________ is a kind of diffusion in which molecules of water pass through a selectively permeable membrane from a region where water has a higher effective concentration to a region where its effective concentration is lower.
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transmembrane proteins
Adhering junctions are formed by cadherins, ________ that cement cells together.
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model
According to the fluid mosaic ________, membranes consist of a fluid phospholipid bilayer in which a variety of proteins are embedded.
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ATP powered pump
A(n) ________ maintains a concentration gradient.
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specific transport proteins
Facilitated diffusion uses ________ to move solutes across a membrane.
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metabolic energy
In active transport, the cell expends ________ to move ions or molecules across a membrane against a concentration gradient.
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Lipid bilayers
________ are flexible and self- sealing and can fuse with other membranes.
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Cells
________ regulate their internal osmotic pressures to prevent shrinking or bursting.
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Porins
________ are channel proteins that form relatively large pores through the membrane for passage of water and certain solutes.
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Plasmodesmata
________ are channels connecting adjacent plant cells.
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Phagocytosis
In ________, the plasma membrane encloses a large particle such as a bacterium, forms a vacuole around it, and moves it into the cell.
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Vesicles
The ________ fuse with lysosomes, and their contents are digested and released into the cytosol.
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Cotransport
In ________, also called indirect active transport, two solutes are transported at the same time.
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Gap junctions
________, composed of the protein connexin, form channels that allow communication between the cytoplasm of adjacent animal cells.
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sheet of tissue
Anchoring junctions include desmosomes and adhering junctions; they are found between cells that form a(n) ________.
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Channel
________ proteins are transport proteins that form passageways through which water and certain ions travel through the membrane.
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Carrier
________ proteins are transport proteins that undergo a series of conformational changes as they bind and transport a specific solute.
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Biological membranes
________ are selectively permeable membranes: they allow the passage of some substances but not others.
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isotonic solution
A(n) ________ has an equal solute concentration compared with that of another fluid, for example, the fluid within the cell.
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Diffusion
________ is the net movement of a substance down its concentration gradient from a region of greater concentration to one of lower concentration.
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osmotic pressure
The concentration of dissolved substances (solutes) in a solution determines its ________.
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Tight junctions
________ seal membranes of adjacent animal cells together, preventing substances from moving through the spaces between the cells.
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Membranes
________ participate in and serve as surfaces for biochemical reactions.
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lower solute concentration
When cells are placed in a hypotonic solution, one that has a(n) ________ than the solute concentration of the cell, water enters the cells and causes them to swell.
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simple diffusion
In ________ through a biological membrane, solute molecules or ions move directly through the membrane down their concentration gradient.
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metabolic energy
The cell expends ________ to carry on exocytosis and endocytosis.
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Biological membranes
________ form compartments within eukaryotic cells that allow a variety of separate functions.
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Diffusion
________ and osmosis are physical processes that do not require the cell to directly expend metabolic energy.
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biological membranes
In almost all ________, the lipids of the bilayer are in a fluid or liquid- crystalline state, which allows the lipid molecules to move rapidly in the plane of the membrane.
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The phospholipid molecules are amphipathic
they have hydrophobic and hydrophilic regions
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Biological membranes are selectively permeable membranes
they allow the passage of some substances but not others
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