24 Questions
Where is the site of ribosomal RNA production?
Nucleolus
What does the nucleolus consist of?
RNA + proteins
In which type of cells is the nucleolus well developed?
Malignant tumors
What does the nucleolar organizer region (NOR) contain?
Repeated genes for rRNAs
How many pairs of human chromosomes contain rRNA genes or NOR’s?
5
What is the size of a nucleolus?
1 µm in diameter
What is the function of the dense fibrillary component in the nucleolus?
Transcripts of rRNA genes
What is the role of the granular components in the nucleolus?
Maturing ribosomes
Which type of cells contain 5-10 million ribosomes?
Actively growing cells
What type of dyes stain the nucleolus?
Basic dyes
What happens if the nuclear chromatin is very condensed?
It is difficult to observe the nucleolus
What is the main function of the nucleolus?
Ribosomal RNA production
What is the function of the nucleolus?
Processing of ribosomes and other ribonucleoproteins
How many copies of the gene that encodes 5.8S, 18S, 28S rRNAs are present in the human genome?
About 200
Which enzyme catalyzes the transcription of the 5S rRNA?
RNA polymerase III
Where are the 5S rRNA genes located in the human genome?
In a single cluster on chromosome 1
What is the main role of the nuclear matrix?
Form a structural framework and organize functional domains of the nucleus
How many types of rRNAs are present in the ribosomes of higher eukaryotes?
4
Which enzyme is responsible for the transcription of large numbers of rRNA?
RNA polymerase I
What is the approximate number of small nucleolar RNAs (snoRNAs) present in the nucleolus?
About 200
What is the function of the nucleolar organizer region (NOR) in a human cell?
Insert into the nucleolus and form NOR regions
What is the function of the dense fibrillary component in the nucleolus?
Chemical modification and nucleolytic processing of precursor rRNA
What happens to the appearance of the nucleolus in a human cell during the cell cycle?
It is visible only in interphase cells
What is the role of telomerase in the nucleolus?
Assemble at the nucleolus
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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