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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.
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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 must a substance pass through to enter or leave a cell?
A substance must pass through the cell membrane in order to enter or leave a cell. This process can occur through various methods such as simple diffusion, facilitated diffusion, active transport, or endocytosis/exocytosis. The cell membrane acts as a barrier that selectively allows certain substances to pass through while blocking others.
Would oxygen particles enter a cell through diffusion more likely than fat particles?
Yes, oxygen particles would enter a cell through diffusion more readily than fat particles due to their smaller size and higher solubility in the cell membrane. Fat particles are larger and less likely to pass through the cell membrane via simple diffusion.
Which substance may enter a cell membrane by simple diffusion?
Water, certain ions, air and glucose molecules.
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.
What is the difference between simple diffusion and facilitated diffusion?
It doesn't. (answer by RRU member Cyrem)
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 must a substance pass through to enter or leave a cell?
A substance must pass through the cell membrane in order to enter or leave a cell. This process can occur through various methods such as simple diffusion, facilitated diffusion, active transport, or endocytosis/exocytosis. The cell membrane acts as a barrier that selectively allows certain substances to pass through while blocking others.
Would oxygen particles enter a cell through diffusion more likely than fat particles?
Yes, oxygen particles would enter a cell through diffusion more readily than fat particles due to their smaller size and higher solubility in the cell membrane. Fat particles are larger and less likely to pass through the cell membrane via simple diffusion.
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
Which substance would most easily pass through a cell membrane?
Small, non-polar molecules like oxygen and carbon dioxide would most easily pass through a cell membrane.
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?
The process is called facilitated diffusion, as it relies on carrier proteins or channel proteins to aid in the movement of the substance across the membrane. It does not require the cell to use energy because the movement is still following the direction of the concentration gradient.
How would you define diffusion?
Cellular diffusion is when molecules in the cell go from high concentration to low concentration to balance out the concentration. Small molecules can diffuse through the cell membrane, but larger molecules need the help of proteins. This is call facilitated diffusion.
When would facilitated diffusion be used?
Facilitated diffusion is used when molecules need to move across a cell membrane from an area of high concentration to an area of low concentration, but cannot pass through the lipid bilayer on their own. In facilitated diffusion, carrier proteins or channel proteins help facilitate the movement of these molecules across the membrane.
