Investigating the Effects of Sucrose Concentration on Osmosis in Potato Tissue
PLANNING
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We have been asked to research the effects of sucrose concentration on
osmosis in potato tissue. Osmosis is the spontaneous movement of a
solvent (-in this case water) from a place where its chemical
potential is higher to another place where it is lower, through a
semi-permeable membrane (-such as a cell membrane). A cell membrane
lets smaller molecules such as water through but does not allow bigger
molecules to pass through. The smaller molecules will continue to
diffuse across the membrane until the area in which the molecules are
found reaches a state of equilibrium, meaning that the molecules are
in a steady state, with molecules moving in and out of the membrane,
however with no net loss or gain.
Plant cells always have a rigid cell wall and cell membrane
surrounding them. When they take up water by osmosis the cells start
to swell up, but the cell wall prevents them from bursting, (-which is
what animal cells, who have no cell walls would do), the plant cell is
then said to be turgid. When turgid, the pressure inside the cell
rises and eventually the internal pressure of the cell is so high that
no more water can enter the cell. This hydrostatic pressure works
against osmosis, even when the plant cell's water potential is greater
than that of the outsides. Turgidity is very important to plants
because this is what makes the plant "stand up" and acts as a form of
support.
The opposite of turgidity is plasmolysis, this is the retraction of
the cytoplasm from the wall of a vacuolated plant cell as a result of
osm...
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...ETY
I will have to wear goggles to prevent the sucrose liquid getting into
my eyes, take care with the sharp scalpel, and to wear aprons to
prevent splashes getting on my uniform.
Preliminary work-shapes my understanding
The preliminary work let me decided on some crucial factors:
-Time for experiment: 10 minutes
-Amount of solution: 5ml
-Length of potato: 3cm-make sure no skin is on the potato, as it will
block the osmosis happening on that part of the potato, therefore
smaller surface area.
-Dry potato after experiment to get rid of excess water-see reasons
for this actions above
- Mixing beaker will be washed using water and dried using paper
towels-see reasons for this actions above
-Concentrations of sucrose to be used:
-0%
-20%
-40%
-60%
-80%
-100%
Charles Darwin once compared the root tips of plants to “the brain of one of the lower animals” he even reported electrical signal systems in plants, much like a nervous system. More than a century after Darwin, a scientist named Mancuso discovered the center for the electrical signals, or action potentials, is located in the root tips. Even small plants had nearly 14 million root tips, all acting in a similar way to a nervous system. Humans and most animals have centralized brains, meaning it is all grouped together in one spot, forming what we envision as a brain. Plants may not have a centralized brain like humans, but that doesn’t mean they lack a brain, in fact plants have “decentralized intelligence” distributed throughout them. Since plants cannot react quickly, they have no way of defending themselves against predators, so by scattering the “brain” plants avoid dying off when damaged (Marinelli). The root tips and sensory cells allow plants to feel and react to different stimuli. It is uncertain as to whether plants feel pain, but they do respond to anesthetics and react to being damaged. For example, when a caterpillar eats a plant’s leaf, the plant begins to secrete defensive chemicals. The censor cells react to the damage being done and cause the leaf to secrete chemicals to fend off the predator, as well as repair the
When the cell has all the water it can take inside of it the osmosis
* Note the mass down in the table at the end of the first page.
molecules go in and out of the cell. There is no net movement of water
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.
I am going to carry out an experiment to measure the change in mass of
If the concentration of sucrose increases, then the mass of the potato will decrease. However, if the concentration of the solution in the beaker is less than that of the potato (such as distilled water), then the mass of the potato will increase. So, as the concentration of sucrose increases the rate of osmosis increases.
the same way as it does potato. I would also widen the range of sugar
repeat the process 3 times in total to ensure a fair test. At the end
When I am not using them I will place them away from my experiment and
Investigation of the Concentration and the Effect of Sucrose on Osmosis in Apple and Potato Tissues
own roots (not just the plant kind), this meant they needed a structure that was different than
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.
When you place a potato chip in a salt or sugar solution, then if the
The strong cells wall prevents bursting. The cell is turgid. If plant cells lose water the cells become limp and flaccid. Water is essential for support in plants.