Exam #3 Flashcards
1
Q
The membrane and membrane bound compartments of euk allow for…
A
greater complexity of structure and function in those cells
2
Q
Major components of membrane structure
A
1) amphipathic lipid bilayer
2) membrane proteins
3) sugars on the non- cytosolic side
4) cytosolic submembrane protein meshwork
3
Q
Fxn of amphipathic lipid bilayer
A
1) gives cells and organelles a barrier in an aqueous environment
2) spontaneous fusion
3) healing
4) sealing
4
Q
Fxn of membrane proteins
A
Gives membranes its complex fxns
1) transport
2) recognition
3) binding
5
Q
Fxn of sugars on non-cytosolic side
A
Gives membranes its complex fxns
1) transport
2) recognition
3) binding
5
Q
Euks use membrane structure and fxn to…
A
Compartmentalize their internal activities
6
Q
Fxn of cytosolic submembrane protein mesh work
A
- Binding and recognition fxns for intracellular activities
- establish fxn domains
- communication with cytoskeleton
7
Q
Major fxn of membranes
A
1) compartmentalization
2) defense and integrity of cellular components
3) selective permeability in 2 directions
4) regulation of internal cellular activities
5) response to signals from outside the cell or from it’s intracellular compartments
8
Q
Endomembrane system includes..
A
1) nucleus
2) endoplasmic reticulum
3) Golgi apparatus
4) lysosomes
5) plasma membrane
6) vesicles
9
Q
Fxn of nucleus
A
1) store
2) protect
3) transcribe the DNA
4) deliver RNAs for translation
10
Q
Fxn of Golgi apparatus
A
Carry out translational modification of membrane lipid n protein constituents by
1) sulfatation
2) adenlyation
3) phosphorylation
4) glycosation**
11
Q
Fxn of endoplasmic reticulum
A
1) lipid biosynthesis
2) protein translation
3) integration of membrane lipid and protein
4) detoxification
5) calcium sequestration (muscle contraction)
12
Q
Fxn of lysosomes
A
Digest cellular components and macromolecules using acidic digestive enzymes
13
Q
Fxn of plasma membrane ( in terms of endomembrane system)
A
1) endocytosis
2) exocyosis
14
Q
Organelles not in the endomembrane system
A
1) mitochondria
2) chloroplast
3) peroxisomes
4) vacuoles (plants)
15
Q
Mitochondria characteristics and fxn
A
Stores, protects, and expresses its own DNA
Fxn-carry out cellular respiration
16
Q
Chloroplast characteristics and fxn
A
Stores, protects, and expresses it’s own DNA
Fxn-carry out photosynthesis
17
Q
Peroxisomes fxn
A
Carry out ROS metabolism, oxidation, and ether lipid synthesis
18
Q
Vacuole fxn
A
Control water and ion exchange (dependent on external environment)
19
Q
Three fibrous components of euks cytoskeleton
A
Microfilaments, microtubules, n intermediate filaments
Allows for cell stability
20
Q
3 structural elements of microfilaments
A
1) G actin monomer
2) Polar with + and - end
3) Many MFAPS that determine the structure and fxn
21
Q
G actin
A
Monomer used for construction of microfilaments
22
Q
MFAPS
A
Determine structure and fxn of microfilaments
23
Q
3 structural elements of Microtubules
A
1) tubulin monomer
2) polar with + and - end
2) many MAPS that determine structure and fxn
24
Tubulin
Monomer used for construction microtubules
25
MAPS
Determine structure and fxn of microtubules
26
2 structural elements of intermediate filaments
1) handful of cell-specific monomers that can be used for construction
2) apolar
27
Bacteria structural elements
ParM and FtsZ
28
ParM
Homolog of actin
| Fxn is analogous to tubulin
29
FtsZ
Homolog to tubulin
| Fxn analogous to actin
30
Molecular motors fxn
Allows filament based intracellular transport
| Driven by ATP hydrolysis
31
Myosin
Molecular motor.
| Moves along microfilaments usually towards + end but can also move towards - end
32
Kinesin
Molecular motor.
Moves along microtubules towards + end
Away from MTOC
33
Dynein
Molecular motor.
Moves along microtubules towards - end
Towards the MTOC
34
Movement of Molecular motors driven by..
ATP hydrolysis
35
Many changing cell functions regulated by
Actin fiber reorganization
- disassembly, nucleation, polymerization
- Depends on MFAPS/Rho
36
Assembly of specific actin structures n fxns depends on..
