Cell Membrane and Tonicity Worksheet Answers
The cell membrane, also known as the plasma membrane, is a thin layer of lipid and protein molecules that separates the internal cell environment from the external environment. It is a semi-permeable membrane that allows certain substances to pass through while restricting others. In this worksheet, we will explore the concept of tonicity and how it affects cells.
What is Tonicity?
Tonicity refers to the concentration of solutes in a solution. A solution can be isotonic, hypotonic, or hypertonic relative to a cell.
- Isotonic solution: A solution that has the same concentration of solutes as the cell. In an isotonic solution, the cell will neither swell nor shrink.
- Hypotonic solution: A solution that has a lower concentration of solutes than the cell. In a hypotonic solution, the cell will swell due to the influx of water molecules.
- Hypertonic solution: A solution that has a higher concentration of solutes than the cell. In a hypertonic solution, the cell will shrink due to the efflux of water molecules.
Effects of Tonicity on Cells
The tonicity of a solution can have significant effects on cells.
- Isotonic solution: No change in cell size or shape.
- Hypotonic solution: Cell swells and may burst (lyse) due to excessive water intake.
- Hypertonic solution: Cell shrinks and may become dehydrated due to excessive water loss.
Examples of Tonicity
- Blood plasma: Isotonic to most cells in the body.
- Seawater: Hypertonic to most cells in the body.
- Freshwater: Hypotonic to most cells in the body.
Cell Membrane and Tonicity Worksheet Answers
What is the main function of the cell membrane? Answer: To separate the internal cell environment from the external environment and regulate the movement of substances in and out of the cell.
What is tonicity? Answer: Tonicity refers to the concentration of solutes in a solution.
What are the three types of tonicity? Answer: Isotonic, hypotonic, and hypertonic.
What happens to a cell in a hypotonic solution? Answer: The cell swells due to the influx of water molecules.
What happens to a cell in a hypertonic solution? Answer: The cell shrinks due to the efflux of water molecules.
What is the effect of an isotonic solution on a cell? Answer: No change in cell size or shape.
Give an example of a hypotonic solution. Answer: Freshwater.
Give an example of a hypertonic solution. Answer: Seawater.
📝 Note: The cell membrane plays a crucial role in maintaining the internal environment of the cell and regulating the movement of substances in and out of the cell. Understanding tonicity is essential in understanding how cells respond to different solutions.
What is the difference between isotonic, hypotonic, and hypertonic solutions?
+Isotonic solutions have the same concentration of solutes as the cell, hypotonic solutions have a lower concentration of solutes, and hypertonic solutions have a higher concentration of solutes.
What happens to a cell in a hypotonic solution?
+The cell swells due to the influx of water molecules.
What is an example of an isotonic solution?
+Blood plasma is an example of an isotonic solution.
In conclusion, understanding the concept of tonicity and its effects on cells is crucial in understanding cellular biology. The cell membrane plays a vital role in regulating the movement of substances in and out of the cell, and the tonicity of a solution can have significant effects on cell size and shape.
