Lecture 6 - Carbohydrate metabolism | Plant Metabolism - Botany PDF Download

 Page 1


 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
                                                                                              
 
Lesson Prepared Under MHRD project “National Mission on 
Education Through ICT” 
Discipline: Botany 
Paper: Plant metabolism 
National Coordinator: Prof. S.C. Bhatla 
Lesson: Carbohydrate metabolism 
Lesson Developer: Dr. Rashmi Shakya 
Department/College: Miranda House, University of Delhi 
Lesson Reviewer: Dr. Manju Lal 
Department/College: Kirori Mal College 
Language Editor: Vinee Khanna 
Department/College: Department of Genetics, University 
of Delhi South Campus 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL 
 
 
 
 
Page 2


 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
                                                                                              
 
Lesson Prepared Under MHRD project “National Mission on 
Education Through ICT” 
Discipline: Botany 
Paper: Plant metabolism 
National Coordinator: Prof. S.C. Bhatla 
Lesson: Carbohydrate metabolism 
Lesson Developer: Dr. Rashmi Shakya 
Department/College: Miranda House, University of Delhi 
Lesson Reviewer: Dr. Manju Lal 
Department/College: Kirori Mal College 
Language Editor: Vinee Khanna 
Department/College: Department of Genetics, University 
of Delhi South Campus 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL 
 
 
 
 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
 
 
Table of contents 
Chapter: Carbohydrate metabolism 
? Introduction to carbohydrates 
? Hexose phosphate pool 
? Constitution of hexose phosphate pool 
? Transport of hexose phosphates 
? Pathways involved in carbohydrate metabolism 
? Glycolysis 
? Pentose phosphate pathway 
? Gluconeogenesis 
? Citric Acid Cycle 
? Glyoxylate cycle 
? Electron transport and Oxidative phosphorylation 
? Anabolism of starch and sucrose 
? Starch synthesis 
? Site of starch synthesis- plastid 
? Reactions involved in starch synthesis in chloroplast 
? Regulation of starch synthesis 
? Sucrose synthesis 
? Site of sucrose synthesis- cytosol 
? Reactions involved in sucrose synthesis in cytosol 
? Regulation of sucrose synthesis 
? Starch synthesis and sucrose synthesis are competing 
processes 
? Catabolism of starch and sucrose 
? Catabolism of starch 
Page 3


 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
                                                                                              
 
Lesson Prepared Under MHRD project “National Mission on 
Education Through ICT” 
Discipline: Botany 
Paper: Plant metabolism 
National Coordinator: Prof. S.C. Bhatla 
Lesson: Carbohydrate metabolism 
Lesson Developer: Dr. Rashmi Shakya 
Department/College: Miranda House, University of Delhi 
Lesson Reviewer: Dr. Manju Lal 
Department/College: Kirori Mal College 
Language Editor: Vinee Khanna 
Department/College: Department of Genetics, University 
of Delhi South Campus 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL 
 
 
 
 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
 
 
Table of contents 
Chapter: Carbohydrate metabolism 
? Introduction to carbohydrates 
? Hexose phosphate pool 
? Constitution of hexose phosphate pool 
? Transport of hexose phosphates 
? Pathways involved in carbohydrate metabolism 
? Glycolysis 
? Pentose phosphate pathway 
? Gluconeogenesis 
? Citric Acid Cycle 
? Glyoxylate cycle 
? Electron transport and Oxidative phosphorylation 
? Anabolism of starch and sucrose 
? Starch synthesis 
? Site of starch synthesis- plastid 
? Reactions involved in starch synthesis in chloroplast 
? Regulation of starch synthesis 
? Sucrose synthesis 
? Site of sucrose synthesis- cytosol 
? Reactions involved in sucrose synthesis in cytosol 
? Regulation of sucrose synthesis 
? Starch synthesis and sucrose synthesis are competing 
processes 
? Catabolism of starch and sucrose 
? Catabolism of starch 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
? Catabolism of sucrose 
 
? Summary 
? Glossary 
? Exercise 
? References 
? Weblinks 
? Suggested readings 
 
 
 
 
 
 
 
 
 
 
 
 
 
Page 4


 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
                                                                                              
 
Lesson Prepared Under MHRD project “National Mission on 
Education Through ICT” 
Discipline: Botany 
Paper: Plant metabolism 
National Coordinator: Prof. S.C. Bhatla 
Lesson: Carbohydrate metabolism 
Lesson Developer: Dr. Rashmi Shakya 
Department/College: Miranda House, University of Delhi 
Lesson Reviewer: Dr. Manju Lal 
Department/College: Kirori Mal College 
Language Editor: Vinee Khanna 
Department/College: Department of Genetics, University 
of Delhi South Campus 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL 
 
 
 
 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
 
 
Table of contents 
Chapter: Carbohydrate metabolism 
? Introduction to carbohydrates 
? Hexose phosphate pool 
? Constitution of hexose phosphate pool 
? Transport of hexose phosphates 
? Pathways involved in carbohydrate metabolism 
? Glycolysis 
? Pentose phosphate pathway 
? Gluconeogenesis 
? Citric Acid Cycle 
? Glyoxylate cycle 
? Electron transport and Oxidative phosphorylation 
? Anabolism of starch and sucrose 
? Starch synthesis 
? Site of starch synthesis- plastid 
? Reactions involved in starch synthesis in chloroplast 
? Regulation of starch synthesis 
? Sucrose synthesis 
? Site of sucrose synthesis- cytosol 
? Reactions involved in sucrose synthesis in cytosol 
? Regulation of sucrose synthesis 
? Starch synthesis and sucrose synthesis are competing 
processes 
? Catabolism of starch and sucrose 
? Catabolism of starch 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
? Catabolism of sucrose 
 
