Lecture2-PYRUVATE METABOLISM&TCA CYCLE

Question 1

What is the primary role of mitochondria?

Answer 1

ATP production via aerobic respiration

Question 2

Acetyl-coA is a common product in what?

Answer 2

catabolism of carbohydrates (glycolysis), amino acids and fatty acids (b-oxidation)

Question 3

What type of pathway is the TCA cycle?

Answer 3

amphibolic pathway

Question 4

What does it mean when the TCA cycle is amphibolic?

Answer 4

involving both catabolism (break down) and anabolism (synthesis) of molecules

Question 5

What does it mean when the TCA cycle is amphibolic?

Answer 5

involving both catabolism (break down) and anabolism (synthesis) of molecules

Question 6

What is the mitochondrial function?

Answer 6

-Tricarboxylic Acid Cycle
-beta-Oxidation of fatty acids
-Respiratory chain with ATP production through oxidative phosphorylation

Question 7

what are the products of the TCA cycle?

Answer 7

NADH, FADH2 and GTP

Question 8

What of the products of TCA cycle used for ?

Answer 8

used for ATP generation

Question 9

what are the structures of the mitochondria?

Answer 9

outer membrane
inner membrane(cristae)
matrix

Question 10

What is happening in the inner membrane (cristae)

Answer 10

oxidative phosphorylation

Question 11

What is happening the matrix of the mitochondria?

Answer 11

PDH complex, TCA, Fatty acid B oxidation

Question 12

Where is the PDH complex done?

Answer 12

matrix of the mitochondria

Question 13

Where is the TCA cycle done?

Answer 13

Matrix of the mitochondria

Question 14

Where does oxidative phosphorylation done?

Answer 14

Inner membrane of mitochondria

Question 15

What are the metabolic fates of pyruvate?

Answer 15

Alanine (transmutation), oxaloacetate (Carboxylation), aceyl CoA(Oxidative decarboxylation) and Lactate (reduction)

Question 16

Tell me about the pyruvate transport

Answer 16

A variety of different transport systems, such as symports and antiports, are present in the inner mitochondrial membrane

• pyruvate transport has a pyruvate symport or shuttle that diffuses pyruvate(-) and H(+) through the inner mitochronial membrane . Since they are opposite charges they do not affect the electron gradient

Question 17

What does the Pyruvate dehydrogenase complex do?

Answer 17

oxidative decarboxylation of pyruvate

Question 18

What is the first step of the PDH complex?

Answer 18

Pyruvate to hydroxyethyl with pyruvate dehydrogenase

Question 19

What allows the lipoid acid prosthetic group to rotate?

Answer 19

Lipoid acid is joined by an amide link to a lysine residue of the transacetylase component of the enzyme complex

Question 20

What is the product of the Dihydrolipidyl transacetylase

Answer 20

Acetyle CoA

Question 21

What is the product of the dihydrolipoyl dehydrogenase

Answer 21

NADH and H+

Question 22

What are the products of the PDH complex?

Answer 22

NADH and H+
Acetyl CoA

Question 23

How do you deactivate the PDH complex?

Answer 23

Active PDH Kinase through phosphorylation of PDH

(high ATP, high acetyl coA)

Question 24

How can you decrease the activity of pyruvate dehydrogenase (PDH) kinase?

Answer 24

Low ATP, Low acetyl CoA

Question 25

How you can increase the activity of pyruvate dehydrogenase (PDH) kinase) ?

Answer 25

HIGH ATP, HIGH acetyl Co-A

Question 26

How do you active the PDH Complex

Answer 26

dephosphrolation of PDH with pyruvate dehydrogenase phosphatase

Question 27

How do you increase the activity of pyruvate dehydrogenase phosphatase

Answer 27

Increase Mg, Insulin

Question 28

What are the sources of Acetyl CoA

Answer 28

Pyruvate, amino acids, fatty acids

Question 29

What are the fates of acetyl CoA

Answer 29

Tricarboxylic acid cycle, ketone bodies, sterols and fatty acids

Question 30

What are the fates of acetyl CoA

Answer 30

Tricarboxylic acid cycle, ketone bodies, sterols and fatty acids

Question 31

what are high energy molecules in the TCA cycle

Answer 31

acetyl coA, and succinyl CoA

Question 32

What three enzymes involve a lot of energy, exergonic?

