W5- Lecture 23- fatty acid oxidation

Question 1

where does beta oxidation take place ?

Answer 1

in the mitochondria

Question 2

describe how carnitine acts as a shuttle for fatty acids transport into the mitochondria ?

Answer 2

CoA a replaced with carnitine
this allows the compound to move through the mitochondrial membrane
Carnitine removed and replace with CoA again
Free carnitine flows back down the conc grad

Question 3

describe how fatty acids are combined with CoA

Answer 3

Fatty acids + ATP-
fatty acyl-adenylate(enzyme bound intermediate )
–fatty acyl-CoA
reaction has to been driven by the lysis of pyrophosphate for energy

Question 4

name the 4 steps of beta oxidation on a

fatty acyl-CoA

Answer 4

oxidation
hydration
oxidation
thiolysis

Question 5

Describe the first step in beta oxidation

Answer 5

Oxidation
Introduction of a trans- C=C bond between alpha and beta carbons
Production of FADH2
catalysis by Acyl-CoA dehydrogenase (3 versions short medium and long chain up to 8,14 and 18 respectively some overlap)
Associated with the inner membrane of mitochondria
feeds electrons into Complex II
(is like the succinate dehydrogenase )

Question 6

Describe the Second step in beta oxidation

Answer 6

Hydration of trans double bond
to introduce a hydroxyl group on the beta carbon atom (aka beta oxidation)
catalysed by Enoyl-CoA hydratase
+ H20 molecule used

Question 7

Describe the third step in beta oxidation

Answer 7

oxidation at the beta carbon to produce a ketone group (from hydroxyl group)
catalysed by 3-Hydroxyacyl-CoA dehydrogenase
Formation of NADH

Question 8

Describe the fourth/final step in beta oxidation

Answer 8

Lysis of the alpha-beta C-C bond
Addition of a coenzyme A

Catalysis of beta-ketoacyl-CoA thiolase

Production of acetyl-CoA
Produced Acyl-CoA (shorter by 2 carbons) can re-enter the citrate cycle

Question 9

for each tern of the cycle how many 
FADH
H20
NAD+
COA
are used 

how many 
Acetyl-CoA
NADH
FADH2 
are produced

Answer 9

input 
1 FADH
1 H20
1 NAD+
1 CoA

output 
(amount of cycles 1)+1Acetyl-CoA
1 NADH
1 FADH2 
are produced

Question 10

in 7 cleavage reactions of Palmitoyl-CoA how many
FADH
H20
NAD+
COA
are used 

how many 
Acetyl-CoA
NADH
FADH2 
are produced

Answer 10

input 
7 FADH
7 H20
7 NAD+
7 CoA

output 
8 Acetyl-CoA
7 NADH
7 FADH2 
are produced