Glycolysis, gluconeogenesis Flashcards
What is the process of turning glucose into pyruvate called?
Glucolysis
What does glucogenesis mean?
Making new glucose
How many ATPs does glycolysis produce?
2
What are the products of glycoslysis?
2 pyruvate
2 ATP
2 NADH
2 H+
2 H20
How many reaction steps does glycolysis have?
10
How many stages are the ten reaction steps of glycolysis divided into?
2
What is stage 1 of glycolysis?
Two steps of phosphorylation to activate hexose followed by bond cleavage to give two triose
How is glucose kept inside the cell?
The hexokinase makes it negatively charged to keep it in the cell
What is the induced fit mechanism?
A substrate binds to an active site and both change shape slightly, creating an ideal fit for catalysis
In the example of glucose, when glucose binds to the active site in hexokinase the conformation changes so that glucose and ATP are brought together with an appropriate orientation
Why does water not hydrolyse the bound ATP in hexokinase during glycolysis?
Water is excluded from the active site
What is enediol?
An intermediate between aldoses and ketoses
What is special about His 95?
The pKa value is close to physiological pH which means that depending on the pH it can act as a weak acid or a weak base (both donate and accept protons)
T/F: The environment in the active site drives the reaction in correct direction (prevents side reactions)
T
What happens in glycolysis stage 2?
G3P is oxidised
1 NADH formed
2 ATP formed
Pyruvate final product
The energy profile of glycolysis (in physiological environment) has … large negative free energy changes (How many?)
3
How is glycolysis regulated
By controlling the three reactions
Glu -> G6P
F6P -> FBP
PEP -> Pyruvate
When pyruvate is turned to lactate it is called…
fermentation
NADH needs to be oxidised with oxygen to regenerate what?
NAD+
If there is no oxygen present, how is NADH oxidised to regenerate NAD+?
An alternative electron acceptor must be used. In muscle cells pyruvate accepts electrons and becomes lactic acid. In yeast acetaldehyde accepts electrons and becomes ethanol
Where is galactose found?
In lactose (milk sugar)
What is the enzyme called that activates galactose?
Galactokinase
Which enzyme can phosphorylate fructose when glucose is not in abundance?
Hexokinase
What happens to fructose when glucose is abundant?
It is phosphorylated to fructose-1-phosphate
What is the enzyme called that phosphorylates fructose?
Fructokinase
