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Which substances are able to cross the membrane, and what determines their ability to do so?
Certain substances, such as small molecules and ions, are able to cross the cell membrane. The ability of a substance to cross the membrane is determined by its size, charge, and solubility in the lipid bilayer of the membrane.
What is transported across a membrane during osmosis?
During osmosis, water molecules are transported across a membrane from an area of higher concentration to an area of lower concentration.
Does transported substances never physically cross the plasma membrane in endocytosis?
In endocytosis, transported substances are enclosed in vesicles formed from the plasma membrane, which do physically cross the plasma membrane. These vesicles then transport the substances into the cell.
What regulates passage of materials into and out of cells?
The cell membrane, or plasma membrane, regulates the passage of materials into and out of cells through selective permeability. This means that only certain substances are allowed to pass through the membrane, while others are blocked or actively transported. This selective permeability helps maintain the internal environment of the cell and allows for proper function and communication with the external environment.
What single characteristic of the semipermeable membrane used in the laboratory determines the substances that can pass through them?
The molecular size of the substances is the single characteristic that determines which substances can pass through a semipermeable membrane in the laboratory. Smaller molecules can pass through while larger molecules are blocked.
What determines whether or not a substance can be actively transported through the membrane?
Active transport can only occur at intact, closed membranes. Such membranes can envelop very different compartments, like the whole cell, vesicles, the vacuole, the mitochondrial matrix, the inner thylacoid space of the chloroplasts, etc.
Under what condition would a molecule need to be actively transport across a membrane?
A molecule would be actively transported when an equal concentration of solutes exist on either side of the cell membrane.
Which is a factor that determies whether a mole can cross a cell membrane?
Lipid solubility determines if it will diffuse across. The presence of specific protein carrier molecules determines if it will be transported across the membrane.
Which molecule would most likely be actively transported?
A larger molecule or a polar molecule that cannot passively diffuse through the cell membrane would most likely be actively transported. Examples include glucose, ions (such as sodium and potassium), and amino acids.
What substance crosses the cell membrane through osmosis?
Only water is transported through the process of osmosis.
What determineds the direction in which a substance diffuses across a membrane?
Concentration gradient determines the direction of flow.
How do materials get in and out of the cell?
Some materials cross the cell membrane by diffusion. Some cross through channels. Some bind to receptors and are actively transported.
What is the limiting factor for the reabsorption of most actively transported solutes in the proximal tubule?
The limiting factor for the reabsorption of most actively transported solutes in the proximal tubule is the number of transport proteins available on the apical membrane of the tubular cells. If there aren't enough transport proteins present, the reabsorption of solutes will be limited, leading to decreased efficiency in solute reabsorption.
What are the sub substances transported in osmosis?
In osmosis, water is the main substance that is transported across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. This movement of water helps to equalize the concentration of solutes on either side of the membrane.
Which substances are able to cross the membrane, and what determines their ability to do so?
Certain substances, such as small molecules and ions, are able to cross the cell membrane. The ability of a substance to cross the membrane is determined by its size, charge, and solubility in the lipid bilayer of the membrane.
When a cell membrane actively surrounds a solid substance and forms a vesicle which moves into the cell this is called what?
This process is known as endocytosis, specifically phagocytosis if the solid substance being engulfed is a large particle or bacterium. Endocytosis involves the cell membrane wrapping around the substance to form a vesicle that is then internalized into the cell.
How is water transported across the membrane?
Water is transported by a passive transport called osmosis. Osmosis is diffusion of water across the membrane.
