WEEK 13: BIOCHEMICAL ENERGY PRODUCTION

the sum total of all the biochemical reactions that take place in a living organism

METABOLISM

2 subtypes of METABOLISM

1) Anabolism

2) Catabolism

is all metabolic reactions in which small biochemical molecules are joined together to form larger ones

ANABOLISM

is all metabolic reactions in which large biochemical molecules are broken down to form smaller ones

CATABOLISM

this reaction usually requires energy

Anabolic

this reaction releases energy

Catabolic

is a series of consecutive biochemical reactions used to convert a starting material into an end product

METABOLIC PATHWAYS

2 metabolic pathways

1) Linear Metabolic Pathway

2) Cyclic Metabolic Pathway

is a series of reactions that generates a final product

Linear Metabolic Pathway

is a series of reactions that regenerates the first reactant

Cyclic Metabolic Pathway

is an organelle that is responsible for the generation of most of the energy for a cell

Mitochondrion (Mitochondria)

outer membrane of Mitochondria

50% lipid & 50% protein

freely permeable

inner membrane of Mitochondria

20% lipid & 80% protein

highly impermeable

interior region of Mitochondria

Matrix

the region between inner & outer membranes

intermembrane space

the folds of the inner membrane that protrude into the matrix

Cristae

composed of small spherical knobs attached to the cristae

ATP synthase complexes

3 important intermediate compounds

1) Adenosine Phosphate

2) FAD & NAD

3) Coenzyme A

is the functional group derived from a phosphate ion that is a part of another molecule which is adenosine

phosphoryl group

bonds that attaches phosphoryl group to the ribose molecule is a

phosphoester bond

is the chemical bond formed when 2 phosphate group react with one another, a water molecule is produced

phosphoanhydride bond

1 phosphate-ribose-adenine

AMP

2 phosphate-ribose-adenine

ADP

3 phosphate-ribose-adenine

ATP

it is the basis for the net energy production that accompanies hydrolysis

reactive bonds / strained bonds

other nitrogen-containing bases associated with nucleotides are also present in triphosphate form

1) uridine triphosphate

2) guanosine triphosphate

3) cytidine triphosphate

involved in carbohydrate metabolism

uridine triphosphate

involved in protein & carbohydrate metabolism

guanosine triphosphate

involved in lipid metabolism

cytidine triphosphate

2 coenzymes that are involved in redox reaction

FAD & NAD

FAD means

flavin adenine dinucleotide

NAD means

nicotinamide adenine dinucleotide

oxidized form of FAD

FAD

reduced form of FAD

FADH2

FAD is compose of

flavin & ribitol

b vitamin that is present in FAD/FADH2

b2 (riboflavin)

reduced form of ribose

ribitol

active portion of FAD in metabolic redox reaction

flavin

b vitamin present in NAD+ / NADH

b3 (nicotinamide)

is an active portion of NAD+ involved in metabolic redox reaction

nicotinamide

coenzyme which is a derivative of a b vitamin pantothenic acid

Coenzyme A (CoA-SH)

2 forms of Coenzyme A

1) CoA-SH

2) Acetyl-S-CoA

complete structure of Coenzyme A involves

2 Aminoethanethiol, Pantothenic acid, & Diphosphate group

is an active portion of Coenzyme A in the ethanethiol subunit of the coenzyme

sulfhydryl group

is the portion of an acetic acid molecule (CH3-COOH) that remains after the -OH group is removed from the carboxyl carbon atom

