Admin Structure and Role of tRNA Structure and Role of tRNA 1. Primary Structure of tRNA These modifications are critical for the structural stability, proper folding, and functional interactions of tRNA during translation. Even in the linear (primary) structure, certain domains (or arms) of tRNA are functionally distinguishable due to the presence of modified bases: 1. … Read more
Mechanism of Translation, Initiation, Elongation and Termination Formation of Aminoacyl tRNA a) Activation of amino acid AA + ATP –ENZYME- (aa1-AMP) -Enz1 + PPi B) The transfer of amino acid to tRNA (aa1-AMP) Enz1 + t-RNA1 —— aa1- t-RNA1 + AMP + Enz1 Initiation of Polypeptide Initiation in eukaryotes Kozak’s ribosome scanning hypothesis for … Read more
RIBOSOME site of protein synthesis OCCURRENCE: Number: Structure: Ultrastructure of Ribosomes Types of Ribosomes 70S ribosomes: 80S ribosomes: Polyribosomes or Polysomes: Origin of ribosomes: Functions of Ribosomes. RIBOSOMAL RNA or rRNA On the basis of their sedimentation coefficient or rate of sedimentation, rRNA molecules may be classified into following categories: Structure of rRNA Function of … Read more
Nuclear mRNA Transport 1. Which of the following proteins is involved in the processing of hnRNA in the nucleus?A. Cap-binding complexB. hnRNPsC. PAB-IID. Exon-junction complex (EJC) ✅ Answer: B. hnRNPsExplanation: hnRNPs are involved in the processing of heterogeneous nuclear RNA (hnRNA) before it is processed into functional mRNA. 2. What is required for the transportation … Read more
RNA Processing (1) 5′ capping (2) 3′ cleavage and polyadenylation (3) Splicing and RNA editing. (A) 5′ Capping (B) 3′ Processing – Cleavage and polyadenylation 1. Export of mature mRNA from the nucleus 2. Affect the stability of some mRNAs 3. Serve as a recognition signal for the ribosome. (C) Splicing Intron Splicing: (i) The … Read more
Eukaryotic transcription I. Pre initiation complex II. Promoter melting and open complex formation III. Abortive initiation IV. Promoter escape V. Elongation Elongation factors: VI. Termination (a) Factor dependent termination (b) Factor independent termination Section I: Pre-initiation Complex & General Transcription Factors Section II: Promoter Melting and Open Complex Formation Section III: Abortive Initiation Section IV: … Read more
Transcription in prokaryotes Initiation, 2. Elongation: 3. Termination: Rho independent or RNA based: Rho dependent or protein-based: Initiation Stage RNA Polymerase Structure Elongation Stage Termination Stage General Mechanisms Advanced Concepts Miscellaneous True/False Style Scenario-Based Final Questions
TRANSCRIPTION RNA polymerase-I or A: RNA polymerase-II or B: RNA polymerase-III or C: Promoters for RNA Polymerase II The transcription unit GENERAL FEATURES of TRANSCRIPTION Promoter, enhancer and silencer sites for initiation of transcription in eukaryotes RNA polymerase I or RNAPI RNA polymerase II or RNAPII RNA polymerase III or RNAPIII RNA Polymerases Transcription Components … Read more
DAMAGE AND REPAIR Introduction to DNA Damage and Repair: DAMAGE Types of Damage: Damage to DNA includes any deviation from the usual double helix structure. 1. Simple Mutations: 2. Deamination: 3. Missing Bases: 4. Chemical Modification of Bases: 5. Formation of Pyrimidine Dimers (Thymine Dimers): 6. Strand Breaks: Repair Mechanisms: 1. Direct Repair: 2. Excision … Read more
REPLICATION Semi-conservative replication of Chromosomes in eukaryotes: Theoretically, there may be following three possible modes of DNA replication: Semiconservative mode is the most accepted of all. DNA Replication is Semi-Conservative: Meselson and Stahl Experiment: Fig. Semiconservative replication. STEPS OF DNA REPLICATION DNA-Replication Stages of Replication The DNA synthesis or replication can be divided into three … Read more
