C3movement Across The Plasma Membrane
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C3Movement across the Plasma Membrane 3.1 The Movement of Substances across the Plasma Membrane. 3.2 The Movement of Substance across the Plasma Membrane in Everyday Life 3.3 Appretiating the Movement of Substances across the Plasma Membrane
The structure of the plasma membrane
Plasma membrane compose mainly of phospholipids and proteins. Phospholipid consist of a)ploar head- hydrophilic B)non-polar-fatty acid tails. Hydrophobic. Plasma membrane phospholipids are arranged in a double layers called phospholipid bilayer. The protein molecule that forms a pore is known as pore protein,while the protein molecule that acts as carrier protein. Some membrane proteins have branching carbohydrates chains attacted to the outer surfaces,forming glycoproteins and glycolipids.
Permeability of plasma memebrane The selective permeability on the plasma membrane depends on the: a)selective barrier of the phospholipid bilayer. b)selective transport proteins build into the membrane. The phospholipid bilayer is permeable to nonpolar molecules and small uncharged molecules. The phospholipid bilayer is not permeable to charged ions and polar molecules.
Passive transport: Simple diffusion
Movement of molecules or ions from a region of high concentration to a region of lower concentration,that is,down the concentration gradient. The cell does not need to expand energy. Can be observed in liquids and gases. Molecules which move across the plasma membrane by simple diffusion include: a)lipid-soluble molecules such as vitamins A,D,E,K. b)small molecules like water c)dissolved gases such as oxygen and carbon dioxide.
Osmosis Diffusion of water molecules across a semipermeable membrane. Movement of water molecules from a region of low solute concentration to a region of high solute concentration thru a semi-permeable membrane. Do not require energy. Water molecules move across phospholipids bilayer and pore protein in the plasma membrane by osmosis.
Fasilitated diffusion
Movement of hydrophylic molecules which love water or ions across the plasma membrane with the help of transport proteins. Do not require energy. Proteins-pore -carrier Carrier protein a)have binding sites tht can combine with specific molecules. b)enable the movement of macromolecules across the plasma membrane. c)its specific – glucose – carrier proteins Pore Protein a)they transport small dissolve particles esp ions. b)usually have specific shapes and changes tht only allowed specific ions to pass thru.
Active Transport Movement of molecules or ions from a region of lower concentration to a region of higher concentration. A.T requires of both carrier proteins and cellular energy to transport molecules against the concentration gradient. a)energy usually is in the form of A.T.P edonosine triphosphate. b)carrier protein has an active site which binds with a particular or ion and another active site which binds the A.T.P molecule.
The movement of substances across the plasma membrane in everyday life. Effects
of hypotonic, hypertonic & isotonic. Hypertonic- solution with higher solute concentration Hypotonic- solution with lower solute concentration. Isotonic- solution in which concentration of solutes are equal.
Animal cellisotonic solution
Cytoplasm of animal cell contains water solutes and other substances. Animal cells contain cytplasmic fluid tht is surrounded by the interstitial fluid or tissue fluid.Therefore, the cell are substantly subjected to osmosis. Since living cells need to be in a stable internal environment, the tissue fluid is usually isotonic to the cytoplasmic fluid within the cells. An isotonic solution is a solution in which the concentration of solutes is equal to tht of the cytoplasm of the cell. a)water difuses into and out of the cell at equal rates b)therefore, there is no net movement of water c)the cells retain their normal shape
Hypotonic solution
Since the concentration of solute outside the cell, there is a net movement of water frm the outside into the cell. The cell gains water, swells and the internal pressure increases. If the solution is extreamly hypotonic the cells may swell up and eventually burst. Eg.red blood cell - this causes the plasma membrane to rupture and the content of cell are release in the surrounding. -this condition is known as haemolysis
Hypertonic solution Since
the concentration of water is higher. There is a net of water movement with the cell.As the result, the cell start to shrink as the internal pressure decreases. Eg.red blood cell. If this would had happen to red blood cell, it is said to undergone crenation.
Plant cellisotonic Same
as animal cell Have cell wall made of cellulose which envolepoes the plasma membrane.the cell wall is fully permeable to solutes & water.
Hypotonic When plant cells are immersed in hypertonic solution water diffuses into the large central vacoule by osmosis. Solution is less concentrated outside the cell than inside. Large central vacoule expands and swells up. The vacoule and cytoplasm outwards against the P.M. Turgor pressure is created T.P is very important to plant cells as its supports and maintance its shape.
Hypertonic
When plant cells have immersed in a hypertonic solution water diffuses out to large central vacoule by osmosis. Both vacoule and cytoplasm loose water to the surroundings and shrink. The plasma membrane pulls away from the cell wall. This phenomenon is called plasmolysis. The plant cell becomes flacid(wilt) and less turgid. If plasmolysis persist,death of plant cell may result.However the plasmolysis plant cell become turgid again. By immersing the cell by hypotonic solution plant cell into 1. Then water moves into the cell and bcomes turgid again.This condition is called deplasmolysis.
