8/18/17

Question 1

Overall Process of glycolysis

Answer 1

Glucose becomes 2 pyruvate, 2 ATP, and 2 NADH

Consume 2 ATP in preparation phase, make 4 ATP in ATP-generating phase

Question 2

Total ATP produced per glucose in aerobic conditions

Answer 2

30-38 depending on shuttle system

Question 3

FA transport

Answer 3

Long chain FA carried by albumin in blood

FA binding proteins help cross plasma membrane

Fatty acyl CoA synthetase activates it to form fatty acyl CoA, diffuse across outer mitochondrial membrane

Carnatine displaces CoA to cross inner mitochondrial membrane, CoA replace carnatine to after pass

Fatty acyl CoA undergoes beta oxidation in mitochondrial matrix

Acetyl CoA transported for TCA cycle or to liver to become ketone bodies

Question 4

FA activation process

Answer 4

FA attacks ATP, fatty acyl CoA synthetase

Form fatty acyl AMP and pyrophosphate (which becomes two inorganic phosphates by inorganic phosphatase) while bound to the enzyme

Leave as fatty acyl CoA from the fatty acyl CoA synthetase cuz AMP breaks off

Occurs in the cytosol, two step enzyme

Question 5

Carnitine transport

Answer 5

Fatty acyl CoA diffuse across outer mitochondrial membrane

Fatty acyl CoA transfers fatty acyl to the carnitine via the carnitine palmitate transferase I (CPT I) to cross the inner mitochondrial membrane through the carnitine acyl-carnitine translocase

Inside matrix CPT II transfers CoA back to the fatty acyl

Question 6

Carnitine

Answer 6

Disease associated with defective CPT II

Obtained from diet or synthesized from side chain of Lys, where start in skeletal muscle but end in liver

Need vitamin C and S-adenosylmethionine

Skeletal muscle is main storage

Question 7

Beta Oxidation

Answer 7

Acyl CoA dehydrogenase reduces FAD to make double bind between alpha and beta of fatty acyl CoA

Enoyl CoA hydratase uses water to add OH to the beta carbon

Beta hydroxy acyl CoA dehydrogenase reduces NAD+ to give keto O to beta carbon

Beta keto thiolase use CoA to cleave at Beta and make acetyl CoA plus two shorter chain

Medium chain acyl CoA dehydrogenase (MCAD) is common, each acyl CoA dehydrogenase for different chain sizes

Question 8

Energy yield from palmitic acid

Answer 8

7 rounds beta oxidation

8 acetyl CoA: 96
7 FADH2: 14
7 NADH: 21
-2 Activation

129 ATP

Question 9

Beta oxidation of odd number FA

Answer 9

Normal amount of acetyl CoA plus Propionyl CoA

Undergoes carboxylase, epimerase, and mutase to become succinyl CoA for the TCA cycle but needs ATP, biotin, and vitamin B12

Question 10

Beta oxidation of unsaturated FA

Answer 10

Use enoyl-CoA isomerase to make cis bond trans then can continue beta oxidation
Enoyl-CoA isomerase: shifts double bond to right spot

Dienoyl-CoA reductase removes one double bond

Need another enoyl-CoA isomerase to shift the double bond once more

The dienoyl CoA reductase uses an NADPH, so unsaturated FAs give less energy

Question 11

Oxidation of very long and branched FAs

Answer 11

Happens in peroxisomes

VLCFA have same beta oxidation by the FADH2 produced in the first step becomes reoxidized to FAD by hydrogen peroxide, use different genes for enzymes, shorter products go to mitochondria via carnitine

Branched chain FA phytanic acid is degradation product of phytol from chlorophyll, has methyl every 4th carbon

Use alpha oxidation pathway to remove one carbon as CO2 to make prostatic acid, can do normal beta oxidation from there

Question 12

Zellweger syndrome and Refsum disease

Answer 12

Zellweger: defect in peroxisome biogenesis, accumulate VLCFA and branched FA, neurological damage

Refsum: defect in one of the alpha oxidation enzymes, neuro damage

Question 13

Omega oxidation of FAs

Answer 13

Occurs in ER of liver and kidney cells

Oxidize end to make a dicarboxylic acid, can be activated at either end to undergo beta oxidation

Make succinate for TCA cycle, adipic acid that is water soluble to be excreted, can also make an 8 carbon compound

Make a bunch of dicarboxylic acids if beta oxidation pathway messed up

Question 14

Beta oxidation regulation

Answer 14

1. During fasting hormaonal stimulation of lipolysis in adipose tissue releases FA, increase beta oxidation
2. Malonyl CoA (part of FA synthesis) allosterically inhibits Carnitine Parmitoyl I enzyme so FA not enter mitochondria, prevents synthesis and degradation of FA at the same time
3. When ATP is high the respiratory chain is inhibited, high NADH and FADH2 inhibit beta oxidation

Question 15

Ketogenesis

Answer 15

Occurs in the liver when acetyl CoA is high

Makes acetoacetate that can become acetone or beta hydroxybutyrate, known as ketone bodies

Ketone bodies travel through blood to tissues like brain and muscles to convert back to acetyl CoA to make ATP from

HMG-CoA synthase is rate limiting step, stimulated during fasting, excess dietary fat, and insulin deficiency

Ketogenic AA: Leu, Ile, Lys, Trp, Phe, and Tyr

Ketogenic diet of 3:1 lipid: carb helps with seizures and treat pyruvate dehydrogenase deficiency

Question 16

Products of the TCA cycle

Answer 16

3 NADPH
1 FADH2
1 GTP
2 CO2

Question 17

Enzyme for ATP from GTP

Answer 17

Nucleoside diphosphate kinase

Question 18

NADP+

Answer 18

Used for glucose-6-phosphate dehydrogenase

NADPH for biosynthetic reactions like FA synthesis

Question 19

Complex I

Answer 19

NADH dehydrogenase

Pumps 4 H+, electrons from NADH to FMN then through iron-sulfur clusters, end at ubiquinone (CoQ) which transfers electrons to Complex III

Complex II is succinate dehydrogenase

Question 20

Complex III

Answer 20

Transfers electrons from CoQ to cytochrome c

Pumps 4 H+

Has iron-sulfur clusters called cytochrome b and c1

Question 21

Complex IV

Answer 21

Cytochrome oxidase

Pumps 2 H+

Has homes that have oxygen bound to make H2O

Question 22

ATP synthase

Answer 22

Uses electrochemical gradient across the intermembrane space

Protons cause the c subunits to rotate, causes structural changes in alpha and beta catalytic subunits