[ 225 ] Life Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Tay-Sachs disease is a rare genetic disorder that impacts muscle coordination and cognition starting at 6 months of age and typically results in death at an early age. The allele for Tay-Sachs disease is recessive. Complete the Punnett square for two parents who are carriers of the gene (Tt). Parent (Tt) Parent (Tt) T t T t Based on a Punnett square for carriers of a Tay-Sachs disease gene (Tt), what is the likelihood that the children of two heterozygous parents will carry the gene for Tay-Sachs disease (homozygous or heterozygous)? TT: ________% Tt: ________% tt: ________% Which of the following statements is NOT true about the endocrine system? A. Diabetes is a disease that affects the production of glucose-regulating insulin in the endocrine system. B. It works toward homeostasis in the body. C. It includes the pituitary, thyroid, thymus, and pancreas. D. Glands in the endocrine system send out chemical messages via hormones.