Notes in L20 - Glycogen Metabolism

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Published	11/02/2024	Lactose is a disaccharide composed of {{c1::galactose}} and {{c1::glucose}}
Published	11/02/2024	Sucrose is a disaccharide composed of {{c1::glucose}} and {{c1::fructose}}
Published	11/02/2024	an aldose is a carbohydrate with an {{c1::aldehyde}} groupa ketose is a carbohydrate with a {{c1::keto}} group
Published	11/02/2024	{{c1::D::L/D}}-sugar form is most common in humans
Published	11/02/2024	Glucose – dietary sources: {{c1::table sugar, starches}}Fructose – dietary sources: {{c1::honey, fruit}}Galactose – dietary sources: {{c1::dairy produ…
Published	11/02/2024	maltose is a disaccharide made of {{c1::2 glucoses}}
Published	11/02/2024	oligosaccharides consist of {{c1::3-10::#}} monosaccharide units and are involved in {{c1::cell-cell connection}}
Published	11/02/2024	polysaccharides consist of {{c1::10+::#}} monosaccharide units and are involved in {{c1::cell structure}} and {{c1::fuel storage}}
Published	11/02/2024	monosaccharides link through {{c1::glycosidic}} bonds with the use of {{c1::glycosyltransferases::enzyme}}
Published	11/02/2024	an α monosaccharide means that the hydroxyl group is facing {{c1::down}}a β monosaccharide means that the hydroxyl group is facing {{c1::up}}
Published	11/02/2024	a reducing sugar is a sugar in which the {{c1::OH group is not linked to another compound}} → can act as a reducing agent
Published	11/02/2024	the main sites of carbohydrate digestion are the {{c1::mouth}} and {{c1::intestinal lumen}}
Published	11/02/2024	{{c1::glycoside hydrolases (glycosidases)}} break down polysaccharides to monosaccharides
Published	11/02/2024	{{c1::starch}} and {{c1::cellulose}} are polysaccharides from plant sources
Published	11/02/2024	humans can not break down cellulose because they do not have {{c1::β1-4 endoglycosidase::enzyme}}
Published	11/02/2024	saliva contains salivary {{c1::α-amylase}} which hydrolyzes {{c1::α-1-4 bonds}}
Published	11/02/2024	saliva cannot hydrolyze {{c1::α1-6 bonds}} so branched oligosaccharides remain
Published	11/02/2024	{{c1::dextrins}} are short-branched and unbranched oligosaccharides
Published	11/02/2024	why is salivary α-amylase inactive in the stomach?{{c1::it's too acidic to function (pH 1-3)}}
Published	11/02/2024	{{c1::secretin}} in the intestin stimulates the pancrease to secrete {{c1::bicarbonate}} to neutralize stomach pH
Published	11/02/2024	{{c1::Pancreatic amylase}} secreted into the intestine continues digestion of the starches and glycogen
Published	11/02/2024	where in the intestines are disaccharides digested?{{c1::duodenum and upper jejunum}}
Published	11/02/2024	the {{c1::upper jejunum}} of the small intestine absorbs most of the monosaccharides
Published	11/02/2024	monosaccharides can be transported into enterocytes via:glucose and galactose - {{c1::SGLT1}}fructose - {{c1::GLUT5 - sodium and ATP independent}}
Published	11/02/2024	glucose, galactose, and fructose are transported into portal circulation through {{c1::GLUT2}}
Published	11/02/2024	if disaccharides reach the colon they can cause GI symptoms such as {{c1::diarrhea}}, {{c1::flatulence}}, and {{c1::bloating}}
Published	11/02/2024	There is an {{c1::age}}-dependent loss of lactase activity due to decreased production
Published	11/02/2024	sucrase-isomaltase deficiency is an {{c1::autosomal recessive::inheritance}} disorder
Published	11/02/2024	glycogen stored in the muscle is used for {{c1::ATP synthesis}} needed for muscle contraction
Published	11/02/2024	glycogen synthesis occurs in the {{c1::cytosol::location in cell}} and requires {{c1::ATP to provide the UTP needed}}
