Question 1

In the glycolytic path from glucose to pyruvate,three steps are practically irreversible.What are these steps,and how is each bypassed in gluconeogenesis? What advantages does an organism gain from having separate pathways for anabolic and catabolic metabolism? What are the disadvantages?

Accepted Answer

The three irreversible steps in glycolys...

Question 2

Show the reaction catalyzed by glycogen synthase.

Accepted Answer

The reaction is the addition o...

Question 3

Why is it important for proper cell function that proteins turn over rather than persisting indefinitely after being synthesized?

Accepted Answer

This is to allow changes in protein expr...

Question 4

Which one of the following directly results in the activation of glycogen synthase?

Accepted Answer

A)  Binding of glucose-6-phosphate
B)  Dephosphorylation of multiple residues by phosphoprotein phosphorylase-1 (PP1) 
C)  Phosphorylation of specific residues by casein kinase II (CKII) 
D)  Phosphorylation of specific residues by glycogen synthase kinase-3 (GSK-3) 
E)  The presence of insulinF) A) and C)
G) C) and D)

Question 5

Order the steps leading to glycogen breakdown resulting from the stimulation of liver cells by glucagon.
1)Activation of protein kinase A (PKA)
2)cAMP levels rise
3)Phosphorylation of phosphorylase b
4)Phosphorylation of phosphorylase b kinase
5)Stimulation of adenyl cyclase

Accepted Answer

The correc...

Question 6

Order the steps leading to glycogen synthesis resulting from the stimulation of liver cells by glucose.
1)Xyulose-5-phosphate is formed
2)Glucose is phosphorylated to glucose-6-phosphate
3)Glycogen synthase is dephosphorylated
4)Protein phosphatase 2A is activated

Accepted Answer

The correc...

Question 7

Which of the following is true of glycogen synthase?

Accepted Answer

A)  Activation of the enzyme involves a phosphorylation.
B)  It catalyzes addition of glucose residues to the nonreducing end of a glycogen chain by formation of ( α\alphaα 1  →\rightarrow→   4) bonds.
C)  It uses glucose-6-phosphate as donor of glucose units
D)  It catalyzes addition of glucose residues at branch points by formation of ( α\alphaα 1 →\rightarrow→  6) bonds.
E)  The enzyme has measurable activity only in liver. F) A) and E)
G) C) and D)

Question 8

Which of the following statements about gluconeogenesis in animal cells is true?

Accepted Answer

A)  A rise in the cellular level of fructose-2,6-bisphosphate stimulates the rate of gluconeogenesis.
B)  An animal fed a large excess of fat in the diet will convert any fat not needed for energy production into glycogen to be stored for later use.
C)  The conversion of fructose 1,6-bisphosphate to fructose 6-phosphate is not catalyzed by phosphofructokinase-1,the enzyme involved in glycolysis.
D)  The conversion of glucose 6-phosphate to glucose is catalyzed by hexokinase,the same enzyme involved in glycolysis.
E)  The conversion of phosphoenol pyruvate to 2-phosphoglycerate occurs in two steps,including a carboxylation.F) A) and D)
G) A) and C)

Exam 15: Principles of Metabolic Regulation

Which of the following is true of glycogen synthase?

Correct Answer
verified

Why is it important for proper cell function that proteins turn over rather than persisting indefinitely after being synthesized?

Correct Answer
verified
This is to allow changes in protein expr...
View Answer

Order the steps leading to glycogen breakdown resulting from the stimulation of liver cells by glucagon. 1)Activation of protein kinase A (PKA) 2)cAMP levels rise 3)Phosphorylation of phosphorylase b 4)Phosphorylation of phosphorylase b kinase 5)Stimulation of adenyl cyclase

Correct Answer
verified
The correc...
View Answer

Order the steps leading to glycogen synthesis resulting from the stimulation of liver cells by glucose. 1)Xyulose-5-phosphate is formed 2)Glucose is phosphorylated to glucose-6-phosphate 3)Glycogen synthase is dephosphorylated 4)Protein phosphatase 2A is activated

Correct Answer
verified
The correc...
View Answer

Which of the following statements about gluconeogenesis in animal cells is true?

Correct Answer
verified

Which one of the following directly results in the activation of glycogen synthase?

Correct Answer
verified

Show the reaction catalyzed by glycogen synthase.

Correct Answer
verified
The reaction is the addition o...
View Answer

In the glycolytic path from glucose to pyruvate,three steps are practically irreversible.What are these steps,and how is each bypassed in gluconeogenesis? What advantages does an organism gain from having separate pathways for anabolic and catabolic metabolism? What are the disadvantages?

Correct Answer
verified
The three irreversible steps in glycolys...
View Answer

Exam 15: Principles of Metabolic Regulation

Which of the following is true of glycogen synthase?

Correct AnswerverifiedShow Answer

Why is it important for proper cell function that proteins turn over rather than persisting indefinitely after being synthesized?

Correct AnswerverifiedThis is to allow changes in protein expr...View AnswerShow Answer

Order the steps leading to glycogen breakdown resulting from the stimulation of liver cells by glucagon. 1)Activation of protein kinase A (PKA) 2)cAMP levels rise 3)Phosphorylation of phosphorylase b 4)Phosphorylation of phosphorylase b kinase 5)Stimulation of adenyl cyclase

Correct AnswerverifiedThe correc...View AnswerShow Answer

Order the steps leading to glycogen synthesis resulting from the stimulation of liver cells by glucose. 1)Xyulose-5-phosphate is formed 2)Glucose is phosphorylated to glucose-6-phosphate 3)Glycogen synthase is dephosphorylated 4)Protein phosphatase 2A is activated

Correct AnswerverifiedThe correc...View AnswerShow Answer

Which of the following statements about gluconeogenesis in animal cells is true?

Correct AnswerverifiedShow Answer

Which one of the following directly results in the activation of glycogen synthase?

Correct AnswerverifiedShow Answer

Show the reaction catalyzed by glycogen synthase.

Correct AnswerverifiedThe reaction is the addition o...View AnswerShow Answer

In the glycolytic path from glucose to pyruvate,three steps are practically irreversible.What are these steps,and how is each bypassed in gluconeogenesis? What advantages does an organism gain from having separate pathways for anabolic and catabolic metabolism? What are the disadvantages?

Correct AnswerverifiedThe three irreversible steps in glycolys...View AnswerShow Answer

Correct Answer
verified

Correct Answer
verified
This is to allow changes in protein expr...
View Answer

Correct Answer
verified
The correc...
View Answer

Correct Answer
verified
The correc...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
The reaction is the addition o...
View Answer

Correct Answer
verified
The three irreversible steps in glycolys...
View Answer