Carbohydrate Metabolism and Glycolysis Flashcards
How many carbohydrate nomenclatures are there and what are they?
3: Hexose, Pentose, and D/L Sugars
How many carbons are in a hexose?
6
What are examples of a hexoses?
Glucose, fructose, sucrose, mannose, and galactose
Hexoses are also named what?
Monosaccharides
How many carbons are on a pentose sugar?
5
What are examples of a pentose sugar?
DNA, RNA, NADH, etc.
In a pentose sugar, the OH is located on what carbon?
2’ carbon
What does a the OH being on a 2’ carbon mean?
Less stable meaning that RNA degrades quickly
An OH attached to a 2’ carbon is an indication of what molecule?
RNA
An H added on a 2’ carbon is an indication of what molecule?
DNA
When an OH is positioned downward on a hexose, what kind of stereoisomer is this?
Alpha
When an OH is positioned downward on a hexose, what type of stereoisomer is present?
Beta
D and L Sugars are known as what?
Enantiomers
What are most sugars in mammals known as?
D- Sugars
What are enatiomers?
Mirroring images of each other
What is the function of glycolysis?
To convert glucose to three carbon compounds using the formation of ATP.
Where does glycolysis occur?
Inside all cells, located specifically in the cytosol
How many steps are there in Glycolysis?
Ten
What is being converted from beginning to end of this process?
Glucose being converted into pyruvate
What is the initial requirement for ATP?
2 ATP
What is the NET production of ATP?
2
What is the oxidative step in Glycolysis?
NAD+ being reduced to NADH
When NAD+ is reduced to NADH, why is this needed?
To be replenished via fermentation or aerobic respiration
What is the rate limiting step of Glycolysis?
Phosphofructokinase
What does the enzyme phosphofructokinase convert?
Fructose-6-phosphate to fructose-1,6-biphosphate
What is the first step of glycolysis?
Glucose converting to glucose-6-phosphate
Glucose enters through … via …
Glut transporter via passive transport
What does hexokinase do to glucose?
Phosphorylates it so it won’t be allowed to leave the cell.
Hexokinase is found in what?
All liver cells
Glucokinase is found where?
Only in in liver and pancreatic beta cells
What is the 2nd step of glycolysis through what enzyme?
Glucose-6-phosphate converted to fructose-6-phosphate via phosphohexose
ISOMERASE
What does the rate limting step of phosphofructokinase indicate?
Addition of phosphate groups, making it mire vulnerable for cleavage by ALDOLASE
What is the 3rd step of glycolysis?
Fructose-6-phosphate converted to fructose-1,6-biphosphate via the rate-limiting step of phosphofructokinase
What is the 4th step of glycolysis?
Fructose-1,6-biphosphate converted to dihydroxyacetone (via ALDOLASE) /glyceraaldehyde-3-phosphate (via PHOSPHOTIROSE ISOMERASE)
Dihydroxyacetone and Glyceraldehyde-3-phosphate are what?
INTERCHANGEABLE
What is the 5th step of glycolysis?
Glyceraldehyde-3-phosphate converted to 1,3-Biphosphoglycerate via GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE
What is the 6th step of glycolysis?
1,3-Biphosphoglycerate converted to 3-Phosphoglycerate via PHOSPHOGLYCERATE KINASE
What is the 7th step of glycolysis?
3-phosphoglycerate converted to 2-phospho-glycerate via PHOSPHOGLYCERATE MUTASE
What is the 8th step of Glycolysis?
2-phospho-glycerate converted to Phosphoenolpyriuvate via ENOLASE
What is the 9th step of Glycolysis?
Phosphoenolpyruvate converted into Pyruvate via PYRUVATE KINASE
During the conversion of 1,3-biphosphoglycerate, what is yield to create the product 3-phosphoglycerate?
ADP which converts to ATP
What is substrate-level phosphorylation?
Substrate particles in an enzyme-catalyzed reaction that yields ATP or GTP
Glycolytic flux is controlled by the need for what?
ATP and/or for intermediates
Where does the control for glycolytic flux occur?
Sites of irreversible reactions
What are the minor regulations?
Hexokinase and pyruvate kinase
What does phosphofructokinase respond to changes in?
Energy state of the cell, H+ concentration, Availability of alternate fuels, and Insulin/glucagon ratio
What is inhibited in high energy state of a cell?
High ATP (product)
What is inhibited of a H+ concentration?
High lactate levels (by-product (anaerobic))
What is inhibited of the availability of alternate fuels?
High citrate levels
the effect of fructose-2,6-biphosphate is an allosteric … ?
Activator
Since F-2,6-BP is an allosteric activator, this means there is an increase or decrease in activity of phosphofructokinase?
Increase
An increase of blood glucose = and increase of … that yields …
Insulin that yields glycolysis
A decrease of blood glucose = an increase of … that inhibits …
Glucagon that inhibits glycolysis
During the regulation of Pyruvate Kinase, a decrease in blood glucose = a … ?
Decrease of glycolysis
Pyruvate kinase is the site of what regulation?
Secondary regulation
The site of secondary regulation of pyruvate kinase undergoes what?
Phosphophorylation-dephosphorylation