Answer 32

Citrate synthase, isocitrate dehydrogenase and alpha ketaoglutarate dehydrogenase

Question 33

What is the rate limiting enzyme in TCA cyle

Answer 33

Isocitrate dehydrogenase -isocitrate to a ketoglutaurate

Question 34

What is the first oxidation step in TCA cycle

Answer 34

NADH, H--> Isocitrate to oxalosuccinate with isocitrate dehydrogenase Extra under oxalosuccinate: electron sink beta to carbon with COO to be removed

Question 35

What is the second oxidation in TCA?

Answer 35

NADH, H --> a-ketoglutrate aKG to succinyl CoA with a ketoglutarate dehydrogenase C is converted to COs2

Question 36

What is the high energy molecule formed in TCA and what step?

Answer 36

GTP and succinyl CoA to succinate with succinyl CoA synthetase

Question 37

what is the 3rd oxidation in TCA

Answer 37

FAHH2 -->Succinate to fumarate with succinate dehydrogenase

Question 38

What the final oxidation in TCA?

Answer 38

NADH+H --> L-malate to oxaloacetate with malt dehydrogenase

Question 39

Where do you regulate the TCA cycle?

Answer 39

The 3 TCA cycle exergonic steps: -Citrate synthase -Isocitrate dehydrogenase (catalyzes rate-limiting step) -a-Ketoglutarate dehydrogenase

Question 40

Where do you regulate the TCA cycle?

Answer 40

The 3 TCA cycle exergonic steps: -Citrate synthase -Isocitrate dehydrogenase (catalyzes rate-limiting step) -a-Ketoglutarate dehydrogenase

Question 41

What inhibits the TCA cycle?

Answer 41

ATP, NADH, succinyl-CoA

Question 42

TCA is activated by what?

Answer 42

ADP and Ca++

Question 43

ADP and CA+ does what to the TCA cycle?

Answer 43

activate it

Question 44

What does ATP, NADH and succinyl-coA do to the TCA cycle?

Answer 44

inhibit it

Question 45

The pyruvate dehydrogenase complex is controlled by what?

Answer 45

allosteric and covalent mechanisms

Question 46

Oxaloactate from the TCA cycle goes where?

Answer 46

Amino acid synthesis

Question 47

Malate from the TCA cycle goes where?

Answer 47

gluconeogenesis

Question 48

succinyl coA from the TCA cycle goes where?

Answer 48

heme synthesis

Question 49

alpha ketoglutarate from the TCA cycle goes where?

Answer 49

Amino acid synthesis

Question 50

Citrate from the TCA cycle goes where?

Answer 50

fatty acid synthesis

Question 51

There is a metabolic problem with the TCA cycle, what is it?

Answer 51

to run TCA cycle you need not only acetyl-CoA but also oxaloacetate

Question 52

What is the solution of the metabolic problem of the TCA cycle?

Answer 52

Pyruvate carboxylase (+biotin) converts pyruvate to oxaloacetate

Question 53

What from the TCA can be toxic?

Answer 53

accumulation of the TCA cycle intermediates (succinate, fumarate) or TCA cycle substrates (pyruvate)

Question 54

an accumulation of TCA cycle intermediates (succinate, fumarate) or TCA cycle substrates (pyruvate) cause what?

Answer 54

particularly toxic to neurons and brain development (encephalopathies)

Question 55

What is Pyruvate dehydrogenase deficiency ?

Answer 55

-leading to chronic lactic acidosis (increased serum levels for lactate, pyruvate, alanine). -Children with this disease frequently exhibit severe neurological defects; resulting in death in many cases - Dietary management may include ketogenic diet

Question 56

What is the management of pyruvate dehydrogenase deficiency?

Answer 56

ketogenic diet (high-fat, adequate- protein, low-carbohydrate diet) with minimal carbohydrates.

Question 57

What is fumarase deficiency?

Answer 57

-Rare autosomal recessive disease with severe neurological impairment. -Urine contains abnormal amounts of fumarate and elevated levels of succinate and other TCA cycle intermediates.

Question 58

What is the mitochondrial function?

Answer 58

-Tricarboxylic Acid Cycle -beta-Oxidation of fatty acids -Respiratory chain with ATP production through oxidative phosphorylation