This set of Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “Nucleus”.
1. Name the control center of the eukaryotic cell?
a) Nucleus
b) Ribosome
c) Cytoplasm
d) Golgi complex
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Explanation: Nucleus contains most of the genetic material of the cell and is called the control center of the eukaryotic cell. Eukaryotic cell may have a single nucleus (uninucleate) or have many nuclei (multinucleate).
2. Red blood cells are multinucleate in nature.
a) True
b) False
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Explanation: Mature red blood cells do not have a nucleus, so, these cells are neither multinucleate nor uninucleate.
3. Which of the following microorganism have two nuclei?
a) Slime molds
b) Cyanobacteria
c) Amoeba
d) Paramecium
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Explanation: Paramecium is unicellular ciliate protozoa which have two nuclei, one is macronucleus and other is micronucleus. Genes for everyday function of the cell is stored in macronucleus and sexual reproduction is controlled by micronucleus.
4. Which of the following is not a component of the nucleus?
a) Chromosome
b) Nucleolus
c) Cytoplasm
d) Nuclear envelope
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Explanation: Cytoplasm is not the component of the nucleus but the nucleus is found in the cytoplasm. The four components of the nucleus are nucleoplasm, nuclear envelope, nucleolus, and chromosomes.
5. Mark the INCORRECT statement about nuclear lamina.
a) Filaments present in the inner membrane of the nucleus
b) Made up of lamin proteins
c) Provide mechanical support to the nucleus
d) It has bounded with the ribosomes
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Explanation: Bounded with the ribosomes is incorrect for nuclear lamina as ribosomes present on the outer membrane of nucleus while nuclear lamina is a network of an intermediate filament which is present on the nuclear side of the inner membrane of the nucleus.
6. Name the structure which is used to transfer macromolecules between the cytoplasm and nucleus.
a) Microtubules
b) Nuclear pores
c) Cilia
d) Centrioles
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Explanation: Nuclear pores are present on the nuclear envelope which helps in transport of macromolecules among nucleus and cytoplasm. Nuclear pores are the part of a nuclear pore complex which includes inner and outer membranes of the nucleus.
7. Name the signal which helps protein to move in or out of the nucleus?
a) Notch signal
b) Paracrine signal
c) Nuclear localization signal
d) Chemical signals
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Explanation: Nuclear localization signals are also known as a nuclear-export signal which helps protein to import and export in the nucleus through nuclear pores. These signals are specific amino acid sequences present on the proteins.
8. Non-membrane bound body of the nucleus which disappears in the late prophase and reappears in telophase_______
a) Nucleolus
b) Chromosome
c) Nucleoplasm
d) Nuclear pore
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Explanation: Nucleolus is the component of the nucleus which is a non-membrane bound body produced by Nucleolar-organizing region of a chromosome. It disappears in the late prophase and then appears again in the telophase stage of cell division.
9. Which of the following is not true for chromatin?
a) Organized structure of DNA and protein
b) These are highly condensed DNA
c) It is found in the nucleus
d) It contains a single dsDNA
View Answer
Explanation: Organized structure of DNA and protein is incorrect as chromatin is less condensed and extended DNA while highly condensed DNA is of chromosomes.
10. Which region of chromatin is transcriptionally silent?
a) Nucleoid
b) Centromere
c) Euchromatin
d) Heterochromatin
View Answer
Explanation: Heterochromatin is darkly stained and highly condensed region of chromatin which is generally believed to be transcriptionally silent.
Sanfoundry Global Education & Learning Series – Life Sciences.
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