1
Question
Osmoregulation is essential to all organisms as it maintains homeostasis of the organism's water content.
Osmoregulation in unicellular freshwater organisms like amoeba and paramecia involves an organelle called the contractile vacuole, which collects excess water as it accumulates in the cell and pumps it out. The graphs below plot contraction rate in contractile vacuoles vs. surrounding solution concentrations.
Which
of the following statements best explains the response when Paramecia
are placed in a beaker of
distilled water to which a 5% NaCl solution is added dropwise?
Osmoregulation is essential to all organisms as it maintains homeostasis of the organism's water content.
Osmoregulation in unicellular freshwater organisms like amoeba and paramecia involves an organelle called the contractile vacuole, which collects excess water as it accumulates in the cell and pumps it out. The graphs below plot contraction rate in contractile vacuoles vs. surrounding solution concentrations.
Which of the following statements best explains the response when Paramecia are placed in a beaker of distilled water to which a 5% NaCl solution is added dropwise?
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Solution
The correct option is A Graph A illustrates the decrease in contraction rate that will occur as a result of negative feedback to the increase in surrounding solute concentration.
Osmoregulation in unicellular organisms occurs due to contractile vacuoles. These vacuoles help in maintaining the osmolarity of the cell by pumping out water and also storing it. When the concentration of the water increases in the cell, these vacuoles will perform the active contraction for removing it. Higher the concentration of water more will be the contractions performed by these vacuoles. As the concentration of the water in the cell decreases, their contractions will also decrease. In graph A, initially, when the concentration of water is more, the contractile vacuole is actively contracting. As the 5% NaCl is added drop-wise, there occurred a reduction in the concentration of the water, due to which a negative feedback developed and the contractions of the contractile vacuole began to decrease.Hence, the correct answer is 'Graph A illustrates the decrease in contraction rate that will occur as a result of negative feedback to the increase in surrounding solute concentration'
Osmoregulation in unicellular organisms occurs due to contractile vacuoles. These vacuoles help in maintaining the osmolarity of the cell by pumping out water and also storing it. When the concentration of the water increases in the cell, these vacuoles will perform the active contraction for removing it. Higher the concentration of water more will be the contractions performed by these vacuoles. As the concentration of the water in the cell decreases, their contractions will also decrease.
In graph A, initially, when the concentration of water is more, the contractile vacuole is actively contracting. As the 5% NaCl is added drop-wise, there occurred a reduction in the concentration of the water, due to which a negative feedback developed and the contractions of the contractile vacuole began to decrease.
Hence, the correct answer is 'Graph A illustrates the decrease in contraction rate that will occur as a result of negative feedback to the increase in surrounding solute concentration'
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