The School of Biomedical Sciences Wiki - User contributions [en]

Glycogen synthase

2011-11-23T13:28:04Z

100307827:

Glycogen Synthase (GS) is an enzyme present in liver and muscle cells that catalyses the production of [[Glycogen|glycogen]]. It catalyses a [[Condensation Reaction|condensation reaction]] between [[UDP-glucose|UDP-glucose]] and Glycogen (n-residues) to form [[Glycogen|glycogen]] (n+1 residues) and [[UDP|UDP]], elongating the glycogen polymer.  

Regulation of the enzyme is achieved through multiple [[Phosphorylation|phosphorylations]] at different sites by multiples [[Kinase|kinases]], including [[Protein kinase B|Protein Kinase B]] (PKB) and [[Glycogen Synthase Kinase 3|Glycogen Synthase Kinase 3]] (GSK3). When insulin is absent from cells, GSK3 phosphorylates Glycogen Synthase, inactivating it, this maintains the level of glucose available to the cells. Upon insulin stimulation, PKB is activated and phosphorylates GSK3, which is also a repressing phosphorylation. GSK3 can now no longer inhibit Glycogen Synthase, thereby increasing the concentration of glycogen and reducing the concentration of glucose within the cells.<ref>Regulation of the enzyme</ref>

 

Insulin also activates a [[Phosphatase|phosphatase]] called [[Protein Phosphatase-1|Protein Phosphatase-1 (PP1)]], which [[Dephosphorylation|dephosphorylates]] GS. The pathway as to how this occurs is unclear.

 

<references /> Harvey Lodish, Arnold Berk, Chris A. Kaiser, Monty Krieger, Matthew P. Scott, Anthony Bretscher and Hidde Ploegh (2008) Molecular Cell Biology, sixth edition,United States of America: W. H. Freeman and Company

Glycogen synthase

2011-11-23T13:27:43Z

100307827:

Glycogen Synthase (GS) is an enzyme present in liver and muscle cells that catalyses the production of [[Glycogen|glycogen]]. It catalyses a [[Condensation Reaction|condensation reaction]] between [[UDP-glucose|UDP-glucose]] and Glycogen (n-residues) to form [[Glycogen|glycogen]] (n+1 residues) and [[UDP|UDP]], elongating the glycogen polymer.  

Regulation of the enzyme is achieved through multiple [[Phosphorylation|phosphorylations]] at different sites by multiples [[Kinase|kinases]], including [[Protein kinase B|Protein Kinase B]] (PKB) and [[Glycogen Synthase Kinase 3|Glycogen Synthase Kinase 3]] (GSK3). When insulin is absent from cells, GSK3 phosphorylates Glycogen Synthase, inactivating it, this maintains the level of glucose available to the cells. Upon insulin stimulation, PKB is activated and phosphorylates GSK3, which is also a repressing phosphorylation. GSK3 can now no longer inhibit Glycogen Synthase, thereby increasing the concentration of glycogen and reducing the concentration of glucose within the cells.<ref />

 

Insulin also activates a [[Phosphatase|phosphatase]] called [[Protein Phosphatase-1|Protein Phosphatase-1 (PP1)]], which [[Dephosphorylation|dephosphorylates]] GS. The pathway as to how this occurs is unclear.

 

<references /> Harvey Lodish, Arnold Berk, Chris A. Kaiser, Monty Krieger, Matthew P. Scott, Anthony Bretscher and Hidde Ploegh (2008) Molecular Cell Biology, sixth edition,United States of America: W. H. Freeman and Company

Glycogen synthase

2011-11-23T13:27:19Z

100307827:

Glycogen synthase

2011-11-23T13:24:40Z

100307827:

Glycogen Synthase (GS) is an enzyme present in liver and muscle cells that catalyses the production of [[Glycogen|glycogen]]. It catalyses a [[Condensation Reaction|condensation reaction]] between [[UDP-glucose|UDP-glucose]] and Glycogen (n-residues) to form [[Glycogen|glycogen]] (n+1 residues) and [[UDP|UDP]], elongating the glycogen polymer.  

