biomed week 4 Flashcards
1
Q
lipids can be broken down into two main classes :
A
fatty acid structure and isoprenoid structure
2
Q
isoprenoids contain
A
repeating 5 C structural units called isoprene units
3
Q
cholesterol is?
A
a steroid mad made of 6 isoprene units
4
Q
steroids with a hydroxyl group at …. may be refered to as ….
A
C3
sterols
5
Q
cholesterol synthesis occurs most significantly in the …. and …..
A
liver and kidney
6
Q
in the cell , cholesterol synthesis occurs in the…….
A
ER
7
Q
what are the four main steps of cholesterol synthesis
A
- condensation of 3 acetyl CoA into mevalonate
- formation of isopentenyl pyrophosphate
- creation of squalene
- uses 6 isopentenyl pyrophosphates - cyclization of squalene into cholesterol
8
Q
condensation of 3 acetyl CoA into mevalonate is a ………… by ……..
A
rate limiting step
HMG CoA reductase
9
Q
conversion of mevalonate into activated isoprenes is when … phosphate groups are added to ….. to form … to form ….. and one is immediately removed
A
3
mevalonate
ATP
isopentenyl pyrophosphate
10
Q
in cholesterol synthesis condensation of …. activated isoprene units form squalene.
A
6
11
Q
how many acetyl CoA are needed to make squalene
A
3
12
Q
in cholesterol synthesis , ring closure is a complex multistep process , linear squalene is converted into ………..
A
cyclic structure of cholesterol
13
Q
how many acetyl CoA are needed to make mevalonate?
A
3
14
Q
HMG CoA is inhibited by
A
high intracellular levels of cholesterol
- enzyme gets blocked
15
Q
HMG CoA will only be transcribed and translated if
A
intracellular cholesterol levels are low
16
Q
high intracellular cholesterol levels also promotes ….. of cholesterol for storage in the cell
A
esterification
17
Q
HMG CoA reductase can also be regulated via …………………….
A
reversible covalent modification
18
Q
……… promotes phosphorylation of HMG CoA reductase , inhibiting the enzyme ……….. cholesterol synthesis
A
Glucagon
inhibiting
19
Q
………. promotes de-phosphorylation of HMG CoA reductase, activating the enzyme ……….. cholesterol synthesis
A
Insulin
promoting
20
Q
HMG CoA reductase tends to exist in its ……………..
A
inactive phosphorylated state
21
Q
fatty acids can form of number of derivatives including ………..
A
phospholipids
22
Q
phospholipids have three components
A
hydrocarbon chain
back bone ( glycerol or cermine )
phosphate alchohol head group
23
Q
if both fatty acids are linked to the glycerol backbone with an ester link is called a ……….
A
phosphatidate
24
Q
if one fatty acid is linked to the glycerol backbone with an ester link while the other has an ether link is is called a …………
A
plasmalogen
25
what are the components of a glycerophospholipid
fatty acid tail (usually 16-18 carbons)
-unbranched, may be saturated
glycerol backbone
- ester linkage
phosphate head
- usually the R is linked to another molecule
- choline
- ethanol-amine , glycerol , inositol , serine
26
phospholipid synthesis occurs primarily on the .......... of the ......... and .....................
luminal surface
smooth ER
inner mitochonrial membrane
27
what are the four basic steps of phospholipid synthesis
synthesis of glycerol backbone
attachment of fatty acids to backbone via ester linkage
addition of head group
exchange / modification of head group
28
glycerol 3 phosphate can be derived from
addition of phosphate group to glycerol
- only occurs in the liver
conversion of glycerol 3 phosphate from dihydroxyacetone phosphate (DHAP)
29
in phospholipid synthesis, two fatty acid CoAs are added to .......... forming phosphatidic acid
gycerol 3 phosphate
30
in the addition of a phospholipid head group, one of the hydroxyl is first activated by ....................... cytosine diphosphate (CDP)
the attahcment of a nucleotide
31
in the adidtion of a headgroup, CMP is displaced via nucleophilic attack and replaced by a .....
head group
32
phosphatidylserine and phosphatidylethanolamine can be interconverted in a ...................
reversible head group exchange reaction
33
phosphatidylethanolamine can be converted to phosphatidylcholine by the addition of ................