? Summary 
? Glossary 
? Exercise 
? References 
? Weblinks 
? Suggested readings 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
 
Introduction 
Carbohydrates are biological macromolecules consisting of carbon, hydrogen and oxygen 
with a 2:1 ratio of hydrogen: oxygen (as in water). For this reason they are also referred to 
as hydrates of carbon. Carbohydrates have empirical formula of C
m
 (H
2
O)
 n
 where m could 
be different from n. The deoxyribose with empirical formula C
5
H
10
O
4
, the sugar component 
in DNA, is an exception to this. Carbohydrate metabolism includes the biochemical 
processes which are responsible for the synthesis, catabolism and interconversion of 
carbohydrates in living organisms.  
Carbohydrates can be classified as monosaccharides, disaccharides and polysaccharides on 
the basis of the number of forming units. The term “saccharide” is derived from Greek word 
“sakcharon” which means sugar. Monosaccharides are formed of only one -sugar unit (e.g. 
glucose). Oligosaccharides contain 2 to 20 monosaccharides linked next to each other by 
glycosidic bonds (e.g. sucrose). Polysaccharides are polymers consisting of more than 20 
monosaccharide units. Based on the degree of polymerization carbohydrates are broadly 
divided in to simple (mono- and oligosaccharides) and complex (polysaccharides) types.  
 
Figure: Classification of carbohydrates. 
Page 5


 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
                                                                                              
 
Lesson Prepared Under MHRD project “National Mission on 
Education Through ICT” 
Discipline: Botany 
Paper: Plant metabolism 
National Coordinator: Prof. S.C. Bhatla 
Lesson: Carbohydrate metabolism 
Lesson Developer: Dr. Rashmi Shakya 
Department/College: Miranda House, University of Delhi 
Lesson Reviewer: Dr. Manju Lal 
Department/College: Kirori Mal College 
Language Editor: Vinee Khanna 
Department/College: Department of Genetics, University 
of Delhi South Campus 
Lesson Editor: Dr Rama Sisodia, Fellow in Botany ILLL 
 
 
 
 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
 
 
Table of contents 
Chapter: Carbohydrate metabolism 
? Introduction to carbohydrates 
? Hexose phosphate pool 
? Constitution of hexose phosphate pool 
? Transport of hexose phosphates 
? Pathways involved in carbohydrate metabolism 
? Glycolysis 
? Pentose phosphate pathway 
? Gluconeogenesis 
? Citric Acid Cycle 
? Glyoxylate cycle 
? Electron transport and Oxidative phosphorylation 
? Anabolism of starch and sucrose 
? Starch synthesis 
? Site of starch synthesis- plastid 
? Reactions involved in starch synthesis in chloroplast 
? Regulation of starch synthesis 
? Sucrose synthesis 
? Site of sucrose synthesis- cytosol 
? Reactions involved in sucrose synthesis in cytosol 
? Regulation of sucrose synthesis 
? Starch synthesis and sucrose synthesis are competing 
processes 
? Catabolism of starch and sucrose 
? Catabolism of starch 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
? Catabolism of sucrose 
 
? Summary 
? Glossary 
? Exercise 
? References 
? Weblinks 
? Suggested readings 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
 
Introduction 
Carbohydrates are biological macromolecules consisting of carbon, hydrogen and oxygen 
with a 2:1 ratio of hydrogen: oxygen (as in water). For this reason they are also referred to 
as hydrates of carbon. Carbohydrates have empirical formula of C
m
 (H
2
O)
 n
 where m could 
be different from n. The deoxyribose with empirical formula C
5
H
10
O
4
, the sugar component 
in DNA, is an exception to this. Carbohydrate metabolism includes the biochemical 
processes which are responsible for the synthesis, catabolism and interconversion of 
carbohydrates in living organisms.  
Carbohydrates can be classified as monosaccharides, disaccharides and polysaccharides on 
the basis of the number of forming units. The term “saccharide” is derived from Greek word 
“sakcharon” which means sugar. Monosaccharides are formed of only one -sugar unit (e.g. 
glucose). Oligosaccharides contain 2 to 20 monosaccharides linked next to each other by 
glycosidic bonds (e.g. sucrose). Polysaccharides are polymers consisting of more than 20 
monosaccharide units. Based on the degree of polymerization carbohydrates are broadly 
divided in to simple (mono- and oligosaccharides) and complex (polysaccharides) types.  
 
Figure: Classification of carbohydrates. 
 Carbohydrate metabolism 
 
Institute of Lifelong learning, University of Delhi  
Source: http://2012books.lardbucket.org/books/an-introduction-to-nutrition/s08-01-a-
closer-look-at-carbohydrates.html 
 
  
 
 
 
Figure: Structure of monosaccharides (glucose, galactose and fructose), disaccharide 
(sucrose) and polysaccharide (Starch, namely amylose and amylopectin). Two types of 
Sucrose