Regulation of the enzyme is achieved through multiple [[Phosphorylation|phosphorylation]]s at different sites by multiples [[Kinase|kinases]], including [[Protein_kinase_B|Protein Kinase B]] (PKB) and [[Glycogen Synthase Kinase 3|Glycogen Synthase Kinase 3]] (GSK3). When insulin is absent from cells, GSK3 phosphorylates Glycogen Synthase, inactivating it, this maintains the level of glucose available to the cells. Upon insulin stimulation, PKB is activated and phosphorylates GSK3, which is also a repressing phosphorylation. GSK3 can now no longer inhibit Glycogen Synthase, thereby increasing the concentration of glycogen and reducing the concentration of glucose within the cells.<references />

 

Insulin also activates a [[Phosphatase|phosphatase]] called [[Protein Phosphatase-1|Protein Phosphatase-1 (PP1)]], which [[Dephosphorylation|dephosphorylates]] GS. The pathway as to how this occurs is unclear.

<references />Harvey Lodish, Arnold Berk, Chris A. Kaiser, Monty Krieger, Matthew P. Scott, Anthony Bretscher and Hidde Ploegh (2008) Molecular Cell Biology, sixth edition,United States of America: W. H. Freeman and Company

Harvey Lodish, Arnold Berk, Chris A. Kaiser, Monty Krieger, Matthew P. Scott, Anthony Bretscher and Hidde Ploegh (2008) Molecular Cell Biology, sixth edition,United States of America: W. H. Freeman and Company

Glycogen synthase

2011-11-22T20:19:06Z

100307827:

Glycogen Synthase (GS) is an enzyme that catalyses the production of [[Glycogen|Glycogen]]. It catalyses a [[Condensation_Reaction|condensation reaction]] between UDP-glucose and Glycogen (n-residues) to form Glycogen (n+1 residues) and UDP, elongating the Glycogen polymer. 

 

Regulation of the enzyme is achieved through the multiple [[Phosphorylation|phosphorylation]] of Glycogen Synthase at different sites by multiples [[Kinase|kinases]], including [[Protein Kinase A|Protein Kinase A]] (PKA) and [[Glycogen Synthase Kinase 3|Glycogen Synthase Kinase 3]] (GSK3). The enzyme is phosphorylated in it's inactive state and must interact with Glucose-6-phosphate to be activated. Binding results in a [[conformational change|conformational change]], increasing the affinity of the enzyme for it's substrate.

 

In the presence of Insulin, glycogen synthesis is increased. This is due to the inhibition of GSK3 by Insulin, preventing Glycogen Synthase being phosphorylated and inactivated. Insulin also activates a [[phosphatase|phosphatase]] called [[Protein Phosphatase-1|Protein Phosphatase-1 (PP1)]], which [[dephosphorylation|dephosphorylates]] GS. The pathway as to how this occurs is unclear.

Glycogen synthase

2011-11-22T20:09:18Z

100307827: Created page with "Glycogen Synthase (GS) is an enzyme that catalyses the production of glycogen. It catalyses a condensation reaction between UDP-glucose and Glycogen (n-residues) to form Glycogen..."

Glycogen Synthase (GS) is an enzyme that catalyses the production of glycogen. It catalyses a condensation reaction between UDP-glucose and Glycogen (n-residues) to form Glycogen (n+1 residues) and UDP, elongating the glycogen polymer. 

Regulation of the enzyme is achieved through the multiple phosphorylation of Glycogen Synthase at different sites by multiples kinases, including Protein Kinase A (PKA) and Glycogen Synthase Kinase 3 (GSK3). The enzyme is phosphorylated in it's inactive state and must interact with glucose-6-phosphate to be activated. Binding results in a conformational change, increasing the affinity of the enzyme for it's substrate.

In the presence of Insulin, glycogen synthesis is increased. This is due to the inhibition of GSK3 by insulin, preventing Glycogen Synthase being phosphorylated and inactivated. Insulin also activates a phosphatase which dephosphorylates GS called protein phosphatase-1 (PP1). The pathway as to how this occurs is unclear.

Plasma membrane

2011-01-10T11:58:03Z

100307827:

A plasma membrane encapsulates each and every [[Cell|cell]], and is also known as the cell membrane. It acts as a selective barrier which is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell. 

The plasma membrane is a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]] which is 5nm thick. Lipid bilayers are composed of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of which is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active [[Carboxylic acid (COOH)|COOH]]. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier which will be impermeable to most hydrophilic molecules.  

The plasma membrane has many functions and is a fundamental part of the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either:

*transporters
*linkers
*receptors  
*[[Enzyme|enzymes]] 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of [[Cholesterol|cholesterol]].

 

 

<references />Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walkter P., (2008) Molecular Biology Of The Cell, 5th edition, Newy York: Garland Science

Plasma membrane

2011-01-10T11:56:47Z

100307827:

A plasma membrane encapsulates each and every [[Cell|cell]], and is also known as the cell membrane. It acts as a selective barrier which is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell. 

