TLS Online TPP Program

#Question id: 6978


Removal of the apical ridge leads to

#Unit 5. Developmental Biology
  1. regeneration of the entire limb bud from underlying mesoderm
  2. formation of structures proximal to the apical ridge, but no formation of new distal structures
  3. regeneration of a new apical ridge from adjacent epidermal tissue
  4. continued development in the progress zone, once the apical ridge has induced progress zone formation
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TLS Online TPP Program

#Question id: 12492

#Unit 8. Inheritance Biology

A young man with phenylketonuria, who was successfully treated following diagnosis on newborn screening, is planning to start a family with his healthy, unaffected, and unrelated partner, who has no family history of phenylketonuria . Phenylketonuria shows autosomal recessive inheritance with an incidence of 1 in 10 000. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?

TLS Online TPP Program

#Question id: 12493

#Unit 8. Inheritance Biology

Cystic fibrosis shows autosomal recessive inheritance with an incidence of 1 in 2500. The unaffected brother of an affected girl is referred for genetic counseling. Assume that the population is in Hardy-Weinberg equilibrium. Which of the following is correct?

TLS Online TPP Program

#Question id: 12494

#Unit 8. Inheritance Biology

Hunter syndrome is a rare form of mucopolysacchararidosis that differs from all other forms in that it shows X-linked recessive inheritance. A woman with two affected brothers is referred for genetic counselling. Which of the following is correct?

TLS Online TPP Program

#Question id: 12495

#Unit 8. Inheritance Biology

Haemophilia A is a severe coagulation disorder that shows X-linked recessive inheritance. Red-green colour blindness also shows X-linked recessive inheritance. A man with both haemophilia A and colour blindness is referred for genetic counseling. Assume that his partner is not a carrier of either of these conditions. Which of the following is correct?

TLS Online TPP Program

#Question id: 12496

#Unit 8. Inheritance Biology

A woman who has two brothers and a maternal uncle (her mother's brother) with non-specific X-linked mental retardation is referred for genetic counselling. There are no diagnostic tests available to help determine whether or not she is a carrier. Which of the following is correct?

TLS Online TPP Program

#Question id: 12497

#Unit 8. Inheritance Biology

In this pedigree A and B represent alleles at a marker locus closely linked to the disease locus. Affected individuals are shown as shaded. The disease status in III 1 is unknown. Which of the following is correct?