3 methyl groups
34
phosphatidylinositol is a less common phospholipid in the cell membrane but it plays an important role in .............
cell signalling
35
can phospholipids spontaneously flip over to the luminal side?
No
need special enzymes such as flippase
36
what happens in inactivation of intracellular signalling
ligand releases from receptor
receptor associated effectors inactivate
2nd messanger is either metabolized or removed
37
a G coupled receptor spans the membrane how many times?
7
38
in G protien coupled receptors , there are three subunits, alpha, beta and gamma
when untimiulated alpha is bound to ........ and BY is bound to a
when stimulated a subunit releases ........ replacing it with ..... and the a subunit disengages from by subunits
GDP
GDP
GTP
39
whan alpha subunit hydrolyzes GTP to GDP it .........
becomes inactivated again
40
in Gs GPCR, Gs releases ...... and binds ..... at the ........
GDP
GTP
alpha subunit
41
Gs binds and activates
adenylyl cyclase
42
adenylyl cyclase does what?
converts ATP to cAMP
43
cAMP binds to ........ inhibitors PK A then detach and .............
protein kinase
allow the active parts of PK A to work
44
PKA releases ......... allowing calcium to move down its concentration gradient (from storage to cytosol)
inhibitors
45
the Gq GPCR uses ...... and ..... and ..... as second messanger systems
Ca2+
IP3
DAG
46
IP3 is a second messanger that has ..... and causes release of ....... from where its stored in the ER
one effect
Ca2+
47
in a resting cell there is about 0.1 micormolar of ...... in the cytosol and 1-3 mmol of ...... in the ER in the extracellular space
calcium
calcium
48
the concentration gradient for calcium is ........ it wants to ..........
very high
enter the cytosol
49
when the concentration of Ca2+ in the cytosol increases, it will then bind to ............ and cause .......
calcium binding proteins
an effect
50
each calmodulin binds ............... before it becomes activated
4 calcium ions
51
once calmodulin is activated, it binds to ...... ex ......
effectors
calmodulin kinase
52
Gq alpha activates ......
phospolipase C
53
phospholipase C cleaves a ...... into ..............
membrane lipid
IP3 and diacylgycerol
54
IP3 is .... and enters the ......
DAG is ....... and stays .........
water soluble , cytosol
lipid soluble , within the cell membrane and then diffuses throughout it
55
IP3 activates ........ release in the ..... resultng in movement of ...... from the ....... to the .....
Ca2+ , ER
Ca2+ , ER, cytosol
56
both Ca2+ and ...... work together to activate membrane bound ...........
DAG
protein kinase C (PK C)
57
why does PK C need to be membrane bound
so it does not phosphorylate things it doesnt need to
58
PK C can modulate ...........
the activity of many effectors
59
Gi GPCR down regulates ....... Gi-a inactivates ...... and Gi-By opens .......
the activity of Gs
adenylyl cyclase
K+ channel
60
what is the nerst potential for k+?
-90 mV
61
if the channel allows sodium to enter the membrane becomes
more inside positive
depolarization
62
if a channel allows potassium to leave the membrane becomes
more inside negative
hyperpolarization
63
if the channel allows calcium to enter the cytosol
it binds calmodulin
64
what is a enzyme coupled receptor
transmembrane protein with ligand binding domain on outer surface of the plasma membrane
65
cytosolic domain has either .....
intrinsic enzyme activity
direct association with the enzyme
66
intrinsic kinase activity : ...........
binding of the ligand ...... the receptor and activates .... within a receptor
the receptor phosphorylates itself on a specific residues of the intracellular face of the receptor
dimerizes
tyrosine kinase
67
ligand examples
insulin
growth factors
cytokines
68
receptor tyrosine kinases (RTKs)
ligand binds to .........
receptor ..... and each half ....... the tyrosine residues on the other half
signaling proteins can then bind to the ....... and also become activated creating a ....
receptor monomers
dimerizes
phosphorylates
phosphorylated receptor signal cascade
69
what is the Ras cascade
how does it become activated?
what does it activate?
what then gets activated?
when Ras encounters an activated RTK, it then binds to GTP and activates
ras activates raf
activated raf causes activation of MAP kinases
70
what do MAP kinases phosphorylate?
transcription factors , enzymes
71
how does Ras inactivate?
inactivates itself by cleaving GTP -> GDP
72
adaptor protein Grb2 activates what
Ras
73
Ras-Raf-MAP kinase pathway is the pathway most commonly associated with
RTK activation
74
PI-3 kinase --> Akt system is .....
a unique signalling mechanism that is key to insulin signaling
75
describe the RTK PI-3-kinase Akt system pathway
what is the second messenger in the system?
