A young woman comes to the emergency room with a vertebral compression fracture. Radiographs of the spine indicate generalized demineralization. She is vegetarian, does not smoke or drink alcohol, has normal plasma potassium concentration of 5.4 mEq/L, sodium concentration of 136 mEq/L, plasma calcium concentration is 7.0 mg/dL. Her vitamin D3 value is several times greater than normal, although her 1,25-dihydroxycholecalciferol concentration is at the lower limit of detectability. She has been in renal failure for the last 5 years and undergoes hemodialysis three times each week. What is the cause of her low 1,25-dihydroxycholecalciferol level?

TLS Online TPP Program

#Question id: 15002

#Unit 8. Inheritance Biology

If you performed a dihybrid cross and found that your results were significantly different from the 9:3:3:1 ratio, what would you suspect?

TLS Online TPP Program

#Question id: 15003

#Unit 8. Inheritance Biology

Laurie met her husband Jim at a support group for families dealing with PKU (phenylketonurea), a recessive genetic disorder. Laurie and Jim both have one sister who is affected with PKU and no other family history of the disorder. They come to you as a genetic counselor to ask what their risk is of having an affected child. What do you tell them?

TLS Online TPP Program

#Question id: 15004

#Unit 8. Inheritance Biology

Which of the following statements about a pedigree would be most definitive in determining a recessive pattern of inheritance?

TLS Online TPP Program

#Question id: 15005

#Unit 8. Inheritance Biology

You identify a previously unidentified plant species and decide to study its genetics. You establish true breeding strains for leaf shape (longer than wide vs equal length and width) and flower color (white vs. yellow). When you perform a dihybrid cross with these strains, you find that your results are very different than those predicted by a 9:3:3:1 ratio. You calculate a chi square and get a p value of less than 0.0001. Which of the following statements is most accurate based on this observation?

TLS Online TPP Program

#Question id: 15006

#Unit 8. Inheritance Biology

Which of the following is not a mechanism for sex determination?

TLS Online TPP Program

#Question id: 15007

#Unit 8. Inheritance Biology

You set up a cross between true breeding wild type male fruit flies and true breeding female flies with a yellow body color. You notice in the F1 generation that half the flies, specifically all the males, have yellow body color while the females are wild type (gray). Which of the following explanations is the most likely?