Pentose Phosphate Pathway

These flashcards cover key vocabulary terms and their definitions related to the Pentose Phosphate Pathway, its phases, enzymes, and significance in metabolic processes.

Pentose Phosphate Pathway

A metabolic pathway generating NADPH for reductive biosynthesis and protection against oxidative stress, occurring in the cytoplasm of all organisms.

NADPH

Nicotinamide adenine dinucleotide phosphate, a reduced coenzyme used in anabolic reactions.

Oxidative Phase

The first phase of the pentose phosphate pathway where glucose 6-phosphate is oxidized to ribulose 5-phosphate, producing NADPH.

Non-Oxidative Phase

The second phase of the pentose phosphate pathway where interconversion of sugars occurs without the production of NADPH.

Glucose 6-Phosphate Dehydrogenase

An enzyme that catalyzes the first and rate-limiting step of the pentose phosphate pathway, converting glucose 6-phosphate to 6-phosphoglucono-6-lactone.

Transketolase

An enzyme that catalyzes the transfer of two carbon units in the non-oxidative phase of the pentose phosphate pathway.

Transaldolase

An enzyme that catalyzes the transfer of three carbon units in the non-oxidative phase of the pentose phosphate pathway.

Reduced Glutathione (GSH)

A tripeptide that combats oxidative stress by reducing reactive oxygen species (ROS) to harmless forms.

Oxidized Glutathione (GSSG)

The oxidized form of glutathione that must be reduced back to GSH to maintain antioxidant function.

Ribose 5-Phosphate

A five-carbon sugar produced in the pentose phosphate pathway used in the synthesis of nucleotides.

Rate-limiting Step

The step in a metabolic pathway that determines the rate of flow through that pathway, often regulated by specific enzymes.

Calvin-Benson Cycle

A set of chemical reactions that take place in chloroplasts during photosynthesis, where ribulose 1,5-bisphosphate is regenerated.

Heinz Bodies

Aggregates formed by cross-linking of hemoglobin caused by oxidative stress, often associated with reduced glutathione deficiency.

Evolutionary Advantage

A genetic trait that allows an organism to survive and reproduce more effectively in a specific environment.

Oxidative Stress

An imbalance between free radicals and antioxidants in the body, which can lead to cell damage.

Cytoplasm

The fluid substance within a cell that contains organelles and is the site of many metabolic processes.