Chapter 7 Flashcards
1
Q
Selective Permeability
A
When the plasma membrane only allows some substances to cross more easily than others.
2
Q
Amphipathic Molecule
A
It contains a hydrophilic region and a hydrophobic region.
3
Q
Problems with the Davson-Danielli model.
A
- Membranes with different functions differ in structure and chemical composition
- Membrane proteins are not very soluble in water
4
Q
Amphi-
A
Dual
5
Q
Aqua-
A
Water
6
Q
-pori
A
A small opening
7
Q
Co-
A
Together
8
Q
Trans-
A
Across
9
Q
Electro-
A
Electricity
10
Q
-genic
A
Producing
11
Q
Endo-
A
Inner
12
Q
Exo-
A
Outer
13
Q
-cyto
A
Cell
14
Q
Hyper-
A
Exceeding
15
Q
-tonus
A
Tension
16
Q
Hypo-
A
Lower
17
Q
Iso-
A
Same
18
Q
Phago-
A
Eat
19
Q
Pino-
A
Drink
20
Q
Plasm-
A
Molded
21
Q
-lyso
A
Loosen
22
Q
Aquaporins
A
A channel protein in the plasma membrane of a plant, animal, or microorganism cell that specifically facilitates osmosis, the diffusion of free water across the membrane
23
Q
Concentration gradient
A
A region along which the density of a chemical substance increases or decreases
24
Q
Cotransport
A
The coupling of the “downhill” diffusion of one substance to the “uphill” transport of another against its own concentration gradient
25
Diffusion
Spontaneous movement of a substance down its concentration or electrochemical gradient, from a region where it is more concentrated to a region where it is less concentrated
26
Electrochemical Gradient
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
27
Electrogenic Pump
An active transport protein that generates voltage across a membrane while pumping ions.
28
Endocytosis
Cellular uptake of biological molecules and particulate matter via formation of vesicles from the plasma membrane
29
Exocytosis
The cellular secretion of biological molecules by the fusion of vesicles containing them with the plasma membrane
30
Flaccid
Limp, when water leaves a plant cell
31
Glycoprotein
A protein with one or more covalently attached carbohydrates
32
Hypertonic
Referring to a solution that, when surrounding a cell, will cause the cell to lose water
33
Hypotonic
Referring to a solution that, when surrounding a cell, will cause the cell to take up water
34
Ion Channel
A transmembrane protein channel that allows a specific ion to diffuse across the membrane down its concentration or electrochemical gradient
35
Membrane Potential
The difference in electrical charge (voltage) across a cell's plasma membrane due to the differential distribution of ions. Membrane potential affects the activity of excitable cells and the transmembrane movement of all charged substances.
36
Osmoregulation
Regulation of solute concentrations and water balance by a cell or organism
37
Plasmolysis
A phenomenon in walled cells in which the cytoplasm shrivels and the plasma membrane pulls away from the cell wall; occurs when the cell loses water to a hypertonic environment
38
Selective Permeability
A property of biological membranes that allows them to regulate the passage of substances across them
39
Sodium-Potassium Pump
A transport protein in the plasma membrane of animal cells that actively transports sodium out of the cell and potassium into the cell
40
Turgid
Swollen or distended
41
Active Transport
Molecule move across the plasma membrane against their concentration gradient
42
A molecule moves down its concentration gradient using a transport protein in the plasma membrane. This is an example of_____.
Facilitated diffusion, there is a net movement of molecules down the concentration gradient. There is a net movement of molecules from where they are more concentrated to where they are less concentrated.
43
Water crosses the plasma membrane through ___________.
through facilitated diffusion or diffusion. Water uses diffusion or facilitated diffusion -- both forms of passive transport -- to cross the plasma membrane.
44
The sodium-potassium pump uses energy from ATP to move sodium ions out of the cell, and potassium ions into the cell. This is an example of _____________.
Active transport. The sodium-potassium pump moves ions across the plasma membrane against their concentration gradients. This requires energy and is an example of active transport.
45
The plasma membrane forms a pocket that pinches inward, forming a vesicle that contains material from outside the cell. This describes the process of ___________.
Endocytosis. The plasma membrane forms a pocket that pinches inward, forming a vesicle that contains material from outside the cell.
46
__________ is the boundary that separates the living cell from its surroundings.
Plasma Membrane
47
The plasma membrane exhibits ____________, allowing some substances to cross it more easily than others.
Selective Permeability
48
_ are fluid mosaics of lipids and proteins
Cellular membranes
49
Plasma membrane is ______ nm of thin film of lipids and proteins
5-8 nm
50
Membrane lipids and membrane proteins are ________, which means they have both hydrophobic and hydrophilic regions.
Amphipathic
51
A simple membrane is a __________ bilayer.
Phospholipid bilayer.
52
________ interactions stabilize the lipid bilayer
Hydrophobic
53
What is membrane fluidity?
Membrane lipids drift laterally, and even "flip-flop"
54
How can you visualize the lateral movement of lipids?
Fluorescence Photobleaching
55
Membranes must be ____ to work properly
Fluid
56
As temperatures cool, membranes switch from a _____ state to a _____ solid state.
Membranes switch from a fluid state to a solid state
57
The temperature at which a membrane solidifies depends on _______.
It depends on the types of lipids.
58
________ and ________ prevent tight packing.
Unsaturated lipids and cholesterol prevent tight packing
59
In what way do the membranes of a eukaryotic cell vary?
Certain proteins are unique to each membrane.
60
According to the fluid mosaic model of membrane structure, proteins of the membrane are mostly ____________.
Embedded in a lipid bilayer.
61
What factor would tend to increase membrane fluidity?
A greater proportion of unsaturated phospholipids
62
What would increase the rate of sucrose transport into the cell?
Adding a substance that makes the membrane more permeable to hydrogen ions
