Patho Chapter 5

In an autosomal recessive disorder, such as cystic fibrosis, if one parent is a carrier, and the other parent is normal, what are the chances that a child would be affected with the disease? To help you answer this question try using the circle exercise as showed on P. 75, Figure 5-6 adjusted for this scenario. A. 0% B. 50% C. 25% D. 100%

0% (In this case, a carrier parent can pass on either an affected gene or a normal gene. The normal parent passes on only a normal gene. Thus, a child would get either normal genes (50% chance) or a combination of a normal gene and an affected gene (50% chance). Because this is an autosomal recessive disease, the normal gene is "dominant" and the disease would not be expressed. The child would have to inherit two of the affected genes to be affected, and this cannot happen with these parents.)

"John has a form of hemophilia which is a disease that causes him to bleed for a longer period of time than normal." If John has children with a woman who neither has hemophilia or is a carrier for it, what is the probability that their sons will have hemophilia. A. 0% B. 25% C. 50% D. 100%

0% (John's sons will not have hemophilia because the affected allele is on his X chromosome. If John has sons, he will be passing on his Y chromosome. The X chromosome will come from the unaffected mother so the sons will not have hemophilia.)

"John has a form of hemophilia which is a disease that causes him to bleed for a longer period of time than normal." If John has children with a woman who neither has hemophilia or is a carrier for it, what is the probability that their sons will have hemophilia. A. 0% B. 25% C. 50% D. 100%

0% NOTE: John's sons will not have hemophilia because the affected allele is on his X chromosome. If John has sons, he will be passing on his Y chromosome. The X chromosome will come from the unaffected mother so the sons will not have hemophilia.

"John has a form of hemophilia which is a disease that causes him to bleed for a longer period of time than normal." If John has a daughter with a woman who neither has hemophilia nor is a carrier for it, what chance will the daughter have of being a carrier of hemophilia? A. 0% B. 25% C. 50% D. 100%

100% (All daughters would be carriers because John will pass down his defective X chromosome to them.)

"John has a form of hemophilia which is a disease that causes him to bleed for a longer period of time than normal." If John has a daughter with a woman who neither has hemophilia nor is a carrier for it, what chance will the daughter have of being a carrier of hemophilia? A. 0% B. 25% C. 50% D. 100%

100% NOTE: All daughters would be carriers because John will pass down his defective X chromosome to them.

Each human cell contains how many chromosomes? A. 23 B. millions C. 46 D. 2

46

A normal cell contains _________________ chromosomes.

46, forty-six, forty six

If one parent is heterozygous for an autosomal dominant disease and the other parent is normal, what are the chances that a child would be affected with the disease? A. 25% B. 50% C. 0% D. 100% E. none of the above

50%

"John has a form of hemophilia which is a disease that causes him to bleed for a longer period of time than normal." Why does this disease affect men more than women? A. Because it is carried on the X chromosome and women have two X chromosomes so the disease won't usually be manifested in women because their "good" X performs normally. B. Because it is carried on the Y chromosome and women have two X chromosomes so they would never get the disease. C. Because a male transmits the disease only to his sons. D. Because it is an autosomal recessive disease and women are less likely to get an autosomal recessive disease.

Because it is carried on the X chromosome and women have two X chromosomes so the disease won't usually be manifested in women because their "good" X performs normally.

The inheritance of the disease __________ __________ _________ may decrease the likelihood of a person's catching malaria.

Both are correct: sickle cell anemia, sickle cell trait

Alternative forms of a gene are called ______________.

Both are correct: alleles, allele

An abnormal number of chromosomes is the cause of which disease? A. fragile X syndrome B. polydactyly C. Down syndrome D. phenylketonuria

Down syndrome

People with Down's Syndrome usually have a normal life expectancy. True or False

False

In an autosomal recessive disease, if both parents are carriers, a son or daughter has a 50% chance of being affected with the disease. True or False

False (A child would have a 25% chance of having the disease)

Down's syndrome is due to having only one chromosome #21. True or False

False (Down's syndrome is due to having an extra chromosome 21.)

