BBCCT-119 IGNOU Solved Assignment 2026-27

BBCCT-119 Solved Assignment TMA Overview

The BBCCT-119 TMA is a mandatory 30% weightage assignment designed to evaluate conceptual understanding of hormone biochemistry, synthesis, and functional roles in biochemical pathways. Below are verified solutions for key blocks, formatted to meet IGNOU’s submission requirements (500 words for Block-1, 250 words for Block-3, etc.).

Block-1: Hypothalamic and Pituitary Hormones

This block explores the biochemical regulation of hypothalamic-releasing hormones (e.g., CRH, GnRH) and anterior/posterior pituitary axes. Key topics include:

• Peptide hormone synthesis in hypothalamic neurons, with emphasis on post-translational modifications like glycosylation in oxytocin.
• Feedback mechanisms involving cortisol (HPA axis) and their biochemical disruption in Cushing’s syndrome.
• Receptor-ligand interactions of GPCRs (e.g., GHRH receptors) and second-messenger cascades (cAMP/PKA).

Sample Solution for Question 1 (500 words):

Compare the biochemical pathways of TRH and GHRH secretion in the hypothalamus.

The thyrotropin-releasing hormone (TRH) is synthesized as a prohormone in parvocellular neurons of the paraventricular nucleus, where it undergoes enzymatic cleavage by prohormone convertase 1/3 (PC1/3) to yield the active tripeptide. In contrast, growth hormone-releasing hormone (GHRH) is processed in the arcuate nucleus via signal peptidase and carboxypeptidase E, yielding a 44-amino acid peptide. Both hormones utilize vesicular transport via VAMP-2 but differ in their neurotransmitter co-release (e.g., TRH co-localizes with dopamine in tuberoinfundibular pathways).

Block-3: Metabolic and Stress Hormones

Focuses on catecholamines (adrenaline/noradrenaline), glucocorticoids, and their biochemical stress responses. Key topics:

• Tyrosine hydroxylase regulation in adrenal medulla and its role in pheochromocytoma pathology.
• 11β-hydroxysteroid dehydrogenase (11β-HSD) isoforms and their modulation of cortisol activity in target tissues.
• Glucocorticoid receptor (GR) activation and downstream effects on lipocortin-1 (anti-inflammatory protein).

Sample Solution for Question 3 (250 words):

Explain the biochemical basis of adrenaline’s role in the “fight-or-flight” response.

Adrenaline (epinephrine) is synthesized via the phenylethanolamine N-methyltransferase (PNMT) pathway in adrenal medulla chromaffin cells. Its β-adrenergic receptor activation triggers Gs-protein coupling, elevating cAMP and activating protein kinase A (PKA). Key biochemical outcomes include:

• Glycogenolysis via PKA-mediated phosphorylase kinase activation (glycogen glucose-6-phosphate).
• Lipolysis through HSL (hormone-sensitive lipase) activation in adipose tissue.
• Vasodilation in skeletal muscle via NO synthase (NOS) activation (β2-receptor pathway).

Block-4: Mechanism of Hormone Action

Covers intracellular signaling, hormone-receptor dynamics, and genomic vs. non-genomic effects. Topics:

• Steroid hormone transport via corticosteroid-binding globulin (CBG) and nuclear receptor dimerization (e.g., PPARγ).
• Tyrosine kinase receptors (e.g., IGF-1R) and downstream PI3K/AKT pathways.
• Hormone degradation (e.g., MAO-A/B in catecholamine metabolism).

FAQs

Submission Deadlines (Current Session)

For the 2024 June Term, the TMA must be submitted within 8 weeks of course commencement (check eGyanKosh for exact dates). Late submissions incur a 20% deduction per week.