physiology (lec 3)
... presynaptic cell and causes V-gated Ca2+ channels to open. Ca2+ rushes in, binds to regulatory proteins & initiates NT exocytosis. NTs diffuse across the synaptic cleft and then bind to receptors on the postsynaptic membrane and initiate some sort of response on the postsynaptic cell. ...
... presynaptic cell and causes V-gated Ca2+ channels to open. Ca2+ rushes in, binds to regulatory proteins & initiates NT exocytosis. NTs diffuse across the synaptic cleft and then bind to receptors on the postsynaptic membrane and initiate some sort of response on the postsynaptic cell. ...
Mitochondrial permeability transition pore
... transition in beef heart mitochondria. In 1987, Martin Crompton et al. implied that the pore is a unique molecular entity that allows the passage of any molecule of <1500daltons across the inner mitochondrial membrane. ...
... transition in beef heart mitochondria. In 1987, Martin Crompton et al. implied that the pore is a unique molecular entity that allows the passage of any molecule of <1500daltons across the inner mitochondrial membrane. ...
(MgCl2 and CaCl2): Osmotic Pressure Calculations
... Simulation studies of ion solutions at finite concentrations have found untimely aggregation of ion pairs.47−49 In-depth analysis of the ion clusters showed the that at conditions where the oppositely charged ions should have formed an SSP, they instead formed direct contact pairs.50−54 This behavior ...
... Simulation studies of ion solutions at finite concentrations have found untimely aggregation of ion pairs.47−49 In-depth analysis of the ion clusters showed the that at conditions where the oppositely charged ions should have formed an SSP, they instead formed direct contact pairs.50−54 This behavior ...
Presence of exposed phospholipids in the outer membrane of Vibrio
... not be an effective barrier to such compounds. This was confirmed by the extensive lysis (about 80%) of these cells following treatment with 0.01% SDS, sodium deoxycholate and Triton X-100. There was no detectable lysis of E. coli cells even at ten times the concentrations of these detergents. When ...
... not be an effective barrier to such compounds. This was confirmed by the extensive lysis (about 80%) of these cells following treatment with 0.01% SDS, sodium deoxycholate and Triton X-100. There was no detectable lysis of E. coli cells even at ten times the concentrations of these detergents. When ...
Chapter 21: Electric potential
... charge particle will increase when we move it against the direction that the electrostatic force would normally tend to move it ...
... charge particle will increase when we move it against the direction that the electrostatic force would normally tend to move it ...
Enhancement of Hippocampal Pyramidal Cell Excitability by the
... of the sAHP. The sAHP can be abolished by neurotransmitters such as noradrenaline (Madison and Nicoll, 1982, 1986; Malenka and Nicoll, 1986; Storm, 1990; Sah and Faber, 2002). In the absence of specific inhibitors, these have been used to study the role of the sAHP in cell excitability and behavior. ...
... of the sAHP. The sAHP can be abolished by neurotransmitters such as noradrenaline (Madison and Nicoll, 1982, 1986; Malenka and Nicoll, 1986; Storm, 1990; Sah and Faber, 2002). In the absence of specific inhibitors, these have been used to study the role of the sAHP in cell excitability and behavior. ...
Early Embryonic Expression of Ion Channels and Pumps in Chick
... an important regulatory role in establishing developmental polarity. For example, in the chick, voltage potentials between the epiblast and hypoblast may determine the dorsoventral polarity of the gastrulating chick embryo (Stern, 1982). In the regenerating planarian, anteroposterior polarity may be ...
... an important regulatory role in establishing developmental polarity. For example, in the chick, voltage potentials between the epiblast and hypoblast may determine the dorsoventral polarity of the gastrulating chick embryo (Stern, 1982). In the regenerating planarian, anteroposterior polarity may be ...
chapter 43 mechanisms of action of antiepileptic drugs
... believed to contribute to their efficacy (2). Voltage-gated sodium channels are multimeric protein complexes, composed of a large α subunit that forms four subunit-like homologous domains (designated I to IV) and one or more smaller β subunits (3). The ion-conducting pore is contained within the α s ...
