Unit 1: Membrane Movement Flashcards
(89 cards)
1
Q
Small ________ molecules such as O2, CO2, and N2 are able to ______ the synthetic lipid bilayer.
A
hydrophobic/lipophilic
pass through
2
Q
Small _______ molecules such as urea and water are able to ______ the synthetic lipid bilayer.
A
uncharged polar
pass through
3
Q
________-based molecules are able to _____ the synthetic lipid bilayer
A
cholesterol (lipophilic)
4
Q
_________ molecules such as amino acids, glucose, and nucleotides are ______ the synthetic lipid bilayer
A
Large uncharged polar
NOT able to pass through
5
Q
_____ such as H+, Na+, HCO3- are _____ the synthetic lipid bilayer
A
Ions
NOT able to pass through
6
Q
Integral proteins refers to any protein ______ the lipid bilayer
A
embedded within
7
Q
Transmembrane proteins are a specific type of ____ protein that _____ the membrane
A
integral
completely spans
8
Q
Peripheral proteins are attached to the ______, not ______ it.
A
membrane surface
embedded within
9
Q
Structural proteins:
Help create _____ which hold _____ together
Connect the _____ to _____ to maintain the shape of the cell
Connect cell to the _______ matrix.
A
cell junctions, tissues
membrane, cell cytoskeleton
extracellular
10
Q
What are the 4 types of integral proteins?
A
structural, transporters, enzymes, and receptors
11
Q
Transport proteins (transporters) move _____ across the membrane
____ or ______
A
molecules
channels, carriers
12
Q
If a molecule moves across the membrane, we say
membrane is ______ to the molecule
molecule is _____
Permeancy of molecule depends on:
A
permeable
permeant
Lipid soluble
nonpolar
small-ish
13
Q
Simple diffusion is the movement of a molecule ______ across the lipid bilayer
_____ transport - no _______ source required
Molecule moves ____ concentration gradient (_____ to ____ concentration)
A
directly
passive, outside energy
down (high, low)
14
Q
Simple diffusion uses _____ energy, but no _______
A
potential, outside energy
15
Q
Effects on simple diffusion:
Increased temperature?
Increased molecular size?
Distance from initial site?
A
increased temperature? Increases
Increased molecular size? Decreases
Distance from initial site? Decreases
16
Q
When does simple diffusion stop?
A
Equilibrium
17
Q
Diffusion rate ∝ _____-
A
Diffusion rate ∝ surface area x concentration gradient x permeability, membrane thickness
MPCs
18
Q
Diffusion rate is _____ proportionate to membrane thickness
A
indirectly
19
Q
Simple diffusion does NOT require ______
A
a membrane protein
20
Q
transporter-mediated movement involves _____ and _____
A
channels
carriers
21
Q
Open channels create a _____ pore
Continuous _______ from outside and inside
A
water-filled
communication
22
Q
Carriers never form an _____ between the two sides of the membrane
A
open channel
23
Q
Channels and carriers are both usually composed of ______
A
subunits
24
Q
_____ have a lot of similarities to enzymes
A
Carriers
25
______ directly connect ECF and ICF
Channels
26
Passive transport:
From ____ to ____ concentration
Flow/go/move ____ the gradient
Move ____ the gradient
high, low
down
with
27
Active transport:
From ___ to ____ concentration
Flow/go/move ____ the gradient
Move _____ the gradient
low, high
up
against
28
Does this substance move by channel or carrier?
Substance A is a 5-carbon molecule, and is moving down concentration gradient
facilitated diffusion carrier
moving down indicates passive transport
channel is usually ions
29
Carriers are similar to enzymes in that both...
A. Have an active site where substrate binds
B. Catalyze a chemical reaction
C. Undergo a permanent conformational change
D. Move molecules across membranes
A. Have an active site where substrate binds
30
Characteristics of mediated transport:
specificity
competition
saturation
31
Competitive inhibition is when another molecule comes into the _____ and ______ the transporter
active site
shuts down
32
Non-competitive inhibition is when another molecule binds to _______ and ______ transporter
allosteric site
shuts down
33
Which substance is also transported by the carrier?
A. a competitor
b. a competitive inhibitor
c. an allosteric or noncompetitive inhibitor
A. a competitor
moves from ECF to ICF by carrier
34
The transport rate is proportional to substrate concentration until the carriers are ______ (_______)
saturated
transport maximum
35
Specificity is illustrated by graph if introducing another molecule (X + Y) does not ____, implying its ______ to X.
change rate, specific
36
Competition is illustrated by graph if ______ changes
transport max
37
Blue molecules have the same concentration on both sides, meaning there is no _____ movement
net
38
Channel-mediated facilitated diffusion - all are ______!
