CSIR NET Life Sciences Fundamental Processes Syllabus

Fundamental Processes syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Fundamental Processes in CSIR NET Life Sciences, not a summary of it.

1. 1

   DNA replication, repair and recombination

   8 topics

   • Unit of replication
   • Enzymes involved in replication
   • Replication origin and replication fork
   • Fidelity of replication
   • Extrachromosomal replicons
   • DNA damage and repair mechanisms
   • Homologous recombination
   • Site-specific recombination
2. 2

   RNA synthesis and processing

   8 topics

   • Transcription factors and machinery
   • Formation of initiation complex
   • Transcription activator and repressor
   • RNA polymerases
   • Capping, elongation, and termination
   • RNA processing
     • RNA editing
     • Splicing
     • Polyadenylation
   • Structure and function of different types of RNA
   • RNA transport
3. 3

   Protein synthesis and processing

   11 topics

   • Ribosome
   • Formation of initiation complex
   • Initiation factors and their regulation
   • Elongation and elongation factors
   • Termination
   • Genetic code
   • Aminoacylation of tRNA
   • tRNA-identity
   • Aminoacyl tRNA synthetase and translational proof-reading
   • Translational inhibitors
   • Post-translational modification of proteins
4. 4

   Control of gene expression at transcription and translation level

   2 topics

   • Regulating the expression of phages, viruses, prokaryotic and eukaryotic genes
   • Role of chromatin in gene expression and gene silencing

Fundamental Processes flashcards for CSIR NET Life Sciences

18 of 78 cards from the Fundamental Processes deck — real questions with worked answers.

1. What is a replicon?

   A unit of replication; a DNA segment replicated from a single origin of replication. Bacteria typically have one replicon per chromosome; eukaryotes have many replicons per chromosome.

2. In which direction does DNA polymerase synthesize new DNA, and which strand is the template read in?

   DNA polymerase synthesizes DNA 5'→3'; it reads the template strand 3'→5'.

3. What is the function of DNA helicase at the replication fork?

   It unwinds the parental DNA double helix by breaking hydrogen bonds, separating the two strands (e.g., DnaB in E. coli).

4. What enzyme synthesizes the RNA primer needed to start DNA replication?

   Primase (DnaG in E. coli), an RNA polymerase that lays down a short RNA primer providing a free 3'-OH.

5. Which E. coli DNA polymerase is the main replicative enzyme, and which removes RNA primers?

   DNA polymerase III is the main replicative enzyme; DNA polymerase I removes RNA primers (5'→3' exonuclease) and fills the gaps.

6. What is the role of DNA ligase in replication?

   It seals nicks by forming phosphodiester bonds, joining Okazaki fragments on the lagging strand into a continuous strand.

7. What is the difference between the leading and lagging strands?

   The leading strand is synthesized continuously 5'→3' toward the fork; the lagging strand is synthesized discontinuously as Okazaki fragments away from the fork.

8. What is the function of single-strand binding (SSB) proteins?

   They bind and stabilize single-stranded DNA at the replication fork, preventing reannealing and protecting it from nucleases.

9. What enzyme relieves the supercoiling tension ahead of the replication fork?

   Topoisomerase (DNA gyrase / topoisomerase II in E. coli) relieves positive supercoils by introducing transient breaks.

10. What is the E. coli origin of replication called and what is its key feature?

    oriC, an AT-rich region (~245 bp) containing DnaA boxes; AT-richness allows easier strand separation to start replication.

11. Describe semiconservative replication.

    Each daughter DNA duplex contains one parental (old) strand and one newly synthesized strand, as demonstrated by Meselson and Stahl (1958).

12. What is the function of the sliding clamp (β-clamp) in replication?

    It encircles DNA and tethers DNA polymerase III to the template, greatly increasing processivity; loaded by the clamp loader (γ complex).

13. How does proofreading contribute to fidelity of replication?

    The 3'→5' exonuclease activity of DNA polymerase removes mismatched nucleotides immediately after incorporation, lowering the error rate.

14. What is the role of mismatch repair (MMR) in replication fidelity in E. coli?

    MMR corrects errors that escape proofreading; MutS recognizes the mismatch, MutL recruits MutH, which nicks the unmethylated (new) strand for excision and resynthesis.

15. In E. coli mismatch repair, how is the newly synthesized strand distinguished from the template?

    By its lack of Dam methylation (transient hemimethylated GATC sites); the unmethylated new strand is cut and corrected.

16. Give two examples of extrachromosomal replicons.

    Plasmids and the genomes of organelles (mitochondrial DNA and chloroplast DNA); also viral genomes.

17. How does theta (θ) replication differ from rolling circle replication?

    Theta replication is bidirectional from one origin producing a theta-shaped intermediate (e.g., E. coli chromosome); rolling circle produces a long single-stranded concatemer (e.g., some plasmids, phage λ, F-plasmid transfer).

18. What is the end-replication problem and how is it solved in eukaryotes?

    Lagging-strand synthesis cannot fully replicate chromosome ends, shortening them each cycle. Telomerase, a reverse transcriptase with an RNA template, extends telomeric repeats.

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