In 1988, Richardson and Richardson observed that certain amino acid residues are statically favored as the amino-terminal caps for the alpha helices in 45 globular proteins. Which of the following statement stand correct with stability of helix?

A. The introduction of a negatively charged side chain at the N-cap, which can neutralize the partial dipole created by the unpaired amide protons, has been shown to increase stability

B. In particular, Gly is often observed at the both C-cap position and N-cap positions

C. In particular, Gly is often observed at the C-cap position only

D. In particular, Gly is often observed at the C-cap position, Asn at the N-cap position, Pro at the Ncap+1 and Asp and Glu at N2 and N3

#Question id: 7115

#Unit 5. Developmental Biology

The ability of the sea urchin embryo to regulate its development illustrates the fact that there are maternally-determined differences along the animal-vegetal axis that are necessary for normal development. Which of the following statements about regulation in sea urchin embryos is consistent with that fact?

#Question id: 7116

#Unit 5. Developmental Biology

Which one statement best describes gastrulation in sea urchins?

a) Gastrulation is initiated by invagination of the micromeres at the vegetal pole.

b) The mouth of the pluteus larva will form from mesomeres on the oral side of the 60-cell embryo.

c) The gut will form from the macromeres at the 16-cell stage.

d) Mesenchymal cells originating at the vegetal pole will invaginate first during gastrulation and will form skeletal structures in the pluteus larva.

Which of the following combination is correct?

#Question id: 7117

#Unit 5. Developmental Biology

Which of the following statements explains why gain-of-function mutation of Pmar1 results in a vegetalized embryo:

#Question id: 7118

#Unit 5. Developmental Biology

At the molecular and cellular level, how does morphogenesis differ from establishment of embryonic axes and the specification of cellular identity?

#Question id: 7119

#Unit 5. Developmental Biology

Adherens junctions play in important role in development; they are composed of:

#Question id: 7120

#Unit 5. Developmental Biology

Which of the following is the only true statement regarding compaction in the mouse embryo?