162b Endo Metabolism Flashcards Preview

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Flashcards in 162b Endo Metabolism Deck (27):
1

3 possible fates of glucose?

enters cell and converted to Glucose-6-P (trapped in cell) then can enter 3 pathways

1) Pentose phosphate shunt - produces NADPH and ribose sugars

2) glycolysis - every cell uses this

3) glycogen synthesis G6P --> G1P) - if enough E is present, storage

2

glucose keys steps

glucose-->G6P-->PEP-->Pyruvate

provides parts for amino acids, TG, glycogen

3

glycolysis - kep steps

hexokinase: G--> G6P
PFK-1: rate determining step, requires ATP
phopho ???

4

aerobic vs anaerobic glycolysis

pyruvate - end of glycolysis

if O2, then can go to mitochondria to generate a lot of ATP

if no O2, then anaerobic (sepsis, exercise):
pyruvate --> lactase (regenerates NAD+ from NADH)

5

regulation of glycolysis

allosteric regulation - metabolities bind and affect enxymes - inhibitors from end products; activators induce activity

post-translational modification - phosphorylation- can activate or inhibit

6

rate limiting step in glycolysis

PFK-1 (F6P --> F1,6 bisP)
+ AMP, F-2,6-bisP
-ATP, citrate

allosteric regulation

7

pentose phosphate pathway

detour pathway from glycolysis

provides NADPH - needed for rxns

produces 5 carbon sugar for nucleotides - DNA/RNA synthesis

active in liver, adrenals, lacting mammory glands

8

G6P dehydrogenase deficiency

red cell lysis if deficient -- triggers will cause lysis (fava beans, antiobotics like sulfa drugs/TB drugs)

x-linked - meditrainian decent

pentose phosphate pathway is very important in RBC to form NADPH --> reduces glutathione to deal with ROS




9

gluconeogensis basic overview

glucose made from lactate (anaerobic glycolysis), glycerol (TG hydrolysis), and amino acids (protein breakdown)

10

gluconeogensis

provides glucose during fasting

occurs in liver, requires E

11

glycogen

a-1,4-glycosidic bonds with a-1,6-glycosidic branching

glucose is added onto the end of these branching chains

12

glycogen synthesis

G --> G6P --> G1P --> UDP-Glucose (via G1P uridyltransferase) --> added to glycogen chain

13

branching enxymes

keeps glycogen branches to about 6 glucose

14

debranching enxymes

remmove 4 closest glucose to branch

15

glycogen phosphorylase

breaks down long chain glycogen after debranchers

+AMP, Pi
-G6P, ATP

16

glycogen synthase

+G6P

17

key organ for blood sugar maintaince

liver

18

muscle

used glucose for E - doesn't regulate glucose levels

19

key distinct enxyme in liver vs msucle

G6phosphatases - trapped glucose in liver (G6P) turned back to glucose and released into circulation

muscle doesn't have G6 phosphotase

20

what regulates glycogen in liver vs muscle?

liver - blood glucose, stress (epi)
muscle - AMP, contraction/Ca

21

fasting - glycogensis goes down where?

liver (muscle remains constant)

22

liver glycogen regulation in stravation and stress

glycogen phosphorylase P to active formed --> glucose shipped out to blood

23

3 ways to activate glyocgen phorphylase in muscle

1) Epi
2) Ca
3) AMP

24

glcyogen storage disease
type 1 - von Gierke's disease

deficient liver G6 Phosphatase --> fasting hypoglycemia, liver enlargment

25

glcyogen storage disease
type IV - andersen's

deficient branching enzyme (can fully branch glycogen --> not soluble) --> liver dysfunction, early death

26

glcyogen storage disease
type V - McAdrdle

deficienct muscle glycogen phosphorylase --> muscle cramps with exercise

27

glcyogen storage disease
Type VII

deficienct muscle phosphofructokinase --> inability to exercise