Chapter Five: Membrane Structure + Synthesis + Transport Flashcards
(110 cards)
1
Q
The Fluid Mosaic Model consists of a double layer of…
A
Phospholipids
2
Q
Phospholipids are _______________, Fatty Acid tails are non-polar, Phosphate heads are polar
A
Amphipathic
3
Q
Each phospholipid layer is called a…
A
Leaflet
4
Q
Polar molecules cannot pass ______________ membrane center
A
Hydrophobic
5
Q
Non-polar molecules can generally _____________ through membranes
A
Diffuse
6
Q
In the Fluid Mosaic Model, proteins are embedded in the…
A
Phospholipid bilayer
7
Q
Protein content of membranes varies from _______-_______ times more Lipid molecules than protein molecules
A
15-70
8
Q
Proteins usually determine the exact ________ of the cell’s different membranes
A
function
9
Q
The proteins do the _______ of the membrane
A
work
10
Q
Peripheral Membrane Proteins are _____ closely associated with the membrane
A
less
11
Q
Membrane proteins are ________ bound to the membrane
A
loosely
12
Q
Peripheral Proteins are bound by __________ or ___________ Bonds to Transmembrane Proteins or the Heads of Phospholipids
A
Hydrogen or Ionic Bonds
13
Q
Exposed portions of Peripheral Proteins are usually __________ for binding
A
polar
14
Q
Membranes may be ____________ with different functions
A
asymmetric
15
Q
Integral Membrane Proteins are (more/less) closely associated with membrane
A
more
16
Q
Exposed portions of membrane proteins are usually ________ for binding
A
non-polar
17
Q
What are the two types of membrane proteins?
A
Transmembrane and Lipid-anchored Proteins
18
Q
Transmembrane proteins transverse the membrane with domains forming…
A
alpha-helices
19
Q
Regions of Transmembrane proteins occur on both sides of the membrane, and may be bound to the…
A
Cytoskeleton
20
Q
Lipid-anchored proteins have a lipid ____________ attached to the protein
A
covalently
21
Q
In lipid-anchored proteins, the lipid is inserted into the ______________ ____________ to anchor the protein
A
Phospholipid bilayer
22
Q
Phospholipids in the membrane are not _______________ bound
A
covalently
23
Q
A phospholipid can move from one end of a _________ cell to the other end in less than a second, and 5-10 seconds in a _____________ cell
A
Prokaryotic
Eukaryotic
24
Q
Are phospholipids allowed to freely move between leaflets?
A
no
25
Are phospholipids free to move?
yes
26
In order for phospholipids to freely move between leaflets, a special protein called __________ is needed to do this using energy rom ATP
Flippase
27
The most common phospholipids have an even number of ____________ (18-20)
Carbons
28
Because of the rarity for a lipid to “flip-flop” the two layers often have the (same/different) lipids
different
29
Up to 25% of the lipid in an animal cell membrane may be…
Cholesterol
30
Plant membranes contain _________________, which are structurally similar to Cholesterol
Phytosterols
31
There will be less Hydrophobic Interactions with what three things?
1. Shorter Hydrocarbon Chains
2. More Unsaturated Hydrocarbon Chains
3. More Cholesterol
32
More cholesterol will make membrane more fluid at _______ temperatures
low
33
More cholesterol will make membrane less fluid at _________ temperatures
higher
34
Membrane proteins, like phospholipids can ____________ through the membrane
diffuse
35
Because of the membrane protein’s ___________, they do not flip-flop
polarity
36
Some proteins exposed to the cytoplasm attach to elements of the ____________, anchoring them in one position, restricting their movements
Cytoskeleton
37
_________________ in membranes occur only as Glycolipids and Glycoproteins
Carbohydrates
38
Carbohydrates only occur in the ___________ leaflet of the Plasma Membrane
exterior
39
Glycolipids and Glycoproteins in the Plasma Membrane may function as _______________, identifying the cells of an organism
antigens
40
Glycolipids and Glycoproteins may label proteins with ___________ for cellular destinations
signals
41
Some cells have a thick layer of ____________ outside the Plasma Membrane
Carbohydrates
42
The _______________ can shield the cell from the immune system of other cells
Glycocalyx
43
Phospholipids are synthesized by the _____________ and inserted into the membrane
Smooth ER
44
After phospholipids are inserted into the ____________ leaflet, Flippase moves some to the exterior leaflet
Cytosolic
45
Phospholipids can be spread throughout the Endomembrane System by…
Lateral Diffusion
46
The Nucleus is continuous with the ER, the Golgi, Plasma Membrane, Mitochondria and Chloroplast are connected by…
Vesicles
47
Lipid Exchange Proteins can extract a lipid from one membrane, diffuse through the ______________, and insert it into any other membrane
Cytoplasm
48
The _____________ and _______________ both synthesize various types of lipids then transfer them to other organelles by Lipid Exchange Proteins
Mitochondria and Chloroplast
49
Most Transmembrane proteins are synthesized in the…
Rough ER
50
Hydrophobic alpha-helices are left in the ER membrane as they are synthesized, forming…
Transmembrane Proteins
51
From the ER, proteins can be moved to other membranes by…
Vesicles
52
Glycosylation of proteins occurs in what two places?
