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Biology
How the body functions.
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Equipment: Carrot, Knife, 6 petri dishes clearly labelled 0.00 to 0.75., scale, salt solutionsThe aim: The aim of the experiment was to see if that osmosis occurs and water can pass into and
out of the cells of the carrot discs which would cause either a uptake or loss of water which would
cause changes in the mass.
Method:
We start the experiment by using the knife to cut the carrot up into thin, round slices and also by
using the marker pen to clearly label each of the discs 0.00 to 0.75 going up in 0.15
Then after cutting up all the slices, gently place these slices into the dishes using tweezers and
spacing them out.
After this, carry all the dishes to the weigh, and weight each of them separately and write down the
weight of each of them.
Using each of the solutions, fill each of the dishes using the correct solutions while ensuring that all
the discs are filled with the same amount of solution.
Leave the dishes for 30 minutes.
When 30 minutes is up, gently drain the dishes in the sink and clean all the solution inside without
touching the carrot.
Weight each of the dishes again and write down the results and calculate the difference in weight
between the before results and the after results.
Concentration
/ Moles
0.00 76.70 82.00 + 5.30 + 4. 30 + 0. 94 +1.31
0.15 129.85 133.75 + 3.90 + 3.35 + 0. 54 + 0.67
0.30 11.20 38.15 + 26.95 + 0.55 -0.31 -7.49
0.45 50.10 48.05 - 2.05 + 0.85 - 1.28 -1.37
0.60 94.35 89.55 - 4.80 -12. 40 -1.75 -0.86
0.75 117.00 111.65 - 5.35 - 27. 30 -1.46 1.55
Analysis
These results suggest that osmosis does occur and that the uptake of or loss of water affects the
weight. This is due to positive change if the water in the carrot is greater than the water outside or a
negative change the other way around. The 0.00 disc has the most positive mass change since
osmosis occurred the most thus making the carrot heavier due to concentration being increased
, inside the carrot cells. The 0.15 is second due to having salt in the solution which would decrease the
difference of water but the water is still greater outside the carrot.
The Last disc have the most negative change due to the difference between the concentration and
how the concentration is greater inside the carrot making the difference negative and osmosis
would occur as the water travels outside the carrot, making the carrot lighter. Compared to other
results, our results were pretty much in line with the others meaning that which may have done our
experiment accurately however one of our results could be an anomaly due to how we did the
experiment and added too much water affecting the process and in effect, creating a
mismeasurement.
The conclusion of the experiment is that osmosis does occur depending on the concentration inside
and outside the carrots slices. Positive mass change is caused by osmosis transferring water into the
carrot making them heavier while negative mass change occurs if osmosis occurs and the water is
diffused out of the carrot making it lighter. The results suggest that this is the case and that osmosis
is a useful process and is influential during the test in changing the weight.
Task 2
Osmosis
It is a form of diffusion but it only involves water and t works by water moving from a high
concentration area to an area of low concentration. Water can go through the membrane by
osmosis since the h20 molecules are small enough and are able to squeeze through bi layer. It is very
similar to simple diffusion and involves the same process but with water. The process also goes
down the concentration gradient meaning that the process moves h 20 molecules form an area of
high concentration of water to an area of low concentration. Water is transported by osmosis
through using their size to pass through the membrane and allowing them to enter the cell. Because
of this, the process does not require the use of ATP or energy to pass through the cell membrane.
Simple Diffusion
Simple diffusion works by allowing lipid soluble solutions to be able to pass through the cell without
any help or assistance. This process involves using diffusion which means moving molecules from a
high concentration are to a low concentration area. Lipid soluble molecules that are required for
simple diffusion include molecules such as oxygen, carbon dioxide and water who are all able to
squeeze through the phospholipids even though the phospholipids are hydrophobic. They like
osmosis go down the concentration gradient by allowing molecules to move to a low concentration
area from a high concentration area. The process does not require energy to occur.
Facilitated diffusion: Carrier
Facilitated diffusion: Carrier works by using carrier proteins to carry molecules across the cell
membrane as they are unable to travel through diffusion. They usually involve membrane transport
protein which would transport ions, small molecules and macromolecules across the membrane.
They do not require energy they also go down the concentration gradient as well.
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