Q.38 Which of the following entity(ies) is/are found inside the intact nucleus of
eukaryotic cells?
(A) Centrosome
(B) Lysosome
(C) Nucleolus
(D) Nucleosome
Correct Answer: (C) and (D)
The intact nucleus of eukaryotic cells contains the nucleolus and nucleosomes, while centrosomes and lysosomes reside in the cytoplasm.
Option Analysis
Centrosome (A)
Centrosomes function as microtubule-organizing centers in animal cells and locate in the cytoplasm near the nucleus. They remain outside the nuclear envelope during interphase.
Lysosome (B)
Lysosomes serve as membrane-bound sacs with hydrolytic enzymes for digestion and exist in the cytoplasm of eukaryotic cells. No lysosomes appear within the nucleus.
Nucleolus (C)
The nucleolus occupies a prominent position inside the nucleus as a non-membrane-bound site for ribosomal RNA synthesis and ribosome assembly.
Nucleosome (D)
Nucleosomes form the basic units of chromatin, with DNA wrapped around histone octamers, and reside throughout the nuclear chromatin.
In eukaryotic cells, the intact nucleus houses genetic material and key structures like the entities inside intact eukaryotic nucleus, distinguishing it from cytoplasmic components. Understanding whether centrosome, lysosome, nucleolus, or nucleosome belong here proves essential for CSIR NET Life Sciences aspirants studying cell biology.
Nuclear Components
The nucleus features a double membrane with pores and contains nucleolus for ribosome biogenesis and nucleosomes as DNA-histone complexes forming chromatin. These entities inside intact eukaryotic nucleus support transcription and packaging.
Cytoplasmic Exclusions
Centrosomes organize microtubules from the cytoplasm near the nucleus, absent in higher plants. Lysosomes digest macromolecules in the cytoplasm via acidic enzymes. Neither enters the intact nucleus.
