B2.1 Membrane and transportD2.3 Water Potential
wow
In this unit we will be able to see characteristics of the cell membrane and how to transport things across it!
go!
Título 2
B2.1.1— Lipid bilayers as the basis of cell membranes.
Subtítulo
B2.1.1— Lipid bilayers as the basis of cell membranes.
Membrane-bound organelles
B2.1.2— Lipid bilayers as barriers.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Interior is non-polar and hydrophobic!
B2.1.4— Integral and peripheral proteins in membranes.
B2.1.4— Integral and peripheral proteins in membranes.
Integral Proteins
Integral proteins penetrate the phospholipid bilayer to remain permanently attached to the membrane
These transmembrane proteins cannot be readily isolated without disrupting the bilayer (e.g. via detergents)
Examples of integral membrane proteins include glycoproteins, ion channels, carrier proteins and protein pumps
B2.1.4— Integral and peripheral proteins in membranes.
Integral Proteins
Integral proteins penetrate the phospholipid bilayer to remain permanently attached to the membrane
These transmembrane proteins cannot be readily isolated without disrupting the bilayer (e.g. via detergents)
Examples of integral membrane proteins include glycoproteins, ion channels, carrier proteins and protein pumps
B2.1.4— Integral and peripheral proteins in membranes.
B2.1.9— Structure and function of glycoproteins and glycolipids..
B2.1.9— Structure and function of glycoproteins and glycolipids..
B2.1.9— Structure and function of glycoproteins and glycolipids..
Glycoproteins and glycolipids also play an important role in maintaining the structural integrity of the extracellular matrix
The extracellular matrix is a network for external molecules that provide structure and biochemical support to surrounding cells
The carbohydrate chains can link these extracellular molecules together to help make the matrix a cohesive network
B2.1.9— Structure and function of glycoproteins and glycolipids..
B2.1.10— Fluid mosaic model of membrane structure.
Cell membranes are represented according to a fluid-mosaic model, due to the fact that they are:
Fluid – the phospholipid bilayer is viscous and individual phospholipids can move position
Mosaic – the phospholipid bilayer is embedded with proteins, resulting in a mosaic of components
B2.1.10— Fluid mosaic model of membrane structure.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Título 2
B2.1.3— Simple diffusion across membranes.
Solutes diffuse from a region of higher solute concentration to a region with lower solute concentration through the membrane.
Simulation:
B2.1.3— Simple diffusion across membranes.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
B2.1.3— Simple diffusion across membranes.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
B2.1.3— Simple diffusion across membranes.
B2.1.6— Channel proteins for facilitated diffusion.
Facilitated diffusion is the passive movement of molecules across the cell membrane via the aid of a membrane protein
It is utilised by molecules that are unable to freely cross the phospholipid bilayer (large, polar molecules and ions)
This process is mediated by two distinct types of transport proteins – channel proteins and carrier proteins
B2.1.6— Channel proteins for facilitated diffusion.
Channel Proteins
Integral lipoproteins which contain a hydrophilic pore via which ions may cross from one side of a membrane to the other
Channel proteins are ion-selective and may be gated to regulate the passage of ions in response to certain stimuli
Channel proteins only move molecules along a concentration gradient (i.e. are not used in active transport)
Channel proteins have a much faster rate of transport than carrier proteins
B2.1.6— Channel proteins for facilitated diffusion.
Carrier Proteins
Integral glycoproteins which bind a solute and undergo a conformational change to translocate the solute across the membrane
Carrier proteins will only bind a specific molecule via an attachment similar to an enzyme-substrate interaction
When a carrier protein moves material against the gradient (using ATP hydrolysis) it is called a protein pump
Carrier proteins have a much slower rate of transport than channel proteins (by an order of ~1,000 molecules per second)
B2.1.7— Pump proteins for active transport.
Active transport implies the use of ATP (energy) in order to move molecules from one side to the other
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
D2.3.1 — Solvation with water as the solvent.
D2.3.1 — Solvation with water as the solvent.
Water can form hydrogen bonds with other molecules, making "water shells with them.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Water can form hydrogen bonds with other molecules, making "water shells with them.
B2.1.5— Movement of water molecules across membranes by osmosis and the role of aquaporins.
Water diffuses from a region of lower solute concentration (and higher water concentration) to a region with higher solute concentration (and lower water concentration) through the membrane.
B2.1.5— Movement of water molecules across membranes by osmosis and the role of aquaporins.
