Biochemistry : Carbohydrate Anabolism
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Example Questions
Example Question #131 : Anabolic Pathways And Synthesis
What two molecules are the links between the urea cycle and gluconeogenesis?
Fumarate and aspartate
Oxaloacetate and citrate
Citrate and aspartate
Fumarate and citrate
Oxaloacetate and fumarate
Fumarate and aspartate
Aspartate can form arginosuccinate, which can then release a fumarate molecule. The fumarate can enter into the Krebs cycle and eventually the pathway can lead to gluconeogenesis. The arginine from the arginosuccinate can continue through the urea cycle.
Example Question #132 : Anabolic Pathways And Synthesis
In order to be added to a growing glycogen chain, glucose must first be activated by which of the following molecules?
UTP
GDP
ADP
ATP
UDP
UDP
UDP-glucose is the activated form of glucose that works to build chains of glycogen. The other listed molecules do not serve this function.
Example Question #11 : Carbohydrate Synthesis
How does ingestion of high amounts of ethanol affect gluconeogenesis?
I. High amounts of ethanol get oxidized producing NADPH.
II. High levels of NADPH inhibit gluconeogenesis.
III. High levels of NADPH stimulate gluconeogenesis.
IV. High amounts of ethanol get oxidized producing NADP.
I and IV
I and II
III only
I and III
II and IV
I and II
Ingestion of high amounts of ethanol leads to increased NADPH. High levels of NADPH inhibit gluconeogenesis followed by low glucose levels in the absence of dietary intake. In acute ingestion of alcohol, hypoglycemia (low levels of glucose in the blood) can follow due to inhibition of gluconeogenesis.
Example Question #11 : Carbohydrate Anabolism
What is the net yield from the pentose phosphate pathway?
I.
II.
III.
IV.
I and II
I only
II only
III only
IV only
I only
The pentose phosphate pathway produces NADPH and five-carbon sugars. The net reaction is:
The pathway is also important in purine precursor synthesis.
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