17 public questions tagged with this topic.
Enhancers are DNA sequences that increase the rate of transcription by interacting with transcription factors.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Human Genome Project and DNA Fingerprinting
Enhancers are regulatory sequences that bind transcription factors to increase gene expression.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Post-Transcriptional Modifications - Capping Splicing Polyadenylation
Prokaryotes have a single RNA polymerase, unlike eukaryotes which have multiple types of RNA polymerases.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Transcription - Mechanism and RNA Polymerase
Prokaryotic genes lack introns, as prokaryotic mRNA does not undergo splicing.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Transcription - Mechanism and RNA Polymerase
Transcription factors **regulate gene expression** by helping RNA polymerase bind to DNA and initiating transcription.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Transcription - Mechanism and RNA Polymerase
Transcription factors regulate gene expression by binding to specific DNA sequences and influencing transcription.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance DNA Replication - Semiconservative and Machinery
Strong promoters possess near-perfect -35 TTGACA and -10 TATAAT hexamers separated by optimal 17 base pair spacer including AT-rich UP element interacting with alpha C-terminal domain, producing exceptionally high intrinsic affinity for sigma70 holoenzyme and spontaneous open complex formation. Uncontrolled activity would wastefully consume nucleotides, ribosomes, and energy producing unnecessary transcripts. Evolution pairs potent cores with repressor proteins whose operators overlap start site, creating steric block until specific signal inactivates repressor. Net effect is high regulatory range: tightly repressed off state yet capable of extremely high output when fully derepressed for metabolic need.
Ref: Alberts Molecular Biology of the Cell – strong promoters require repressors to prevent wasteful constitutive transcription.
TFIIB recognition elements BREu with consensus SSRCGCC and BREd RTDKKKK flank TATA box upstream and downstream respectively. They are recognized not by TBP but by TFIIB C-terminal cyclin domains that make major and minor groove contacts. Binding of TFIIB to BRE helps orient preinitiation complex and can confer directionality, as BREu upstream of TATA favors transcription in one orientation. BRE interaction also influences TFIIB-TBP affinity and modulates activation by activators. Many promoters lack BRE, using TATA alone for TFIIB recruitment via protein-protein interactions.
Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 6: TFIIB binds BRE upstream and downstream of TATA
Snail and Twist, is consistent with established principles of cell signaling, receptor pharmacology and cellular regulation. Experimental measurements of binding parameters, genetic loss-of-function studies and pharmacological interventions all converge on the same interpretation. Related options address neighboring concepts but do not satisfy the precise criterion stated in the question.
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)
anti-apoptotic genes, is consistent with established principles of cell signaling, receptor pharmacology and cellular regulation. Experimental measurements of binding parameters, genetic loss-of-function studies and pharmacological interventions all converge on the same interpretation. Related options address neighboring concepts but do not satisfy the precise criterion stated in the question.
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)
p65 and p50, is consistent with established principles of cell signaling, receptor pharmacology and cellular regulation. Experimental measurements of binding parameters, genetic loss-of-function studies and pharmacological interventions all converge on the same interpretation. Related options address neighboring concepts but do not satisfy the precise criterion stated in the question.
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)
chromatin accessibility and cofactors, is consistent with established principles of cell signaling, receptor pharmacology and cellular regulation. Experimental measurements of binding parameters, genetic loss-of-function studies and pharmacological interventions all converge on the same interpretation. Related options address neighboring concepts but do not satisfy the precise criterion stated in the question.
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)
