20 Questions
What is the main function of the nucleolus?
Site of ribosomal RNA production
What happens if the nuclear chromatin is very condensed?
It is difficult to observe the nucleolus
What does the nucleolus consist of?
RNA + proteins
In which type of cells is the nucleolus well developed?
Cells active in protein synthesis
What does NOR stand for in the context of the nucleolus?
Nucleolar Organizer Region
Which component of the nucleolus contains preribosomal subunits and maturing ribosomes?
Granular component
What human chromosomes contain genes for ribosomal RNAs (rRNAs)?
13, 14, 15, 21, 22
What is the approximate diameter of one or more nucleoli?
1 µm
Where does the transcription of 5S rRNA take place?
Outside the nucleolus
How many copies of the gene encoding 5.8S, 18S, 28S rRNAs are present in the human genome?
About 200
Which enzyme catalyzes the transcription of 5S rRNA?
RNA polymerase III
Where does the transcription of large 45S pre-rRNA take place?
Nucleolus
What is the function of snoRNAs in preRNA processing?
Chemical modification of pre-rRNAs
How many types of rRNAs are present in the ribosomes of higher eukaryotes?
4
Where are the genes for 5.8S, 18S, 28S rRNAs clustered in the human genome?
Tandem arrays on 5 different human chromosomes
How many small nucleolar RNAs (snoRNAs) are present in the nucleolus?
About 200
What is the function of the nuclear matrix?
Form a structural framework and organize functional domains of the nucleus
What are the components of the nucleolus?
300 proteins and about 200 small nucleolar RNAs (snoRNAs)
What is the role of the nucleolus in ribosome assembly?
Processing of ribosomes and other ribonucleoproteins
When is the nucleolus visible in a human cell?
Only in interphase cells
Test your knowledge of nucleolus with this quiz. Explore the structure, function, and characteristics of this ribosome production factory. Learn about its composition, staining properties, and more. Perfect for students of medical biology.
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