LO-6 Chem 153C

Learning Objectives 4

Heme Metabolism / Jaundice

1. Draw, using names only, and including enzymes the heme synthetic pathway.

2 Define the regulation and manifestations of deficiencies (porphyria) for enzymes in the heme synthetic pathway.

3. Draw, using names only, the pathway for heme degradation (including post hepatic).

4. Define the difference between conjugated and unconjugated bilirubin.

5. Compare the differences in types of hyperbilirubinemia produced in anemia, hepatitis, biliary duct stones and newborn jaundice.

Overview of Biochemical Endocrinology

1. Define hormone and receptor and identify associated properties, both chemically and with respect to their biochemical and physiological significance.

2. Identify the lipophilic hormones that bind to intracellular receptors and the hydrophilic amine and peptide hormones that bind to the cell surface.

3. Identify the second messengers that are associated with specific hormones and specific types of receptors.

4. Describe the general mechanism of signal transduction via G-proteins.

5. Discuss the process leading to the production of IP₃ and DAG, and the general mechanism of action of these second messengers.

Vitamin A and Vision

1. Identify provitamin A / b-carotene, vitamin A / retinol, vitamin A ester / retinol palmitate, retinaldehyde / retinal and retinoic acid (all-trans and 9-cis) in terms of their positions on the pathway of vitamin A metabolism. Delineate which reactions are reversible and which are not.

2. Describe the biological function of each of the forms of vitamin A.

3. Outline the actions of noncovalent vitamin A binding proteins including: RBP, CRBP, CRABP, RAR and RXR.

4. Describe the role of vitamin A in the visual cycle, in particular the roles played by: retinal isomerase, opsin, rhodopsin, metarhodopsin, transducin, cGMP, phosphodiesterase, Na²⁺, Ca²⁺, recoverin, rhodopsin kinase, arrestin.

5. Define progressive vitamin A deficiency clinically and biochemically.

6. Discuss why excess vitamin A is toxic to skin, bones, liver and gut.

7. Classify vitamin A and its RAR with the ligands for PPAR, the thyroid hormone receptor (TR) and the vitamin D receptor (VDR).