How Does Phospholipid Solute Across Membranes Build A Cell Membrane
MOVEMENT ACROSS MEMBRANES
Intracellular fluid Extracellular fluid Pond water Blood plasma
K+ A-
ClNa+
Cl+
K+ Na+ Cl-
Na+
Na+
Gill epithelial cell Intestinal epithelial cells
Cl-
Cell membrane Anionic proteins (a) Ion concentration inside a single animal cell
(b) Ion concentration across gill epithelium of a freshwater fish Blood capillary
Intestinal lumen
Glucose from meal
Cross section of small intestine
(c) Glucose transport across intestinal epithelium into the blood system
MEMBRANE STRUCTURE
Extracellular fluid Glycoproteins and -lipids
Phospholipid bilayer Cytoplasm
Integral and peripheral proteins
Cholesterol Cytoskeleton
How do phospholipids build a membrane?
1
Phospholipid …show more content…
1. Lipid solutes (steroids and fatty acids): enter the interior of the cell membrane because of their hydrophobic nature. 2. Molecular oxygen (O2): enter interior of membrane because of their small and nonpolar nature. 3. Inorganic ions: low permeability across membrane, but can diffuse passively through cell membranes at rapid rates due to ion channels. Ion channels allow only passive transport across membranes. They do not bind the ions that pass through them. They are selective in determining which ion can pass. Types include: voltage-gated, stretch-gated, phosphorylation-gated and ligand-gated …show more content…
gradient and electrical effect move it into the cell.
10
PASSIVE: Facilitated diffusion
Polar organic solutes (glucose, amino acids) are hydrophilic: diffuse through membrane with the help of carrier proteins: • In direction of electrochemical gradient • Facilitated because faster than simple diffusion • Reversible and non-covalent binding
PASSIVE SOLUTE TRANSPORT - SUMMARY
• Passive transport moves towards the electrochemical equilibrium. • The permeability of a membrane for a lipid solute depends on how readily the the solute enters into and moves across the membrane lipid bilayer – simple diffusion. For inorganic ions, the permeability depends on the number of ion channels. • Polar organic solutes (glucose, amino acids) move across membranes with the help of transporter proteins in the direction of the electrochemical equilibrium (facilitated diffusion).
• Simple diffusion depends on the concentration gradient for an uncharged solute. In case of a charged solute, conc. gradients and electrical effects contribute to diffusion.
11
Primary and secondary ACTIVE
Intracellular fluid Extracellular fluid Pond water Blood plasma
K+ A-
ClNa+
Cl+
K+ Na+ Cl-
Na+
Na+
Gill epithelial cell Intestinal epithelial cells
Cl-
Cell membrane Anionic proteins (a) Ion concentration inside a single animal cell
(b) Ion concentration across gill epithelium of a freshwater fish Blood capillary
Intestinal lumen
Glucose from meal
Cross section of small intestine
(c) Glucose transport across intestinal epithelium into the blood system
MEMBRANE STRUCTURE
Extracellular fluid Glycoproteins and -lipids
Phospholipid bilayer Cytoplasm
Integral and peripheral proteins
Cholesterol Cytoskeleton
How do phospholipids build a membrane?
1
Phospholipid …show more content…
1. Lipid solutes (steroids and fatty acids): enter the interior of the cell membrane because of their hydrophobic nature. 2. Molecular oxygen (O2): enter interior of membrane because of their small and nonpolar nature. 3. Inorganic ions: low permeability across membrane, but can diffuse passively through cell membranes at rapid rates due to ion channels. Ion channels allow only passive transport across membranes. They do not bind the ions that pass through them. They are selective in determining which ion can pass. Types include: voltage-gated, stretch-gated, phosphorylation-gated and ligand-gated …show more content…
gradient and electrical effect move it into the cell.
10
PASSIVE: Facilitated diffusion
Polar organic solutes (glucose, amino acids) are hydrophilic: diffuse through membrane with the help of carrier proteins: • In direction of electrochemical gradient • Facilitated because faster than simple diffusion • Reversible and non-covalent binding
PASSIVE SOLUTE TRANSPORT - SUMMARY
• Passive transport moves towards the electrochemical equilibrium. • The permeability of a membrane for a lipid solute depends on how readily the the solute enters into and moves across the membrane lipid bilayer – simple diffusion. For inorganic ions, the permeability depends on the number of ion channels. • Polar organic solutes (glucose, amino acids) move across membranes with the help of transporter proteins in the direction of the electrochemical equilibrium (facilitated diffusion).
• Simple diffusion depends on the concentration gradient for an uncharged solute. In case of a charged solute, conc. gradients and electrical effects contribute to diffusion.
11
Primary and secondary ACTIVE