Four types:
1.
2.
3.
4.
all are passive!
1. Open
2. Ligand-gated (chemically gated) channel
3. Mechanically gated channel (membrane movement)
4. Voltage-gated channel (change in membrane potential)
39
______ is essentially the only molecule that moves freely between cells and the extracellular fluid. Because of this free movement of _____, the extracellular and intracellular compartments reach a state of ______, in which the ______ are equal on two sides of the cell membrane.
Water
water
osmotic equilibrium
fluid concentrations
40
Although the overall concentrations of the ECF and ICF are equal, some solutes are _____ in one of the two body compartments than in the other. This means the body is in a state of ________.
more concentrated
chemical disequilibrium
41
The concentration differences of chemical disequilibrium are a hallmark of a living organism, as only the continual input of _____ keeps the body in this state.
energy
42
Primary active transporter uses ATP to go ______ the concentration gradient
against
43
Secondary active transporter uses the gradient established by a _______ and uses the kinetic energy of a molecule going ______ its concentration gradient
primary active transporter
down
44
Axes of a transport graph?
x-axis --> substrate concentration
y-axis --> rate of transport
PAY CLOSE ATTENTION!
45
In competitive inhibition...
another molecule comes in and shuts down transporter
46
In non-competitive inhibition...
another molecule binds to allosteric site and shuts down transporter
47
Saturation is illustrated on a transport graph by...
plateau which represents transport maximum
48
Competition is illustrated on a transport graph by...
if transport max changes
49
As concentration of substrate increases, the substrate _____ the competitive inhibitor.
Graph looks...
Less steep than uninhibited graph at first but eventually reaches the same transport max
Remember: inhibitor concentration stays constant in these scenarios
50
Noncompetitive inhibitor:
As concentration of the substrate increases, the substrate cannot ______ with the noncompetitive inhibitor
Graph looks...
cannot reach Tmax
51
the shape of carrier-mediated transport graph is ...
hyperbolic
52
shape of simple diffusion transport graph is...
linear
53
Which is NOT categorized as a "means/mode/method" of movement?
A. simple diffusion
B. channel-mediated diffusion
C. symporter
D. primary active transport
C. symporter
54
Direction of secretion:
ECF --> Lumen
Basolateral ---> apical
55
Direction of absorption:
Lumen --> ECF
Apical --> Basolateral
56
To determine if a molecule moves into a cell via simple diffusion or facilitated diffusion, consider whether the molecule is _____ (likely simple diffusion) like _______ or ________ (likely facilitated diffusion, requiring a transport protein to cross the membrane) like ______
small and non-polar, O2, CO2, N2
large, polar, or charged, glucose
57
non-polar = hydro-______
hydrophobic
58
Axes for a simple diffusion transport graph?
x-axis --> substrate concentration
y-axis --> rate of diffusion
59
Given the average cell, list the ones that are more concentrated in the ICF than ECF:
What are molecules that can move across the membrane by simple diffusion?
K+, CO2
O2, CO2
60
Diffusion is passive transport -- no ______ energy is required
outside
61
According to Fick's law, diffusion rate is _______ proportionate to membrane thickness
indirectly
62
Regarding diffusion, all _____ movement of molecules stops at equilibrium
net
63
An increase in temperature by 5ºC will _____ diffusion rate
increase
64
Aldosterone moves into target cell by means of _______ because ______
simple diffusion (steroid)
its a nonpolar molecule
65
Steroid hormone moving out of endocrine cell moves by _______ because ______
simple diffusion
its moving down its concentration gradient
66
Glucose moves into renal proximal tubule cell by means of _______ because _______
active transport
its moving against concentration gradient
*inside of tubule cell has higher glucose concentration, low → high (AGAINST concentration gradient)
67
Glucose moves into a muscle cell by means of _______ because _________-
facilitated diffusion (carrier-mediated)
its moving down concentration gradient.
