Animal cell culture — identify the main constituents required in the medium to support robust cell growth and division. Consider carbon/energy sources (e.g., glucose and glutamine) as well as signaling supplements (growth factors and cytokines). Choose the most complete answer.

Introduction / Context:
Animal cells grown in vitro require carefully formulated media that provide energy, biosynthetic precursors, and extracellular signals. Understanding what a “complete” medium contains is fundamental in cell culture and bioprocess engineering.

Given Data / Assumptions:

• Candidates include metabolic substrates (glucose, glutamine) and regulatory additives (growth factors and cytokines).
• We assume standard mammalian culture for proliferation rather than minimal survival only.
• Balanced salts and pH buffers are necessary but not sufficient for sustained growth.

Concept / Approach:

Cells need both nutrients and signals. Glucose provides ATP via glycolysis and oxidative pathways. Glutamine fuels the TCA cycle and nitrogen metabolism. Growth factors (such as insulin, EGF, FGF) and selected cytokines convey mitogenic and survival signals through receptor pathways (MAPK/ERK, PI3K/AKT), enabling progression through the cell cycle and preventing apoptosis. Therefore, a complete answer must encompass all categories.

Step-by-Step Solution:

Verification / Alternative check:

Common media (DMEM, RPMI-1640) are typically supplemented with serum (a source of many growth factors and cytokines) or with defined recombinant factors in serum-free formulations, plus glucose and glutamine or stabilized dipeptides.

Why Other Options Are Wrong:

Glucose and glutamine alone lack mitogenic signals; growth factors or cytokines alone cannot provide metabolic substrates; salts/buffers maintain osmolality and pH but not growth.

Common Pitfalls:

Assuming serum alone is sufficient without attention to glucose/glutamine stability; overlooking that glutamine can degrade, requiring monitoring or use of stable dipeptides (e.g., alanyl-glutamine).

Final Answer:

All of these