Expression n activity of MFAP in specific cellular locations
37
Regulation of active actin structure
Rho-family signaling pathway
38
Actin filaments help regulate
1) many changing cell activities
2) long term activities
3) movement
39
How are microtubules used to regulate structure and fxn of cytoskeleton
Organization
Destabilization
Depends on MAPS
40
What are microtubules used to regulate
Movement and positioning of materials and the cells
41
Assembly of specific tubulin structure and fxn depends on
Expression/activities of MAPS in specific locations
42
Most stable element in cytoskeleton
Intermediate filaments
43
How is intermediate filament fxn and structure regulated
Covalent modifications
| Phosphorylation n glycosylation
44
stable cell adhesions
- result from binding the cytoskeleton to outside structures
- can be used for cell movement
45
integrin-based hemidesosomes
-result from binding to neighboring cells
-can be used to block the movement of molecules between cells
(cadherin and claudin/occludin)
46
cadherin superfamily anchoring jxns
- forms anchoring jxns
| - binds the cytoskeleton of two adjacent cells togethr to from strong tissue interactions
47
claudin/occludin proteins
-form occulading/tight jxns between two adjacent -epithelial cells that are impermeable to most solutes
48
specialized adhesions
- allows the cell to temporarily bind outside structures to accomplish specific transient or unique factors
- (selectins/immunoglobin)
49
selectins
- plays a part in specialized adhesions
- intermediate transient cell to cell adhesion interactions in the bloodstream during an inflammatory response governing traffic of leukocytes
50
immunoglobulin (Ig) superfamily
- plays a part in specialized adhesions
| - especially during development and regeneration
51
movement of materials between the cytosol and nucleus
- bidirectional
| - requires recognition at the nuclear pore complexes
52
What is the vesicle transport system used for
-used for movement of materials from the nucleus outward, from the plasma membrane inward, and movement within the cytosol
53
Vesicle Transport
Moves materials that are sequestered in vesicles through the cytosol
54
Vesicle Transport System
1) budding of the original membrane
2) transport through cytosol
3) targeting and fusion of the vesicle to the target membrane
55
Coat Proteins
Responsible for vesicle formation and budding
56
What transports vesicles along the cytoskeleton?
Molecular motors bind and transport vesicles along the cytoskeleton
57
Rab proteins
Used for identification of the target membrane
58
SNARE proteins
Carry out vesicle fusion to the target membrane
59
How is vesicular material secreted from the cell?
1) Constitutive Secretion (continuous) or
| 2) Regulated Secretion (specialized)
60
Constitutive Secretion
- aides in secreting vesicular material from the cell
- occurs continuously as needed
- automatic transport from the trans-cisterna of the Golgi to the Plasma Membrane
61
Regulated Secretion
- aides in secreting vesicular material from the cell
- used only by specialized vesicles that dock under the plasma membrane
- requires a secondary signal to induce fusion of the vesicle to the plasma membrane
62
Types of Specialized transport of vesicular material
1) to the lyosomes
2) to the mitochondria
3) to the chloroplast
4) inward flow of material from outside the cell
63
Neurotransmitters
1) axon electrical gradient must be built
2) synapse must be built to transfer info
3) mechanisms for building/transport of regulated secretion vesicles is required
4) regulated secretion triggers must be built to carry our de/repolarizaton
5) mechanisms linking the stimulus to vesicular fusion must be built
64
prokaryotes membranes
cytoplasm bound by plasma membrane
| -no organelles, no nucleus, DNA is in unbound region called nucleiod
65
major components of the euk membrane system
1)plasma membrane 2)nuclear envelope 3)endoplasmic reticulum 4)golgi apparatus 5)mitochondria and chloroplast 6)lyosome 7)peroxisome 8)vacuoles
66
most fundamental structure of the membrane
amphipathic lipid bilayer (double layer of phosolipids)
67
phosatidyethanolamine
only NH3
68
phosphatidyl-serine
NH3 and COO
69
phosphatidyl-chlorine
CH3
70
sphingomyelin
OH
71
sphringosine
No fxn group
72
glycolipids
lipids with carbohydrate attached
- makes up the lipid bilayer
- used for energy and recognition
- Ex: cholestreal
73
What can/cannot pass through lipid bilayer
- small hydophobic (non-polar) molecules can pass through rapidly (H20, O2, CO2, Urea, hydrocarbons, testasterones, chlostreal, estradiol)
- charged/polar molecules can not cross easily (ions, sugars, proteins)
74
What provides the bulk of specific membrane fxns?
