Bio. Lab. Report - Membrane Transport
Objectives:
To study the effects of hypotonic, hypertonic and isotonic solutions on plant and animal cells.
Materials and Apparatus: * Microscope * Electronic balance * Stirring rod * Small knife * Glass slide and cover * 250, 500 ml beakers * Distilled water * Cotton * Test tubes * Spatula * Onion * Ethanol (70%) * Filter paper * Table sugar (sucrose) * Table salt (NaCl) * Potato
EXPERIMENT 1
PART 1
Procedure:
1. The epidermal layer of an onion is scaled off carefully and placed on a drop of distilled water on the glass slide; 2. The glass slide is slowly lowered down on the epidermal layer using the needle;
3. The onion cells are examined through the microscope; 4. The structure of the onion cells is drawn as observed under the microscope.
Results & Observations:
In the hypotonic solution the water will move from the solution to the onion cells which will become bigger.
PART 2 Procedure: 1. The distilled water is removed using the filter paper; 2. A drop of 5% of sucrose solution is placed at a side of the cover slip and the solution across the epidermal layer is drawn by placing filter paper on the other side of the cover slip; 3. The onion cells are examined once again through microscope. The structure of the onion cells is drawn as observed under the microscope.
Results & Observations:
In the isotonic solution, there is no difference in the osmolarity, no change in the cells sizes.
PART 3
Procedure:
1. Repeat step (1 – 3 of PART 2) using 30% of sucrose solution.
Results & Observations:
In the hypertonic solution we can notice the shrinking of the cell membrane due to the loose of water.
Discussion & Conclusion:
Water will move in or out of the onion cells according to the concentration of sucrose in and out of the onion cells: in an isotonic solution no change will happen; in a hypertonic solution the cells
To study the effects of hypotonic, hypertonic and isotonic solutions on plant and animal cells.
Materials and Apparatus: * Microscope * Electronic balance * Stirring rod * Small knife * Glass slide and cover * 250, 500 ml beakers * Distilled water * Cotton * Test tubes * Spatula * Onion * Ethanol (70%) * Filter paper * Table sugar (sucrose) * Table salt (NaCl) * Potato
EXPERIMENT 1
PART 1
Procedure:
1. The epidermal layer of an onion is scaled off carefully and placed on a drop of distilled water on the glass slide; 2. The glass slide is slowly lowered down on the epidermal layer using the needle;
3. The onion cells are examined through the microscope; 4. The structure of the onion cells is drawn as observed under the microscope.
Results & Observations:
In the hypotonic solution the water will move from the solution to the onion cells which will become bigger.
PART 2 Procedure: 1. The distilled water is removed using the filter paper; 2. A drop of 5% of sucrose solution is placed at a side of the cover slip and the solution across the epidermal layer is drawn by placing filter paper on the other side of the cover slip; 3. The onion cells are examined once again through microscope. The structure of the onion cells is drawn as observed under the microscope.
Results & Observations:
In the isotonic solution, there is no difference in the osmolarity, no change in the cells sizes.
PART 3
Procedure:
1. Repeat step (1 – 3 of PART 2) using 30% of sucrose solution.
Results & Observations:
In the hypertonic solution we can notice the shrinking of the cell membrane due to the loose of water.
Discussion & Conclusion:
Water will move in or out of the onion cells according to the concentration of sucrose in and out of the onion cells: in an isotonic solution no change will happen; in a hypertonic solution the cells
References: 1. http://movementofsubstances.blogspot.com/2011/02/32-movement-of-substance-across-plasma.html 2. http://internalandexternalenvironments2012.wikispaces.com/Hypertonic,+hypotonic+and+isotonic+effects+on+plants+and+animal+cells.