Figure 5.1 Membrane Molecular Structure

1
Figure 5.1 Membrane Molecular Structure
Outside of cell
Extracellular matrix
Phospholipid
Cytoskeleton
Inside of cell
2
In-Text Art, Ch. 5, p. 64
Head
Tails
3
In-Text Art, Ch. 5, p. 65
Outside of cell (aqueous)
Hydrophobic interior of bilayer
Inside of cell (aqueous)
4
In-Text Art, Ch. 5, p. 66
Cells
5
Figure 5.2 Rapid Diffusion of Membrane Proteins
(Part 1)
Proteins embedded in a membrane can diffuse
freely within the membrane.
Membrane proteins
Mouse cell
Human cell
6
Figure 5.2 Rapid Diffusion of Membrane Proteins
(Part 2)
Proteins embedded in a membrane can diffuse
freely within the membrane.
Membrane proteins
Mouse cell
Human cell
Heterokaryon
Membrane proteins can diffuse rapidly in the
plane of the membrane.
7
Figure 5.2 Rapid Diffusion of Membrane Proteins
(Part 3)
The experiment was repeated at various
temperatures with the following results
Cells with mixed proteins ()
Temperature (?C)
0 15 20 26
0 8 42 77
Plot these data on a graph of Percentage Mixed
vs. Temperature. Explain these data, relating the
results to the concepts of diffusion and membrane
fluidity.
8
Figure 5.3 Osmosis Can Modify the Shapes of
Cells (Part 1)
Hypertonic on the outside (concentrated solutes
outside)
Isotonic (equivalent solute concentration)
Hypotonic on the outside (dilute solutes outside)
Inside of cell
Outside of cell
9
Figure 5.3 Osmosis Can Modify the Shapes of
Cells (Part 2)
Hypertonic on the outside (concentrated solutes
outside)
Isotonic (equivalent solute concentration)
Hypotonic on the outside (dilute solutes outside)
Animal cell (red blood cells)
10
Figure 5.3 Osmosis Can Modify the Shapes of
Cells (Part 3)
Hypertonic on the outside (concentrated solutes
outside)
Isotonic (equivalent solute concentration)
Hypotonic on the outside (dilute solutes outside)
Plant cell (leaf epithelial cells)
11
Figure 5.4 A Ligand-Gated Channel Protein Opens
in Response to a Stimulus
Outside of cell
Stimulus molecule (ligand)
Binding site
Channel protein
Hydrophobic interior of bilayer
Hydrophilic pore
Closed channel
Inside of cell
12
Figure 5.5 Aquaporins Increase Membrane
Permeability to Water (Part 1)
Aquaporin increases membrane permeability to
water.
Aquaporin mRNA
Aquaporin channel
Protein synthesis
13
Figure 5.5 Aquaporins Increase Membrane
Permeability to Water (Part 2)
Aquaporin increases membrane permeability to
water.
Aquaporin mRNA
Aquaporin channel
Protein synthesis
3.5 minutes in hypotonic solution
Aquaporin increases the rate of water diffusion
across the cell membrane.
14
Figure 5.5 Aquaporins Increase Membrane
Permeability to Water (Part 3)
Oocytes were injected with aquaporin mRNA (red
circles) or a solution without mRNA (blue
circles). Water permeability was tested by
incubating the oocytes in hypotonic solution and
measuring cell volume. After time X in the upper
curve, intact oocytes were not visible
X
With mRNA
Without mRNA
Relative volume
Time (min)
A. Why did the cells increase in volume? B. What
happened at time X? C. Calculate the relative
rates (volume increase per minute) of swelling
in the control and experimental curves. What
does this show about the effectiveness of mRNA
injection?
15
Figure 5.6 A Carrier Protein Facilitates
Diffusion (Part 1)
Outside of cell
High glucose concentration
Glucose
Glucose carrier protein
Inside of cell
Low glucose concentration
16
Figure 5.6 A Carrier Protein Facilitates
Diffusion (Part 2)
Rate of diffusion into the cell
Glucose concentration outside the cell
17
Figure 5.7 Primary Active Transport The
SodiumPotassium Pump
Outside of cell
High Na concentration, low K concentration
Na
Na K pump
K
K
ATP
Pi
Na
Pi
Pi
ADP
Pi
K
Inside of cell
High K concentration, low Na concentration
18
Figure 5.8 Endocytosis and Exocytosis (Part 1)
(A) Endocytosis
Outside of cell
Plasma membrane
Inside of cell
Endocytotic vesicle
19
Figure 5.8 Endocytosis and Exocytosis (Part 2)
(B) Exocytosis
Secretory vesicle
20
Figure 5.9 Receptor-Mediated Endocytosis (Part 1)
Clathrin molecules
Cytoplasm
Coated vesicle
Outside of cell
Specific substance binding to receptor proteins
Coated pit
21
Figure 5.9 Receptor-Mediated Endocytosis (Part 2)
Outside of cell
Specific substance binding to receptor proteins
Coated pit
Cytoplasm
Coated vesicle
Clathrin molecules
22
Figure 5.10 Chemical Signaling Concepts
Receptor
Secreting cell
Target cell
Target cell
Circulatory vessel (e.g., a blood vessel)
Target cell
23
Figure 5.11 Signal Transduction Concepts
Signal molecule
Receptor
Short-term responses enzyme activation, cell
movement
Inactive signal transduction molecule
Activated signal transduction molecule
Long-term responses altered DNA transcription
24
Figure 5.12 A Signal Binds to Its Receptor
Ligand
Outside of cell
Cell membrane
Inside of cell
25
In-Text Art, Ch. 5, p. 76
Signal molecule
Receptor
R L
RL
26
Figure 5.13 A Protein Kinase Receptor
Signal (insulin)
Outside of cell
Receptor
ATP
Protein kinase domain (inactive)
ADP
Phosphate groups
Target
Cellular responses
Inside of cell
27
Figure 5.14 A G ProteinLinked Receptor (Part 1)
Outside of cell
Signal (hormone)
GDP
G protein-linked receptor
Inactive effectorprotein
Inactive G protein
Inside of cell
28
Figure 5.14 A G ProteinLinked Receptor (Part 2)
Outside of cell
GTP
Activated G protein
Inside of cell
29
Figure 5.14 A G ProteinLinked Receptor (Part 3)
Outside of cell
Activated effector protein
GDP
Product
Reactant
Amplification
Inside of cell
30
Figure 5.15 The Discovery of a Second Messenger
(Part 1)
A second messenger mediates between receptor
activation at the plasma membrane and enzyme
activation in the cytoplasm.
Liver
Cytoplasm contains inactive glycogen
phos-phorylase
Membranes contain epinephrine receptors
31
Figure 5.15 The Discovery of a Second Messenger
(Part 2)
A second messenger mediates between receptor
activation at the plasma membrane and enzyme
activation in the cytoplasm.
Active glycogen phosphorylase is present in the
cytoplasm.
A soluble second messenger, produced by
hormone-activated membranes, is present in the
solution and activates enzymes in the cytoplasm.
The activity of previously inactive liver
glycogen phosphorylase was measured with and
without epinephrine incubation, with these
results
Enzyme activity (units)
Condition
Homogenate Homogenate epinephrine Cytoplasm
fraction Cytoplasm epinephrine Cytoplasm
membranes Cytoplasm membranes epinephrine
0.4 2.5 0.2 0.4 0.4 2.0

