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Draw a large labelled diagram of a transverse section through a young root - Leaving Cert Biology - Question c - 2008
Question c
Draw a large labelled diagram of a transverse section through a young root. Water enters the outermost cells of the root by osmosis. What does this tell you about t... show full transcript
Worked Solution & Example Answer:Draw a large labelled diagram of a transverse section through a young root - Leaving Cert Biology - Question c - 2008
Step 1
Draw a large labelled diagram of a transverse section through a young root.
Answer
To create a labeled diagram of a transverse section of a young root, draw the following features:
- Dermal Tissue: The outermost layer of cells, providing protection to the root.
- Ground Tissue: This tissue is located beneath the dermal layer and is involved in storage and photosynthesis.
- Vascular Tissue: Represented by xylem and phloem, responsible for the transport of water, nutrients, and organic compounds.
Ensure all parts are clearly labeled.
Step 2
Water enters the outermost cells of the root by osmosis. What does this tell you about the cell sap of these outermost cells?
Answer
This indicates that the cell sap of the outermost cells has a higher solute concentration compared to the surrounding soil water. Consequently, water moves into these cells by osmosis, where it moves from an area of lower solute concentration (soil) to an area of higher solute concentration (cell sap).
Step 3
Osmosis has been described as a special case of diffusion. Explain why.
Answer
Osmosis is considered a special case of diffusion because it specifically refers to the movement of water (solvent) across a selectively permeable membrane. Unlike general diffusion, which involves the movement of solutes from an area of higher concentration to lower concentration, osmosis focuses solely on water moving along its concentration gradient until equilibrium is reached.
Step 4
Describe an investigation that you carried out to demonstrate osmosis.
Answer
In the investigation, I used a potato piece and placed it in two different solutions: one with high salt concentration and one with pure water. The potato piece in the high salt solution shrank, indicating water was drawn out, while the one in pure water swelled, showing water entered the cells. This demonstrated osmosis through changes in mass and size due to varying concentrations.
Step 5
Describe how minerals such as nitrates enter the root of a plant from the soil.
Answer
Minerals such as nitrates enter the root of a plant primarily through diffusion and active transport. As the concentration of nitrates in the soil is often higher than in the root cells, they move into the root consistently through diffusion. However, when necessary, plants can actively transport nitrates into their root cells, utilizing energy to move minerals against their concentration gradient.