Chapter 7 - Membrane Structure Flashcards

0
Q

Having both a hydrophilic and hydrophobic region

A

Amphipathic

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1
Q

The plasma allows some substances to cross it more easily than others

A

Selective permeability

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2
Q

Currently accepted model of the cell membrane structure, which envisions the membrane as a mosaic of protein molecules drifting laterally in a fluid bilayer of phospholipids

A

Fluid mosaic model

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3
Q

Proteins that penetrate the hydrophobic interior of the lipid bilayer; majority are transmembrane proteins

A

Integral proteins

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4
Q

Proteins not embedded in the lipid bilayer at all; they are appendages loosely bound to the surface of the membrane often to expose parts of integral proteins

A

Peripheral proteins

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5
Q

Short, branched chains of carbohydrates covalently bonded to lipids

A

Glycolipids

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6
Q

Short, branched chains of carbohydrates covalently bound to proteins

A

Glycoproteins

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7
Q

A transmembrane protein that helps a certain substance or class of closely related substances to cross the membrane

A

Transport proteins

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8
Q

Channel protein that facilitates the passage of water molecules through the membrane in certain cells; allows up to 3 billion water molecules per second

A

Aqua poring

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9
Q

Movement of particles of any substance so that they spread out into the available space

A

Diffusion

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10
Q

Region along which the density of a chemical substance increases or decreases

A

Concentration gradient

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11
Q

Diffusion of free water across a selectively permeable membrane whether artificial or cellular

A

Osmosis

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12
Q

The ability of a surrounding solution to cause a cell to gain or lose water

A

Tonicity

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13
Q

No net movement of water across the cell membrane; equal solutes

A

Isotonic

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14
Q

Solution causing a cell to lose water due to higher concentration of solutes outside the cell

A

Hypertonic

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15
Q

Solutions causing cell to take up water due to lower concentration of solutes outside the cell

16
Q

Control of solute concentrations and water balance

A

Osmoregulation

17
Q

very firm; healthy state for most plants (hypotonic)

18
Q

Limp; no net tendency for water to enter the plant cell (isotonic)

19
Q

Process causing a plant to wilt and can lead to death; caused by hypertonic conditions

A

Plasmolysis

20
Q

Polar molecules and ions impeded by the lipid bilayer of the membrane diffuse passively with the help of transport proteins that span the membrane

A

Facilitated diffusion

21
Q

Channel proteins that transport ions

A

Ion channels

22
Q

Ion channels that open or close in response to stimulus

A

Gated channels

23
Q

Movement of a solute across a membrane against its gradient requiring the expenditure of energy

A

Active transport

24
Transport system which exchanges Na+ for K+ across the plasma membrane of animal cells
Sodium-potassium pump
25
Voltage across a membrane ranging from about -50 to -200 millivolts
Membrane potential
26
Combination of forces acting on an ion; these forces are a chemical force (the ion's concentration gradient) and an electrical force (the effect of the membrane potential on the ion's movement)
Electrochemical gradient
27
Transport protein that generates voltage across a membrane
Electrogenic pump
28
Main electrogenic pump of plants, fungi, and bacteria which actively transports protons (H+) out of the cell transferring positive charge from the cytoplasm to the extra cellular solution
Proton pump
29
Mechanism when a transport protein can couple the "downhill" diffusion of the solute to the "uphill" transport of a second substance against its own concentration gradient
Cotransport
30
Cell secretion of certain molecules by the fusion of vesicles with the plasma membrane
Exocytosis
31
Cell intake of molecules and particulate matter by forming new vesicles from the plasma membrane
Endocytosis
32
Any molecule that binds specifically to a receptor site on another molecule
Ligands
33
Cell engulfs a particle by extending pseudopodia around it and packaging it within a food vacuole; the particle is digested after the vacuole fuses with a lysosome
Phagocytosis
34
Cell gulps droplets of extra cellular fluid into tiny vesicles
Pinocytosis
35
Specialized type of pinocytosis that enables the cell to acquire bulk quantities of specific substances even though those may not be concentrated in the extra cellular fluid
Receptor-mediated endocytosis