Experiment to show the effect of Temperature on membrane permeability In beetroot
Experiment to show the effect of
Temperature on membrane permeability
In beetroot
Joseph Colledge
Introduction
Plants are unique among the eukaryotic organisms whose cells have membrane enclosed nuclei and organelles, because they can manufacture their own food. Chlorophyll, which gives plants their green colour, enables them to use sunlight to convert water and carbon dioxide into sugars and carbohydrates, chemicals the cell uses for fuel. Like the fungi, another kingdom of eukaryotes, plant cells have retained the protective cell wall structure of their prokaryotic ancestors. The basic plant cell shares a similar construction with the typical eukaryote cell, but does not have centrioles, lysosomes, intermediate filaments, cilia, or flagella, as does the animal cell. (Reed 1998)
Plant cells do, however, have a number of other specialized structures, including a rigid cell wall, central vacuole, plasmodesmata, and chloroplasts. In prokaryotes and plants, the plasma membrane is an inner layer of protection since a rigid cell wall forms the outside boundary for their cells. The cell wall has pores that allow materials to enter and leave the cell, but they are not very selective about what passes through.
The plasma membrane, which lines the cell wall, provides the final filter between the cell interior and the environment. Lipids and proteins are the staple ingredients of membranes, and, the most abundant lipids in membranes are phospholipids. A phospholipid is an amphipathic molecule, which basically means that it has structure containing a hydrophilic and hydrophobic region, the phosphate group found at one end being the hydrophilic (water loving) and the lipid tail region being hydrophilic (water fearing) In each layer of a plasma membrane, the hydrophobic tails are orientated inwards and the hydrophilic phosphate groups are aligned to face outwards.
In 1972 Singer and Nicholson advocated a revised model of the previous membrane model which became known as the fluid mosaic model. (See fig 1) This model was widely accepted as an accurate representation of the actual membrane structure found by using the freeze-fracture method under an electron microscope. (Reed 1998)
Temperature on membrane permeability
In beetroot
Joseph Colledge
Introduction
Plants are unique among the eukaryotic organisms whose cells have membrane enclosed nuclei and organelles, because they can manufacture their own food. Chlorophyll, which gives plants their green colour, enables them to use sunlight to convert water and carbon dioxide into sugars and carbohydrates, chemicals the cell uses for fuel. Like the fungi, another kingdom of eukaryotes, plant cells have retained the protective cell wall structure of their prokaryotic ancestors. The basic plant cell shares a similar construction with the typical eukaryote cell, but does not have centrioles, lysosomes, intermediate filaments, cilia, or flagella, as does the animal cell. (Reed 1998)
Plant cells do, however, have a number of other specialized structures, including a rigid cell wall, central vacuole, plasmodesmata, and chloroplasts. In prokaryotes and plants, the plasma membrane is an inner layer of protection since a rigid cell wall forms the outside boundary for their cells. The cell wall has pores that allow materials to enter and leave the cell, but they are not very selective about what passes through.
The plasma membrane, which lines the cell wall, provides the final filter between the cell interior and the environment. Lipids and proteins are the staple ingredients of membranes, and, the most abundant lipids in membranes are phospholipids. A phospholipid is an amphipathic molecule, which basically means that it has structure containing a hydrophilic and hydrophobic region, the phosphate group found at one end being the hydrophilic (water loving) and the lipid tail region being hydrophilic (water fearing) In each layer of a plasma membrane, the hydrophobic tails are orientated inwards and the hydrophilic phosphate groups are aligned to face outwards.
In 1972 Singer and Nicholson advocated a revised model of the previous membrane model which became known as the fluid mosaic model. (See fig 1) This model was widely accepted as an accurate representation of the actual membrane structure found by using the freeze-fracture method under an electron microscope. (Reed 1998)
