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Biochem block 3 > Glycogen > Flashcards

Flashcards in Glycogen Deck (28):
1

When is glycogen used?

in the gap between the fall of the blood glucose after a meal and the start of gluconeogenesis

2

where are the main stores of glycogen?

liver + skeletal muscle

3

what are the 2 types of glycosidic bonds that are found in glycogen?

Alpha (1-4) linkage
Alpha (1-6) linkage [branching one]

4

what enzyme will elongate glycogen chains?

glycogen synthase

5

why are branches important in glycogen?

they provide additional ends for synthesis and breakdown

6

what enzyme creates branches in glycogen?

branching enzyme

7

what is the rate limiting step in the degradation of glycogen?

PLP in the conversion of glycogen to glucose 1-P

8

what enzyme breaks down glycogen in the lysosomes?

lysosomal alpha (1-4) glucosidase

9

what two enzymes are the regulatory enzymes for glycogen synthesis and degradation?

glycogen synthase
glycogen phosphorylase

10

what up regulates/ activates glycogen synthase in the liver and muscle?

insulin

11

what deactivates glycogen synthase in muscle?

epinephrine

12

what deactivates glycogen synthase in the liver?

glucagon
epinephrine

13

what activates glycogen phosphorylase in the liver?

glucagon
epinephrine

14

what activates glycogen phosphorylase in muscle?

epinephrine
AMP
Ca2+

15

what deactivates glycogen phosphorylase in liver and muscle?

insulin

16

what deficiency is Von Gierke?

G6PD

17

What are the 6 key symptoms of Von Gierke?

severe fasting hypoglycemia
lactic acidosis (fasting)
hepatomegaly
hyperlipidemia
hyperuricemia
short stature

18

what is a common secondary symptom from the hyperuricemia in Von Gierke ?

Gout

19

What is the lactic acidosis from in Von Gierke?

buildup of G6PD stops gluconeogenesis
formation of lactate from pyruvate is favored and lactate from RBCs cannot be used for gluconeogenesis

20

what is the deficiency in Pompe?

lysosomal alpha 1-4 glucosidase deficiency

21

what is the deficiency in Cori Disease?

debranching enzyme

22

what are the symptoms in Cori Disease?

mild hypoglycemia
liver enlargement

23

what is the deficiency in Anderson disease?

branching enzyme

24

what are the 3 key symptoms in Anderson disease?

infantile hypotonia (low muscle tone)
cirrhosis
early death (liver and hear severely damaged)

25

what is the deficiency in McCardle disease?

muscle glycogen phosphorylase

26

what are the 2 key symptoms of mccardle disease?

muscle cramps and weakness on exercise
myoglobinuria

27

what is the deficiency in Hers disease?

liver glycogen phosphorylase deficiency

28

what are the key symptoms of Hers disease?

mild fasting hypoglycemia
hepatomegaly
cirrhosis