Seed science Starch_Breakdown_in_Cereals.pptx

NisargaR17 0 views 6 slides Oct 14, 2025
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Starch breakdown


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Breakdown of Starch in Cereals During Germination Starch hydrolysis and sugar mobilization

1. Starch Composition and Initial Breakdown Starch granules are made of: - Amylose (linear) - Amylopectin (branched) Enzyme α-amylase acts on both: - Amylose → Glucose + Maltose - Amylopectin → Maltose + Limit dextrin + Glucose

2. Further Breakdown of Amylopectin Debranching enzyme acts on limit dextrins and glucose oligomers. α-glucosidase (maltase) breaks down: - Maltose → 2 Glucose - Glucose oligomers → Glucose

3. Glucose Utilization Pathways a. Glucose → Glucose-1-Phosphate → UDP-Glucose b. UDP-Glucose + Fructose → Sucrose + UDP

4. Key Enzymes Involved • α-Amylase – breaks down starch • Debranching enzyme – acts on branched chains • α-Glucosidase – converts maltose to glucose • UDP-Glucose Pyrophosphorylase – forms UDP-Glucose • Sucrose synthetase – synthesizes sucrose

5. Final Products • Glucose – used for energy via respiration • Sucrose – transported to growing regions of the seedling
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