Many bacterial responses are controlled by two component regulatory systems. What will happen at the high concentration of glutamine and at the low concentration of glutamine?

a) At high concentrations glutamine binds to a sensor domain of NtrB conformational change in the protein that inhibits its histidine kinase activity

b) NtrC phosphorylation takes place causes a conformational change in NtrC that unmasks the NtrC DNA-binding domain so that it can bind to the glnA enhancers

c) At the same time, the regulatory domain of NtrC blocks its DNA-binding domain from binding the glnA enhancers

d) At low concentrations of glutamine dissociates from the sensor domain in the NtrB protein, leading to activation of a histidine kinase transmitter domain

Which of the following given combination is correct?

#Question id: 7292

#Unit 5. Developmental Biology

How is plant cell cytokinesis different from animal cell cytokinesis?

#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?