TLS Online TPP Program

#Question id: 23682


Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to

#Unit 13. Methods in Biology
  1. insert the fragments cut with X directly into the plasmid without cutting the plasmid.
  2. cut the plasmid with restriction enzyme X and insert the fragments cut with Y into the plasmid.
  3. cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme.
  4. cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X.
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TLS Online TPP Program

#Question id: 13197

#Unit 1. Molecules and their Interaction Relevant to Biology

In helical nature of DNA is its periodicity each base pair is displaced (twisted) from the previous one by

TLS Online TPP Program

#Question id: 13198

#Unit 6. System Physiology – Plant

The sugar is a carbohydrate that are generally translocated  in the phloem in which form?

TLS Online TPP Program

#Question id: 13199

#Unit 6. System Physiology – Plant

The non-reducing sugar sucrose is most commonly translocated in the phloem rather than reducing sugar. Why?
a.) because they are less reactive than their reducing counterparts
b.) because sucrose contains more energy than a monosaccharides
c.) because the ketone or aldehyde group is reduced to an alcohol or combined with a similar group on another sugar so as not to be oxidized 
Which one of the following statements is true about translocation of non-reducing sugar?

TLS Online TPP Program

#Question id: 13200

#Unit 6. System Physiology – Plant

In the modification of translocation pathways, Interference with a translocation pathway by wounding or pruning can alter the patterns established by proximity and vascular connections. In the absence of direct connections between source and sink, vascular interconnections, called

TLS Online TPP Program

#Question id: 13201

#Unit 6. System Physiology – Plant

Phloem loading in the apoplastic pathway thought to mediate the transport of sucrose from the apoplast into the sieve element– companion cell complex. Which of the following  are involved in such sucrose transporting by apoplast?
a) Sucrose is at a higher concentration in the sieve element–companion cell complex indicates that sucrose is actively transported against its chemical-potential gradient
b) Sugars transport from the apoplast into the sieve elements and companion cells energy driven process
c) Phloem loading in the apoplastic pathway involves a sucrose–H+ symporter
d) the route of phloem loading is−mesophyll cells→ bundle sheath cells→ phloem parenchyma cell→ ordinary companion cell→ sieve elements
Which of the following is incorrect?

TLS Online TPP Program

#Question id: 13202

#Unit 6. System Physiology – Plant

Which of the following sucrose-H+ symporter appear to be the major sucrose transporters in phloem loading into the companion cells;