Complete the following sentence - Leaving Cert Biology - Question 9 - 2017
Question 9
Complete the following sentence.
Osmosis is the movement of water molecules through a selectively-permeable membrane,
from a region of (i) ________________ concentr... show full transcript
Worked Solution & Example Answer:Complete the following sentence - Leaving Cert Biology - Question 9 - 2017
Step 1
(i) Complete the following sentence.
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Answer
Osmosis is the movement of water molecules through a selectively-permeable membrane,
from a region of (i) higher concentration of water molecules to a region of (ii) lower concentration of water molecules.
Step 2
(ii) Suggest a control that you might use in this activity.
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Answer
A control could be using a piece of potato or tubing that has not been exposed to any solution, ensuring that any changes observed are solely due to the osmosis demonstration.
Step 3
(iii) State the result(s) of the demonstration.
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The results of the demonstration can include: the tubing or cut potato becoming heavier or swelled with more liquid, indicating the movement of water into the area of lower water concentration.
Step 4
(iv) Briefly explain the result(s).
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The result can be explained by stating that water moves from an area of higher concentration of water molecules to an area of lower concentration. This is driven by the osmotic gradient.
Step 5
(v) Suggest how storing food in salty water prevents the growth of bacteria or fungi.
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Storing food in salty water dehydrates microorganisms, as the high concentration of salt causes the water to move out of the cells, thus inhibiting their growth.
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