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Phase 1 - S2 Metabolism, Endocrinology, Haematology > Energy Storage > Flashcards

Flashcards in Energy Storage Deck (54)
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1

which cells have an absolute requirement for glucose

RBCs, lens of the eye, medulla of the kidney and neutrophils

2

at what glucose plasma level does death and brain damage result from

0.6 mmol/L

3

what can be used in blood tests to determine plasma glucose levels

HbA1c

4

what is glucose stored as

glycogen

5

what does muscle glycogen supply

glucose to skeletal muscle cells

6

what does liver glycogen supply

glucose to the body

7

describe the structure of glycogen

there is a central protein glycogenin with glucose residues branching off linked by alpha-1,4 and alpha-1,6 glyosidic bonds

8

what is glycogenesis

to production of glycogen

9

outline glycogenesis

- glucose and ATP are converted into G6P and ADP by hexokinase
- G6P is converted into G1P by phosphoglucomutase
- G1P, UTP and H20 are converted into UDP-glucose by G1P uridylyltransferase
-UDP-glucose reacts with glycogen to add the glucose residue onto the glycogen molecule

10

which 2 enzymes can add the glucose residue from the UDP-glucose onto the glycogen molecule

- glycogen synthase for alpha-1,4 bonds
- branching enzyme for alpha-1,6 bonds

11

what is glycogenolysis

breakdown of glycogen

12

outline glycogenolysis

- G1P is released from the glycogen by glycogen phosphorylase or de-branching enzyme
- G1P is converted into G6P by phosphoglucomutase

13

true or false: glycogenolysis is the reversal of glycogenesis

false - different enzymes allow inhibition and stimulation of the different pathways

14

what happens to the G6P produced by liver cells

converted into glucose and released into the blood for use by other tissues

15

what happens to the G6P produced by muscle cells

used by muscle cells in glycolysis for energy production

16

what enzyme in the liver converts G6P into glucose

glucose-6-phosphatase

17

what is the rate limiting enzyme in glycogen synthesis

glycogen synthase

18

what is the rate limiting enzyme in glycogen degradation

glycogen phosphorylase

19

what hormone increases the activity of glycogen synthase

insulin

20

what hormone increases the activity of glycogen phosphorylase

glucagon

21

true or false: AMP is an allosteric activator of glycogen phosphorylase

true - but only in the muscles not in the liver

22

give 2 examples of glycogen storage diseases

1. von Gierke's disease
2. McArdle disease

23

what is von Gierke's disease

deficiency in glucose 6 phosphatase

24

what is McArdle disease

deficiency in muscle glycogen phosphorylase

25

what is gluconeogenesis

production of glucose

26

what are the 3 major precursors of glucose

- lactate
- glycerol
- amino acids

27

where does gluconeogenesis occur

liver (and also the kidney)

28

in what cycle is lactate used in respiration

cori cycle

29

outline the cori cycle

glucose is converted into lactate in muscle which then travels in the blood to the liver where its converted back to glucose

30

what are the 3 key enzymes in gluconeogensis

- glucose-6-phosphatase
- fructose 1,6-bisphosphatase
- PEPCK