Published	11/02/2024	{{c1::UDP-glucose}} is the building block of glycogen
Published	11/02/2024	UDP-glucose is synthesized from {{c1::glucose 1-phosphate (G1P)}} and {{c1::UTP}} by UDP-glucose pyrophosphorylase
Published	11/02/2024	UDP-glucose pyrophosphorylase cuts 2 phosphates off {{c1::UTP}} and attaches UDP to glucose that is then removed once {{c1::glucose is added to glycog…
Published	11/02/2024	an α(1→4) linkage can connect up to {{c1::14::#}} glucosyl residues
Published	11/02/2024	glycogen synthesis requires a primer in the form of {{c1::at least 4 glucose monomers}} and {{c1::glycogenin}} to accept {{c1::UDP-glucose}}
Published	11/02/2024	glycogen synthase catalyzes {{c1::α(1→4) linkages}} of glucose residues and is active when {{c1::dephosphorylated}}
Published	11/02/2024	branching enzyme is also known as {{c1::4:6 transferase}} and catalyzes {{c1::α(1→4) to α(1→6) transfer}}
Published	11/02/2024	branching enzyme cuts {{c1::6-8::#}} glucosyl resides from the {{c1::non-reducing}} end and attaches them to a {{c1::non-terminal residue}}
Published	11/02/2024	glycogen phosphorylase requires {{c1::PLP}} and cleaves {{c1::α(1→4) bonds}} from the branch until there are {{c1::4}} residues left
Published	11/02/2024	glycogen phosphorylase produces {{c1::G1P}} that can be converted by {{c1::phosphoglucomutase}} to G6P
Published	11/02/2024	unlike muscle cells, the liver contains {{c1::G6Pase}} that can dephosphorylate G6P allowing it to {{c1::leave the cell}}
Published	11/02/2024	G6P in muscle cells proceeds towards {{c1::glycolysis}}
Published	11/02/2024	debranching enzyme has 2 enzymatic catalytic activities:{{c1::glucotransferase}} {{c2::removes the outer 3 of the 4 glucosyl resides and attaches it t…
Published	11/02/2024	glycogen phosphorylase is active when {{c1::phosphorylated}}
Published	11/02/2024	insulin promotes {{c1::glycogen}} synthesis and inhibits the breakdown of {{c1::glycogen}} in both the liver and muscle
Published	11/02/2024	insulin activates {{c1::protein phosphatase}} which therefore {{c1::dephosphorylates}} glycogen synthase
Published	11/02/2024	through GPCRs, glucagon activates PKA which phosphorylates {{c1::glycogen synthase}}, turning it {{c2::off}}, and {{c1::glycogen phosphorylase}}, turn…
Published	11/02/2024	glucagon activates breakdown of glycogen in the {{c1::liver}} but does not impact {{c1::the muscle}}
Published	11/02/2024	epinephrine activates PKA which phosphorylates {{c1::glycogen synthase}}, turning it {{c2::off}}, and {{c1::glycogen phosphorylase}}, turning it …
Published	11/02/2024	free glucose inhibits {{c1::glycogen phosphorylase}} in the liver
Published	11/02/2024	G6P inhibits {{c1::glycogen phosphorylase}} and activates {{c1::glycogen synthase}} in liver and muscle
Published	11/02/2024	ATP inhibits {{c1::glycogen phosphorylase}} in {{c2::muscle and liver}}AMP activates {{c1::glygocen phosphorylase}} in {{c2::the muscle}}
Published	11/02/2024	ca2+ activates {{c1::glycogen phosphorylase}} in the muscle
Published	11/02/2024	glycogen storage disease involve issues with {{c1::glycogen breakdown}}
Published	11/02/2024	McArdle Disease – muscle {{c1::glycogen phosphorylase}} deficiency
Published	11/02/2024	Hers disease – liver {{c1::glycogen phosphorylase}} deficiency
Published	11/02/2024	Pompe Disease – lysosomal {{c1::α(1→4)-glucosidase}} deficiency
Published	11/02/2024	Cori Disease – glycogen {{c1::debranching enzyme}} deficiency
Published	11/02/2024	the GLUT 5 transporter is {{c1::sodium}} and {{c1::ATP}} independent and transports fructose into enterocytes
Status	Last Update	Fields