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CSIR NET Life Sciences Fundamental Processes Flashcards
78 question-and-answer cards covering Fundamental Processes as it is examined in CSIR NET Life Sciences. 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the Fundamental Processes deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
Name the prokaryotic translation initiation factors and their roles.
IF1 (blocks A site), IF2 (a GTPase that delivers fMet-tRNA to the P site), and IF3 (prevents premature subunit joining / aids mRNA selection).
What is the role of EF-Tu and EF-G in bacterial elongation?
EF-Tu (GTP) delivers aminoacyl-tRNA to the A site; EF-G (GTP) catalyzes translocation, moving the ribosome one codon along the mRNA.
What catalyzes peptide bond formation during translation?
Peptidyl transferase activity, a ribozyme located in the large subunit's 23S rRNA (50S in prokaryotes).
How does translation terminate?
A stop codon in the A site is recognized by release factors (RF1/RF2 in bacteria; eRF1 in eukaryotes), which trigger hydrolysis and release of the polypeptide; RF3/eRF3 (GTPases) assist.
What is aminoacylation (charging) of tRNA?
Attachment of the correct amino acid to its tRNA's 3' CCA end by aminoacyl-tRNA synthetase, using ATP (forming aminoacyl-AMP intermediate), producing aminoacyl-tRNA.
What is tRNA identity?
The set of nucleotide features (identity elements, often in the anticodon and acceptor stem) that allow an aminoacyl-tRNA synthetase to recognize and charge the correct tRNA.
How does aminoacyl-tRNA synthetase perform translational proofreading?
Through editing (proofreading) activity that hydrolyzes incorrectly activated amino acids or mischarged tRNAs (pre-transfer and post-transfer editing), ensuring fidelity.
What are the two classes of aminoacyl-tRNA synthetases?
Class I (mostly monomeric, charge the 2'-OH of tRNA, approach the minor groove) and Class II (often dimeric, charge the 3'-OH, approach the major groove).
Name a translation inhibitor that blocks the prokaryotic 30S subunit and its effect.
Streptomycin binds the 30S subunit causing misreading and inhibiting initiation; tetracycline blocks aminoacyl-tRNA binding to the A site of the 30S.
How does chloramphenicol inhibit translation?
It binds the 50S subunit and inhibits peptidyl transferase activity, blocking peptide bond formation in prokaryotes.
How does puromycin inhibit translation?
It mimics aminoacyl-tRNA, enters the A site, accepts the growing chain, and causes premature chain termination/release; acts on both pro- and eukaryotes.
How does cycloheximide inhibit translation, and what does it spare?
It blocks the peptidyl transferase/translocation step of the eukaryotic 60S subunit; it does not affect prokaryotic ribosomes.
How does diphtheria toxin inhibit eukaryotic translation?
It ADP-ribosylates eEF2 (elongation factor 2), inactivating it and blocking translocation.
Give three examples of post-translational modifications of proteins.
Phosphorylation, glycosylation, and proteolytic cleavage; others include acetylation, methylation, ubiquitination, lipidation, and disulfide bond formation.
What is the function of the signal sequence in protein targeting?
An N-terminal hydrophobic sequence recognized by the signal recognition particle (SRP) that directs ribosomes to the ER for co-translational translocation of secretory/membrane proteins.
How does the lac operon function as a model of prokaryotic gene regulation?
In absence of lactose, the LacI repressor binds the operator blocking transcription; allolactose (inducer) inactivates the repressor (negative control); CAP-cAMP activates transcription when glucose is low (positive control).
What is catabolite repression (the glucose effect)?
When glucose is present, cAMP is low, CAP cannot bind, and operons like lac are poorly transcribed even with inducer, ensuring glucose is used preferentially.
How is the trp operon regulated by repression and attenuation?
High tryptophan activates the Trp repressor (corepressor = Trp) to block transcription; attenuation uses a leader RNA that forms a terminator hairpin when tryptophan/charged tRNA is abundant, prematurely halting transcription.
How does phage lambda choose between lytic and lysogenic cycles?
The cI repressor (maintains lysogeny by binding OR/OL) versus Cro protein (promotes lytic cycle) compete; their balance, influenced by host conditions, determines the genetic switch.
What is the role of chromatin remodeling in eukaryotic gene expression?
ATP-dependent remodeling complexes (e.g., SWI/SNF) reposition or evict nucleosomes to expose or occlude promoters, regulating transcription factor access.
How do histone acetylation and deacetylation affect gene expression?
Histone acetylation (by HATs) loosens chromatin and activates transcription; deacetylation (by HDACs) compacts chromatin and represses transcription.
How does DNA methylation contribute to gene silencing in eukaryotes?
Methylation of cytosines at CpG islands (by DNA methyltransferases) typically represses transcription by blocking factor binding and recruiting repressive complexes; basis of heterochromatin and imprinting.
What are the structural and functional differences between euchromatin and heterochromatin?
Euchromatin is loosely packed, gene-rich, and transcriptionally active; heterochromatin is condensed, gene-poor, generally transcriptionally silent, and often methylated/marked by H3K9me.
What is RNA interference (RNAi) and its role in gene silencing?
Small RNAs (siRNA/miRNA) loaded into RISC guide sequence-specific mRNA cleavage or translational repression, silencing gene expression post-transcriptionally; Dicer generates the small RNAs.
What this deck covers
The Fundamental Processes deck follows the CSIR NET Life Sciences Fundamental Processes syllabus — 4 chapters and 29 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 19.5 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 162 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
Fundamental Processes flashcards FAQ
How many Fundamental Processes flashcards are in this CSIR NET Life Sciences deck?
78 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these CSIR NET Life Sciences flashcards free?
Yes. The preview here is free to read with no signup, and the full 78-card deck is free inside the Examius app.
What do the Fundamental Processes cards cover?
They follow the CSIR NET Life Sciences Fundamental Processes syllabus — 4 chapters and 29 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.