How does glutamate contribute to both ammonium production and aspartate formation in the urea cycle?

• A. Glutamate is converted into glutamine, which then forms aspartate.
• B. Glutamate is used to synthesize ATP, which is then used to form aspartate.
• C. Glutamate is directly converted into urea and aspartate.
• D. Glutamate provides ammonium by being converted to alpha-ketoglutarate and forms aspartate by donating an amino group to oxaloacetate.

Answer: (D)