Unit 3

• Cellular Reprogramming to Pluripotency:
• First pioneered by Shinya Yamanaka (2006, Yamanaka factors: Oct4, Sox2, Klf4, c-Myc) and James Thomson (2007):
• Differentiated adult somatic cells are reprogrammed into pluripotent stem cells (iPSCs) by the ectopic transfection of defined core transcription factor cocktails:

(The classic Thomson reprogramming gene cocktail).

• nalysis:
• (Pou5f1, Sox2, Nanog, Lin28): Correct factor combination.

Correct option: (1) PouSft, Sox2, Nanog, Lin28.

• Glycolysis Inhibition by Fluoride: Sodium Fluoride (NaF) is the anticoagulant and preservative of choice in blood tubes used for plasma glucose determination.
• Mechanism of Action: Fluoride ions ($F^-$) bind inorganic phosphate and magnesium to form a magnesium fluorophosphate complex that strongly inhibits enolase (phosphopyruvate hydratase), blocking the dehydration of 2-phosphoglycerate to phosphoenolpyruvate ($2\text{-PGA} \to \text{PEP}$).
• Preservation: This halts in vitro glycolysis by erythrocytes and leukocytes, preventing artificial decline in measured blood glucose levels.

Correct option: (3) Sodium Fluoride

• Anaerobic Glycolysis: In tissues lacking oxygen or lacking mitochondria (such as mature mammalian red blood cells), pyruvate cannot undergo oxidative decarboxylation into acetyl-CoA.
• End Product: Pyruvate is reduced to lactate by cytosolic lactate dehydrogenase (LDH):

• Significance: This reaction is essential because it re-oxidizes $\text{NADH}$ to $\text{NAD}^+$, which is required by glyceraldehyde-3-phosphate dehydrogenase (GAPDH) to maintain ongoing ATP generation via substrate-level phosphorylation.

Correct option: (3) Lactate