The structure of the plasma membrane
Plasma membrane compose mainly of phospholipids and proteins. Phospholipid consist of a)ploar head- hydrophilic B)non-polar-fatty acid tails. Hydrophobic. Plasma membrane phospholipids are arranged in a double layers called phospholipid bilayer. The protein molecule that forms a pore is known as pore protein,while the protein molecule that acts as carrier protein. Some membrane proteins have branching carbohydrates chains attacted to the outer surfaces,forming glycoproteins and glycolipids.
Permeability of plasma memebrane The selective permeability on the plasma membrane depends on the: a)selective barrier of the phospholipid bilayer. b)selective transport proteins build into the membrane. The phospholipid bilayer is permeable to nonpolar molecules and small uncharged molecules. The phospholipid bilayer is not permeable to charged ions and polar molecules.
Passive transport: Simple diffusion
Movement of molecules or ions from a region of high concentration to a region of lower concentration,that is,down the concentration gradient. The cell does not need to expand energy. Can be observed in liquids and gases. Molecules which move across the plasma membrane by simple diffusion include: a)lipid-soluble molecules such as vitamins A,D,E,K. b)small molecules like water c)dissolved gases such as oxygen and carbon dioxide.
Osmosis Diffusion of water molecules across a semipermeable membrane. Movement of water molecules from a region of low solute concentration to a region of high solute concentration thru a semi-permeable membrane. Do not require energy. Water molecules move across phospholipids bilayer and pore protein in the plasma membrane by osmosis.
Fasilitated diffusion
Movement of hydrophylic molecules which love water or ions across the plasma membrane with the help of transport proteins. Do not require energy. Proteins-pore -carrier Carrier protein a)have binding sites tht can combine with specific molecules. b)enable the movement of macromolecules across the plasma membrane. c)its specific – glucose – carrier proteins Pore Protein a)they transport small dissolve particles esp ions. b)usually have specific shapes and changes tht only allowed specific ions to pass thru.
Active Transport Movement of molecules or ions from a region of lower concentration to a region of higher concentration. A.T requires of both carrier proteins and cellular energy to transport molecules against the concentration gradient. a)energy usually is in the form of A.T.P edonosine triphosphate. b)carrier protein has an active site which binds with a particular or ion and another active site which binds the A.T.P molecule.
The movement of substances across the plasma membrane in everyday life. Effects
of hypotonic, hypertonic & isotonic. Hypertonic- solution with higher solute concentration Hypotonic- solution with lower solute concentration. Isotonic- solution in which concentration of solutes are equal.
Animal cellisotonic solution
Cytoplasm of animal cell contains water solutes and other substances. Animal cells contain cytplasmic fluid tht is surrounded by the interstitial fluid or tissue fluid.Therefore, the cell are substantly subjected to osmosis. Since living cells need to be in a stable internal environment, the tissue fluid is usually isotonic to the cytoplasmic fluid within the cells. An isotonic solution is a solution in which the concentration of solutes is equal to tht of the cytoplasm of the cell. a)water difuses into and out of the cell at equal rates b)therefore, there is no net movement of water c)the cells retain their normal shape
Hypotonic solution
Since the concentration of solute outside the cell, there is a net movement of water frm the outside into the cell. The cell gains water, swells and the internal pressure increases. If the solution is extreamly hypotonic the cells may swell up and eventually burst. Eg.red blood cell - this causes the plasma membrane to rupture and the content of cell are release in the surrounding. -this condition is known as haemolysis
Hypertonic solution Since
the concentration of water is higher. There is a net of water movement with the cell.As the result, the cell start to shrink as the internal pressure decreases. Eg.red blood cell. If this would had happen to red blood cell, it is said to undergone crenation.
Plant cellisotonic Same
as animal cell Have cell wall made of cellulose which envolepoes the plasma membrane.the cell wall is fully permeable to solutes & water.
Hypotonic When plant cells are immersed in hypertonic solution water diffuses into the large central vacoule by osmosis. Solution is less concentrated outside the cell than inside. Large central vacoule expands and swells up. The vacoule and cytoplasm outwards against the P.M. Turgor pressure is created T.P is very important to plant cells as its supports and maintance its shape.
Hypertonic
When plant cells have immersed in a hypertonic solution water diffuses out to large central vacoule by osmosis. Both vacoule and cytoplasm loose water to the surroundings and shrink. The plasma membrane pulls away from the cell wall. This phenomenon is called plasmolysis. The plant cell becomes flacid(wilt) and less turgid. If plasmolysis persist,death of plant cell may result.However the plasmolysis plant cell become turgid again. By immersing the cell by hypotonic solution plant cell into 1. Then water moves into the cell and bcomes turgid again.This condition is called deplasmolysis.
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