Aquaporins Help water move through the internal hydrophobic part of the phospholipid bilayer Discovered by Peter Agre and colleagues
https://pubmed.ncbi.nlm.nih.gov/1373524/
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
Water is always moving in and out of the cell, even in isotonic solutions
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
Contractile Vacuoles
Unicellular organisms (such as protists) may possess a contractile vacuole to regulate the osmotic conditions within the cell
Excess water is absorbed into the contractile vacuole, causing it to swell (this is called diastole)
The vacuole then fuses to the plasma membrane and contracts, expelling the water (this is systole)
The amount of water expelled and the rate of contractions are determined by the extracellular conditions
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Título 2
D2.3.7—Medical applications of isotonic solutions
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
Unsaturated fatty acids have double bonds in their lipid chain which results in a kinked hydrocarbon tail
This means the lipids are harder to pack together, lowering their viscosity (and increasing fluidity)
Unsaturated fatty acids in lipid bilayers also have lower melting points, so membranes are more fluid and flexible at temperatures experienced by a cell.
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
Saturated fatty acids have no double bonds in their lipid chain which results in a straight hydrocarbon tail
This means the lipids will be easier to pack together, increasing their viscosity (and lowering fluidity)
Saturated fatty acids have higher melting points and make membranes stronger and more stable at higher temperatures
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
B2.1.12— Cholesterol and membrane fluidity in animal cells
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
B2.1.11— Membrane fluidity and the fusion and formation of vesicles
Exocytosis Endocytosis
B2.1.11— Membrane fluidity and the fusion and formation of vesicles
B2.1.11— Membrane fluidity and the fusion and formation of vesicles
Subtítulo
B2.1.15— Sodium–potassium pumps as an example of exchange transporters
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
n example of antiport is the translocation of sodium and potassium ions by the sodium-potassium pump
This pump is used by nerve cells (neurons) to establish an electrochemical gradient across the membrane (resting potential)
B2.1.16— Sodium-dependent glucose cotransporters as an example of indirect active transport
In this case, a molecule of Na+ is necessary to introduce a molecule of glucose in the cell. That molecule, then, goes to the Na+/K+ pump to re-balance the ions
B2.1.17— Adhesion of cells to form tissues
Cell adhesion is the attachment of cells to other cells or to the extracellular matrix via specialised membrane proteins called cell adhesion molecules (CAMs) There are different forms, depending on their function.
B2.1.17— Adhesion of cells to form tissues
U2.2_B2.1 Membrane and Transport
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Transcript
B2.1 Membrane and transportD2.3 Water Potential
wow
In this unit we will be able to see characteristics of the cell membrane and how to transport things across it!
go!
Título 2
B2.1.1— Lipid bilayers as the basis of cell membranes.
Subtítulo
B2.1.1— Lipid bilayers as the basis of cell membranes.
Membrane-bound organelles
B2.1.2— Lipid bilayers as barriers.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Interior is non-polar and hydrophobic!
B2.1.4— Integral and peripheral proteins in membranes.
B2.1.4— Integral and peripheral proteins in membranes.
Integral Proteins Integral proteins penetrate the phospholipid bilayer to remain permanently attached to the membrane These transmembrane proteins cannot be readily isolated without disrupting the bilayer (e.g. via detergents) Examples of integral membrane proteins include glycoproteins, ion channels, carrier proteins and protein pumps
B2.1.4— Integral and peripheral proteins in membranes.
Integral Proteins Integral proteins penetrate the phospholipid bilayer to remain permanently attached to the membrane These transmembrane proteins cannot be readily isolated without disrupting the bilayer (e.g. via detergents) Examples of integral membrane proteins include glycoproteins, ion channels, carrier proteins and protein pumps
B2.1.4— Integral and peripheral proteins in membranes.
B2.1.9— Structure and function of glycoproteins and glycolipids..
B2.1.9— Structure and function of glycoproteins and glycolipids..
B2.1.9— Structure and function of glycoproteins and glycolipids..
Glycoproteins and glycolipids also play an important role in maintaining the structural integrity of the extracellular matrix The extracellular matrix is a network for external molecules that provide structure and biochemical support to surrounding cells The carbohydrate chains can link these extracellular molecules together to help make the matrix a cohesive network
B2.1.9— Structure and function of glycoproteins and glycolipids..
B2.1.10— Fluid mosaic model of membrane structure.
Cell membranes are represented according to a fluid-mosaic model, due to the fact that they are: Fluid – the phospholipid bilayer is viscous and individual phospholipids can move position Mosaic – the phospholipid bilayer is embedded with proteins, resulting in a mosaic of components
B2.1.10— Fluid mosaic model of membrane structure.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Título 2
B2.1.3— Simple diffusion across membranes.
Solutes diffuse from a region of higher solute concentration to a region with lower solute concentration through the membrane.
