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#cell survival

6 public questions tagged with this topic.

Immunological Applications

Hybridoma cells survive in HAT medium because they:

Survival in HAT environment demands functional purine and pyrimidine salvage enzymes inherited from normal B parent. B lymphocytes express HPRT1 locus on X chromosome encoding 24 kDa hypoxanthine-guanine phosphoribosyltransferase that catalyzes phosphoribosyl transfer from PRPP to hypoxanthine yielding IMP plus pyrophosphate and to guanine yielding GMP, bypassing de novo steps requiring folate. They also express cytosolic thymidine kinase 1 cell-cycle regulated peaking in S phase and mitochondrial kinase 2 constitutive, phosphorylating thymidine supplied in medium to TMP using ATP. Hybridoma c

Ref: Janeway Immunobiology salvage pathway HGPRT; Freshney Animal Cell Culture hybrids survive HAT via HGPRT TK from B cell.

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Protein Sorting and Trafficking

Which process is activated during nutrient deprivation?

During prolonged starvation cells must recycle internal components to maintain energy and biosynthetic precursors. In fed state mTORC1 kinase anchored at lysosome via Rag GTPases phosphorylates ULK1 and ATG13, keeping initiation complex inactive. When amino acids fall, Rag switches off, mTORC1 dissociates, inhibitory phosphorylation is lost. Concurrently low ATP raises AMP, activating AMPK which phosphorylates ULK1 at distinct activating sites Ser317 Ser777 and inhibits mTORC1 via TSC2 and Raptor. Free ULK1 complex phosphorylates Beclin-1 and ATG14L, activating VPS34 class III PI3K to produce

Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 12: Intracellular Vesicular Traffic and Autophagy Regulation.

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Cancer

Anoikis mainly prevents

The extrinsic pathway is initiated by binding of death ligands such as FasL or TNF to their cognate death receptors. Receptor clustering recruits adaptor proteins and caspase-8, forming the death-inducing signaling complex. Anoikis is a specialized form of apoptosis triggered by loss of integrin-mediated attachment to the extracellular matrix, thereby preventing survival of detached cells.

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)

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Cancer

Requirement of normal cells for attachment to ECM for survival is called

Anchorage dependence, 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)

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Cell Communication

Why do endothelial cells lacking VE-cadherin fail to survive despite N-cadherin adhesion? (Dec 2013)

VE-cadherin acts as co-receptor for VEGF signaling, 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)

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Cell Signaling Fundamental PrinciplesI

AKT promotes cell survival by inactivating

BAD, 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)

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