Metabolism — Flashcards

Flashcard 1411: TSH increases which 2nd messenger?_____

Answer: cAMP

Flashcard 1412: Vitamin B12 and folate deficiency result in mildly elevated _____ levels, increasing risk for thrombosis

Answer: homocysteine

Flashcard 1413: A _____ enzyme joins two molecules together using a source of energy (e.g., ATP)

Answer: Synthetase (Ligase)

Extra: **Synthetase**: Requires energy (usually from ATP hydrolysis) to join two molecules together. Categorized as **Ligases**. **Synthase**: Catalyzes a synthesis process without requiring energy from nucleoside triphosphates (ATP/GTP). Often categorized as **Lyases** or **Transferases**.

Flashcard 1414: Synthesis of GABA from glutamate requires _____ as a cofactor

Answer: vitamin B6

Flashcard 1415: D-dimers are derived from splitting of _____

Answer: cross-linked fibrin

Flashcard 1416: _____ is a measure of the percent of transferrin molecules that are bound by iron

Answer: % saturation

Flashcard 1417: Which second messenger is released upon binding of cholecystokinin to CCKA receptors?_____

Answer: IP3/Ca2+

Flashcard 1418: Glycogen phosphorylase is allosterically activated by _____ (muscle)

Answer: AMP

Flashcard 1419: The **Amyloid Precursor Protein (APP)** on neurons is broken down by **\_\_\_\_\_ cleavage**, resulting in the formation of **A$\beta$ amyloid** particles.

Answer: $\beta$ (beta) cleavage

Extra: APP is normally cleaved by $\alpha$-secretase (non-amyloidogenic). Cleavage by $\beta$-secretase followed by $\gamma$-secretase results in the production of A$\beta$ (amyloid beta) peptides, which aggregate to form the plaques seen in Alzheimer's disease.

Flashcard 1420: Which neurotransmitter(s) are broken down by monoamine oxidase A (MAO-A)? _____

Answer: Serotonin, norepinephrine, and dopamine