14 public questions tagged with this topic.
rRNA forms the structural and catalytic part of ribosomes, playing a key role in translation. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.
RNA polymerase I is responsible for synthesizing ribosomal RNA (rRNA) in eukaryotic lls. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.
Nucleolus is non-membrane-bound condensate within nucleus formed by liquid-liquid phase separation around nucleolar organizer regions on chromosomes 13,14,15,21,22 containing tandem arrays of 45S rRNA genes 400 copies in humans. RNA polymerase I, with transcription factors UBF and SL1, transcribes 47S pre-rRNA precursor containing 18S, 5.8S, 28S sequences separated by internal and external transcribed spacers. Co-transcriptional processing involves snoRNPs C/D box guiding 2'-O-methylation and H/ACA box guiding pseudouridylation, endonucleolytic cleavages generating mature rRNAs. 5S rRNA transc
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 6: Nucleolus and rRNA Synthesis.
Nucleolar organization reflects sequential ribosome assembly. Fibrillar centers contain transcriptionally inactive rDNA, border to dense fibrillar component active transcription. Dense fibrillar component appears as tight fibrillar mesh containing fibrillarin methyltransferase, Nop56, Nop58 and U3 snoRNP required for early cleavages of forty seven S precursor at sites A0, A1 and A2 within external and internal transcribed spacers, plus two prime O methylation directed by box C/D snoRNAs and pseudouridylation by box H/ACA snoRNAs. This processing trims precursor into eighteen S, five point eigh
Ref: Boisvert Annu Rev Biochem; nucleolus DFC fibrillarin early cleavage methylation pseudouridylation.
rRNA does not carry genetic information; that function is performed by mRNA.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
rRNA (ribosomal RNA) is the structural and catalytic component of ribosomes, aiding in protein synthesis.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Regulation of Gene Expression - Lac Operon
rRNA (ribosomal RNA) functions as a catalytic molecule in translation, aiding in peptide bond formation.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Genetic Code and Translation
cRNA (complementary RNA) is not a recognized type of RNA, whereas mRNA, tRNA, and rRNA are essential for protein synthesis.
Ref: NCERT Class 11 Biology Chapter 9: Biomolecules Enzymes - Properties Classification and Cofactors
Genetic, biochemical, and crystallographic studies established that peptide bond formation is catalyzed by ribosomal RNA, not protein side chains. The peptidyl transferase center resides within domain V of large subunit 23S rRNA in prokaryotes, conserved as 28S rRNA in eukaryotes, where nucleotides position the 3' CCA ends of P-site and A-site tRNAs for nucleophilic attack of amino group on ester carbonyl. Key adenine A2451 contributes orientation and pKa perturbation rather than direct acid-base chemistry. Deproteinized large subunit retains catalytic activity, demonstrating the ribosome is a
Ref: Alberts Molecular Biology of the Cell Fig 6-80; NCBI Bookshelf NBK21760 - peptidyl transferase center composed of 23S rRNA, ribosome is ribozyme
Anti-Shine-Dalgarno sequence resides at 3' terminal region of 16S rRNA in 30S small subunit, conserved nucleotides 1534 to 1540 with sequence CCUCCU complementary to Shine-Dalgarno AGGAGG in mRNA. Located in a single-stranded tail of 16S, it becomes accessible for base-pairing upstream of start codon, anchoring mRNA with optimal spacing five to nine nucleotides from AUG for initiator tRNA engagement. Mutations altering complementarity impair translation of canonical mRNAs, while engineered systems exploit altered anti-SD for orthogonal translation regulating gene expression synthetically.
Ref: Watson Molecular Biology of the Gene, 7th ed., Chapter 15, 16S rRNA anti-Shine-Dalgarno sequence CCUCCU at 3' end
The bulk of rRNA nucleotide modifications, pseudouridylation and 2'-O-methylation totaling over 200 sites in human rRNA, occurs in nucleolus, the site of rRNA synthesis and early ribosome assembly. Modification is mediated by small nucleolar RNPs, H/ACA guiding pseudouridine synthase dyskerin and C/D guiding fibrillarin methyltransferase, base-pairing with nascent 45S pre-rRNA co-transcriptionally. Nucleolar concentration of factors couples transcription, modification, folding and protein binding, ensuring modified nucleotides cluster at functional centers like decoding and peptidyl transferas
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 6, Nucleolar snoRNP-guided rRNA modifications
Bacterial ribosomal RNA operons (rrn) are transcribed as long polycistronic precursors rather than individual genes. The primary transcript typically around 30S contains 16S, 23S, 5S rRNAs and interspersed tRNAs co-transcribed in one unit. This polycistronic organization allows stoichiometric production of rRNAs. The transcript folds into extensive double-stranded processing stems recognized by RNase III for initial cleavage, followed by RNase E, RNase G, RNase T and other nucleases for secondary trimming, ultimately releasing mature rRNAs ready for ribosomal assembly and coordinated growth re
Ref: Berg et al., Biochemistry, 9th ed., Chapter 32, Bacterial rRNA operons and polycistronic transcription
