Question

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The membranes of fishes that live in extreme cold have a high proportion of _________________ hydrocarbon tails, enabling them to stay fluid.For example, cold-adapted organisms such as winter wheat increase the percentage of _________________ phospholipids in their membranes in the autumn to prevent the membranes from solidifying during winter.There are two major populations of membrane proteins: ___________ and _____________.Integral proteins penetrate the hydrophobic interior of the lipid bilayer, usually completely spanning the membrane as ________________ proteins.________________ proteins are not embedded in the lipid bilayer at all.

_____________ of specific solutes into or out of cells._____________ activity, sometimes catalyzing one of a number of steps of a metabolic pathway._____________, relaying hormonal messages to the cell._____________ recognition, allowing other proteins to attach two adjacent cells together.Intercellular joining of adjacent cells with gap or tight junctions.Membrane carbohydrates may be covalently bonded to lipids, forming ________________, or more commonly to proteins, forming ________________.The four human blood groups (A, B, AB, and O) differ in the _________________ part of glycoproteins on the surface of red blood cells. Substances do not move across the barrier indiscriminately; membranes are ______________ permeable.Nonpolar molecules, such as hydrocarbons, ________, and ________, are hydrophobic and can dissolve in the lipid bilayer and cross easily, without the assistance of membrane proteins.The hydrophobic interior of the membrane impedes the direct passage of ________ and _________molecules, which are hydrophilic. Cell membranes are permeable to specific ions and a variety of polar molecules, which can avoid contact with the lipid bilayer by passing through ______________ proteins that span the membrane.Some transport proteins called ______________proteins have a hydrophilic channel that certain molecules or ions can use as a tunnel through the membrane.The passage of water through the membrane can be greatly facilitated by channel proteins known as __________.Some transport proteins called ______________ proteins bind to molecules and change shape to shuttle them across the membrane.Each substance diffuses down its own concentration gradient, _______________ of the concentration gradients of other substances.The diffusion of a substance across a biological membrane is ___________ transport because it requires no energy from the cell to make it happen.In the end, the effect is the same: Water diffuses across the membrane from the region of _________ solute concentration (higher free water concentration) to the region of __________ solute concentration.If a cell without a cell wall, such as an animal cell, is immersed in an environment that is _________ to the cell, there is no net movement of water across the plasma membrane.If the cell is immersed in a solution that is ______________ to the cell, water enters the cell faster than it leaves, and the cell swells and lyses (bursts) like an overfilled water balloon.A plant cell in a solution hypotonic to the cell contents swells due to osmosis until the elastic cell wall exerts ______________ pressure on the cell that opposes further water uptake.If a plant cell and its surroundings are isotonic, there is no movement of water into the cell. The cell becomes ______________ (limp), and the plant may wilt.Eventually, the plasma membrane pulls away from the wall. This ______________ is usually lethal.The passive movement of molecules down their concentration gradient with the help of transport proteins is called _____________________ diffusion.Two types of transport proteins facilitate the movement of molecules or ions across membranes: ____________ proteins and _____________ proteins.Some transport proteins can move solutes across membranes against their _____________- gradient, from the side where they are less concentrated to the side where they are more concentrated._________ supplies the energy for most active transport by transferring its terminal phosphate group directly to the transport protein.The voltage across a membrane is called a ______________ potential and ranges from −50 to −200 millivolts (mV). The inside of the cell is negative compared to the outside.Two combined forces, collectively called the __________________ gradient, drive the diffusion of ions across a membrane.A single ATP-powered pump that transports a specific solute can indirectly drive the active transport of several other solutes in a mechanism called ___________________.Plants commonly use the gradient of H⁺ generated by proton pumps, which are not technically part of the co-transport process, to drive the active transport of _______________ into the cell.One specific transport protein couples the diffusion of H⁺ out of the cell and the transport of ___________ into the cell.In _____________, a transport vesicle budded from the Golgi apparatus is moved by the cytoskeleton to the plasma membrane.During _______________, a cell brings in biological molecules and particulate matter by forming new vesicles from the plasma membrane.There are three types of endocytosis: _____________ (“cellular eating”), ______________ (“cellular drinking”), and __________________ endocytosis.

Answer 1

1. Unsaturated

2. Unsaturated

3. Integral or Intrinsic

4. Peripheral or Extrinsic

5. Transmembrane

6. Peripheral

7. Transport

8. Enzymatic