Which one of the following statements about animal cells and plant cells is correct?
Animal cells have only cell membrane not cell wall, but plant cells have both.
Comparing Animal and Plant Cells: Cell Wall and Cell Membrane
Understanding the differences between animal cells and plant cells is fundamental in biology. One of the most significant distinctions lies in the presence or absence of a cell wall and a cell membrane.
Cell Membrane: A Universal Boundary
The cell membrane is a crucial component of all cells, both prokaryotic and eukaryotic, including animal and plant cells. It acts as a selective barrier, controlling the passage of substances into and out of the cell. It is composed primarily of a phospholipid bilayer and proteins.
Cell Wall: A Plant Specialty
Unlike animal cells, plant cells have an additional layer outside the cell membrane called the cell wall. The plant cell wall is rigid and provides structural support, protection, and maintains the shape of the cell. It is primarily composed of cellulose.
Key Differences Summarized
Let's summarize the presence of these structures in animal and plant cells:
| Feature | Animal Cell | Plant Cell |
|---|---|---|
| Cell Membrane | Present | Present |
| Cell Wall | Absent | Present (outside cell membrane) |
Analyzing the Given Statements
Now let's examine each statement in the context of these differences:
- Statement 1: Animal cells have only cell membrane not cell wall, whereas plant cells have only cell wall not cell membrane.
This statement is incorrect. Plant cells have both a cell wall and a cell membrane.
- Statement 2: Animal cells have only cell membrane not cell wall, but plant cells have both.
This statement accurately describes the presence of the cell membrane and absence of the cell wall in animal cells, and the presence of both in plant cells.
- Statement 3: Both animal and plant cells have cell membrane and cell wall.
This statement is incorrect because animal cells do not have a cell wall.
- Statement 4: Only some cells of animals have cell wall and all plant cells have cell membrane.
This statement is incorrect. Animal cells never have a cell wall. While it is true that all plant cells have a cell membrane, the first part of the statement is false.
Based on this analysis, Statement 2 is the correct description of the presence of cell membranes and cell walls in animal and plant cells.
Revision Table: Animal vs. Plant Cell Structures
| Feature | Animal Cell | Plant Cell |
|---|---|---|
| Cell Membrane | Yes | Yes |
| Cell Wall | No | Yes |
| Chloroplasts | No | Yes (for photosynthesis) |
| Large Central Vacuole | No (may have small vacuoles) | Yes |
Additional Information: Functions of Cell Structures
- Cell Membrane: Regulates the passage of substances in and out, maintains cell integrity, involved in cell signaling.
- Cell Wall (Plants): Provides structural support, protection against mechanical stress and osmotic lysis, maintains cell shape.
- Chloroplasts (Plants): Sites of photosynthesis, converting light energy into chemical energy.
- Large Central Vacuole (Plants): Stores water, nutrients, and waste products; helps maintain turgor pressure against the cell wall.
Important Questions from Cell
In a plant cell, which one of the following contains their own DNA?
Which one of the following structures or components is not always present in living cells?
- Which one of the following statements about vacuoles' is not correct?
- A cell is unable to synthesize lipids. Which of its cell organelles might be defective?
In prokaryotic organisms, nuclear region is not surrounded by a membrane. This undefined nuclear region is known as
