82 Chapter 3
George has a grandparent on each side who suffered similar
symptoms, which indicates that he should be tested for Gau-
cher’s disease. This is an autosomal recessive trait, so the
affected person must inherit the defective gene from each
parent. Gaucher’s is the most common of the lysosomal stor-
age diseases, and causes the hepatomegaly, splenomegaly,
and bone and joint pain that George suffers. The defective
enzyme, glucocerebrosidase, can now be produced com-
mercially and is fortunately available for enzyme replacement
therapy. George admits to alcohol and drug abuse, which
would explain the unusually extensive agranular endoplas-
mic reticulum in his liver cells, which contain enzymes that
metabolize alcohol and other drugs.
See the three additional chapter 3 Clinical Investigations
on Mitochondrial Disease, Macular Degeneration, and
Breast Cancer Treatment in the Connect site for this text.| CHECKPOINTS Clinical Investigation SUMMARY
- Draw a simple diagram of the semiconservative
replication of DNA using stick figures and two colors.
10a. Describe the cell cycle using the proper symbols to
indicate the different stages of the cycle.
10b. Define apoptosis and explain its significance.
11a. List the phases of mitosis and briefly describe the
events in each phase.
11b. Distinguish between mitosis and meiosis, describe
the phases of meiosis, and explain its functional
significance.