Growth hormone secretion is regulated by negative feedback, three feedback loops including both long and short loops are involved,

a.  GHRH inhibits its own secretion from the hypothalamus via an ultrashort-loop feedback.

b. Somatomedins, which are by-products of the growth hormone action on target tissues, inhibit secretion of growth hormone by the anterior pituitary.

c. Both growth hormone and somatomedins stimulate the secretion of somatostatin by the hypothalamus.

d. SRIF is also secreted by the hypothalmus and acts on the somatotrophs to stimulate growth hormone secretion.

Which one of the following represents all correct statements?

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#Question id: 12509

#Unit 8. Inheritance Biology

In this pedigree I 1 and II 2 have Becker muscular dystrophy which shows X-linked recessive inheritance. III 2 has oculocutaneous albinism which shows autosomal recessive inheritance with an incidence in the general population of 1 in 10 000. The disease status for both Becker muscular dystrophy and oculocutaneous albinism is unknown for IV 1 and IV 2.

What is the probability that IV 1 is a carrier of oculocutaneous albinism? 

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#Question id: 12510

#Unit 8. Inheritance Biology

In this pedigree I 1 and II 2 have Becker muscular dystrophy which shows X-linked recessive inheritance. III 2 has oculocutaneous albinism which shows autosomal recessive inheritance with an incidence in the general population of 1 in 10 000. The disease status for both Becker muscular dystrophy and oculocutaneous albinism is unknown for IV 1 and IV 2.

What is the probability that IV 2 will be affected with Becker muscular dystrophy?

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#Question id: 12511

#Unit 8. Inheritance Biology

In this pedigree I 1 and II 2 have Becker muscular dystrophy which shows X-linked recessive inheritance. III 2 has oculocutaneous albinism which shows autosomal recessive inheritance with an incidence in the general population of 1 in 10 000. The disease status for both Becker muscular dystrophy and oculocutaneous albinism is unknown for IV 1 and IV 2.

What is the probability that IV 2 will be affected with oculocutaneous albinism?

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#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?

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#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?

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#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?