Chapter 5 Flashcards

0
Q

Having both a hydrophilic region and a hydrophobic region

A

Amphipathic

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1
Q

Allows substances to cross more easily than others

A

Selective Permeability

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2
Q

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

A

Fluid mosaic model

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3
Q

They penetrate the hydrophobic interior of the lipid bilayer

A

Integral proteins

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4
Q

They are not embedded in the lipid bilayer, but instead are appendages loosely bound to the surface of a membrane, often to exposed parts of integral proteins

A

Peripheral proteins

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5
Q

A protein that spans the membrane may provide a hydrophilic channel across the membrane that is selective for a particular solute. Other transport proteins shuttle a substance from one side to the other by changing shape

A

Transport

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6
Q

A protein built into the membrane may be an enzyme with its active site exposed to substances in the adjacent solution. In some cases several enzymes in a membrane are organized as a team that carries out sequential steps in a metabolic pathway

A

Enzymatic activity

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7
Q

Microfilaments or other elements of the cytoskeleton may be noncovalently bound to membrane proteins, a function that helps maintain cell shape, and stabilize the location of certain membrane proteins

A

Attachment to the cytoskeleton and EMC

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8
Q

Some glycoproteins serve as identification tags that are specifically recognized by membrane proteins of other cells

A

Cell-cell recognition

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9
Q

Membrane proteins of adjacent cells may hook together in various kinds of junctions, such as gap junctions or tight junctions.

A

Intercellular joining

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10
Q

A membrane protein may have a binding site with a specific shape that fits the shape of a chemical messenger, such as a hormone. The external messenger may cause the protein to change shape, allowing it to relay the message to the inside of a cell, binding it to a cytoplasmic protein.

A

Signal transduction

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11
Q

Membrane carbohydrates that are covalently bonded to lipids, forming molecules.

A

Glycolipids

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12
Q

Membrane carbohydrates covalently bonded to proteins

A

Glycoproteins

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13
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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14
Q

A channel membrane in the plasma membrane of a plant, animal, or microorganism cell that specifically facilitates osmosis, the diffusion of free water across the membrane.

A

Aquaporins

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15
Q

The random thermal motion of particles of liquids, gases, or solids. I the presence of a concentration or electrochemical gradient, _____ results in the net movement of a substance from a region where it is more concentrated to a region where it is less concentrated.

A

Diffusion

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16
Q

The region along which the density of a substance increases or decreases.

A

Concentration gradient

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17
Q

The diffusion of a substance across a biological membrane.

A

Passive transport

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18
Q

The diffusion of free water molecules across a selectively permeable membrane.

A

Osmosis

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19
Q

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

A

Tonicity

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20
Q

Referring to a solution that, when surrounding a cell, causes no net movement of water into or out of a cell.

A

Isotonic

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21
Q

Referring to a solution that, when surrounding a cell, will cause the cell to lose water.

A

Hypertonic

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22
Q

Referring to a solution that, when surrounding a cell, will cause a cell to take up water.

A

Hypotonic

23
Q

The control of solute concentrations and water balance.

A

Osmoregulation

24
Q

Very firm.

A

Turgid

25
Q

Limp or wilted.

A

Flaccid

26
Q

A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when a cell loses water in a hypertonic environment.

A

Plasmolysis

27
Q

The passage of molecules or ions down their electrochemical gradient across a biological membrane with the assistance of specific transmembrane transport proteins, requiring no energy expenditure.

A

Facilitated diffusion

28
Q

Channel proteins that transport ions.

A

Ion channels

29
Q

A transmembrane protein that opens or closes in response to a particular stimulus.

A

Gated channels

30
Q

The movement of a substance across a cell membrane against its concentration or electrochemical gradient, mediated by specific transport proteins and requiring an expenditure of energy.

A

Active transport

31
Q

A transport system that exchanges Na+ for K+ across the plasma membrane of animal cells.

A

Sodium-Potassium pump

32
Q

The difference in electrical charge across a cell’s plasma membrane due to the differential distribution of ions.

A

Membrane potential

33
Q

The diffusion gradient of an ion which is affected by both the concentration difference of an ion across a membrane and the ion’s tendency to move relative to the membrane potential.

A

Electrochemical gradient

34
Q

A transport protein that generates voltage across a membrane.

A

Electrogenic pump

35
Q

The main electronic pump of plants, fungi, and bacteria which actively transport proteins out of the cell.

A

Proton pump

36
Q

The coupling of the “downhill” diffusion of one substance and the “uphill” transport of another against its own concentration gradient.

A

Cotransport

37
Q

The process in which cells secrete certain biological molecules by the fusion of vesicles with the plasma membrane.

A

Exocytosis

38
Q

The process of cells taking in molecules and particles by forming me vesicles from the plasma membrane.

A

Endocytosis

39
Q

When a cell engulfs a food particle, packaging it within a membranous sac called a food vacuole. “Cell eating”

A

Phagocytosis

40
Q

When a cell continually “gulps” droplets of extra cellular fluid in tiny vesicles. “Cellular drinking”

A

Pinocytosis

41
Q

A specialized type of pinocytosis that enables the cell to acquire bulk quantities of specific substances even though those substances may not be very concentrated in the extracellular fluid.

A

Receptor-mediated Endocytosis

42
Q

A secreted molecule that influences cells near where it is secreted.

A

Local regulators

43
Q

One of many types of secreted chemicals that are formed in specialized cells, travel in body fluids, and act on specific target cells in other parts of the boys, changing the target cells’ functioning.

A

Hormones

44
Q

First stage of cell signaling, the target cell’s detection of a signaling molecule coming from outside the cell

A

Reception

45
Q

Second stage of cell signaling, a series of steps that converts the signal to a form that can bring about specific cellular response.

A

Transduction

46
Q

A sequence of changes in a series of different molecules often called relay molecules

A

Signal transduction pathway

47
Q

Third stage of cell signaling, almost any imaginable cellular activity, a response to the signal.

A

Response

48
Q

A signaling molecule that specifically binds to another molecule, often a larger one.

A

Ligand

49
Q

A cell-surface transmembrane receptor that works with the help of a G protein.

A

G protein-coupled receptor (GPCR)

50
Q

A protein that binds the energy-rich molecule GTP, which is similar to ATP.

A

G protein

51
Q

A membrane receptor that has a region that can act as a gate for ions when the receptor assumes a certain shape.

A

Ligand-gated ion channel

52
Q

An enzyme that transfers phosphate groups from ATP to a protein.

A

Protein kinase

53
Q

Enzymes that can rapidly remove phosphate groups from proteins.

A

Protein phosphatases

54
Q

Poop

A

Cyclic AMP (cAMP)