*glucose is moving from blood → muscle cell, higher glucose concentration in blood (moving WITH concentration gradient)
68
In emphysema, loss of _____ means that less oxygen will diffuse from alveoli to capillaries
surface area
69
In fibrosis, scar tissue causes increased _______ resulting in lower gas exchange.
diffusion distance
70
Can actively transport substances
Operates at high rates, transporting millions of molecules per second
Forms a direct connection between the ECF and ICF
Is a transmembrane protein
Binds the substrate at an active site and changes configuration
Can be described as a symporter and antiporter
Carrier
Channel
Channel
Both
Carrier
Carrier
71
Substance B is an ion and is moving against its concentration gradient. Therefore, substance B must move by:
active transport
72
Substance C is an ion moving rapidly down its concentration gradient. Therefore, substance C is likely moving by:
channel-mediated facilitated diffusion
73
The Na/K ATPase has been found in every cell type examined to date. The Na/K ATPase . . .(choose all correct)
Is a transmembrane protein
Allows cells to communicate
Is part of the lipid bilayer
Performs one of the specific functions of the membrane
Fits into the functional category of membrane enzymes
Is a transmembrane protein
Performs one of the specific functions of the membrane
74
*Na/K ATPase is _____ in the lipid bilayer, but isn't actually a part of it
*Na/K ATPase is a _____, NOT a membrane enzyme
embedded
transporter
75
The three characteristics of carrier-mediated movement are:
specificity
competition
saturation
76
Glucose absorption is the classic example of epithelial transport. To answer this question, correctly order the steps in epithelial transport of glucose.
1. The Na/K ATPase pumps sodium out of the cell, creating gradient
2. Sodium binds to apical SGLT
3. Affinity of SGLT for glucose is increased
4. Glucose becomes concentrated inside the epithelial cell
5. Glucose moves passively into blood
77
Chapter 1 Reasoning Styles:
Mechanistic:
Teleological:
Mechanistic: How? (the mechanism in which it happens)
Each step of the process
Focus of this course!
Teleological:
Why? (why does it happen)
Function
78
What's typically higher in ECF?
What's in the ICF?
ECF:
Na+
Cl-
glucose (except for transport epithelial cells)
O2
Ca2+
ICF:
K+
CO2
79
Functions of cell membrane:
Physical isolation: separate inside (ICF) from outside (ECF)
Regulation of exchange with the environment: controls entry
Communication between the cell and the environment: in response to changes in the external environment
Structural support: Cell-cell and cell-matrix junctions stabilize the structure of tissues
80
Lipophilic:
- Lipid-_____
- Hydro-_____
- Often _____ (_____ exception)
Lipophobic:
- Lipid-_____
- Hydro-_____
- Often ____
Lipophilic:
- Lipid-soluble
- Hydrophobic
- Often small, non-polar (steroid hormones exception)
Lipophobic:
- Lipid-insoluble
- Hydrophilic
- Often large, charged, polar
81
Simple, channel-mediated, and facilitated diffusion is when molecules are going from _____ concentration to _____ concentration
high --> low
82
Channel-mediated diffusion can only be ______
uniporter
83
Ca2+ from ECF into cells
Moves by movement through a water-filled channel because it is following electrochemical gradient
*Hint if its an ion its most likely channel
84
K+ from ECF into cells
Moves by active transport because its moving AGAINST its concentration gradient
85
Glucose into red blood cell
Moves by facilitated diffusion because it is moving down its concentration gradient
86
Physiology Reference Man!
Weight:
Total Body Water (TBW):
Volumes of Distribution:
Weight: 155 lbs / 70 kg (155/2.2 = 70)
Total Body Water (TBW): 60%
Volumes of Distribution:
1/3 - ECF
2/3 - ICF
87
Which one is a type of primary active transporter?
a. Na+/K+ pump
b. Aquaporins
c. K+ leak channels
d. Voltage-gated Na+ channels
a. Na+/K+ pump
88
If you put a drug that acts as an inhibitor of the Na+/K+ pump on a
neuron and then stimulate the neuron repeatedly, what do you
expect to happen to action potentials generated by that neuron?
a. They cease immediately
b. There is no immediate effect, but they diminish with repeated
stimulation and eventually disappear
c. They get smaller immediately, then stabilize with smaller amplitude
d. The drug would have no effect on action potentials.
b. There is no immediate effect, but they diminish with repeated
stimulation and eventually disappear
89
Professor George, a 51 year old male, has been admitted for muscle
weakness and hypertension. After a number of tests alongside a
normal catecholamine test results, his physician has concluded that
the professor’s hypertension is due to a hormone secreting tumor in
his adrenal gland. His physician recommends immediate surgical
removal of the tumor but Professor George has a grant due in two
weeks and would like to postpone the surgery. His physician decides
to prescribe a medication in the meantime to manage Professor
George’s condition. What is one of possible actions of this drug?
a. Increase Na+/K+ ATPase expression in the kidney
b. Increase glucose secretion in the kidney
c. Decrease K+ secretion in the kidney
d. Increase ECF volume
c. Decrease K+ secretion in the kidney