The plasma membrane is a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]] which is roughly 5nm thick. Lipid bilayers are composed of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of which is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active [[Carboxylic acid (COOH)|COOH]]. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier which will be impermeable to most hydrophilic molecules.  

The plasma membrane has many functions and is a fundamental part of the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either:

*transporters
*linkers
*receptors  
*[[Enzyme|enzymes]] 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of [[Cholesterol|cholesterol]].

<references />Alberts B., Johnson A., Lewis J., Raff M., Roberts K., Walkter P., (2008) Molecular Biology Of The Cell, 5th edition, Newy York: Garland Science

Plasma membrane

2011-01-10T11:47:38Z

100307827:

A plasma membrane encapsulates each and every [[Cell|cell]], and is also known as the cell membrane. It acts as a selective barrier which is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell. 

The plasma membrane is a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]] which is roughly 5nm thick. Lipid bilayers are composed of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of which is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active [[carboxylic acid (COOH)|COOH]]. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier which will be impermeable to most hydrophilic molecules.  

The plasma membrane has many functions and is a fundamental part of the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either:

*transporters
*linkers
*receptors  
*[[Enzyme|enzymes]] 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of [[Cholesterol|cholesterol]].

Plasma membrane

2011-01-09T19:15:08Z

100307827:

A plasma membrane encapsulates each and every [[Cell|cell]], and is also known as the cell membrane. This membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell.

The plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Lipid bilayers are composed of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active COOH. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The plasma membrane has many functions and is a fundamental part of the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: [[Protein transporters|transporters]], linkers, receptors or [[Enzyme|enzymes]]. 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of cholesterol.

Plasma membrane

2011-01-09T19:14:27Z

100307827:

A plasma membrane encapsulates each and every [[Cell|cell]], and is known as the cell membrane. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell.

The plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Lipid bilayers are composed of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active COOH. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The plasma membrane has many functions and is a fundamental part of the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: [[Protein transporters|transporters]], linkers, receptors or [[Enzyme|enzymes]]. 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of cholesterol.

Plasma membrane

2011-01-09T19:09:34Z

100307827:

A plasma membrane encapsulates each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell.

The plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Lipid bilayers are composed of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active COOH. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The plasma membrane has many functions and is a fundamental part of the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: [[Protein transporters|transporters]], linkers, receptors or [[Enzyme|enzymes]]. 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of cholesterol.

Plasma membrane

2011-01-09T19:05:38Z

100307827:

A plasma membrane encapsulates each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell.

The structure of the plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Most lipid bilayers are comprised of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active COOH. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The plasma membrane has many functions and is a fundamental part to the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: [[Protein transporters|transporters]], linkers, receptors or [[Enzyme|enzymes]]. 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of cholesterol.

Plasma membrane

2011-01-09T19:04:18Z

100307827:

A plasma membrane encapsules each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell.

The structure of the plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Most lipid bilayers are comprised of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active COOH. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The plasma membrane has many functions and is a fundamental part to the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: [[Protein transporters|transporters]], linkers, receptors or [[Enzyme|enzymes]]. 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of cholesterol.

Amphipathic

2011-01-09T18:59:38Z

100307827: Created page with 'A term that describes something which is both hydrophillic (water-loving) and hydrophobic (water-hating).'

A term that describes something which is both hydrophillic (water-loving) and hydrophobic (water-hating).

Plasma membrane

2011-01-09T18:58:12Z

100307827:

Plasma membrane

2011-01-09T18:57:47Z

100307827:

A plasma membrane encapsules each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the cell.

The structure of the plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Most lipid bilayers are comprised of [[Phospholipid|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tail component of the phospholipid is comprised of two fatty acid chains, long hydrocarbon structures with a chemically active COOH. Since the head is hydrophilic and the tails are [[Hydrophobic|hydrophobic]], the phospholipid is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The plasma membrane has many functions and is a fundamental part to the cell. It communicates with the environment and other cells by means of a [[Glycocalyx|glycocalyx]], a system of protein-linked and lipid-linked [[Carbohydrate|carbohydrates]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: [[protein transporters|transporters]], linkers, receptors or [[Enzyme|enzymes]]. 

The lipids within the bilayer can freely move, they can diffuse laterally along the membrane, or rotate along their axis. They are said to be fluid within the system.This fluidity is dependent on:

*the length of the phospholipid tail
*whether the tail is saturated or not
*the presence of cholesterol. 

