First inducers (in early gastrula stages) of the lens may be:

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#Question id: 14762

#Unit 2. Cellular Organization

Following statements are regarding to determination of filament formation by actin concentration.

A. The critical concentration (Cc) is the concentration at which G-actin monomers are in equilibrium with actin filaments.

B. At monomer concentrations below the Cc, no polymerization takes place. 

C. When polymerization is induced at monomer concentrations above the Cc, filaments assemble until steady state is reached and the monomer concentration falls to Cc.

D. At steady state, the concentration of monomeric actin below the critical concentration.

Which of the following statements promotes spontaneous filament assembly?

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#Question id: 15621

#Unit 13. Methods in Biology

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?

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#Question id: 4448

#Unit 3. Fundamental Processes

Three defined steps in a transcription cycle; choose correct one

1a. Closed complex	In this form, the DNA remains double-stranded, and the enzyme is bound to one face of the helix. I
1b. Open complex	In which the DNA strands separate over a distance of 13 bp around the start site to form the transcription bubble. In the next stage of initiation,
2. Promoter escape	Incorporation of the first 10 or so ribonucleotides is a rather inefficient process, and at that stage, the enzyme often releases short transcripts and then begins synthesis again
3. Initial transcribing complex.	Once an enzyme makes a transcript longer than 10 nucleotides, it is said to have

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#Question id: 28164

#Unit 13. Methods in Biology

It is possible to calculate the number of clones that must be present in a gene library to give a probability of obtaining a particular DNA sequence. This correct formula is:

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#Question id: 18738

#Unit 13. Methods in Biology

what do we mean by housekeeping genes?