RTK is activated causing activation of PI3k
PI3k attaches an additional phosphate to PIP2 to form PIP3
PIP3 accumulates and forms lipid rafts in the membrane
what is the second messenger in the system?
PIP3
76
PDK1 becomes activated by
when activated it activates ,.......
PIP3
Akt
77
Akt is the
effector
78
PIP3 brings .... and ..... together at the membrane
PDK1 and Akt
79
nitric oxide relaxes ...... , ...... and ....
smooth muscle , blood vessels and visceral organs
80
nitric oxide is a ...... that diffuses easily and quickly
hydrophobic gas
81
how is nitric oxide produced?
enzymatically by the action of nitric oxide synthase on L - arginine
82
nitric oxide ...... rapidly because.........
degrades
it reacts with oxygen and water
83
describe nitric oxide mediated signalling
cytosolic calcium increases
- by activated ligand on ion channel to let
calcium in
increased calcium activates NO
NO produces NO from L - arginine
NO binds and activates guanylyl cyclase
cytosolic cGMP activates a protein kinase (usually PKG)
causes changes in cellular activity due to PKG activity
84
what does guanylyl cyclase produce
cGMP to GTP
85
flow is ...
the movement of a substance from one point in a system to another point in the system
86
what is the driving force of flow between point A and B
energy gradient
87
amount of flow is directly related to the
size of the energy gradient between A and B
88
what is poiseuilles law equation
F = P1 - P2 x (pi radius ^4 / 8ul)
89
flow in poiseuilles law increases when
hydrostatic and radius increase
90
flow in poiseuilles law decreases when
the viscocity of the fluid and length of the tube increase
91
in poiseuilles law, as the tubes become more branched or irregular it is hard to ......
quantify resistance
when flow becomes turbulent
when the tube is flexible
radius is the most important determinant of resistance
92
flow is
the amount of substance moving accross a barrier per unit time
93
force driving flux is
the concentration gradient
94
resistances could be
membrane surface area and membrane thickness
permeability of the membrane to the substance
95
What is ficks law equation
F = k x (A(Ca-Cb)/t)
96
A in ficks law is a measurement of the
surface area on the membrane
97
k, a constant in ficks law increases when
the substance is a smaller molecule that dissolves better in the barrier
permeability of the membrane to the substance
98
in ficks law, flow increases when
flow, surface area and k constant increase
99
ficks law flow decreases when
thickness increases
100
flow flux in ficks law can be affected by
concentration difference
surface area avalible for the solute . gas to cross
the permeability of the membrane
solubility of the membrane
distance between the two compartments
101
ohms law equation
I = V/R
102
in ohms law, current increases when
voltage increases
103
in ohms law, current decreases when
resistance decreases
104
what are some ohms law take aways
opposite charges repel
particles move down a gradient of voltage according to their charge
105
in biology, ohms law is most useful when thinking about
unequal distributions of chrages very close to either side of the membrane
106
what is the starling forces equation
flux = Lp ((p cap - PISF) - 0(pie cap - pi ISF)
pi =osmotic pressure
P = hydrostatic pressure
107
charged particles in nerst potential can move across membranes based on
electrostatic forces
108
dissolved particles in nerst potenial can move across membranes based on
their concentration gradient
109
nerst equatiion accounts for:
diffusion of ions very close to either side of the membrane
the charged particle
the ratio of the particles concentration intracellular:extracellular
it gives energy gradient
110
what is the nerst potential equation
Ep =( (-60mV)/ zp) log 10 (Pi / Po)
Ep = the membrane voltage at which a particle (P) moves into ad out of the cell at the same rate
111
nerst potential - why is there an unequal distribution of sodium and potassium across the membrane
ATPase
112
in nerst potential why is there an unequal distribution charge
because 3 sodium leave and 2 potassium enter the cell
113
why is nerst equation important?