1. What do these data show?
2. Propose an experiment to show that the factor
   that activates the enzyme is stable on heating
   and give predicted data.
3. Propose an experiment to show that cAMP can
   replace the particulate fraction and hormone
   treatment and give predicted data.

32
Figure 5.16 The Formation of Cyclic AMP (Part 1)
Adenylylcyclase
cAMP
PPi
ATP
33
Figure 5.16 The Formation of Cyclic AMP (Part 2)
Adenine
Phosphate groups
ATP
34
Figure 5.16 The Formation of Cyclic AMP (Part 3)
Cyclic AMP (cAMP)
35
Figure 5.17 A Cascade of Reactions Leads to
Altered Enzyme Activity (Part 1)
Epinephrine
Outside of cell
1
ActivatedG proteinsubunit
Plasma membrane
Epinephrinereceptor
Activatedadenylylcyclase
GTP
ATP
cAMP
20
Active glycogensynthase
Inactive protein kinase A
Active protein kinase A
20
Inactive glycogensynthase
Inactive phosphorylase kinase
Active phosphorylase kinase
100
36
Figure 5.17 A Cascade of Reactions Leads to
Altered Enzyme Activity (Part 2)
100
Active phosphorylase kinase
Inactive glycogen phosphorylase
1,000
Active glycogen phosphorylase
Glycogen
10,000
Glucose 1-phosphate
Glucose
Inside of cell
10,000
Blood glucose
Outside of cell
37
Figure 5.18 Signal Transduction Regulatory
Mechanisms (Part 1)
Protein kinase
ATP
P
Inactiveenzyme
Activeenzyme
Proteinphosphatase
Pi
38
Figure 5.18 Signal Transduction Regulatory
Mechanisms (Part 2)
Receptor binding
InactiveG protein
ActiveG protein
GTP
GDP
GTPase
39
Figure 5.18 Signal Transduction Regulatory
Mechanisms (Part 3)
Adenylylcyclase
Phosphodiesterase
AMP
cAMP
ATP
40
Figure 5.19 Caffeine and the Cell Membrane (Part
1)
Outside of cell
Plasmamembrane
Inside of cell
41
Figure 5.19 Caffeine and the Cell Membrane (Part
2)
Caffeine
Adenosine