Rough ER and Golgi Apparatus
53
Oligosaccharides are synthesized in the Lumen of the __________ on a ___________ lipid then transferred as a unit to the ___________ group of an amino acid on the protein
ER
Dolichol
Side
54
In the ________, an Oligosaccharide chain can be synthesized and transferred to an amino acid
Golgi
55
Proteoglycans are often secreted from the cell to help form the…
Extracellular Matrix
56
What is involved in membrane synthesis that is also a component of Mucus?
Proteoglycans
57
Biological Membranes because of their Hydrophobic interior, are ____________ ____________, allowing some materials to pass and others not
selectively permeable
58
Molecules are passed through membranes by what two types of transport?
Passive or Active
59
What kind of transport does not require the input of outside energy but depends on the Kinetic Energy of the solute molecule itself?
Passive
60
What type of energy is the energy of molecules in motion?
Kinetic Energy
61
All molecules are in ____________ motion
constant
62
___________ or __________ Diffusion is the net movement of a substance form an area of high concentration to an area of low concentration
Simple or Passive
63
The diffusion of the respiratory gases are primary examples of molecules that move by ________ or __________ Diffusion
Simple or Passive
64
Passive Diffusion is due to…..
Kinetic Energy
65
Rate of diffusion depends upon these four things:
1. Electrical Charge
2. Temperature
3. Concentration
4. Molecular Size
66
In membranes transport, diffusion over _______ distances is very effective
short
67
What type of molecules can diffuse throughout a cell?
Nonpolar
68
What type of molecules need special means to transport them?
Polar
69
The diffusion of macromolecules and polar molecules through membranes using proteins
Facilitated Diffusion
70
The proteins associated with facilitated diffusion are either __________ or _____________ proteins
Channel or Carrier
71
These proteins are transmembrane proteins that form channels through the membrane through which certain molecules/solutes can diffuse
Channel Proteins
72
Channel proteins may be ________ and only allow transport when this is opened
gated
73
Ligand-gated channels open when a __________ molecule is bound
signal
74
The types of channels open when a membrane is depolarized, by a change in electrical charge across the membrane
Voltage-gated
75
These type of proteins bind the solute and are then carried through the membrane, usually by a conformational change in the protein
Transporter Protein
76
In facilitated direction, the solute can diffuse in either direction according to its….
Concentration Gradient
77
What type of transporter transports one solute molecule?
Uniports
78
What type of Transporter transports two in the same direction?
Symport
79
What type of transporter transports two in different directions?
Antiport
80
The transport of a substance against its concentration gradient with the expenditure of energy
Primary Active Transport
81
What is the energy source often used in Primary Active Transport?
ATP
82
What is a classic example of ATP being used in Primary Active Transport?
Sodium Potassium Pump
83
Pumping two cations at uneven rates results in an ___________ ___________ across the plasma membrane
electrical charge
84
What type of active transport uses active transport to drive facilitated diffusion?
Secondary Active Transport
85
The diffusion of water through a semipermeable membrane
Osmosis
86
Water diffuses through special pores in membranes (Aquaporins) of some cells occurs in…
Osmosis
87
Water can also hitchhike, bound to ________ when they pass through pores
Cations
88
Water molecules pass single file through the pore, which _______ other molecules
excludes
89
Has the same concentration so the volume does not change
Isotonic
90
Solution has a high concentration of solute (less water) so cell loses volume
Hypertonic
91
Solution has a lesser concentration os solute (more water) so cell gains volume
Hypotonic
92
Brings large sized materials into cells using Vesicle formation
Endocytosis
93
Receptor-mediated Endocytosis: Uses receptors to ____________ materials before bringing them in
concentrate
94
In endocytosis, after the vesicle imports material from outside the cell, it can fuse with a….
Primary Lysosome
95
In Endocytosis, macromolecules are digested to __________ before they are transported to the Cytoplasm
Monomers
96
Discards materials from cells using vesicles
Exocytosis
97
In exocytosis, ___________ are added to the Plasma Membrane
Phospholipids
98
Cells produce an _______________ _________ for strength and support
Extracellular Matrix
99
Most cell junctions are composed of _______________, and play a variety of roles in cells
proteins
100
Many cell junctions function only to hold ____________ cells together
adjacent
101
Anchoring Junctions depend on ___________ proteins passing through the cell membrane and connecting to elements of the cytoskeleton of adjacent cells
Integral
102
In anchoring junctions, cadherins are fibrous proteins connected to __________ _______________ in the cytoplasm
actin microfilaments
103
In anchoring junctions, cadherins extend into the extracellular matrix where _________ ions help to bind to each other
Ca2+
104
____________ are composed of two subunits that bind other proteins which bind to actin microfilaments in the cytoplasm
Integrins
105
In the extracellular matrix, integrins bind to __________ which binds to elements of the matrix such as collagen fibers
Fibronectin
106
Tight junctions form ___________ between cells
seals
107
Tight junctions limit movement of materials through _______________ ____________
intercellular spaces
108
Tight Junctions limit movement of proteins within the…
Membrane
109
In Gap Junctions, __________ proteins form channels connecting the cytoplasm of two adjacent cells
Connexon
110
What type of Junction allows passage of ions and small molecules for communication between cells?
Gap Junctions
