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Flashcards in Biochem metabolism Deck (129)
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1

ATP is carrier molecule for what

phosphoryl groups

2

NADH, NADPH, FADH2 is carrier molecule for what

electrons

3

Coenzyme A, lipoamide is carrier molecule for what

Acyl groups

4

Biotin is carrier molecule for what

CO2

5

THF is carrier molecule for what

1 carbon units

6

SAM is carrier molecule for what

CH3 groups

7

TPP is carrier molecule for what

aldehydes

8

What processes is NADPH used in? why?

anabolic processes (steroid & FA synthesis) to reduce equivalents;
Respiratory bursts;
p-450;
Glutathione reductase

9

What is NADPH a product of?

HMP shunt

10

what are the universal electron acceptors?

Nicotinamides (NAD+ from vitB3 & NADP+) & flavin nucleotides (FAD+ from vit B2);
NADPH

11

What processes is NAD+ used in?

Catabolic processes to carry reducing equivalents away as NADH

12

Describe the 1st step in glycolysis & 1st step of glycogen synthesis in the liver. what is the result?

phosphorylation of glucose to G-6-P via hexokinase or glucokinase

traps glucose inside the cell

13

Describe where, speed and what leads to use of hexokinase

ubiquitous w/ high affinity (low Km), low capacity (low Vmax)
UNINDUCED by insulin

inhibited by G-6-P

14

Describe where, speed and what leads to use of glucokinase

Liver & Beta cells of pancreas use GLUT-2 which has low affinity (high Km), high capacity (high Vmax)
INDUCED by insulin
High Vmax bc it cannot be satisfied

15

Describe how glucose is sequestered dependent on its concentration

At low glucose (low insulin) then hexokinase sequesters glucose into the tissue;
At high glucose, excess glucose is stored in the liver

16

Where does glycolysis occur?

cytoplasm

17

Since RBC's use glycolysis only, What will occur if the MC enzyme deficiency is present?

Pyruvate kinase deficiency will decrease pyruvate along w/ leading to hemolytic anemia due to the cell swelling & increased bilirubin

18

Gluconeogenesis & Glycolysis are regulated by what?

F-2,6-BisP & PFK-2

19

The pyruvate DH complex contains 3 enzymes that require 5 cofactors - name them

1) pyrophosphate (B1, thiamine (TPP))
2) FAD (B2, riboflavin)
3) NAD (B3, niacin)
4) CoA (B5, pantothenate)
5) Lipoic acid

20

Other than the fed state, what else activates the pyruvate DH complex? what is the result?

exercise leads to
increased NAD+/NADH ratio
increased ADP
increased Ca+

21

What 2 complexes use the same cofactors w/ similar substrate & action?

Pyruvate DH complex to make Acetyl-CoA & alpha-KG DH complex in TCA cycle to make succinyl-CoA

22

What poison will damage the pyruvate DH & alpha-KG DH complexes? what is the result?

Arsenic inhibits lipoid acid leading to vomit, rice water stools, garlic breath

23

If you have a muscle Bx that reveals increased glycogen, increased F-6-P & decreased pyruvate, what is the cause?

deficiency in PFK-1

24

What are the enzymes responsible for increased & decreased levels of F-2,6-BP?

PFK-2 increases
FBP-2 decreases

25

Describe how a SANS response will change F-2,6-BP in the liver & muscle

Liver levels will decrease thus decreasing glycolysis
Muscle levels will increase to activate PFK-1 to increase glycolysis

26

Pyruvate DH complex deficiency will lead to a backup of what? result?

pyruvate & alanine resulting in lactic acidosis

27

What are most cases of Pyruvate DH complex deficiency due to? What are the findings?

XL gene for E1-alpha subunit of PDC causing neuro defects that typically start in infancy

28

Acquired Pyruvate DH complex deficiency can come from what?

Arsenic poison;
Decreased in B vitamins especially thiamine

29

What is the Tx for Pyruvate DH complex deficiency?

increase intake of ketogenic nutrients such as HIGH FAT content or increased lysine (dairy, fish) & leucine (eggs, soy)

30

What are the 4 products & cofactors of pyruvate metabolism?

Alanine via Alanine aminotransferase, B6;
Oxaloacetate via pyruvate carboxylase, biotin;
Acetyl-CoA via Pyruvate DH (B1-3,5, Lipoic acid);