substance may enter a cell membrane by simple diffusion?
Water, certain ions, air and glucose molecules.
How does active transport differ from the process of diffusion across a membrane?
Diffusion is the process in which a certain substance achieves equal concentrations in a specific area. Diffusion across a membrane means that the substance is equally distributed between both sides of the membrane, assuming the substance can pass through that membrane (the membrane is permeable to the substance).Active transport is just that, active. It requires energy because it is usually moving substances to a place where they would not naturally move or increases the rate of their disbursing. Active transport can move molecules against a concentration gradient, whereas diffusion cannot.Simply, active transport means that energy is needed to transport the object/molecule while diffusion is a naturally occurring process dependent on the concentration gradients between the membrane.
What is the difference between simple diffusion and facilitated diffusion?
It doesn't. (answer by RRU member Cyrem)
What are metaphors for 'diffusion'?
Diffusion is the movement of a mineral or nutrient moving across the concentration gradient of a membrane. The closest word to diffusion would probobly be osmosis, which is the movement of water through a membrane.
What is active transport permeable membrane?
"Active" in this context means that energy is required. A substance will flow in a certain direction, through diffusion, without having to provide additional energy. To force the substance in the opposite direction would require energy; the cell has to be "active" to achieve this, and this requires energy.
What do water passes through a membrane by?
It's called osmosis. The water will travel across the membrane to equal out concentrations so they are both the same. This is because water is a small molecule, able to move through the membrane.Think of it this way. If there were no membrane then the dissolved substance would diffuse throughout the mixture. If you put a membrane there then the same idea works but this time it is only the water that can move. So the water moves through the membrane until the same concentration of water molecules appear on each side.
What substances would be moved across the cell membrane by diffusion?
Smaller particles are more likely to move by diffusion. Fat soluble substances are also more likely to move through diffusion also.
What is the only substance that can carry out osmosis?
Strictly speaking, osmosis means the diffusion of waterthrough a semipermeable membrane. I'm not certain what the generic term for other solvents would be.
Which process would describe the movement of sugar molecules through a membrane from a region of higher concentration of a region of lower concentration?
Diffusion
When a substance moves across the plasma membrane along a concentration gradient at a rate faster than would be expected by simple diffusion alone but without the expenditure of metabolic energy?
It is called facilitated diffusion. It is a type of passive transport.
How does boiling a potato effect osmosis?
Boiling the potato destroys the cell membrane which is a partially permeable membrane. Thus osmosis is unable to occur as osmosis occurs through a partially membrane and only diffusion would occur.
