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Which of the following named structures does not have a membrane directly around it?

A. nucleus
B. nucleolus
C. mitochondria
D. peroxisome

User ArcticZero
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1 Answer

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Final Answer:

The nucleolus is a structure within the nucleus of a cell and is not surrounded by a separate membrane. It is a dense region involved in the synthesis of ribosomal RNA (rRNA) and the assembly of ribosomes. In contrast, the nucleus is surrounded by a nuclear membrane, and both mitochondria and peroxisomes have their own membranes. So the corrrect option is B. Nucleolus

Step-by-step explanation:

The nucleolus is a substructure located within the nucleus of a cell and is not enclosed by a distinct membrane. It plays a pivotal role in ribosome biogenesis, orchestrating the synthesis and assembly of ribosomal RNA (rRNA) with proteins. While it lacks a surrounding membrane, the nucleus itself, indicated in option A, is enclosed by a double membrane, separating its contents from the cytoplasm.

In contrast, mitochondria (C) and peroxisomes (D) are membrane-bound organelles with specific functions related to energy production and metabolic processes. The nucleolus, despite its membrane-less state, is integral to cellular function, contributing to the cell's capacity to synthesize the molecular machinery essential for protein synthesis and cellular activities.

User Dogbert
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