Anyone good at Ap bio

[From: ] [author: ] [Date: 11-05-09] [Hit: ]

25%B. 50%C. 75%D. 100%E. Her probability of inheriting the disease cannot be calculated without a genetic test.Suppose a wooly mammoth is walking on top of a glacier,......

Joan is a 35 year old woman whose mother died of Huntington’s disease. Neither Joan’s father nor her older brother show any signs of Huntington’s. What is the probability that Joan inherited the disease?
A. 25%
B. 50%
C. 75%
D. 100%
E. Her probability of inheriting the disease cannot be calculated without a genetic test.

Suppose a wooly mammoth is walking on top of a glacier, slips into a crack, and gets trapped. The animal freezes in the ice until the glacier starts to melt thousands of years later when a paleontologist recovers a small sample of the preserved animal. In order to compare the wooly mammoth’s DNA with DNA from living elephants, which of the following procedures should she use to increase the amount of DNA available to test?
A. Gel electrophoresis
B. Restriction fragment length polymorphism analysis
C. Polymerase chain reaction
D. Recombinant DNA technology
E. Gene therapy

Achondroplastic dwarfism is a dominant genetic trait that causes the head and torso of the body to develop normally, but the arms and legs to develop shorter than normal. The homozygous dominant condition is lethal, and the heterozygotes will be dwarfed. Mark has a family history of achondroplasia; however, he is not a dwarf. His wife, Susan, does express the trait. Mark and Susan are planning to have children and want to know the probability of having a child who is a dwarf.
The genotypes of the parents are most probably:
A. Mark AA; Susan Aa
B. Mark Aa; Susan aa
C. Mark aa; Susan aa
D. Mark aa; Susan Aa
E. Mark Aa; Susan Aa

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1. D, there are two alleles for each trait, and there are 5 traits, so 2^5= 32
2. D, If each parent is heterozygous for each trait, there is a 1/4 chance of the offspring being phenotypically reccesive for that trait, so 1/4x1/4x1/4= 1/64
3. D, If the parents have a son with hemophilia, the father will contribute the Y chromosome and the mother has to give an X, which has the faulty gene on it. However there is a possibility that the mother's other X chromosome does not have the faulty gene, so you can only conclude that one of her X's has the gene for hemophilia.
4. C.
5. D
6. B. Cirlces represent females. Shading represents an individual expressing the trait.
7. B. Huntington's is a dominant genetic disorder. If her brother shows no signs, then it is most likely that her mother was heterozygous for the disorder. If her father showed no signs, he was recessive for the disorder. If you draw a punnett square, you'll see that she has a 50% chance of inheriting the disorder.
8. C. Polymerase chain reactions amplify quantities of DNA.
9. D. If mark shows no dwarfism then he has to be aa. If Susan is a dwarf she has to be Aa, otherwise the pregnancy would have been aborted due to the lethality of the homozygous dominant form.

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