Wild type E. coli metabolizes the sugar lactose by expressing the enzyme ß-galactosidase. You have isolated a mutant that you call lac1–, which cannot synthesize ß-galactosidase and cannot grow on lactose (Lac–). During an condition Lac– strain, called lac3–, is linked to the Tn5 insertion. From a strain carrying the Tn5 insertion and lac3– mutation you isolate an F’ that caries a region of the chromosome that includes both Tn5 and the linked Lac region. Introduce this F’ into an F– strain carrying lac1– by selecting for Kanr. These merodiploids express ß-galactosidase normally. If the merodiploid were Lac–, 

a) the two mutations lie in the different gene.

b) Both mutation are complement each other

c) the two mutations lie in the same gene.

d) Both of the mutations is dominant to wild type.

what could you conclude about the relationship between the lac3– and lac1– mutations from  these statements?

TLS Online TPP Program

#Question id: 14709

#Unit 5. Developmental Biology

Choose right statement about cleavage pattern and gastrulation movements;

1.At the end of cleavage the animal embryo is essentially a closed sheet of cells, which is often in the form of a sphere enclosing a fluid-filled interior. Gastrulation, strictly the formation of the gut, converts this sheet into a solid three-dimensional embryonic animal body. 

2.During cleavage, cells move into the interior of the embryo, and the regions of endoderm. and mesoderm. which were originally adjacent in the cell sheet, take up their appropriate positions in the embryo.

3. Gastrulation results from a well- defined spatio-temporal pattern of change in cell shape, cell movement, and change in cell adhesiveness, the main forces of which are generated by localized contractions.

TLS Online TPP Program

#Question id: 14710

#Unit 5. Developmental Biology

Splitting of one cellular sheet into two more or less parallel sheets. While on a cellular basis it resembles ingression, the result is the formation of a new (additional) epithelial sheet of cells, choose right gastrulation movement;

TLS Online TPP Program

#Question id: 14711

#Unit 5. Developmental Biology

Choose right explanations of gastrulation movements,  

TLS Online TPP Program

#Question id: 14712

#Unit 5. Developmental Biology

 Match the following cleavage pattern, with their egg type and cleavage type

TLS Online TPP Program

#Question id: 14713

#Unit 5. Developmental Biology

Match their cleavage patterns with their belonging animals;

TLS Online TPP Program

#Question id: 14714

#Unit 5. Developmental Biology

Eggs are grouped into three types on the basis of the distribution of yolk present in them, choose right combinations accordingly,