Question

16. Look at Figure 10.8 Who contributes the cytoplasm and organelles to the zygote? 17. Important What is nondisjunction? 18. What is an aneuploidy? 19. Describe a monosomy: Trisomy: 20. What is trisomy 21? 21. Why does mothers' age play a role in this? 22. What is a Barr body? 23. Describe Turners Syndrome: 24. Describe Klinefelter's Syndrome: 25. What happens during a deletion? 26. What is duplication? 27. What is an inversion? 28. What is a translocation? 29. Summarize Cri du chat: 30. What is the Philadelphia chromosome? ACULDADLE ABCD ACDEF Deletion ABCODE — CODE Duplication AEDCBE mersion ABCOKL GHIEF 31. Describe the figure above.

Answer 1

Qns 16 The eggs contributes all the cytoplasm and organelles to the zygote.The sperm only contributes one set of chromosomes.The sperm.and egg have only half the number of chromosomes as other cells in the body

Qns 17. Nondisjunction is tje failure of homologous chromosomes or sister chromatids to seperate properly during cell division eg: trisomy,Down syndrome

Qns 18. Aneuploidy is a condition in which a person has one or a few chromosomes above or below tje normal chromosome number eg: downs syndrome

Qns 19. monosomy means that we can either find extra or missing chromosomes in the cells as a result of mistakes that occur during cell division.In a monosomy, one chromosome of a homologous pair is missing

Trisomy: it is the presence of three copies of a chromosome rather than the normal two. The most common trisomies in newborns are trisomy 13 (Patau syndrome), trisomy 18(Edwards syndrome), and trisomy 21 (down syndrome)

Qns 20. Trisomy 21 is caused by an extracopy of chromosome number 21.it is a common form of downs syndrome

Qns 21.The mothers age increases the egg become older.older egg has a greater risk of improper chromosome division

Qns 22.a small, well-defined body which stains intensely with nuclear dyes .It is present in a large proportion of nuclei of female origin and absent in male nuclei.

23.The most common sex chromosome disorder in females, characterized by short stature, webbed neck, broad shield-like chest, wide-spaced nipples, increased carrying angle at the elbow ,short fourth finger, and malformations of the heart and aorta.

24.condition in males who have XXY sex chromosomes, rather than the usual XY. Some also have additional X chromosomes, or more than one Y chromosome. XXY is one of the most common chromosomal abnormalities.

25.deletion mutation occurs when part of a DNA molecule is not copied during DNA replication. This uncopied part can be as small as a single nucleotide or as much as an entire chromosome. The loss of this DNA during replication can lead to a genetic disease.

26. Duplication.occur when part of chromosome 1is copied abnormally resulting in extra genetic material from the duplicated segment

27.defect in the chromosomes in which a segment of the chromosomes breaks off and reinserted in the same place but in the reverse direction relative to the rest of the chromosome

28.Translocation means a change in location. It usually refers to genetics, when part of a chromosome is transferred to another chromosome. Chromosomes are structures that carry genes, our units of heredity. When this type of translocation occurs

29.Cri-du-chat syndrome is an autosomal deletion syndrome caused by a partial deletion of the p arm of chromosome 5 (5p) and is characterized by a distinctive, high-pitched, catlike cry in infancy with growth failure microcephaly, facial abnormalities, and mental retardation throughout life

30.The Ph chromosome is an abnormally short chromosome 22 that is one of the two chromosomes involved in a translocation (an exchange of material) with chromosome 9. This translocation takes place in a single bone marrow cell and, through the process of clonal expansion (the production of many cells from this one mutant cell), it gives rise to the leukemia.

31.This figure shows different abnormalities of chromosome division such as deletion translocation duplication and inversion.