cellular signalling
transport of substances
regulation of cell volume
114
the membrane potential is about -75 mV but the nerst potential for postassium is close to -90mV
why is the membrane potneital of a neuron close to but not the same as the equilibrium for K+
there are other ions
115
cholesterol intercalates between ...... with the ,.... closest to the aqueous surface
phospholipids
-OH
116
the amount of cholesterol impacts membrane ......
smaller amounts ........ causing ........... and large amounts .......... and increase ....
fluidity
stiffen the membrane , decreased fluidity
interfere with the interactions between the lipid tails , increasing fluidity
117
sphingolipids decrease ..........
membrane fluidity
118
what are glycocalyx
protiens and lipids that are bound to carbs that vary in size
119
what formation of membrane lipids is favoured
phospholipid bilayer (most favoured) or micelle
120
membranes inside the cell dont need to ........... ,............. , ............. therefore there is no need for sphingolipids and there is much less cholesterol in the cell membranes
signal to other cells
protect cells from harsh environments
form a glycocalyx
121
most cells express many ....... in the plasma membrane which allows for high water conductace
auquaporins
122
NA+/K+ ATPase is a key plasma membrane transporter, each cycle of transport involves ..... out and ...... into the cytosol
this involves hydrolysis of .......
3 NA+
2 K+
1 ATP
123
facillitated transport is
a protein carrier that binds to a substance and transports it across a membrane , allowing it to FOLLOW its concentration gradient
ex. glucose transporter (GLUT)
124
Co- transport is
the transportation of 2 substances (X and Y) are coupled using the same protein
concentration gradient of X favours movement into the cell
Y is pulled along even if its not its favourable concentration gradient
ex .
sodium glucose co- transporter
125
counter transport is
X and Y move in opposite directions across the cell membrane , the gradient of one of the molecules supplies the energy to drive the transport
ex.
counter transporter
126
most membrane receptors have
hydrophobic domains that extend through the lipid bilayer
an extracellular domain that binds to the message
an intracellular domain that amplifies the signal
127
membrane protiens that link the cell to extracellular structures are known as
tight junctions
128
tight junctions separate cells into .... and ..... compartments
apical and basal
129
junctions can be very selective and ......
leak proof
130
what is the anchoring junction desmosome ?
what binds to these plaques?
intracellular component
a plaque that is formed of molecules associated with cadherins
intermediate filaments
extracellular component
- cadherins on one cell interact with cadherins on a neighbouring cell
purpose : structural integrity
131
what is a hemi desmosome
extracellular component involves a protein known as integrin
plaque still binds to intermediate filament
integrin commonly binds to the basement membrane
usually how epitheilial cells stay anchored to the basement membrane and underlying connective tissue
132
adherens junction
these junctions contain a plaque and may connect to :
- another cell
- a basement membrane - integrins
however they do not connect with intermediate filaments
MICROFILAMENTS
133
the cytoskeleton permits the following
cellular movement
organization of cellular components
cellular structure
communiciation
134
microtubules are responsible for
- trafficing of organelles and cell division
- organization of overall cellular structure
- cellular movement
- molecule - tubulin
135
microfilaments
- cellular movement
- structural organization of the plasma membrane
- molecule - actin
136
intermediate filaments
- overall structural integrity of the cell
- variety of the molecules - keratins and desmin
137
what are the features of the cytoskeleton
dynamic
- constantly building into polymer strands (actin)
tightly regulated
- filament assembly and disassembly is regulaed by
a huge array of intracellular signals
- structure and formation of polymers
can generate force
- many proteins interact with the strands of the
cytoskeleton
- generate power or motion in cells through
contraction
138
momomer ..-actin polymer ..... - actin
G actin
F actin
139
when F actin is formed .......
