TLS Online TPP Program

#Question id: 5691


Which of the following most accurately explains the cause for the abnormal numbers of chromosomes during human reproduction that can result in Down syndrome, Turner’s syndrome, or Klinefelter’s syndrome?

#Unit 8. Inheritance Biology
  1. The occurrence of nondisjunction of homologous chromosomes during meiosis

  2. The duplicative production of extra chromosomes during DNA replication

  3. The abnormal pairing of nonhomologous chromosomes during prophase of meiosis I

  4. The selective loss of particular chromosomes from the sex cells after formation of the mature gamete

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TLS Online TPP Program

#Question id: 7289

#Unit 5. Developmental Biology

The following scheme shows the flowering status of a plant species and the photoperiodism. Which of the following conclusions is most appropriate?

TLS Online TPP Program

#Question id: 7287

#Unit 5. Developmental Biology

Following statements are regarding to the the floral quartet model and the underlying ABCDE model of organ identity determination in Arabidopsis thaliana.

A. Five floral organ identities (sepals, petals, stamens, carpels, and ovules) are specified by the formation of floral organ-specific tetrameric complexes of MADS-domain transcription factors that bind to two nearby enhancer elements, forming a DNA loop in between.

B. A complex of two class A proteins (APETALA 1) and two class E proteins  (SEPALLATA) determines petal identity.

C. A complex of one class A protein, one class E protein, and one of each of the class B proteins (APETALA 3 and PISTILLATA) determines sepal identity.

D. A complex of one class E protein, two class B proteins, and one class C protein (AGAMOUS) determines stamen identity, while a complex of two class E proteins and two class C proteins determines carpel identity.D. A complex of one class E protein, two class B proteins, and one class C protein (AGAMOUS) determines stamen identity, while a complex of two class E proteins and two class C proteins determines carpel identity.

E. A complex of one class E protein, one class C protein, and one of each of the class D proteins (SHATTERPROOF and SEEDSTICK) controls ovule identity.

Which of the following combination are correct?

TLS Online TPP Program

#Question id: 6942

#Unit 5. Developmental Biology

How long does embryonic development (before 1st instar larva hatches) take in this organism?

TLS Online TPP Program

#Question id: 6943

#Unit 5. Developmental Biology

The portion of the blastoderm-stage embryo which will give rise to most ectodermal, mesodermal, and endodermal tissues is called the:

TLS Online TPP Program

#Question id: 6944

#Unit 5. Developmental Biology

Which would lead to a dorsalized embryo? (Recall that genes in Drosophila are named for their mutant phenotype.

TLS Online TPP Program

#Question id: 6945

#Unit 5. Developmental Biology

The portion of the Drosophila body plan which will produce the wing is called