Multiple Choice
Passage
Nerve cells must maintain the composition of their myelin sheaths to function properly. Galactocerebroside (GC) , shown in Figure 1, is a hydrolyzable lipid and an important component of the myelin sheath.
Figure 1 Structure of the myelin sheath component galactocerebrosideHomeostasis of GC is maintained by its dynamic synthesis and degradation, as shown in Figure 2. GC is synthesized by the enzyme ceramide galactosyltransferase (CGT) using UDP-galactose (UDP-Gal) and ceramide (Cer) as substrates. It is degraded by the enzyme galactocerebrosidase (GalC) , which hydrolyzes the glycosidic bond to release galactose (Gal) and ceramide. A deficiency in GalC activity leads to a buildup of GC, and prior research has connected this buildup with neurodegeneration.
Figure 2 Schematic of GCT and GalC activity in healthy and GalC deficient cellsOver 100 inactivating GalC mutations have been identified. Five of the most common mutations are listed in Table 1. The changes to both DNA and amino acid sequence are shown.Table 1 Five Common Galactocerebrosidase Mutations

-GC can be classified as:
A) a glycerophospholipid.
B) a phosphosphingolipid.
C) a glycosphingolipid.
D) a phosphoglycolipid.
Correct Answer:

Verified
Correct Answer:
Verified
Q20: Passage<br>The Ankyrin repeat and SOCS box containing
Q21: Passage<br>Leukocyte common antigen (LCA) enzymes play several
Q22: Passage<br>Leptin signaling is vital for maintaining adequate
Q23: Passage<br>NDPK is an enzyme in budding yeast
Q24: Passage<br>Myalgic encephalopathy (ME), or chronic fatigue syndrome
Q26: Passage<br>Physical activity produces an increased energy requirement
Q27: Passage<br>The ABO blood groups are determined by
Q28: Passage<br>Upon entering muscle cells, glucose is immediately
Q29: Passage<br>NDPK is an enzyme in budding yeast
Q30: Passage<br>Leptin signaling is vital for maintaining adequate