Membrane proteins
75
Membrane protein variation allows what for the cell?
Allows for cellular identification
76
Integral Proteins
- permanently attached/inserted into the membrane
| - transmembranes/endo and ectoproteins
77
Peripheral proteins
-interact with integral proteins
78
Transmembrane proteins
Type of integral protein
- Has domains on both sides of the membrane (all the way through)
- single pass
- multiple pass
- barrel/channel/pump
- TRANSPORT PROTEINS
79
Endo/Ecto Proteins
Type of integral protein
- Only on one side of the membrane
- single sheath proteins
- anchored proteins
80
Fxn of membrane proteins
1) transport (trans)
2) enzymatic activity (both)
3) signaling receptors (trans)
4) cell recognition (carbohydrates)
5) cell-cell recognition
6) intracellular joining (tight jxns)
7) attachments to cytoskeleton and ECM
81
How do molecules move across the membrane?
1) Diffusion (small ions)
2) Facilitated Diffusion (transport protein)
3) Active transport (ATP)
82
Diffusion
small hydophobic (non-polar and some polar) molecules can easily move across the membrane down the concentration gradient
83
Facilitated Diffusion
Diffusion across the membrane with aide of a transport protein/channel/pump down a concentration gradient
84
Active Transport
Must have a transport protein and ATP allows molecules to move up a concentration gradient
85
protein:lipid ratio
protein: lipid ratio varies in different proteins
- serves as identification
- more activities=more proteins
86
Myelin protein:lipid
20% protein 80% lipid
| -wraps around neurons and cuts down number of activities to speed up the signal
87
outer mitochodria protein:lipid
50% protein 50% lipid
88
inner mitochondria protein:lipid
80% protein 20% lipid
89
Where are sugars found on the membrane?
- On the non-cytosolic face
| - attached to glycolipids(carbohydrate layer)
90
Structures within the Submembrane protein meshwork
1) membrane identificatoin proteins
2) anchor proteins for cadherins and integrins
3) 2nd messengers for signaling pathways
4) Ribosome docking proteins
5) chaperoin docking proteins
91
glycosylation
- happens in the golgi
| - attachement/removal of carbohydrate residues
92
free radials
-molecules that are reduced/oxidized in the peroxisome
93
The lipid bilyaer is considered to be amphipathic because??
it has both a hyrdophopic and hydrophilic regions
94
Which structure/activity does not involve actin filaments??
movement of mucus carrying debris through the airway
95
What activities are actin filaments involved in?
- cell migration
- formation of focal adhesions
- muscle contractions
- mitotic contractile ring
96
What is the fxn of the MTOC??
allows y-tubulin nucleation of microtubule
97
Name a molecular motor and its fxn??
Dynein moves along the microtubule toward the MTOC
98
What structure is not enclosed in a membrane??
Ribosome
99
What is true about the membrane of different organelles??
- Each membrane possess its own lipid and sugar signature
| - each faces protein/lipid signature are asymmetric
100
Which molecules are able to diffuse across a membrane??
H20, CO2, O2, Urea
101
Why is the lipid:protein of oligodendrocyte 80:20??
Because its fxn is to selectively block the diffusion of sodium and potassium ions
102
What is NOT true about the submembrane meshwork??
-always on the noncytosoic side
its always on the cytosolic side!!!
103
What is NOT fxn of the membranes in cells??
Organization of the chromosomal DNA in the nucleus
104
What is NOT a fxn of the ER??
Activation of targeting for final destinations
105
What happens to vesicles that are filled with neurotransmitters when they reach the synapse??
They stay on the cytosolic side of the membrane until signaled to fuse
106
What is NOT true about microtubule disassembly??
Severing catalyzed by kenesin 13 contributes to mt disassembly
107
Microtubule severing is catalyzed by..
katanin
108
katanin
catalyzes severing of microtubules
109
What can prevent microtubule disassemly?
Tau binding at the plus end
110
Tau
binds at plus end of microtubules to prevent dissasembly
111
unphosphorylated stathmin
Do not directly cause microtubule disassembly
112
phosphorylated stathmin
Does not directly cause microtubule disassemly
113
What is NOT true about proteins that are transported through the endomembrane system??