it spontaneously degrades
- each G actin is ATP bound
140
overtime G actin hydrolyzes .... to ..... which makes it more likely that is will ........... the F actin strand
ATP
ADP
fall off
141
what does the stability of F actin depend on
concentration of G actin
caps that can be applied to F actin that prevent dissassemby
proteins that speed up or slow down the rate that G actin hydrolyzes ATP
nucleating factors or inhibitory factors
142
a muscle cell needs actin to
generate alot of force
- actin is long lasting and very precisely organized
143
a fibroblast needs actin to
crawl to an area in order to deposit collagen
needs to explore its environemnt in order to find the right place to deposit collagen
therfore organized actin into meshes , fibers
144
microtubules are made of 2 types of
tubulin
beta and alpha form dimers
- organized in helical tube
- beta monomers hydrolyze a nucleotide triphosphate
145
dynamic instability is
tubilin cleaves GTP to GDP and phosphate
after GDP is cleaved, the dimer falls off of microtubule and it falls apart
146
microtubules are important for
cellular organization
form a cellular scaffolding
147
MTOC is composed of
2 centrioles that form a centrosome
- unique shape
148
microtubules are important for
cellular movement
- cillia and flagella
cell division
- spilts chromosomes
signalling
- primary cillium found on most cells
- able to sense important stimuli in the extracellular environment
149
F actin ---> ........ is a protien that can "walk on the track"
myosin
150
what is the purpose of intermediate filaments
much more diverse and stable than actin and tubulin
151
what is a intermediate filament
a long protien with an alpha helix conformation that coils around other monomers to form dimers
152
what are the 4 types of intermediate filaments
lamins , keratins , vimentin family , neurofilaments
153
what is the function of lamins (intermediate filaments)
a network of filaments just under the nuclear membrane
154
what is the function of keratins (intermediate filaments)
epithelial cells, hair, nails , modified to limit water permiability
155
what is the vimentin family responsible for ? (intermediate filaments)
confer stablilty and structure to
- mesenchymal cells
- muscle cells, some epithelial cells
- glial cells
156
what are neurofilaments responsible for? (intermediate filaments)
found in neurons
157
nasal cavity and nasopharynx location
back of the nose and throat that leads to the larynx
158
larynx structure
cartilaginous structure that contains the vocal cords
159
the trachea structure
mid line , non paired conducting airway
160
bronchi structure
branching airways that contain variable amounts of cartilage
161
what are bronchioles
branching airways that lack cartilidge but are surrounded by smooth muscle
162
what are alveoli
delicate, ballon like structures that are the main site of gas exchange
site of pulmanary microvasculature
163
what is ventilation
skeltal muscles change the volume of the thoracic cavity causing pressure changes and air movement through the conducting air ways
164
diffusion is known as the
respiratory exchange zone
165
what are the components of the ventilatory apparatus
the lungs
the chest wall
muscles
166
during inspiration the external intercostal muscles and diaphragm
contract
167
inspiration causes volume of the thoracic cavity to ... , causing a ... in intrathoracic pressure
the drop in intrathoracic pressure causes a ..... of the airspaces of the lungs causing movement of air from .....
increases , decrease
drop in pressure, atomosphere into the lungs
168
during expiration the diaphragm and external intercoastal muscles
relax
169
during expiration the volume of the thoracic cavity .... causing an .. in intrathoracic pressure
decreases
increase
170
how does the chest wall/ diaphram connect to the lungs
the pleura
171
trachea , main bronchus , ......... , .......
lobar bronchus , segmental (tertiary) bronchus
172
the inferior lobe spaces desend from the .... rib prosteriorly to the .... on deep inspiration
10th , 12th
173
what are the rioles of the nasal cavity , nasophaynx and larnyx
warminf and moistning of air
phonoation(speaking)
protection of airways from foods and liquids
174
pleural effusion is ......
causes?
fluid in the pleura space
- difficult for airways to expand
- difficult to hear breath sounds
- lungs dull to percussion
unilateral
cancer, infection , trauma
bilateral
congestion due to heart failure , bilateral infection
175
consolidation is
causes?
gunk in the airways
- fluid transmits sound in the airspaces better than air
- dull to percussion
- decreased breath sounds
coarse crackles
fine crackles
pneumia , OPD
176
fluid in small airways
fine crackles
- pulmanary edema
with pressure can collapse
177
wheeze is
when a small airwat is narrowed or constricteed
- high pitched musical sound
asthma , COPD , pul edema
178
stridor is
when large airways are constricted or narrowed
- louder harsh sound on inspiration
airway obstruction due to infection, trauma
