The image below shows an early chicken embryo during cleavage.

Which type of cleavage is depicted? Choose the CORRECT answer

a) Capture an image of the Dpy-18(ok162) ‘’Dumpy’’

mutant (1 mark). Label TWO features that

distinguishes it from the wild type worm (use arrows)  (2 marks).

b) Capture an image of the Lon-2(e678) ‘’Long’’

mutant (1 mark). Label ONE feature that

distinguishes it from the wild type worm (use arrow) (1 mark).

Note: Label your images in Photoshop or Powerpoint

(the latter is easiest) and up-load to Moodle as a single file,  as a pdf

or jpeg.

The figure below shows two types of viable cells derived from a parent cell after cell division (cell A and cell B). Cell B then expresses transcription factor 1 (in green) but not cell A.

Why might cell B express the transcription factor, but not cell A? Choose the CORRECT answer.

Imagine you are studying neural tissue specification in the Xenopus model. The dorsal (“top”) part of the Xenopus blastula, called the “animal cap”, normally forms ectoderm-derived neural tissue and epidermis.

When the animal cap is cut away from the rest of the blastula and grown by itself in culture, it only forms epidermis. This suggests some sort of secreted factor is required for induction of neural tissue. You add a growth factor protein called Noggin to the cultured animal cap and carry out staining for a marker of neural tissue. This is the result, where positive staining is dark:

What conclusion can be drawn? Choose the CORRECT answer.

Consider the figure below.

What type of molecule is denoted by the black arrow? Choose the CORRECT answer