Metabolism — Flashcards

Flashcard 1131: Which two organs does galactose primarily enter?

Answer: Liver and kidneys

Extra: Galactose metabolism primarily occurs in the liver, with a secondary contribution from the kidneys. Both organs express the GLUT2 transporter, allowing for insulin-independent uptake of galactose. While galactose is used in the brain for the synthesis of galactolipids (like cerebrosides), the bulk of dietary galactose is cleared by the liver and kidneys.

Flashcard 1132: Which is a better intracellular buffer in physiologic pH range, oxy- or deoxyhemoglobin?_____

Answer: Deoxyhemoglobin

Flashcard 1133: Which steroid hormone enzyme deficiency (21- or 11-hydroxylase) presents with decreased renin activity?_____

Answer: 11-hydroxylase

Flashcard 1134: What enzyme converts DHF back to THF?_____

Answer: Dihydrofolate reductase

Flashcard 1135: What amino acids (3) are necessary for purine synthesis? _____

Answer: Glycine, Aspartate, Glutamine

Flashcard 1136: Vitamin B12 (cobalamin) is found in _____ products

Answer: animal

Flashcard 1137: A _____ enzyme catalyzes transfer of a phosphate group from a high-energy molecule (e.g. ATP) to a substrate

Answer: kinase

Flashcard 1138: The acetyl-CoA from acetoacetyl-CoA (ketone body metabolism) is used to generate energy via the _____

Answer: Kreb's cycle

Flashcard 1139: Phosphorylation of glycogen synthase causes enzyme _____ (activation/inactivation)

Answer: inactivation

Flashcard 1140: Which growth factors/cytokines utilize **receptor tyrosine kinase** (intrinsic) signaling?

Answer: Insulin, IGF-1, FGF, PDGF, EGF, and **TGF-α**

Extra: In contrast, **TGF-β** utilizes a receptor **serine/threonine kinase** pathway (SMAD signaling). Most other cytokines (e.g., ILs, IFNs, EPO, G-CSF) utilize the **JAK/STAT** pathway (non-receptor tyrosine kinase).