Simulation:
B2.1.3— Simple diffusion across membranes.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
B2.1.3— Simple diffusion across membranes.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
B2.1.3— Simple diffusion across membranes.
B2.1.6— Channel proteins for facilitated diffusion.
Facilitated diffusion is the passive movement of molecules across the cell membrane via the aid of a membrane protein It is utilised by molecules that are unable to freely cross the phospholipid bilayer (large, polar molecules and ions) This process is mediated by two distinct types of transport proteins – channel proteins and carrier proteins
B2.1.6— Channel proteins for facilitated diffusion.
Channel Proteins Integral lipoproteins which contain a hydrophilic pore via which ions may cross from one side of a membrane to the other Channel proteins are ion-selective and may be gated to regulate the passage of ions in response to certain stimuli Channel proteins only move molecules along a concentration gradient (i.e. are not used in active transport) Channel proteins have a much faster rate of transport than carrier proteins
B2.1.6— Channel proteins for facilitated diffusion.
Carrier Proteins Integral glycoproteins which bind a solute and undergo a conformational change to translocate the solute across the membrane Carrier proteins will only bind a specific molecule via an attachment similar to an enzyme-substrate interaction When a carrier protein moves material against the gradient (using ATP hydrolysis) it is called a protein pump Carrier proteins have a much slower rate of transport than channel proteins (by an order of ~1,000 molecules per second)
B2.1.7— Pump proteins for active transport.
Active transport implies the use of ATP (energy) in order to move molecules from one side to the other
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
D2.3.1 — Solvation with water as the solvent.
D2.3.1 — Solvation with water as the solvent.
Water can form hydrogen bonds with other molecules, making "water shells with them.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Water can form hydrogen bonds with other molecules, making "water shells with them.
B2.1.5— Movement of water molecules across membranes by osmosis and the role of aquaporins.
Water diffuses from a region of lower solute concentration (and higher water concentration) to a region with higher solute concentration (and lower water concentration) through the membrane.
B2.1.5— Movement of water molecules across membranes by osmosis and the role of aquaporins.
Aquaporins Help water move through the internal hydrophobic part of the phospholipid bilayer Discovered by Peter Agre and colleagues
https://pubmed.ncbi.nlm.nih.gov/1373524/
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
Water is always moving in and out of the cell, even in isotonic solutions
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
Contractile Vacuoles Unicellular organisms (such as protists) may possess a contractile vacuole to regulate the osmotic conditions within the cell Excess water is absorbed into the contractile vacuole, causing it to swell (this is called diastole) The vacuole then fuses to the plasma membrane and contracts, expelling the water (this is systole) The amount of water expelled and the rate of contractions are determined by the extracellular conditions
D2.3.2—Water movement from less concentrated to more concentrated solutions D2.3.3—Water movement by osmosis into or out of cells
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Título 2
D2.3.7—Medical applications of isotonic solutions
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
Unsaturated fatty acids have double bonds in their lipid chain which results in a kinked hydrocarbon tail This means the lipids are harder to pack together, lowering their viscosity (and increasing fluidity) Unsaturated fatty acids in lipid bilayers also have lower melting points, so membranes are more fluid and flexible at temperatures experienced by a cell.
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
Saturated fatty acids have no double bonds in their lipid chain which results in a straight hydrocarbon tail This means the lipids will be easier to pack together, increasing their viscosity (and lowering fluidity) Saturated fatty acids have higher melting points and make membranes stronger and more stable at higher temperatures
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
B2.1.11— Relationships between fatty acid composition of lipid bilayers and their fluidity
B2.1.12— Cholesterol and membrane fluidity in animal cells
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
B2.1.11— Membrane fluidity and the fusion and formation of vesicles
Exocytosis Endocytosis
B2.1.11— Membrane fluidity and the fusion and formation of vesicles
B2.1.11— Membrane fluidity and the fusion and formation of vesicles
Subtítulo
B2.1.15— Sodium–potassium pumps as an example of exchange transporters
Esto es un párrafo listo para contener creatividad, experiencias e historias geniales.
n example of antiport is the translocation of sodium and potassium ions by the sodium-potassium pump This pump is used by nerve cells (neurons) to establish an electrochemical gradient across the membrane (resting potential)
B2.1.16— Sodium-dependent glucose cotransporters as an example of indirect active transport
In this case, a molecule of Na+ is necessary to introduce a molecule of glucose in the cell. That molecule, then, goes to the Na+/K+ pump to re-balance the ions
B2.1.17— Adhesion of cells to form tissues
Cell adhesion is the attachment of cells to other cells or to the extracellular matrix via specialised membrane proteins called cell adhesion molecules (CAMs) There are different forms, depending on their function.
B2.1.17— Adhesion of cells to form tissues