All of the above are true
- they can be active transport pumps
- they can be part of ECM
- translation can occur in the lumen of ER
114
What is TRUE about actin filament polymerizaton??
profilin-bound G-actin subunits are used for actin filament polymerization
115
What type of G-actin subunits are used for actin filament polymerization??
Profilin-bound
116
Profilin bound G-actin
Used for actin filament polymerization
117
What is required for microtubule building??
y tubulin ring complex, tubulin, MTOC
118
What is NOT true about microtubule assembly??
Microtubule assembley may occur without a nucleation event
119
Microtubule assembly cannot occur without which event?
nucleation
120
What kind of tubulin is needed for microtubule assembly?
-free tubulin
| not bound by stahmin
121
What happens to a microtubule that is bound by MAP2 (towards the plus end)
It may continue to undergo polymerization but cannot be depolymerized
122
Where are microtubules attached to the y tubulin ring complex?
the centromere at the minus end
123
Where do microtubules undergo polymerization?
the plus end
124
A high amount of unphosphorylated stathmin
prevents micrtotubule assembly
125
What about the cell membrane is true??
both b and c
- Euk use the membrane structure and fxn to compartmentalize their intrnal activities
- provides complexity n structure to a cell
126
What is NOT true about the fxn of the amphipathic lipid bilayer??
the structure gives the cell the ability to prevent all molecules from entering the cell
-*it allows SOME to diffuse across
127
What is true about proteins and sugars of the membrane??
Membrane proteins and sugars allow the membrane to perform complex fxns such as intracellular transport, binding, and recognition.
128
What cannnot diffuse across a cell membrane??
Calcium IONS
129
What is the fxn of the cytosolic subprotein meshwork??
provides many of the binding and recognition fxns for INTRACELLULAR activities.
130
What is TRUE about the cytoskeleton??
cells can regulate many of their fxns via control of the structures and fxns of their cytoskeletons
131
Which of the following combo of molecular motors and filament can be used for intracellular transport??
Myosin motors work on microfilaments.
132
Which of the conditions is most suited for fast microfilament assembly??
Higher concentratoin of proliferin than thymosine in a specific cellular location
133
What is a difference between the nucleation of microfilaments and mircotubules??
MIcrotubules nucleate from centriosomes while microfilaments nucleate from short polymers
134
Where do microtubules nucleate
from the centrisomes
135
where do microfilaments nucleate
from short polymers
136
How can a cell identify the cytosolic face of its membrane from the noncytosolic face??
- lipid signature is relatively asymmetric
- protein signature is absolutely asymmetric
- sugars are absolutely asymmetric
- the locaton of the submembrane protein meshwork is absolutely asymmetric
137
What is regulated by the assembly and disassembly of microtubules??
The movement and positioning of materials inside the cell
138
Why are there so many variations of proteins??
-They provide specific membrane fxns and are the primary determinant of cell identity
139
What is NOT true about cell adhesion??
Cell to cell adhesion can only occur between two cells that are of the same type
140
Stable cell adhesions result from
the anchorage of the transmembrane adhesion proteins onto the cytoskeleton
141
What gives tissue its integrity and stability?
integrin-based hemidesmosomes attach cells to the fiberous components of their ECM
142
What about cell to cell adhesion is NOT true??
The non-cytosolic domain of integrin can ONLY interact with a protein in the extracellular matrix
143
What will determine whether an integrin protein can anchor to the cytoskeleton??
- A and C
- The binding of anchoring proteins to the cytosolic domain of the integrin
- the binding of extracellular matrix proteins to the extracellular domain of the integrin
144
Caherin-based anchoring jxns between adjacent cells form..?
Strong tissue adhesions
145
Which adhesion molecules have homophilic binding and can only bind to the same molecule outside of the cell??
cadherin
146
What is NOT true about the transport of materials within the cell??
itnracellular triffiking requires a very simple utilizing system
147
Where is intracellular traffiking informormation stored and transferred?
- stored in the DNA
| - transferred to protein sequence and protein activitty
148
What is NOT true about the cytosoic vs non cytosoic relationship in the endomembrane system?
- carbohydrate residues are always found on the cytosoic face of the membrane
- **sugars found on the noncytoslic face!
149
Which is NOT a normal vesiculular pathway?
proteins made in ER->golgi->inner mitochondria membrane
-**nothing from outside the mitochodria reaches the INNER membrane
150
What plays a role in budding, transport, and targeting of a vesicle to its target organelle??