Acetyl group

an acetyl group bonds to CoA-SH through a _____ to give acetyl CoA

thioester bond

classification of metabolic intermediate compounds

1) intermediates for the storage of energy and transfer of phosphate groups

2) intermediates for the transfer of electrons in metabolic redox reaction

3) intermediates for the transfer of acetyl groups

is a compound that has a greater free energy of hydrolysis than that of a typical compound

high-energy phosphate compound

is the amount of energy released by a chemical reaction that is actually available for further use at a given temperature & pressure

free energy

example of high-energy phosphate compound

phosphoric acid

a notation often employed to denote strained bonds

squiggle (~)

enol phosphate example

phosphoenolpyruvate

acyl phosphates

1-3-biphosphoglycerate acetyl phosphate

guanidine phosphates

creatine phosphate

arginine phosphate

triphosphate

ATP --> AMP + PPi*

diphosphate

PPi --> 2Pi

ADP --> AMP + Pi

sugar phosphates

glucose 1-phosphate

fructose 6-phosphate

AMP --> adenosine + Pi

glucose 6-phosphate

glycerol 3-phosphate

overview of the biochemical energy production

> energy needed to run the human body is obtained from food

> multi-step process that involves several different catabolic pathways

4 general steps in the biochemical energy production process

stage 1: digestion

stage 2: acetyl group formation

stage 3: citric acid cycle

step 4: electron transport chain & oxidative phosphorylation

it begins in the mouth, continues in the stomach, completed in small intestine

digestion

end products of digestion

> Glucose and monosaccharides from carbohydrates

> Amino acids from proteins

> Fatty acids and glycerol from fats and oils

the small molecules from stage 1 are further oxidized

acetyl group formation

end products of these oxidation

acetyl CoA

glucose metabolism

cytosol

fatty acid metabolism

mitochondria

this takes place inside the mitochondria

citric acid cycle & ETC, and oxidative phosphorylation

a series of biochemical reactions in which the acetyl portion of acetyl CoA is oxidized to carbon dioxide and the reduced coenzymes FADH2 & NADH are produced

citric acid cycle (Kreb's Cycle / TCA)

who elucidated the citric acid cycle

Hans Kreb

two important types of reactions in the citric acid cycle

1) oxidation of NAD+ & FAD to produce NADH & FADH2

2) decarboxylation of the citric acid cycle also produces 2 ATP by substrate level phosphorylation from GTP

1st step of citric acid cycle

formation of citrate

2nd step of citric acid cycle

formation of isocitrate

3rd step of citric acid cycle

oxidation of isocitrate and formation of CO2

4th step of citric acid cycle

oxidation of a-ketoglutarate and formation of CO2

5th step of citric acid cycle

thioester bond cleavage in succinyl CoA and phosphorylation of GDP

6th step of citric acid cycle

oxidation of succinate

7th step of citric acid cycle

hydration of fumarate

8th step of citric acid cycle

oxidation of L-malate to regenerate oxaloacetate

enzyme involved in formation of citrate

citrate synthase

enzyme involved in formation of isocitrate

aconitase

enzyme involved in oxidation of isocitrate and formation of CO2

isocitrate dehydrogenase

enzyme involved in oxidation of a-ketoglutarate and formation of CO2

a-ketoglutarate dehydrogenase complex

enzyme involved in thioester bond cleavage in succinyl CoA and phosphorylation of GDP

succinyl CoA synthetase

enzyme involved in oxidation of succinate

succinate dehydrogenase

enzyme involved in hydration of fumarate

fumarase

enzyme involved in oxidation of L-malate to regenerate oxaloacetate

malate dehydrogenase

in what step was the first redox reaction in the citric acid cycle

step 3

2nd redox reaction

step 4

3rd redox reaction

step 6

4th redox reaction

step 8

what alcohol is Citrate

tertiary alcohol

what alcohol is Isocitrate

secondary alcohol

reactants in step 3

NAD+ & isocitrate

reactants in step 4

NAD, CoA-SH, and a-ketoglutarate

reactants in step 5

succinyl CoA, GDP, free phosphate group

reactants in step 6

succinate & FAD

reactants in step 7

fumarate & H2O

reactants in step 8

L-malate & NAD+

product of step 8

oxaloacetate

product of step 7

L-malate

product of step 6

fumarate