Pentose Phosphate Pathway Flashcards
What does the pentose phosphate pathway primarily produce?
Ribose and NADPH
What is the main enzyme used in the pentose phosphate pathway?
Glucose 6 phosphate dehydrogenase
What is another name for the pentose phosphate pathway?
Hexose monophosphate pathway
Where does the hexose monophosphate pathway take place?
Cytosol
Is ATP used in the hexose monophosphate pathway?
No ATP is produced or consumed
What nitrogenous bases are considered purines?
Guanine and adenine
What nitrogenous bases are considered pyrimidines?
Thymine, cytosine, and uracil
What is a nucleoside?
Base and a sugar
What is a nucleotide?
Base, sugar, and phosphate
NADH is oxidized in the electron transport chain to make what?
ATP
NADPH is an electron donor during what processes? (Hint: Fantastic Four)
- Reductive biosynthesis
- Respiratory burst
- Detoxification
- Regeneration of antioxidants
What are the individual steps of the pentose phosphate pathway in general?
- Dehydrogenation
- Hydrolysis
- Oxidative decarboxylation
- Isomerization
What enzymes build a reversible link between the pentose phosphate pathway and glycolysis?
Transketolases and transaldolases
What system does the liver utilize to perform detoxification?
P450 monooxygenase system
What cellular structure in the liver contains the cytochrome P-450 mono-oxygenase system?
Endoplasmic reticulum
The cytochrome P-450 mono-oxygenase system adds hydroxyl groups to what types of compounds?
Aromatic and aliphatic compounds
Respiratory burst creates harsh chemistry within the body in order to kill pathogens. What is the reactant, product, and enzyme of this process?
Reactant: Hydrogen peroxide
Product: Hypochlorus acid
Enzyme: Myeloperoxidase
This is a substance that inhibits oxidation and is capable of counteracting the damaging effects of oxidation in body tissue.
Antioxidant
This is an atom or molecule that has one or more unpaired electrons. It is very reactive.
Free radical
What are three common radicals/reactive species?
Superoxide, Hydrogen peroxide, Hydroxyl
This is the process by which electronically excited molecules are inactivated.
Quenching
When free radicals are quenched, what happens to antioxidants?
They are oxidized
This is the process by which the antioxidant’s reducing power is restored.
Regeneration
When antioxidants are regenerated, they are being what?
Reduced
What are some important enzymes that may quench free radicals?
- Superoxide Dismutase (Quenches superoxide)
- Catalase (Quenches hydrogen peroxide)
- Glutathione Peroxidase (Quenches hydrogen peroxide)
Where does superoxide dismutase act?
- Extracellular
- Cytoplasm
- Mitochondria
What is the function of superoxide dismutase?
- Eliminate superoxide
- Produce hydrogen peroxide
What does superoxide dismutase require?
- Zinc
- Copper
- Manganese (mitochondria)
Where does catalase act?
- Mostly in cell peroxisomes
- Smaller amounts in cytoplasm, mitochondria, and microsomes
What is the function of catalase?
Eliminate hydrogen peroxide by turning it into water
Where does glutathione peroxidase act?
Cytosol and mitochondria
What is the function of glutathione peroxidase?
Turns hydrogen peroxide into water
