Diffusion is the movement of a molecule from an area of higher concentration to an area of lower concentration.
True or False?
True
False
The Correct Answer is A
Diffusion is a passive process that does not require energy input from the cell. It is driven by the random motion of molecules that results in a net movement from regions of higher concentration to regions of lower concentration.
Diffusion is one of the ways that substances can cross the cell membrane, such as oxygen, carbon dioxide, and water. Diffusion is important for cellular functions, such as gas exchange, nutrient uptake, and waste removal. Diffusion also helps maintain the homeostasis of the cell by balancing the concentration gradients of different molecules. Therefore, diffusion is the movement of a molecule from an area of higher concentration to an area of lower concentration.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is B
Explanation
Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration across a semi-permeable membrane. Diffusion stops when there is no net movement of particles across the membrane, which means that the rate of diffusion in one direction is equal to the rate of diffusion in the opposite direction.
This does not necessarily mean that there is an equal concentration of particles on both sides of the membrane, but rather that there is a dynamic equilibrium between the two sides. For example, if a semi-permeable membrane separates a solution of 10% sugar and 90% water from a solution of 20% sugar and 80% water, diffusion will occur until the sugar concentration on both sides is 15%.
However, if the membrane only allows water to pass through, diffusion will occur until the water concentration on both sides is equal, which means that the sugar concentration on one side will be higher than the other. Therefore, diffusion does not always result in an equal concentration of particles on both sides of a semi-permeable membrane.
Correct Answer is D
Explanation
Choice A rationale: Distilled water is not a positive control, but a negative control for the iodine test. Distilled water is a pure solvent that does not contain any starch or other carbohydrates. It does not react with the iodine solution and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.
Choice B rationale: Olive oil is not a positive control, but a negative control for the iodine test. Olive oil is a lipid that does not contain any starch or other carbohydrates. It does not react with the iodine solution and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.
Choice C rationale: Albumin solution is not a positive control, but a negative control for the iodine test. Albumin is a protein that does not contain any starch or other carbohydrates. It does not react with the iodine solution and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.
Choice D rationale: Starch solution is a positive control for the iodine test. Starch is a polysaccharide that contains many glucose units linked by glycosidic bonds. Starch reacts with the iodine solution and produces a blue-black color. A positive control is used to confirm that the test works and gives a positive result when the substance is present³.
Choice E rationale: Glucose solution is not a positive control, but a negative control for the iodine test. Glucose is a monosaccharide that does not contain any glycosidic bonds. Glucose does not react with the iodine solution and does not produce any color change. A negative control is used to confirm that there is no response to the reagent or the microorganism used in the test. It is used to set the baseline and verify that the detecting reagent is working properly³.
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