A herbicides dichlorophenyldimethylurea (DCMU) is known as diuron an inhibitor of photosynthetic electron transport. Which one of the following option would be correct about diuron?

a.) Blocks electron flow at the plastoquinone acceptors of PSII by competing for the binding site of plastoquinone

b.) causes a partial inhibition of stomatal closing

c.) accepts electrons from the early acceptors of PSI such as A0 and then reacts with oxygen to form superoxide, O2 –

d.) causes a partial inhibition of light-stimulated stomatal opening

#Question id: 7291

#Unit 5. Developmental Biology

Five different genes are known to specify floral organ identity in Arabidopsis: APETALA1 (AP1), APETALA2 (AP2), APETALA3 (AP3), PISTILLATA (PI), and AGAMOUS (AG).

Which one of the following statement is incorrect?

#Question id: 7290

#Unit 5. Developmental Biology

Following figure regarding to regulatory network in the Arabidopsis shoot meristem stem-cell niche.

A. The transcription factor WUS is synthesized in the cell A and moves via plasmodesmata into cell B, where one of its functions is to induce expression of the CLV3.

B. The transcription factor CLV3 is synthesized in the cell A and moves via plasmodesmata into cell B, where one of its functions is to induce expression of the WUS.

C. Secreted CLV3 protein from cell B binds to the receptor protein kinase on the surface of cell A; there, it activates a signal that represses WUS transcription.

D. Secreted WUS protein from cell B binds to the receptor protein kinase on the surface of cell A; there, it activates a signal that represses CLV3 transcription.

Which of the following combination is correct?

#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?

#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?

#Question id: 6942

#Unit 5. Developmental Biology

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

#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: