An Investigation into Osmosis
Introduction
In this investigation, I am trying to find the answer to these two key
questions below:
1 What are the factors that determine whether water moves in or out of
the potato?
2 How does the concentration of a solution surrounding a cell affect
movement in and out of cell across its semi- permeable membrane?
In order to do this I will need to consider what osmosis is and make
some experiments to help me investigate and find answers for the key
questions.
Background Information
[IMAGE]
Osmosis is diffusion of water molecules moving from a particularly
permeable membrane from a high concentration to a lower concentration.
The water molecules can pass both ways through the membrane in two-
way traffic, but there is a steady net flow of water molecules into
the lower concentration of water. In figure 1 is a diagram showing how
osmosis takes place.
Figure 1 - What happens in Osmosis
Osmosis is important for living things such as plant and animal cells.
For animal cells they can easily burst if they take in too much water
by osmosis as they do not have a cell all to contain it. However, for
plant cells, osmosis makes them swell up when they are surrounded by
weak solution and makes the flaccid cells to become turgid cells, this
means that it gives the cells support to open the stomatal porb guard
cells and to support the plant tissues. Leaves from plants are
supported by the turgar pressure, without this, the plant will wilt
and the leaves will droop, and plasmolysis will take place in the
plant cells.
Another plant cell that osmosis can affect is the root hair cell. The
root cells are responsible to absorb minerals such as water from the
soil fro growth. The concentration of minerals is higher in the root
cell than in the soil, meaning osmosis of diffusion will not take
place for the root to absorb the minerals.
help give a better idea of how the rate of osmosis is affected by the
Considering the fact that Marc has both been sweating and drinking minimal amounts of water, Marc is now dehydrated. This means he has less than the required amount of water for his body to complete the processes necessary to maintain its health. As stated in the question, the process of sweating causes the loss of more water than solutes. This means that as the level of water decreases, the level of solute concentration will increase, creating a change in the water to solute ratio.
The Effect of Solute Concentration on the Rate of Osmosis Aim: To test and observe how the concentration gradient between a potato and water & sugar solution will affect the rate of osmosis. Introduction: Osmosis is defined as, diffusion, or net movement, of free water molecules from high to low concentration through a semi-permeable membrane. When a substance, such as sugar (which we will be using in the experiment we are about to analyse), dissolves in water, it attracts free water molecules to itself, and in doing so, stops them from moving freely. The effect of this, is that the concentration of (free) water molecules in that environment goes down. There are less free water molecules, and therefore less water molecules to pass across a semi-permeable membrane, through which sugar molecules and other molecules attached to them are too big to diffuse across with ease.
Osmosis Experiment Planning Aim: The main subject that I will be planning to investigate is the effects of a concentrated sucrose solution on potato cells on the basis of the Osmosis theory. Background knowledge: The plant cell and its structure To understand osmosis in detail I will need to explain the plant cell (which is the cell included in the osmosis experiment) and its cell membrane. Below I have a diagram of a plant cell: [IMAGE] Osmosis is about the movement of particles from a higher concentrated solution to a lower concentrated solution to create an ethical balance via a partially or semi permeable cell membrane. Osmosis in simple terms is the exchange of particles between the cytoplasm inside the cell and the solution outside the cell. What makes this exhange is the partially permable cell membrane.
An Investigation of Factors Affecting the Rate of Osmosis Introduction Osmosis is the movement of water molecules across a semi permeable membrane from a region of high water concentration to a region of low water concentration. [IMAGE] A semi permeable membrane is a membrane with very small holes in it; they are so small that only water molecules can pass through them. Bigger molecules such as glucose cannot pass through it. In actual fact water molecules pass both ways through the membrane, but because there are more water molecules in the high concentration region than the other there is a steady net flow into the lower concentration region. The lower concentration is the stronger solution, such as a glucose solution.
The experiment is aimed at giving a better understatement of osmosis process and the different conditions in which osmosis occurs.
Investigate the Osmosis of Potato Cells in Various Salt Solutions. Introduction I have been asked to investigate the effect of changing the concentration of a solution on the movement of water into and out of potato cells. I will be able to change the input of my experiment. The input variable is the concentration of the solution.
If a plant cell is places in a hypotonic solution the cell has a lower water concentration to that of the solution. Water will move into the cell by osmosis from a high water concentration outside the cell to a lower water concentration inside the cell through a selectively permeable membrane. The cell becomes turbid
When a partially permeable membrane divides two such solutions, the water will move from the area of high concentration to the area of low concentration until both sides are equal. In plant cells water flows through the cell wall and cell surface membrane into the vacuole from the outside. As a result, the cell swells up. It doesn't burst as the cell wall stops the cell expanding too much; at this point we say a cell is fully turgid. Aim
So what is happening is water is moving from a high concentration, i.e. a dilute solution to a more concentrated solution. Preliminary Work on Osmosis I am going to test carrots in a small osmosis experiment to see how the experiment works with carrots and salt solution and water. Variables 1) Temperature - Keep the same 2) Number of days left soaking - Keep the same 3) Size of beaker - Keep the same 4) Size of carrots - Keep the same 5) Concentration of salt solution -
Diffusion and osmosis in living cells are greatly effected by factors such as solution concentration, temperature, and surface area of the cell. This was studied using agar cubes of different sizes, dialysis tubing, and potato cores to demonstrate how the different factors affect cells. The process of cellular respiration can be altered due to temperature differences. Enzymes also greatly affect the molecular processes that occur. Enzymes are denatured at variety of pH and causes inactivity of the enzyme in the reactions.
- The nurse’s mistake will increase the saltiness due to the double amount of saline in the bag.
when to do it etc. This should lead me to good results at the end of
== = This experiment is based on the concept of Osmosis. Osmosis is the diffusion of water molecules from a region of high water concentration to a low water concentration through a semi permeable membrane (in this case, the cell potato cell membrane). The cell walls of the potato cells are semi permeable meaning that water molecules (which are small) can fit through but other bigger molecules such as glucose cannot pass through. The water molecules can flow both ways through the membrane, letting molecules both in and out.
Osmosis in Potato Tubes Osmosis: Osmosis is the movement of water molecules through a semi-permeable membrane from a high concentration to a low concentration. Diagram: [IMAGE] [IMAGE] Aim: To see the effects of different concentration of sugar solution on Osmosis in potato tubes. Key factor: In the investigation we change the sugar solution from: 0%-10%-20%-30%-40%-50% this is the independent variable; the dependant variable is the change in mass. Prediction: I predict that all the potato tubes in pure water or low concentration sugar solution will swell because water enters their cells by osmosis.