Biochem - Metabolism (Part 3) Flashcards Preview

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Flashcards in Biochem - Metabolism (Part 3) Deck (171)
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1

Insulin binds to what type of receptor to activate protein phosphatase, which goes on to inactivate glycogen phosphorylase kinase and glycogen phosphorylase?

Tyrosine kinase

2

An activated glycogen phosphorylase will begin what process?

Glycogenolysis

3

During glycogen metabolism, glucose-1-phosphate is converted to UDP-glucose by which enzyme?

UDP-glucose pyrophosphorylase; UDP-glucose is the substrate for glycogen synthase

4

During glucose metabolism, UDP-glucose is converted to the storage form of glycogen by which enzyme?

Glycogen synthase

5

In which organ does glycogen undergo rapid glycogenolysis during exercise?

Skeletal muscle

6

In which organ does glycogen undergo glycogenolysis to maintain blood sugar within an appropriate range?

Liver

7

What type of bond is found at glycogen branch points?

(1,6) bonds

8

What type of bond is found at side-by-side linkages of glucose in glycogen?

(1,4) bonds

9

What enzyme creates a new branch point when assembling glycogen molecules?

Branching enzyme

10

What enzyme digests glycogen to create a limit dextran?

Glycogen phosphorylase

11

Once a limit dextran has been created, what enzyme is necessary for further digestion of the glycogen molecule?

Debranching enzyme

12

Glycogen digestion in the lysosome occurs through which enzyme?

-1,4-glucosidase

13

What molecules are the end products of glycogenolysis?

Glucose and Pi

14

What conversion must occur for the glucose-1-phosphate produced during glycogenolysis to be converted to glucose?

The phosphate group has to be moved from the 1 carbon to the 6 carbon

15

Which enzyme reacts with a limit dextran (four glucose residues in branched configuration) during degradation of glycogen to form glucose?

Debranching enzyme

16

Which enzyme is responsible for the conversion of glucose-1-phosphate to glucose-6-phosphate?

Phosphoglucomutase

17

Which enzyme degrades glycogen to glucose in the lysosome?

Lysosomal acid maltase (-1,4-glucosidase)

18

Glycogen storage diseases involve an abnormal accumulation of toxic levels of what substance within cells?

Glycogen

19

How many types of glycogen storage diseases are there?

Twelve glycogen metabolism enzyme deficiencies have been described in humans

20

What is another name for glycogen storage disease type I?

von Gierke's disease

21

A patient has severe fasting hypoglycemia, increased stores of glycogen in the liver, hepatomegaly, and elevated levels of lactate in his blood. What is the likely underlying metabolic deficiency?

von Gierke's disease (glycogen storage disease type I) resulting from glucose-6-phosphatase deficiency

22

Glycogen storage disease type I results from a deficiency of what enzyme?

Glucose-6-phosphatase

23

What is the prognosis for a child diagnosed with Pompe disease?

Early death

24

Name four glycogen storage diseases.

Von Gierke's disease (type I), Pompe;s disease (type II), Cori's disease (type III), McArdle;s disease (type V) (remember: Very Poor Carbohydrate Metabolism)

25

How can you differentiate between a patient with Cori's disease and one with von Gierke's disease using blood samples?

Patients with Cori's disease have normal blood lactate levels due to intact gluconeogenesis, whereas those with von Gierke's have elevated blood lactate

26

What is another name for glycogen storage disease type II?

Pompe's disease

27

In a patient with McArdle's disease, would you expect increased or decreased levels of glycogen on muscle biopsy?

Increased levels of glycogen, because the muscle cannot break it down

28

What is another name for -1,4-glucosidase?

Acid maltase

29

What disease is the result of a deficiency of lysosomal -1,4-glucosidase?

Pompe;s disease (glycogen storage disease type II)

30

Pompe;s disease (glycogen storage disease type II) is associated with the enlargement of what organ?

The heart (remember: Pompe's trashes the Pump)