*the [[Glycocalyx|glycocalyx]]
*more about [[Proteins|proteins]]

Glycocalyx

2010-11-29T12:37:50Z

100307827: Created page with 'The glycocalyx is a system of protein-linked and lipid-linked carbohydrates which have a number of important functions, for example in cellular recognition, communication, adhesi…'

The glycocalyx is a system of protein-linked and lipid-linked carbohydrates which have a number of important functions, for example in cellular recognition, communication, adhesion and structureal support by binding to the extracellular matrix.

Plasma membrane

2010-11-29T10:11:54Z

100307827:

A plasma membrane encapsules each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the [[Cell|cell]] and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the [[Cell|cell]].

The structure of the plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Most lipid bilayers are comprised of [[Phospholipids|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tails component of the [[Phospholipid|phospholipid]] are two fatty acid chains, long hydrocarbon structures with chemically active COOH. Since the head is [[Hydrophilic|hydrophilic]] and the tails are [[Hydrophobic|hydrophobic]], the [[Phospholipid|phospholipid]] is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The function of the plasma membrane is to communicate with the environment and other cells, by means of the [[Glycocalyx|glycocalyx]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: transporters, linkers, receptors or [[Enzyme|enzymes]]. 

The lipids within the bilayer can freely move, they are said to be fluid within the system. This fluidity is dependent on the length of the phospholipid tail, whether the tail is saturated or not and the presence of cholesterol. Lipids can diffuse laterally along the membrane, or rotate along their axis.

 

*the [[Glycocalyx|glycocalyx]]
*more about [[Proteins|proteins]]

Plasma membrane

2010-11-28T21:54:55Z

100307827:

A plasma membrane encapsules each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the [[Cell|cell]] and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the [[Cell|cell]].

The structure of the plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Most lipid bilayers are comprised of [[Phospholipids|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tails component of the [[Phospholipid|phospholipid]] are two fatty acid chains, long hydrocarbon structures with chemically active COOH. Since the head is [[Hydrophilic|hydrophilic]] and the tails are [[Hydrophobic|hydrophobic]], the [[Phospholipid|phospholipid]] is said to be [[Amphipathic|amphipathic]]. The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The function of the plasma membrane is to communicate with the environment and other cells, by means of the [[Glycocalyx|glycocalyx]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: transporters, linkers, receptors or [[Enzyme|enzymes]]. 

*fluidity of the lipid bilayer
*the glycocalyx
*more about proteins

Plasma membrane

2010-11-28T20:48:14Z

100307827:

A plasma membrane encapsules each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the [[Cell|cell]] and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the [[Cell|cell]].

The structure of the plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Most lipid bilayers are comprised of [[Phospholipids|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tails component of the [[Phospholipid|phospholipid]] are two fatty acid chains, long hydrocarbon structures with chemically active COOH. Since the head is [[Hydrophilic|hydrophilic]] and the tails are [[Hydrophobic|hydrophobic]], the [[Phospholipid|phospholipid]] is said to be [[Amphipathic|amphipathic]].

The structure of the bilayer is such that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The function of the plasma membrane is to communicate with the environment and other cells, by means of the [[Glycocalyx|glycocalyx]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: transporters, linkers, receptors or [[Enzyme|enzymes]].

Plasma membrane

2010-11-28T20:45:41Z

100307827:

A plasma membrane encapsules each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the [[Cell|cell]] and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the [[Cell|cell]].

The structure of the plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Most lipid bilayers are comprised of [[Phospholipids|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tails component of the [[Phospholipid|phospholipid]] are two fatty acid chains, long hydrocarbon structures with chemically active COOH. Since the head is [[Hydrophilic|hydrophilic]] and the tails are [[Hydrophobic|hydrophobic]], the [[Phospholipid|phospholipid]] is said to be [[Amphipathic|amphipathic]].

The structure of the bilayer is so that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The function of the plasma membrane is to communicate with the environment and other cells, by means of the [[Glycocalyx|glycocalyx]]. It allows passage of selective molecules in and out of the cell via [[Carrier proteins|carrier]] or [[Channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: transporters, linkers, receptors or [[Enzyme|enzymes]].

Plasma membrane

2010-11-28T18:10:17Z

100307827:

A plasma membrane encapsules each and every [[Cell|cell]]. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the [[Cell|cell]] and it's environment. [[Eukaryotic cells|Eukaryotic cells]] have internal membranes which surround [[Organelles|organelles]], allowing different constituent concentrations within the [[Cell|cell]].

