Question

Observation: Sex Chromosome Anomalies A female with Turner syndrome (XO) has only one sex chromosome, an X chromosome; the O signifies the absence of the second sex chromosome. Because the ovaries never become functional, these females do not undergo puberty or menstruation, and their breasts do not develop. Generally, females with Turner syndrome have a short build, folds of skin on the back of the neck, difficulty recognizing various spatial patterns, and normal intelligence. With hormone supplements, they can lead fairly normal lives. When an egg having two X chromosomes is fertilized by an X-bearing sperm, an individual with poly-X syndrome results. The body cells have three X chromosomes and therefore 47 chromosomes. Although they tend to have learning disabilities, poly-X females have no apparent physical anomalies, and many are fertile and have children with a normal chromosome count. When an egg having two X chromosomes is fertilized by a Y-bearing sperm, a male with Klinefelter Syndrome results. This individual is male in general appearance, but the testes are underdeveloped, and the breasts may be enlarged. The limbs of XXY males tend to be longer than average, muscular development is poor, body hair is sparse, and many XXY males have learning disabilities. Jacob syndrome occurs in males who are usually taller than average, suffer from persistent acne, and tend to have speech and reading problems. At one time, it was suggested that XYY males were likely to be criminally aggressive, but the incidence of such behavior has been shown to be no greater than that among normal XY males. Label each karyotype in Figure 21.6 as one of the syndromes just discussed. Explain your answers on the lines provided. Figure 21.6 Sex chromosome anomalies. (a) O CNRISPLScience Source: (b) OCNRUSPLIScience Source; ic) O CNRI/SPL/Science Source: id) O CNRISPL/Science Source XKKK PXKK XKk XKKK XKKK 1. 3.

Answer 1

1.poly-x syndrome

Figure 21.6 Sex chromosome anomalies. 6) OCNRISPL/Science Source () OCNRI/PL/Science Source ) OCNRI/SPEScience Source () OCNRISPL/Science Source XXIKIKEKER if 111 11 i 11 i ii 11 123 14 24 133 KLINEFELTER POLY X SYNDROME TURNER SYNDROME JACOB SYNDROME

2.turner syndrome

3.klinefelter syndrome

4.jacob syndrome