Metabolic Pathways

what occurs in a catabolic pathway?

breakdown of macomolecules to simple precursors

what are catabolic pathways generally used for?

to generate ATP and reduce power (NADH and FADH2)

what are examples of catabolic pathways?

glycolysis, lipolysis, and glycogenolysis

what occurs in an anabolic pathway?

synthesis or macromolecules from simple precursors

what are anabolic pathways generally used for?

ATP and reducing power that is generated from catabolic pathways are used to drive anabolic reactions

what are examples of anabolic reactions?

gluconeogenesis

lipogenesis

glyconeogenesis

nucleic acid synthesis

what does phosphatase do?

removes a phosphate

what does phosphorylase do?

adds phosphate

what does kinase do?

move phosphate around

what is dehydrogenase?

oxidation/reduction reactions

what does carboxylase do?

adds a carbon

what does decarboxylase do?

removes a carbon

what does aconitase do?

makes isomers

what happens in a well fed state?

increased glucose levels trigger the release of insulin from the pancreas

what metabolic pathways occur in the fed state?

glycolysis

glycogenesis

cholesterol synthesis

lipogenesis

what pathways fall under aerobic glycolysis?

pyruvate dehydrogenase complex

kreb’s

electron transport chain

what cycle falls under anaerobic glycolysis?

cori cycle

what occurs in a fasting state?

decreased glucose levels trigger release of glucagon from the pancreas

what metabolic pathways occur in the fasting state?

glycogenolysis

gluconeogenesis

lipolysis

ketogenesis

what is the goal of glycolysis?

glucose to 2 pyruvate

where does glycolysis take place?

cytosol

what stimulates glycolysis?

insulin

what inhibits glycolysis?

glucagon

what are the regulatory enzymes for glycolysis?

hexokinase

phosphofuctokinase

pyruvate kinase

what does hexokinase regulate?

glucose → glucose-6-phosphate

what does phosphofructokinase regulate?

fructose-6-phosphate → fructose 1,6-biphosphate

what does pyruvate kinase regulate?

phosphoenol pyruvate → pyruvate

when does aerobic glycolysis occur?

with presence of oxygen

what is the net gain of aerobic glycolysis?

2 ATP and 2 NADH

what does aerobic glycolysis proceed through?

kreb’s cycle and oxidative phosphorylation

when does anaerobic glycolysis occur?

in the absence of oxygen

what is the net gain of anaerobic glycolysis?

2 ATP, 2 NAD+, 2 lactate

what is the goal of anaerobic glycolysis?

glucose → 2 lactate

what does anaerobic glycolysis proceed through?

lactic acid fermentation or ethanol fermentation

what is the goal of the Kreb’s cycle?

acetyl coA → NADH, FADH2 and GTP

where does the Kreb’s cycle take place?

mitochondrial matrix

what are the AKA’s of the Kreb’s cycle?

citric acid cycle or TCA cycle

what are the regulatory enzymes of the kreb’s cycle?

citrate sybthase

isocitrate dehydrognease

alpha-ketoglutarate dehydrogenase

what does citrate synthase regulater?

acetyl coA + oxaloacetate → citrate

what does isocitrate dehydrogenase regulate?

isocitrate → alpha-ketoglutrate

what does alpha-ketoglutrate dehydrogenase regulate?

alpha-ketoglutrate → succinyl coA

what are the 9 intermediates of the kreb’s cucyle?

citrate

cis-aconitate

isocitrate

alpha-ketoglutrate

succinyl coA

succinate

fumarate

maltate

oxaloactetate

how many NADH are produced per Kreb’s cycle?

3

how much ATP is produced form 3 NADH in the Kreb’s cycle?

9 ATP

how many FADH2 is produced per kreb’s cycle?

1

how much ATP is produced form 1 FADH2 in the Kreb’s cycle?

2 atp

how many GTP are produced from kreb’s cycle?

1

how much ATP is produced form 1 GTP in the Kreb’s cycle?

1 ATP

how many total ATP molecules are produced from kreb’s cycle?

