Chapter 16- Glycolysis Flashcards
What are the 3 stages of the generation of energy from food?
- Large molecules in food are broken down into smaller molecules in the process of digestion
- Many small molecules are processed into key molecules of metabolism (acetyl CoA)
3 ATP is produced from the complete oxidation of the acetyl component of acetyl CoA
Slide 2
What is starch glycogen and cellulose?
What are they converted to and by what?
Why can’t we digest cellulose? (Difference between cellulose and starch/glycogen)
Starch and glycogen are degraded to glucose, maltose and oligosaccharides by salivary and pancreatic amylases
In ruminants, cellulose is converted to glucose by cellulase
Can’t digest cellulose because it has beta 1-4 linkages while starch and glycogen have alpha 1-4 link
What are the 3 main sugars in the small intestine?
What are they converted to and by what?
- Lactose (milk sugar)- converted to glucose and galactose by lactase (β-galactosidase)
- Sucrose (common sugar)- converted to glucose and fructose by sucrase (invertase)
- Maltose- converted to glucose by maltase
Galactose and fructose can be further converted to glucose if not converted in small intestine they go to liver to be metabolized
These monosaccharides are then transported into the cells and then to bloodstream
Difference between glycogen and starch?
Glycogen is highly branched compared to starch
What is glucose?
What is glucose transporter GLUT2?
Glucose is main source of energy for us
GLUT2 is found in liver and pancreatic β cells
In the pancreas it regulates insulin
In the liver, it removes excess glucose from the blood
Memorize the possible pathway of glucose on slide 5.
Glucose
2 pyruvate
2 ethanol + 2CO2, 2 acetyl CoA, 2 lactate
4CO2 + 4H2O
What enzyme traps glucose in the cell and begins glycolysis?
What are the types in muscle and liver?
Hexokinase
Phosphorylates hexoses in various tissues
Muscle uses hexokinase I and liver uses hexokinase IV (glucokinase)
Slide 7 picture slide 8 lists
What is the isomerization of glucose 6 phosphate (G6P) to fructose 6-phosphate (F6P) on slide 9?
What enzyme catalyzes this reaction?
Look on slide 9
Catalyzed by phosphoglucose isomerase
How is fructose 6-phosphate (F6P) then converted to Fructose 1,6- bisphosphate (F16BP)?
What enzyme catalyzes this?
Look on slide 10
Catalyzed by phosphofructokinase catalyzes this reaction
Look at graph on slide 11
How is fructose 1,6-bisphosphate (F16BP) then converted to dihydroxyacetone (DHAP) and Glyceraldehyde 3-phosphate (GAP)?
What enzyme catalyzes this reaction?
Look at diagram on slide 12
Aldolase catalyzes this reaction
How is dibydroxyacetone phosphate (DHAP) converted to glyceraldehyde 3-phosphate (GAP)?
What enzyme catalyzes this?
Look on slide 13
Triose phosphate isomerase catalyzes this reaction
How is glyceraldehyde 3-phosphate (GAP) converted to 1,3-biphosphoglycerate (13BPG)?
What enzyme catalyzes this?
Look at slide 14
Glyceraldehyde 3-phosphate dehydrogenase catalyzes this reaction
Slide 15 example of reaction
How is 1,3-biphosphoglycerate (13BPG) converted to 3-phosphoglycerate?
What enzyme catalyzes this reaction?
Look at slide 16
Catalyzed by phosphoglycerate kinase
How is 3-phosphoglycerate converted to 2-phosphoglycerate?
What enzyme catalyzes this?
Look at slide 17
Phosphoglycerate mutase catalyzes this
How is 2-phosphoglycerate converted to phosphenolpyruvate then to pyruvate and what enzymes do this?
Slide 17!
Enolase converts 2PG to phophenolpyruvate
Pyruvate kinase converts phosphenolpyruvate to pyruvate