... believed to contribute to their efficacy (2). Voltage-gated sodium channels are multimeric protein complexes, composed of a large α subunit that forms four subunit-like homologous domains (designated I to IV) and one or more smaller β subunits (3). The ion-conducting pore is contained within the α s ...
Cells of the Nervous System
... The Action Potential The only place where a myelinated axon comes into contact with the extracellular fluid is at a node of Ranvier, where the axon is naked. In the myelinated areas there can be no inward flow of Na+ when the sodium channels open, because there is no extracellular sodium. The axon c ...
... The Action Potential The only place where a myelinated axon comes into contact with the extracellular fluid is at a node of Ranvier, where the axon is naked. In the myelinated areas there can be no inward flow of Na+ when the sodium channels open, because there is no extracellular sodium. The axon c ...
2017 Lecture PDF
... Below are some example historical research finding related to cell membranes from the JCB Archive and other sources. 1957 The invention of freeze fracture EM and the determination of membrane structure (http://jcb.rupress.org/cgi/content/full/168/2/174-a) Russell Steere introduces his home-made cont ...
... Below are some example historical research finding related to cell membranes from the JCB Archive and other sources. 1957 The invention of freeze fracture EM and the determination of membrane structure (http://jcb.rupress.org/cgi/content/full/168/2/174-a) Russell Steere introduces his home-made cont ...
Ionic Channels in Biological Membranes
... properties of the 3 × (55/0.15) ×104 = 1.1 × 107 atoms surrounding them. Similarly, to calculate the properties of 10,000 Ca++ ions in a 0.002 molar solution, one must also calculate the properties of 3× (55/0.002) ×104 = 8.3 × 108 atoms. It is very difficult to perform simulations of this size and ...
... properties of the 3 × (55/0.15) ×104 = 1.1 × 107 atoms surrounding them. Similarly, to calculate the properties of 10,000 Ca++ ions in a 0.002 molar solution, one must also calculate the properties of 3× (55/0.002) ×104 = 8.3 × 108 atoms. It is very difficult to perform simulations of this size and ...
The Nervous System
... subdivisions of autonomic neurons: sympathetic and parasympathetic. Autonomic motor neurons, together with their central control centers, constitute the autonomic nervous system, the focus of chapter 9. The structural classification of neurons is based on the number of processes that extend from the ...
... subdivisions of autonomic neurons: sympathetic and parasympathetic. Autonomic motor neurons, together with their central control centers, constitute the autonomic nervous system, the focus of chapter 9. The structural classification of neurons is based on the number of processes that extend from the ...
A note on the fine structure of a spirochaete By A. V. GRIMSTONE
... organisms this coarse outer layer is lacking: there may be either no outer layer at all (fig. 3, E), or else only a vague indication of a homogeneous layer of low density. The outer layer, where present, is probably sticky, since not infrequently organisms are found apparently adhering at the points ...
... organisms this coarse outer layer is lacking: there may be either no outer layer at all (fig. 3, E), or else only a vague indication of a homogeneous layer of low density. The outer layer, where present, is probably sticky, since not infrequently organisms are found apparently adhering at the points ...
Biology
... The Resting Neuron When resting, the outside of the neuron has a net positive charge. The inside of the neuron has a net negative charge. The cell membrane is electrically charged because there is a difference in electrical charge between its outer and inner surfaces. Slide 13 of 38 End Show ...
... The Resting Neuron When resting, the outside of the neuron has a net positive charge. The inside of the neuron has a net negative charge. The cell membrane is electrically charged because there is a difference in electrical charge between its outer and inner surfaces. Slide 13 of 38 End Show ...
Tubular secretion
... cotransport at the luminal membrane. 4 Reabsorption of water by osmosis. Water reabsorption increases the concentration of the solutes that are left behind. These solutes can then be reabsorbed as they move down their concentration gradients: 5 Lipid-soluble substances diffuse by the transcellular r ...
... cotransport at the luminal membrane. 4 Reabsorption of water by osmosis. Water reabsorption increases the concentration of the solutes that are left behind. These solutes can then be reabsorbed as they move down their concentration gradients: 5 Lipid-soluble substances diffuse by the transcellular r ...