12

how much NADH is produced per 1 glucose molecule?

6

how much FADH2 is produced per 1 glucose molecule?

2

how much GTP is produced per 1 glucose molecule?

2

how much ATP is produced form 2 GTP in one glucose molecule?

2 atp

how much ATP is produced form 2 FADH2 in one glucose molecule?

4 atp

how much ATP is produced form 6 NADH in one glucose molecule?

18 atp

how many total ATP molecules are produced from one glucose molecule?

24 atp

what is oxidative phosphorylation composed of?

the electron transport chain and chemiosmosis

what happens in the electron transport chain?

electrons passed from one molecule to another which forms an electrochemical gradient

what is chemiosmosis?

energy stored in the gradient used to make ATP

where does the ETC take place?

inner mitochondrial matrix

what occurs in complex 1 of ETC?

electrons carried to the first complex by NADH

NADH is converted to NAD via NADH dehydrogenase

hydrogen ions are pumped from the mitochondrial matrix into intramembrane space

what carries electrons in complex 1 of the ETC?

NADH

what is NADH converted to in complex 1 of the ETC?

NAD via NADH dehydrogenase

where are hydrogen ions pumped from and to in complex 1 of the ETC?

from mitochondrial matrix to intramembrane space

what occurs in complex 2 of the ETC?

electrons are carried to the second complex by FADH2

FADH2 is converted to FAD

no hydrogen ions are pumped into intramambrane space

what carried electrons in complex 2 of the ETC?

FADH2

what is FADH2 converted to in complex 2 of the ETC?

FAD

what is true of hydrogen ions in complex 2 of the ETC?

no hydrogen ions are pumped into intramembrane space

where is coenzyme q produced naturally?

in the liver

what does coenzyme q have a similar structure to?

vitamin k

what is sent to coenzyme q from complex 1 and 2 in the ETC?

NADH and FAD

what occurs during complex 3 of the ETC?

passes electrons (hydrogen) to cytochrome C

what does cytochrome C do in the ETC?

transports hydrogen (electrons) to complex 4

what occurs in complex 4 of teh ETC?

passes electrons to O2

oxygen is then reduced to water

what is the ultimate acceptor of electrons in the ETC?

oxygen

what is known as complex 5 of the ETC?

chemiosmosis and ATP synthase

what are the proton pumps of the ETC?

complexes 1,3, and 4

what is the one channel in the intramembrane space that hydrogen ions now use?

ATP synthases

what triggers ATP synthase?

the flow of hydrogen ions that are moving down into thei electrochemical gradient

as ATP synthase turns, what does it convert?

ADP to ATP

the number of ATP molecules produced is directly proportional to what in the ETC?

the number of protons pumped from the mitochondrial matrix into the intramembrane space

what is the goal of glycogen synthesis?

glucose → glycogen

what stimulates glycogen synthesis?

insulin

what inhibits glycogen synthesis?

glucagon

what is the enzyme that regulates glycogen synthesis?

glycogen synthase

what is a major intermediate of glycogen synthesis and degradation?

UDP-glucose

what is the goal of glycogen degradation?

glycogen → glucose

what stimulates glycogen degradation?

glucagon and epinephrine

what inhibits glycogen degradation?

insulin

what is the regulator enzyme of glycogen degradation?

glycogen phosphorylase

what does glycogen phosphorylase break?

alpha 1,4 linkages of glycogen

what is the AKA for the HMP shunt?

pentose phosphate pathway?

what does the HMP shunt make?

ribose

where does the HMP shunt take place?

cytosol

what is the regulatory enzyme of the HMP shunt?

glucose-6-phosphate dehydrogenase

what is true of ATP in the HMP shunt?

there is no net gain or loss

what are the functions of the HMP shunt?

produce NADPH for both fatty acid and steroid synthesis

produce ribose-r-phosphate for nucleotide synthesis

what type of process is fatty acid synthesis?

reductive

what is the goal of fatty acid synthesis?

acetyle coA → fatty acids

where does fatty acid synthesis take place?

cytosol