Transport Across Membrane
Experiment 2 : Transport Across Membrane
Name :
Matrix No :
Group : B
Semester : 1
Date of Experiment : 05.09.2013
Lecturer’s Name : Miss
OBJECTIVE
To study the effects of hypotonic, hypertonic and isotonic solutions on plant and animal cells.
INTRODUCTION
In cellular biology the term membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes, which are lipid bilayers that contain proteins embedded in them. The regulation of passage through the membrane is due to selective membrane permeability - a characteristic of biological membranes which allows them to separate substances of distinct chemical nature. In other words, they can be permeable to certain substances but not to others.
The movements of most solutes through the membrane are mediated by membrane transport proteins which are specialized to varying degrees in the transport of specific molecules. As the diversity and physiology of the distinct cells is highly related to their capacities to attract different external elements, it is postulated that there is a group of specific transport proteins for each cell type and for every specific physiological stage. This differential expression is regulated through the differential transcription of the genes coding for these proteins and its translation, for instance, through genetic-molecular mechanisms, but also at the cell biology level: the production of these proteins can be activated by cellular signaling pathways, at the biochemical level, or even by being situated in cytoplasmic vesicles.
Hypotonic refers to a lesser concentration. A hypotonic solution has a lower concentration of solutes in its surroundings, so in an attempt to balance concentrations, water will rush into the cell, causing swelling.
Some organisms have evolved intricate methods of circumventing hypotonicity. For example, saltwater is hypertonic to the
Name :
Matrix No :
Group : B
Semester : 1
Date of Experiment : 05.09.2013
Lecturer’s Name : Miss
OBJECTIVE
To study the effects of hypotonic, hypertonic and isotonic solutions on plant and animal cells.
INTRODUCTION
In cellular biology the term membrane transport refers to the collection of mechanisms that regulate the passage of solutes such as ions and small molecules through biological membranes, which are lipid bilayers that contain proteins embedded in them. The regulation of passage through the membrane is due to selective membrane permeability - a characteristic of biological membranes which allows them to separate substances of distinct chemical nature. In other words, they can be permeable to certain substances but not to others.
The movements of most solutes through the membrane are mediated by membrane transport proteins which are specialized to varying degrees in the transport of specific molecules. As the diversity and physiology of the distinct cells is highly related to their capacities to attract different external elements, it is postulated that there is a group of specific transport proteins for each cell type and for every specific physiological stage. This differential expression is regulated through the differential transcription of the genes coding for these proteins and its translation, for instance, through genetic-molecular mechanisms, but also at the cell biology level: the production of these proteins can be activated by cellular signaling pathways, at the biochemical level, or even by being situated in cytoplasmic vesicles.
Hypotonic refers to a lesser concentration. A hypotonic solution has a lower concentration of solutes in its surroundings, so in an attempt to balance concentrations, water will rush into the cell, causing swelling.
Some organisms have evolved intricate methods of circumventing hypotonicity. For example, saltwater is hypertonic to the