(III) From Aqueous Solutions with Sodium Dodecyl Sulfate
... transfer a substance adsorbed on them (sublate) from one liquid into another. The method was suggested for the first time by Sebba in 1962 [1,2]. Solvent sublation is a combination of the flotation of ions or molecules with liquid extraction. In this case, the term sublate refers to a chemically ind ...
... transfer a substance adsorbed on them (sublate) from one liquid into another. The method was suggested for the first time by Sebba in 1962 [1,2]. Solvent sublation is a combination of the flotation of ions or molecules with liquid extraction. In this case, the term sublate refers to a chemically ind ...
Chapter 3
... Neurons are electrically excitable due to the voltage difference across their membrane Communicate with 2 types of electric signals ...
... Neurons are electrically excitable due to the voltage difference across their membrane Communicate with 2 types of electric signals ...
Transcription- and translation-dependent changes in membrane
... caused a slight increase in anisotropy; Cam, Pur or Rif induced a significant (12–15%) reduction in anisotropy (Fig. 2), which started after a reproducible lag period and was completed in about 30 min, despite the fact that growth ceased almost immediately. Final changes in anisotropy are presented ...
... caused a slight increase in anisotropy; Cam, Pur or Rif induced a significant (12–15%) reduction in anisotropy (Fig. 2), which started after a reproducible lag period and was completed in about 30 min, despite the fact that growth ceased almost immediately. Final changes in anisotropy are presented ...
Membrane potential
Membrane potential (also transmembrane potential or membrane voltage) is the difference in electric potential between the interior and the exterior of a biological cell. With respect to the exterior of the cell, typical values of membrane potential range from –40 mV to –80 mV.All animal cells are surrounded by a membrane composed of a lipid bilayer with proteins embedded in it. The membrane serves as both an insulator and a diffusion barrier to the movement of ions. Ion transporter/pump proteins actively push ions across the membrane and establish concentration gradients across the membrane, and ion channels allow ions to move across the membrane down those concentration gradients. Ion pumps and ion channels are electrically equivalent to a set of batteries and resistors inserted in the membrane, and therefore create a voltage difference between the two sides of the membrane.Virtually all eukaryotic cells (including cells from animals, plants, and fungi) maintain a non-zero transmembrane potential, usually with a negative voltage in the cell interior as compared to the cell exterior ranging from –40 mV to –80 mV. The membrane potential has two basic functions. First, it allows a cell to function as a battery, providing power to operate a variety of ""molecular devices"" embedded in the membrane. Second, in electrically excitable cells such as neurons and muscle cells, it is used for transmitting signals between different parts of a cell. Signals are generated by opening or closing of ion channels at one point in the membrane, producing a local change in the membrane potential. This change in the electric field can be quickly affected by either adjacent or more distant ion channels in the membrane. Those ion channels can then open or close as a result of the potential change, reproducing the signal.In non-excitable cells, and in excitable cells in their baseline states, the membrane potential is held at a relatively stable value, called the resting potential. For neurons, typical values of the resting potential range from –70 to –80 millivolts; that is, the interior of a cell has a negative baseline voltage of a bit less than one-tenth of a volt. The opening and closing of ion channels can induce a departure from the resting potential. This is called a depolarization if the interior voltage becomes less negative (say from –70 mV to –60 mV), or a hyperpolarization if the interior voltage becomes more negative (say from –70 mV to –80 mV). In excitable cells, a sufficiently large depolarization can evoke an action potential, in which the membrane potential changes rapidly and significantly for a short time (on the order of 1 to 100 milliseconds), often reversing its polarity. Action potentials are generated by the activation of certain voltage-gated ion channels.In neurons, the factors that influence the membrane potential are diverse. They include numerous types of ion channels, some of which are chemically gated and some of which are voltage-gated. Because voltage-gated ion channels are controlled by the membrane potential, while the membrane potential itself is influenced by these same ion channels, feedback loops that allow for complex temporal dynamics arise, including oscillations and regenerative events such as action potentials.