The portion of the blastoderm-stage embryo which will give rise to most ectodermal, mesodermal, and endodermal tissues is called the:

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#Question id: 1863

#Unit 4. Cell Communication and Cell Signaling

Di George syndrome results from a defect in:

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#Question id: 21960

#Unit 2. Cellular Organization

When the metaphase chromosome is formed the scaffold associated regions are found 

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#Question id: 15562

#Unit 12. Applied Biology

Deletion of which gene not only was accompanied by the abolition of antibiotic formation but also severely impaired growth on agar media.

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#Question id: 141

#Unit 1. Molecules and their Interaction Relevant to Biology

At the isoelectric pH of an amino acid which has two pKa values the net charge is

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#Question id: 12409

#Unit 6. System Physiology – Plant

The Chemical Structure of ABA Determines Its Physiological Activity, 15 carbon compound 

a) The orientation of the carboxyl group at carbon 2 determines the cis and trans isomers of ABA. Nearly all the naturally occurring ABA is in the cis form

b) S enantiomer is the natural form; commercially available synthetic  ABA is a mixture of approximately equal amounts of the S and R forms.

c) The S enantiomer is the only one that is active in fast responses to ABA, such as stomatal closure

d) In long-term responses, such as seed maturation, only R-enantiomers are active

e) In contrast to the cis and trans isomers, the S and R forms cannot be interconverted in the plant tissue

Which of the following is the correct prediction about the active form  of ABA?