Membrane Transport Flashcards

1
Q

Boundary that separates the living cell from its surroundings. Exhibits selective permeability. Allows some substance to cross the membrane more easily than other substance

A

Plasma membrane

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2
Q

Most abundant lipid in the plasma membrane

A

Phospholipids

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3
Q

Contain both hydrophilic and hydrophobic regions

A

Amphipathic molecules

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4
Q

can exist as a stable boundary between 2 aqueous compartments

A

phospholipid bilayer

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5
Q

A membrane that is a fluid structure with a “mosaic” of various proteins embedded in it. Proteins are not randomly distributed in the membrane

A

Fluid Mosaic Model

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6
Q

direction where lipids, and some proteins drift

A

laterally

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7
Q

determine most of the membrane’s specific functions

A

Membrane protein

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8
Q

Proteins Bound to the surface of the membrane

A

Peripheral protein

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9
Q

Proteins that Penetrate the hydrophobic core

A

Integral proteins

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10
Q

Integral proteins that span the membrane

A

Transmembrane protein

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11
Q

6 major function of membrane proteins

A

transport, enzymatic activity, signal transduction, cell to cell recognition, intercellular joining, attachment

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12
Q

Role of Membrane Carbohydrates in Cell-Cell Recognition

A

Cells recognize each other by binding to molecules, often containing carbohydrates, on the extracellular surface of the plasma membrane

Membrane carbohydrates may be
covalently bonded to lipids (glycolipids) or more commonly to proteins (glycoproteins)

Carbohydrates on the external side of the plasma membrane vary among species, individuals, and even cell types in an individual

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13
Q

Can dissolve in the lipid bilayer and pass through the membrane rapidly

A

Hydrophobic

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14
Q

Includes ions and polar molecules that do not pass the membrane easily

A

Hydrophilic

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15
Q

Allows the passage of hydrophilic substance across the membrane

A

Transport Proteins

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16
Q

With hydrophilic channel that certain molecules can use as a tunnel (transport protein)

A

Channel proteins

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17
Q

Facilitate the passage of water (under channel protein)

A

Aquaporins

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18
Q

Bind to molecules and change shape to shuttle them across the membrane, uses energy (transport protein)

A

Carrier proteins

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19
Q

Movement of molecules from an area of higher concentration to an area of lower concentration without any energy investment
The tendency for molecules to spread out evenly into the available space

A

Diffusion

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20
Q

Substances diffuse down their concentration gradient
No work must be done to move the substances down the gradient (type of transport)

A

Passive Transport

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21
Q

Diffusion of water across the selectively permeable membrane from the region of lower solute concentration to the region of higher solute concentration until the concentration is equal on both sides

A

Osmosis

22
Q

Ability of a surrounding solution to cause a cell to gain or lose water

A

Tonicity

23
Q

Solute concentration is the same as inside the cell. No net movement of water across the membrane

A

Isotonic solution

24
Q

Solute concentration is greater outside the cell
Cell loses water, Cell becomes shrivelled

A

Hypertonic solution

25
Q

Solute concentration is less than the inside of cell. Cell gains water, Cell may swell or burst

A

Hypotonic solution

26
Q

Control of solute concentrations and water balance
Needed for organisms that has problems with the hypertonic or hypotonic environments

A

Osmoregulation

27
Q

Transport proteins speed up the passive movement of molecules across the plasma membrane

A

Facilitated Diffusion

28
Q

Undergo subtle change in shape that translocates the solute-binding site across the membrane (facilitated diffusion)

A

Carrier proteins

29
Q

Provide corridors to allow specific molecules to cross the membrane (facilitated diffusion)

A

Channel proteins

30
Q

Facilitate diffusion of water

A

Aquaporin

31
Q

Facilitate diffusion of ions. Some are known as gated channels. They open and close in response to a stimulus (facilitated diffusion)

A

lon channel

32
Q

Moves substances against their concentration gradient
Requires energy, usually in the form of ATP
Performed by specific proteins embedded in the plasma membrane
Allows cells to maintain concentration gradients that differ than their surroundings
Sodium-potassium pump is one type of the active transport

A

Active Transport

33
Q

Voltage difference across a membrane Created by differences in the distribution of positive and negative ions across a membrane

A

Membrane Potential

34
Q

2 combined forces, Drive the diffusion of ions across a membrane

A

Electrochemical Gradient

35
Q

lon’s concentration gradient (force)

A

Chemical force

36
Q

Effect of membrane potential on the ion’s movement (force?

A

Electrical force

37
Q

A transport protein that generates voltage across the membrane, Help store energy that can be used for cellular work

A

Electrogenic Pump

38
Q

Major electrogenic pump for animal cells

A

Sodium-potassium pump

39
Q

Major electrogenic pump for plants, fungi, and bacteria

A

Proton pump

40
Q

Coupled transport by a membrane protein
Occurs when active transport of a solute indirectly drives transport of

A

Cotransport

41
Q

same direction of passage in cotransport

A

Symport

42
Q

opposite direction of passage in cotransport

A

antiport

43
Q

Movement of proteins or macromolecules into and out of the cell, Requires energy

A

Bulk Transport

44
Q

2 types of Bulk Transport

A
  • Exocytosis
  • Endocytosis
45
Q

Transport vesicles migrate to the
membrane, fuse it, and release their
contents outside the cell
* Many secretory cells use exocytosis to export their products

A

Exocytosis

46
Q

Cells take in macromolecules by forming vesicles from plasma membrane

A

Endocytosis

47
Q

3 types of Endocytosis

A

Phagocytosis, Pinocytosis, Receptor-mediated endocytosis

48
Q

cellular eating, Cell engulfs a particle in a vacuole. The vacuole fuses with a lysosome to digest the particle

A

Phagocytosis

49
Q

cellular drinking, Molecules dissolved in droplets are taken up when extracellular fluid is “gulped” into tiny vesicles

A

Pinocytosis

50
Q

Binding of ligands to receptors triggers vesicle formation

A

Receptor-mediated endocytosis

51
Q

Any molecule that binds specifically to a receptor site of another molecule

A

Ligand

52
Q

2 HIV receptors

A

CD4 and CCR5