Eukaryotic cells are much more complex as compared to prokaryotes. Which one of the following structures is exclusively present in a eukaryotic cell?
Mitochondria
Understanding Eukaryotic vs. Prokaryotic Cell Structures
Cells are the basic units of life and can be broadly classified into two major types: prokaryotic cells and eukaryotic cells. Eukaryotic cells are generally larger and significantly more complex than prokaryotic cells. A key difference lies in the presence of a true nucleus and various membrane-bound organelles within eukaryotic cells, which are absent in prokaryotic cells.
Let's examine the given structures to determine which one is exclusively found in eukaryotic cells:
- Cell wall: A cell wall provides structural support and protection. While many prokaryotic cells (like bacteria and archaea) have cell walls, the composition differs from that found in eukaryotic cells like plant cells and fungal cells. However, since it's present in both domains (though with different composition in some), it is not exclusively eukaryotic.
- Plasma membrane: The plasma membrane, also known as the cell membrane, is a selective barrier that encloses the cytoplasm of all cells. It regulates the passage of substances into and out of the cell. This structure is fundamental to all known forms of life, both prokaryotic and eukaryotic. Therefore, it is not exclusively eukaryotic.
- Nucleic acid: Nucleic acids, primarily DNA and RNA, carry genetic information. DNA serves as the genetic material for all cellular organisms, and RNA plays crucial roles in protein synthesis and gene expression. Both prokaryotic and eukaryotic cells contain nucleic acids. Thus, nucleic acid is not exclusively eukaryotic.
- Mitochondria: Mitochondria are often called the "powerhouses" of the cell because they are the primary sites of aerobic respiration, generating adenosine triphosphate (ATP), the cell's main energy currency. Mitochondria are membrane-bound organelles. Prokaryotic cells lack membrane-bound organelles like mitochondria. They perform similar energy-generating processes using enzymes embedded in their plasma membrane or cytoplasm. Mitochondria are characteristic features of almost all eukaryotic cells.
Based on this analysis, mitochondria are the structure exclusively present in a eukaryotic cell among the given options.
| Feature | Prokaryotic Cells | Eukaryotic Cells |
|---|---|---|
| Nucleus | Absent (genetic material in nucleoid region) | Present (membrane-bound) |
| Membrane-bound Organelles | Absent | Present (e.g., mitochondria, chloroplasts, endoplasmic reticulum, Golgi apparatus, lysosomes) |
| Size | Generally smaller (0.1-5 μm) | Generally larger (10-100 μm) |
| DNA Form | Usually circular, located in nucleoid | Linear, organized into chromosomes in the nucleus |
| Ribosomes | Present (70S) | Present (80S in cytoplasm, 70S in mitochondria/chloroplasts) |
| Cell Wall | Often present (e.g., peptidoglycan in bacteria) | Present in plants (cellulose), fungi (chitin), some protists; absent in animals |
Revision Table: Key Differences
To reinforce the concept, let's summarize the exclusivity of the given structures:
- Cell wall: Found in some prokaryotes and some eukaryotes.
- Plasma membrane: Found in all prokaryotes and all eukaryotes.
- Nucleic acid: Found in all prokaryotes and all eukaryotes.
- Mitochondria: Found exclusively in eukaryotic cells (most types).
Additional Information on Cellular Structures
Understanding the function of these structures helps clarify their roles:
- Mitochondria: Perform cellular respiration to produce ATP. This complex process requires the specialized internal membranes found within mitochondria.
- Nucleus: The defining feature of eukaryotic cells, housing the majority of the cell's genetic material and controlling cell growth and reproduction.
- Chloroplasts: Another type of membrane-bound organelle found exclusively in plant cells and some protists, responsible for photosynthesis.
- Endoplasmic Reticulum (ER) and Golgi Apparatus: Membrane systems involved in protein and lipid synthesis, modification, and transport, found only in eukaryotes.
The presence of a nucleus and complex membrane-bound organelles like mitochondria enables eukaryotic cells to carry out more specialized functions and reach larger sizes compared to prokaryotic cells.
Similar Questions
- Which of the following organelles have their own DNA and ribosomes ?
Consider the following statements:
1. DNA replication takes place when chromatin is opened up.
2. Chromatin organizes itself into rod-shaped chromosomes before cell division.
3. Both prokaryotes and eukaryotes have the same process for cell division.
Which of the statements given above is/are correct?
Which of the following statements regarding animal cell membrane is correct?
Which one of the following structures is not present in a prokaryotic cell?
Which one of the following structures or components is not always present in living cells?
Consider the following statements regarding cell wall composition :
1. Bacterial cell wall is made of peptidoglycan.
2. Fungal cell wall is made of cellulose.
3. Animals lack cell wall and have extracellular matrix made up of sugar and proteins.
Select the correct answer using the code given below:
In a plant cell, which one of the following contains their own DNA?
- 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?
Which one of the following statements about animal cells and plant cells is correct?
Important Questions from Cell
The full form of DNA is:
________ is called ‘the power house of the cell’.
A Eukaryotic cell has membrane bound organelles, including a nucleus, which allow cellular processes to be carried out in _________
Which of the following is a unicellular organism?
What is the name of the first mammal clone (sheep)?
