**Question:** Cori's cycle is concerned with transport of

A. Glucose
B. Lactate
C. Pyruvate
D. Amino acids

**Correct Answer:** C. Pyruvate

**Core Concept:**
Cori's cycle, also known as the gluconeogenesis pathway, is a series of chemical reactions that occur in the liver and kidney to produce glucose from non-carbohydrate sources. This process is essential for maintaining blood glucose levels, as well as gluconeogenesis, and glycogen synthesis. The cycle involves the conversion of various organic acids and compounds into glucose, which is then released into the bloodstream and distributed to other tissues for energy production.

**Why the Correct Answer is Right:**
Cori's cycle is primarily concerned with the transport and conversion of pyruvate, an intermediate product of glycolysis in the cytoplasm of cells. Pyruvate enters the mitochondria, where it is converted into oxaloacetate by the enzyme pyruvate carboxylase. The oxaloacetate is then converted into citrate, which is further processed into glucose through gluconeogenesis.

**Why Each Wrong Option is Incorrect:**
A. Glucose is not a primary product of Cori's cycle; it is primarily involved in maintaining blood glucose levels and gluconeogenesis.
B. Lactate is a product of anaerobic glycolysis and is not a primary component of Cori's cycle.
D. Amino acids are not the main focus of Cori's cycle; it primarily deals with glucose production.

**Clinical Pearl:**
Understanding Cori's cycle is crucial for medical professionals as it highlights the interdependence of various cellular processes and the role of the liver in maintaining blood glucose levels. Knowledge of this cycle helps in diagnosing and treating conditions like diabetes and hypoglycemia, as well as understanding the relationship between glycolysis, gluconeogenesis, and glycogenesis.