- protein signature identify specific target membrane
- fusion depends on good match b/t lipid signatures
- cytosolic submembrane meshwork
- coat proteins regulate budding
151
What does fusion of vesicle depend on?
a good match b/w the vesicles and target membranes lipid signatures
152
What is NOT true about the mitochondira??
the lipids of the outer memrane arise from itself
153
Where do most protiens of the inner membrane of the mitochondia arise from?
expresion of genes matintained in the mitochondria itself
154
Where do proteins of the outer membrane of the mitochondira arise from?
expression of genes maintained in the nucleus or expressed on free ribosomes.
155
How can proteins of the outer membrane of the mitochondira be traffiked?
-the ER or Golgi
156
Why is there a need for two different secretory patways??
-to ensure that there is at least one mechanism that releases secretory protiens only when required.
157
What is TRUE about the transport of molecules between the nucleus and cytosol??
movement is bidirectional and requires recognition at the nuclear pore complexes
158
What is NOT true about lysosomal enzymes??
they are quickly denatured in the lyosome due to the low pH
159
Optimal pH of lysosomal enzyme activiity
5.0
160
What are lysosomal enzymes first translocated?
in the ER lumen (where they are inactive)
161
The DNA info for which activiity is NOT controlled by the mitochondiran?
Rates of ATP production
162
What DNA information does Mitochondria control?
- DNA replication
- reproduction by binary fission
- transcription and translation
- type of ATP production
163
What about microtubule assembly is NOT true??
-the presence of a high amount of phophorylated stathim can prevent microtubule assembly.
**-UNPHOSPHYLSTED stathim prevents assesmbly
164
What statement is NOT true about proteins that are transported through the endomembrane system??
-the translation of these proteins occurs in the lumen of the ER
165
What is TRUE about adhesion proteins?
-binding of the cytosolic domain may effect the activity of the extracellular domain
166
Fxns of Intracelluar traffiking
1) recycling of membrane lipids
2) recycling of membrane proteins
3) recylcling of nucleic acid
4) recylcing of extracellular matrix components
167
Main fxn of the Golgi
-glycoslsyation
168
When is a proton pump active?
Only when it reaches the lysosome where membrane fusion activates it
169
What is TRUE about vesicles that are formed and fused into target organelles during vesiculular transport??
-the membrane of each vesicle possesses its own lipid and protein signature and aprticular submemnrane protein meshwork
170
Which protein pair is incorrect??
dynamin-uncoating
171
Coat protein basic fxn
vesicle formation and budding
172
rab proteins basic fxn
target identification
173
SNARE proteins basic fxn
vescile docking
174
What is NOT a fxn of the endosomal system??
-activation of signal transduction pathways
175
Fxn of the endosomal system
1) plasma membrane protein removal and recycling
2) extracelluar matrix turnover and remodeling
3) phagocytosis and pinocytosis
176
Why must vesicles be moved from the ER throught each of the Golgi cesternae before reaching its target membrane??
- ALL
- fusion of two membranes depends on reasonably good match between the lipid compositions of the two bilayers
- the lipid signature of the ER is closely matched with the cis-cisterna of the Gogli
- the lipid signare of the Cis-cesterna is closely matched with medial-cisterna
177
What is NOT ture about intermediate filaments??
- Since intermediate filaments provide support for the basic structure of a cell, they cannot undergo further assebly/disassembly once formed
- **they undergo changes all the time
178
How is the assembley/dissasembely of intermediate filaments regulated?
-covalent modifications
179
What is a simiarity between the lateral spacing of microfilaments and microtubule bundles??
-lateral spacing cause by TAU in micotubules is small like fimbrin in microfilaments
180
What protein did NOT have to go through the ER during its synthesis and processing??
-Kinesin
181
What process is involved in regulated secretion of neurotransmitters??
-the flow of ca+ into the cytosol
182
What is NOT a key fxn of nucleus-ER complex??
-water sequestion
183
NOT a fxn of intermediate filaments??
- support intercellular jxns that provide flexibility to tissues
- **VERY STABLE NOT FLEXIBLE
184
Fxn of intermediate filaments
1) long-term, stable cytoslic support
2) lnuclear support
3) form prominent intracelluar connections to intercelluar fxns
185
What event leads to nuclear membrane disintergration??
-intermediate filament subunits are phophoylated
