Plasma Membrane Selectivity Explained
The plasma membrane, also known as the cell membrane, surrounds the cell and controls what enters and leaves.
Why Selectively Permeable?
It's called selectively permeable because it doesn't allow all substances to pass through freely. Instead, it acts like a gatekeeper:
- Allows passage: Certain essential substances, like nutrients and water, can cross the membrane.
- Restricts passage: Other substances, such as waste products or large molecules, are prevented from entering or leaving, or their movement is strictly regulated.
This selective nature is crucial for maintaining the cell's internal environment (homeostasis) and ensuring proper cell function.
Evaluating Option C
Option C accurately describes this characteristic: "It allows only certain substances to pass through while restricting others." This directly matches the definition of a selectively permeable membrane.
Other Options Analysis
- Option 1 is incorrect because the membrane does not allow free and equal movement of all substances.
- Option 2 is incorrect because the membrane does not prevent all materials from moving; essential transport occurs.
- Option 4 is incorrect because energy production primarily occurs in mitochondria, not the plasma membrane.
Important Questions from Biology
Which of the following statements about living and non-living being is/are correct?
1. While living being can demonstrate growth and repair, non-living being cannot.
2. While living being demonstrates metabolic processes, non-living being does not.
Select the correct answer using the code given below.Movement of materials to different parts of cytoplasm and nucleus is generally carried out by
The gaseous product of a process in plants is a requirement for another vital process that releases energy. Given below are four combinations of the process and product. Identify the correct answer.
Which one of the following cell organelles may play a role in expelling excess water and wastes in case of unicellular organisms?
Transformation of meristematic cells into specific permanent tissues occurs by the process of
