Biochemistry II Palmer: Exam 3

Which of the following enzymes breaks an alpha 1-6 bond?

glucosidase

Which situation results in glycogenesis?

excess glucose

Which situation initiates glycogenolysis?

insufficient glucose

All of the following enzymes form glucose-6-phosphate except?

phosphofructokinase

Which of the following enzymes converts glucose-6-phosphate to glucose-1-phosphate?

phosphoglucomutase

Which of the following enzymes either makes or breaks an alpha-1-6 bond?

glucosidase

Which of the following enzymes forms glucose-1-phosphate?

glycogen phosphorylase

You forgot to eat, which of the following hormones activates glycogen phosphorylase?

glucagon

You just had a coffee and a donut, which hormone do you expect to be active?

insulin

An angry bear is chasing you through the woods, which of the following hormones would you expect to be active?

epinephrine

Which hormone prevents blood glucose levels from dropping?

glucagon

Insulin activates which of the following enzymes?

glycogen synthase

What is the predominant form of glucose formed by glycogenolysis?

glucose-1-phosphate

Which of the following enzymes breaks an α 1-6 bond?

glucosidase

Which of the following enzymes DOES NOT form glucose-6-phosphate?

phosphofructokinase

Which of the following enzymes forms an α 1-4 bond?

glycogen synthase

Which of the following enzymes forms free glucose?

glucosidase

You forgot to eat, which hormone would you expect to be active?

glucagon

Which of the following hormones drives glycogenesis?

insulin

Which of the following enzymes is activated by insulin?

glycogen synthase

An angry bear is chasing you through the woods, which enzyme would you expect to be activated IN YOUR MUSCLES?

glycogen phosphorylase

The cafe is having an all you can eat buffet, which hormone would you expect to be active as a result of an abundance of eating?

insulin

All of the following enzymes are gluconeogenic enzymes except?

pyruvate kinase

Which of the following enzymes forms oxaloacetate in gluconeogenesis?

pyruvate carboxylase

How many molecules of NADH are required to form one molecule of glucose by gluconeogenesis?

2

How many ATP are produced in gluconeogenesis?

0

Which of the following enzymes forms glucose?

glucose-6-phosphatase

Which of the following enzymes forms phosphoenolpyruvate?

PEP carboxylase

Which of the following molecules crosses the inner mitochondrial membrane in gluconeogenesis?

malate

All of the following enzymes act on glucose except?

glucose-6-phosphatase

All of the following molecules are products or reactants of the action of glucose 6-phosphatase except?

ATP

Which of the following enzymes does NOT form glucose 6-phosphate?

glycogen phosphorylase

Which of the following molecules is seen in gluconeogenesis ONLY IF mitochondrial pyruvate is the substrate?

malate

Insulin activates which of the following processes?

glycogenesis

How many molecules of pyruvate are required to form one molecule of glucose by gluconeogenesis?

2

Which of the following enzymes catalyzes the reversible conversion of glucose 1-phosphate to glucose 6-phosphate?

phosphoglucomutase

Which of the following pairings of glycolytic enzymes and gluconeogenic bypasses is INCORRECT?

pyruvate kinase and phosphoglycerate kinase

Which of the following enzymes would you expect to be activated by glucagon?

glycogen phosphorylase

Which of the following enzymes is NOT a gluconeogenic enzyme?

pyruvate kinase

Which of the following enzymes makes a 1-6 bond?

branching enzyme

What is glycogen?

storage form of glucose

What are the 3 sources of glucose?

-diet

-gluconeogenesis

-degradation of glycogen

What are the sources of glycogen?

-released from kidney and liver

-degraded from exercising muscle

What is the function of muscle glycogen?

fuel reserve for the synthesis of ATP

What is the function of liver glycogen?

maintain the blood glucose concentration, particularly during the early stages of a fasting period

What is the primary bond in glycogen?

alpha 1-4 linkage

What is the structure of glycogen?

long, branched chain of α glucose subunits;

the subunits are joined by both 1,4 and 1,6 glycosidic bonds making the molecule branched

When does liver glycogen increase?

when well fed

When does liver glycogen decrease?

during a fasting period

When is muscle glycogen decreased?

only after long periods of a fast

Where do glycogen synthesis & degradation go on simultaneously?

cytoplasm

What is glycogenolysis?

breakdown of glycogen to glucose

What is glycogenesis?

formation of glycogen from glucose

What is gluconeogenesis?

synthesis of glucose from non-carbohydrate precursors