Which observation proves that a cell is a eukaryote?.
A)It contains DNA.
B)It has DNA inside a nucleus..
C)It has a cell membrane..
D)it contains ribosomes.
The Correct Answer and Explanation is:
The correct answer is B) It has DNA inside a nucleus.
Explanation:
Eukaryotic cells are characterized by the presence of a well-defined, membrane-bound nucleus that houses the cell’s genetic material (DNA). This is a key feature that distinguishes eukaryotes from prokaryotes. Let’s break down the other options to explain why they are not sufficient proof of a cell being a eukaryote:
- A) It contains DNA. While it is true that all living organisms, including both eukaryotes and prokaryotes, contain DNA, this alone does not differentiate eukaryotic cells from prokaryotic cells. Prokaryotes (such as bacteria) also contain DNA, but their DNA is not enclosed in a membrane-bound nucleus. Instead, it is found in a region called the nucleoid.
- C) It has a cell membrane. The presence of a cell membrane is common to all cells, whether eukaryotic or prokaryotic. The cell membrane is a fundamental structure that surrounds and protects the cell, regulating the movement of substances in and out of the cell. This feature does not distinguish eukaryotes from prokaryotes because both types of cells have a cell membrane.
- D) It contains ribosomes. Ribosomes are essential for protein synthesis and are found in both eukaryotic and prokaryotic cells. In eukaryotes, ribosomes can be free in the cytoplasm or attached to the rough endoplasmic reticulum, while in prokaryotes, they are found freely in the cytoplasm. Therefore, the presence of ribosomes is not a definitive characteristic of eukaryotes.
In contrast, B) It has DNA inside a nucleus is a distinguishing feature of eukaryotic cells. The nucleus in eukaryotes not only stores the genetic material but also regulates gene expression and protects DNA from the cytoplasm. This compartmentalization of genetic material allows for greater complexity in eukaryotic cell functions and is a defining trait of eukaryotic organisms, including plants, animals, fungi, and protists.