18 Questions
Which molecule makes PFK activity more responsive to substrate?
F-2,6-BP
Which enzyme catalyzes an irreversible step in the glycolytic pathway with no meaningful back-reaction?
PFK
What effect does F-2,6-BP have on PFK activity in relation to ATP and FBPase?
Decreases the inhibitory effects of ATP and opposes FBPase activity
What role does substrate cycling play in the glycolytic pathway?
It enhances the regulation of enzyme activities
Which molecules act as 'brakes' in regulating enzyme activities within the glycolytic pathway?
ADP and AMP
What type of regulation is described when enzymes within the glycolytic pathway are allosterically regulated by effectors like gas and brake pedals?
Allosteric regulation
What is the role of F-2,6-BP in the regulation of PFK?
Activates PFK
How does ATP affect PFK regulation?
Inhibits PFK
What is the main function of substrate cycling in glycolysis?
To maintain metabolic balance
How is FBPase regulated in the glycolytic pathway?
Inhibition by ATP
Which statement best describes enzyme allosteric regulation?
It can occur even with high substrate concentrations
How does AMP affect enzyme activity in the glycolytic pathway?
Activates enzyme activity
What is the major rate-determining step in glycolysis?
Conversion of F6P to FBP by PFK
What inhibits phosphofructokinase (PFK) activity, indicating high energy levels in the cell?
ATP
What is the regulatory molecule that stimulates phosphofructokinase (PFK) activity?
AMP
Which statement describes the allosteric regulation of PFK accurately?
ATP inhibits PFK by binding to the regulatory site, promoting the R state.
What is the role of fructose-2,6-bisphosphate in regulating phosphofructokinase (PFK)?
It enhances PFK activity by acting as an allosteric activator.
Which molecule has the highest potential to stimulate a significant increase in phosphofructokinase (PFK) activity?
$102$-fold increase in ATP levels
Explore the different roles of glucokinase in liver and pancreatic cells, focusing on its importance in glycogen synthesis and storage in the liver, as well as its role as a glucose sensor in pancreatic beta cells. Understand how glucokinase-driven glycolysis affects the ATP/ADP ratio and insulin secretion.
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