Familial diseases are diseases in which a single gene has been identified as the cause. True or False

False (In familial diseases, the cause seems to be the effect of several genes working together.)

"John has a form of hemophilia which is a disease that causes him to bleed for a longer period of time than normal." If John has hemophilia, his father must have it also. True or False

False (John has hemophilia because he inherited the abnormal X from his mother. The Y came from his father. Because hemophilia is sex-linked on the X chromosome, boys inherit it from their mothers.)

"John has a form of hemophilia which is a disease that causes him to bleed for a longer period of time than normal." If John has hemophilia, his father must have it also. True or False

False NOTE: John has hemophilia because he inherited the abnormal X from his mother. The Y came from his father. Because hemophilia is sex-linked on the X chromosome, boys inherit it from their mothers.

________ encode information for the synthesis of proteins.

Genes

Which of the following is a sex chromosome anomaly? A. Down's syndrome B. Sickle cell anemia C. Klinefelter syndrome D. Marfan's syndrome

Klinefelter syndrome (XXY)

A genetic disease in which the children of one affected parent have a 50% chance of having the disease is said to be passed in an autosomal dominant manner. True or False

True

Fragile X syndrome mostly affects males. True or False

True

If a female is a carrier of a sex-linked disease, the children have a 50% chance of receiving the abnormal allele. True or False

True

People with Turner's syndrome and Klinefelter's syndrome may develop secondary sexual characteristics but cannot reproduce. True or False

True

Sex-linked chromosomal disorders generally result from defective genes on the X chromosome. True or False

True

Which of the following are examples of congenital diseases? A. cleft lip and palate B. cerebral palsy C. spina bifida D. all of the above E. B and C only

all of the above

The carrier of a genetic disease is someone who has a defective gene and: A. apparently normal health B. the associated disease C. a disease which is delayed until middle age D. a genetic abnormality which is not passed onto children

apparently normal health

Congenital diseases are those that: A. are due to chromosomal abnormalities B. appear at birth or soon after C. are due to abnormal genes D. arise in adolescence

appear at birth or soon after

Which is a sex-linked disease? A. chondroplastic dwarfism B. fragile X syndrome C. sickle cell anemia D. Tay-Sachs

fragile X syndrome

The procedure that involves identification, manipulation, and transference of genetic segments into a host to replace defectives genes is called ________ ___________.

gene therapy

According to your text, the most common genetic disorder in the U.S. is ___________, an iron storage disease.

hemochromatosis

Inability to clot blood is characteristic of this inherited disorder: A. albinism B. sickle cell anemia C. hemophilia D. fragile X syndrome

hemophilia

When alleles are different, the combination is said to be: A. dominant B. homozygous C. heterozygous D. recessive

heterozygous

When alleles are the same, the gene type is said to be: A. homozygous B. heterozygous C. dominant D. recessive

homozygous

The complete chromosomal composition of the nucleus is called the _____________ of the cell. Hint: We can extract the chromosomes and photograph them under a microscope to look at this.

karyotype

Sex-linked diseases affect men more than women because: A. men have two X chromosomes B. men have two Y chromosomes C. men have one X chromosome D. sex-linked diseases affect men and women evenly

men have one X chromosome (Men have one X chromosome and one Y chromosome. Women have 2 X chromosomes. Therefore, if a male inherits a diseased X chromosome, he will express (have) the disease since he doesn't have another normal X chromosome to counteract the diseased one.)

What combination of alleles manifest themselves only when the person is homozygous for the trait? A .heterozygous B. dominant C. recessive D. familial

recessive

"John has a form of hemophilia which is a disease that causes him to bleed for a longer period of time than normal." How is this disease inherited? A. autosomal dominant B. autosomal recessive C. sex-linked - Y chromosome D. sex-linked - X chromosome

sex-linked - X chromosome