Human Genetics and Disorders Fill in chart given

Human Genetics and Disorders Fill in chart given

Chapter 8 Section 4 Complex Patterns of Heredity Cystic Fibrosis (CF) • _______ recessive genetic disorder • Caused by a defective gene that normally produces a chloride protein responsible for moving ______ ions into and out of cells – This causes the formation and accumulation of a thick _____ in the _______, mucus lungs _____, liver intestines, and _______ pancreas Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Section 4 Complex Patterns of Heredity fatal • Cystic fibrosis is the most common ______ hereditary disorder among Caucasians. • One in ____ 25 Caucasian individuals has at least ____ copy of the defective gene one – These individuals don’t have cystic fibrosis but carriers they are considered ________ 2500 • About one in _____ Caucasians born in the United States inherits cystic fibrosis Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Tay - Sachs Disease • Caused by recessive alleles that produce a defective ______ enzyme. brain Jewish • Common in ______ populations nervous ______ system • In early childhood, the ______ system begins to break down, eventually leading to death ______ Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Section 4 Complex Patterns of Heredity Sickle Cell Anemia • Sickle cell anemia is also caused by inheriting two ______ recessive alleles. – These alleles produce a defective form of the protein hemoglobin __________, which causes many red blood cells to sickle bend into a _______ shape, affecting their ability to carry oxygen ________ Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

damage • Tissue ________ may result if certain cells are not receiving enough oxygen block • The sickle cells may also _______ small vessels and _______ easily rupture Heterozygous • ___________ individuals actually have _____ normal red blood cells and sickle cells both – Due to this occurrence, many texts actually list this codominant disease as being controlled by ______ inheritance instead of simple recessive Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

• Heterozygous individuals are protected from the affects of a parasite that invades red blood cells and malaria causes __________ – The sickle shape causes resistance to the ________ parasite • Sickle cell alleles are most common in ______ Americans African 12 – One in ______ African Americans are heterozygous for the disease 500 African Americans has sickle cell – One in ______ anemia Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Section 4 Complex Patterns of Heredity Hemophilia • Another recessive genetic disorder is hemophilia, a clot condition that impairs the blood’s ability to ____. sex-linked trait because the • Hemophilia is a _______ genes that control blood clotting are found on the _____ X chromosome. – How many recessive alleles must a female inherit to have hemophilia? 2 – And males? 1 Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Section 4 Complex Patterns of Heredity Huntington’s Disease (HD) • Huntington’s disease is a genetic disorder caused by a ______ dominant allele located on an ______. autosome – How many alleles does an individual need to inherit to have HD? 1 • The first symptoms of HD— mild forgetfulness, irritability, and slurred speech —appear in victims in their _____ or 30 s _____ 40 s – Many people have had children by this age, so HD is often ______ on in families. passed • In time, HD causes loss of ______ muscle control, uncontrollable physical spasms, severe mental illness, and eventually ______. death Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 8 Section 4 Complex Patterns of Heredity Treating Genetic Disorders • Most genetic disorders cannot be cured, although progress is being made. • A person with a family history of genetic disorders testing may wish to undergo genetic ________ and counseling parent _______ before becoming a ______. • In some cases, a genetic disorder can be treated ______ if it is diagnosed early enough. Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

• Example 1 – Phenylketonuria or _______ PKU is treatable genetic disorder caused by a faulty enzyme that is incapable of breaking down the amino acid __________. phenylalanine – Phenylalanine is found in food products like ____ and ________ sweeteners milk artificial – If newborns with PKU eat these food products, they will develop irreversible symptoms of ________________ mental retardation Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

test – After birth, infants are given a PKU ______. – If positive for PKU, what do you think would be an easy and appropriate form of treatment for the infant? Eliminating phenylalanine from their diet HD • Example 2 …there also tests to detect ______. . . if positive, couples may choose to _____ refrain from having children Chapter menu Resources Copyright © by Holt, Rinehart and Winston. All rights reserved.

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