Certain proteins or mRNAs that are regionally localized within the unfertilized egg and regulate development are called

• gene regualtors

• morphometric determinants

• cytoplasmic determinants

• mosaic forming factors

Given are certain facts which define 'determination' of a developing embryo.

A. Cells have made a commitment to a differentiation program.

B. A phase where specific biochemical actions occur in embryonic cells.

C. The cell cannot respond to differentiation signals.

D. A phase where inductive signals trigger cell differentiation.

Which of the above statements best define determination?

• B and D

• A and C

• Only A

• Only B

Sperm cell behaviour during double fertilization in Arabidopsis can be stated as follows. Identify the INCORRECT statement:

• Pollen tube bursts and discharges sperm cells.

• Sperm cells produce pollen tubes and enter into the female gametophyte.

• The receptive antipodal cells break down when the pollen tube enters the female gametophyte.

• One sperm nucleus fuses with the egg cell and the other fuses with the central cells.

According to the ABC model of floral development in Arabidopsis as shown below,

several genes/transcription factors, eg. AP1, AP2, AP3, AG etc are involved. Which one of the following statements is correct?

• Apetala 2 (AP2) transcripts expressed during sepal and petal development.

• Agamous AG is considered as class A gene.

• AP1 expressed during carpel development.

• AP3 expressed during sepal development.

During development, if a cell has committed to a particular fate, it is said to be

• pluripotent

• totipotent

• determined

• differentiated

The initial dorsal-ventral ais in amphibian embryos is determined by

• the point os sperm entry.

• gravity

• the point of contact with the uterus.

• genetic differences in the cells.

If you remove a set of cells from an early embryo, you observe that the adult organism lacks the structure that would have been produced from those cells. Therefore, the organism seems to have undergone

• autonomous specification

• conditional specification

• morphogenic specification

• syncytial specification

What is the genotype of male Drosophila fly that has yellow body colour and red eyes. Brown (y⁺) is dominant over yellow (y) and red (w⁺) is dominant over white (w). Both are carried on X chromosome.

• X^w+y Y

• X^wyY

• X^wy+Y

• X^wy+X^wy+Y

Bones of vertebrates are derived fro embryonic

• ectoderm

• epiderm

• mesoderm

• endoderm

What would happen as a result of the transplantation experiment in a chick embryo where the leg mesenchyme is placed directly beneath the wing apical ectodermal ridge (AER)?

• Distal hindlimb structures develop at the end of the limb.

• A complete hindlimb will form in the region where the forelimb should be.

• The forelimb would form normally.

• Neither a forelimb nor a hindlimb would form since the cells are already determined.