The structure of the plasma membrane is made up of a [[Lipid bilayer|lipid bilayer]] embedded with [[Proteins|proteins]] and [[Cholesterol|cholesterol]]. Most lipid bilayers are comprised of [[Phospholipids|phospholipids]], the most common being [[Phosphatidylcholine|phosphatidylcholine]]. The head part of it is made up of a [[Phosphate|phosphate]] and a [[Hydrophilic|hydrophilic]] [[Choline|choline]], the tails component of the [[Phospholipid|phospholipid]] are two fatty acid chains, long hydrocarbon structures with chemically active COOH. Since the head is [[hydrophilic|hydrophilic]] and the tails are [[Hydrophobic|hydrophobic]], the [[Phospholipid|phospholipid]] is said to be [[Amphipathic|amphipathic]].

The structure of the bilayer is so that the tails are shielded from contact with [[Water|water]], creating a selectively-permeable barrier.  

The function of the plasma membrane is to communicate with the environment and other cells, by means of the [[glycocalyx|glycocalyx]]. It allows passage of selective molecules in and out of the cell via [[carrier proteins|carrier]] or [[channel proteins|channel proteins]] embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: transporters, linkers, receptors or [[Enzyme|enzymes]].

Plasma membrane

2010-11-28T17:40:38Z

100307827:

A plasma membrane encapsules each and every cell. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. Eukaryotic cells have internal membranes which surround organelles, allowing different constituent concentrations within the cell.

The structure of the plasma membrane is made up of a lipid bilayer embedded with proteins and cholesterol. Most lipid bilayers are comprised of phospholipids, the most common being phosphatidylcholine. The structure of which is seen in figure 1. The head part of it is made up of a phosphate and a hydrophilic choline, the tails component of the phospholipid are two fatty acid chains, long hydrocarbon structures with chemically active COOH. Since the head is hydrophilic and the tails are hydrophobic, the phospholipid is said to be amphipathic.

The structure of the bilayer is so that the tails are shielded from contact with water, creating an impenetrable barrier to most molecules.

 

The function of the plasma membrane is to communicate with the environment and other cells, by means of the glycocalyx. It allows passage of selective molecules in and out of the cell via carrier or channel proteins embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: transporters, linkers, receptors, enzymes.

Plasma membrane

2010-11-28T17:39:36Z

100307827:

A plasma membrane encapsules each and every cell. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. Eukaryotic cells have internal membranes which surround organelles, allowing different constituent concentrations within the cell.

The structure of the plasma membrane is made up of a lipid bilayer embedded with proteins and cholesterol. Most lipid bilayers are comprised of phospholipids, the most common being phosphotadylcholine. The structure of which is seen in figure 1. The head part of it is made up of a phosphate and a hydrophilic choline, the tails component of the phospholipid are two fatty acid chains, long hydrocarbon structures with chemically active COOH. Since the head is hydrophilic and the tails are hydrophobic, the phospholipid is said to be amphipathic.

The structure of the bilayer is so that the tails are shielded from contact with water, creating an impenetrable barrier to most molecules.

 

The function of the plasma membrane is to communicate with the environment and other cells, by means of the glycocalyx. It allows passage of selective molecules in and out of the cell via carrier or channel proteins embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: transporters, linkers, receptors, enzymes.

Plasma membrane

2010-11-28T17:39:15Z

100307827: Created page with ' A plasma membrane encapsules each and every cell. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it'…'

 A plasma membrane encapsules each and every cell. The plasma membrane is necessary to allow different concentrations of substances to be maintained between the cell and it's environment. Eukaryotic cells have internal membranes which surround organelles, allowing different constituent concentrations within the cell.

The structure of the plasma membrane is made up of a lipid bilayer embedded with proteins and cholesterol. Most lipid bilayers are comprised of phospholipids, the most common being phosphotadylcholine. The structure of which is seen in figure 1. The head part of it is made up of a phosphate and a hydrophilic choline, the tails component of the phospholipid are two fatty acid chains, long hydrocarbon structures with chemically active COOH. Since the head is hydrophilic and the tails are hydrophobic, the phospholipid is said to be amphipathic.

The structure of the bilayer is so that the tails are shielded from contact with water, creating an impenetrable barrier to most molecules.

The function of the plasma membrane is to communicate with the environment and other cells, by means of the glycocalyx. It allows passage of selective molecules in and out of the cell via carrier or channel proteins embedded within the membrane, and it regulates cell growth, shape change, movement and division. 

The membrane is associated with proteins, both integral and peripheral which act as either: transporters, linkers, receptors, enzymes.

 The most  The lipids are arranged so that the hydrophobic tails are shielded from contact with water. 