Intro to Carbs Flashcards
Glycosidic bonds
-Covalently link monosaccharides -Named based on α/β configuration of anomeric carbon and the numbers of the connecting carbons
Amylose
-Starch -Linear polysaccharide consisting of glucose residues in α-1,4 linkage
Amylopectin
- Starch
- Branched polysaccharide consisting of glucose residues in α-1,4 linkage with α-1,6 branches
Lactose
- Disaccharide
- Galactose and glucose in β-1,4 linkage
- Found in milk and dairy products
Sucrose
- Table sugar
- Disaccharide
- Glucose and fructose in α-1,2 linkage
- Non-reducing sugar
Glycogen
- Branched polysaccharide with glucoses in α-1,4 linkage with α-1,6 branches
- More highly branched than amylopectin
- Storage form of glucose
Cellulose
- Major component of dietary fiber
- Linear polysaccharide
- Glucose residues in β-1,4 linkage
- Cannot be digested by hummans because we don’t have an enzyme to clear the β-1,4 linkage of glucose
Glycosidases
-Convert polysaccharides and disaccharides to monosaccharides
Endoglycosidases
-Cleave internal glycosidic bonds in sugar polymers
Exoglycosidases
-Cleave terminal glycosidic bonds in sugar polymers
Disaccharidases
-Cleave glycosidic bonds in disaccharides
α-Amylase
- Endoglycosidase
- Hydrolyzes random internal α-1,4 bonds between glucose residues in starch (amylopectin and amylose)
- Salivary
- Pancreatic
Glucoamylase
- Exoglucosidase
- Cleaves terminal α-1,4 bonds between glucoses in oligo and disaccharaides beginning at the non reducing end
- Substrates: maltose, maltotriose, α-dextrins, amylose, amylopectin
- Produces:Glucose and isomaltose
Maltase
- Cleaves α-1,4 bond in maltose and maltotriose
- Produes maltose and glucose
Isomaltase
- Cleaves α-1,6 bond in isomaltose and α-dextrins
- Produces glucose and glucose polymers
Sucrase
- Cleaves α-1,2 bond in sucrose
- Produces glucose and fructose
Lactase
- Cleaves β-1,4 bonds in lactose
- Produces glucose and galactose
Glycolysis
-Oxidation of glucose to generate ATP and pyruvate
Glycogen synthesis
- To covert glucose into a storage polymer for later use
- Major in liver and muscle
Pentose phosphate shunt
- Oxidation of glucose to a 5 carbon sugar to produce NADPH needed for biosynthetic pathways
- 5 carbon sugar then re-enters the glycolytic pathway for further oxidation or nucleotide synthesis
Citric acid cycle
- Cells with a supply oxygen use it
- Oxidation of acetyl CoA to CO2 and H2O to produce high energy electrons in the form of FADH2 and NADH
- These electrons used to produce ATP via electron transport and oxidative phosphorylation
Glycogenolysis
-Breakdown of glycogen to glucose
Gluconeogenesis
-Synthesis of glucose from non-carbohydrate sources such as amino acid
Glucagon
- Mobilizes fuels and increases blood glucose
- Increased glycogen breakdown
- Increased gluconeogenesis
- Increased lipolysis
- Released during fasting
Insulin
- Promotes fuel storage
- Increased glycogen synthesis
- Increased fatty acid synthesis
- Increased triglyceride synthesis
- Released during the fed state
