TLS Online TPP Program

#Question id: 10911


Researchers have investigated bidirectional transport by applying two different radiotracers to two source leaves, one above the other. Researcher wanted to see how bidirectional transport happens in sieve elements. Which one of the following is INCORRECT interpretation for bidirectional transport?

#Unit 6. System Physiology – Plant
  1. Transport in two directions has often been detected in sieve elements of different vascular bundles in stems
  2. Transport in two directions has also been seen in adjacent sieve elements of the same bundle in petioles
  3. simultaneous bidirectional transport in a single sieve element has also been demonstrated
  4. Bidirectional transport in adjacent sieve elements can occur in the petiole of a leaf that is undergoing the transition from sink to source and simultaneously importing and exporting photosynthates through its petiole
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TLS Online TPP Program

#Question id: 5755

#Unit 8. Inheritance Biology

A researcher studying bacterial toxin predicts that a lysine within the toxin is important for binding it’s target cell.  She used site-directed mutagenesis to change a codon for lysine (AAA) to one for asparagine (AAU).  However, the mutant toxin still binds to its target cell just as well as the wild-type toxin bound and appears to have no other changes. This type of mutation is probably

TLS Online TPP Program

#Question id: 5756

#Unit 8. Inheritance Biology

Type of mutation caused by an addition or deletion of a base in a polypeptide-encoding part of a gene

TLS Online TPP Program

#Question id: 5757

#Unit 8. Inheritance Biology

A new E. coli mutant was tested for auxotrophy. The mutant grows on:

minimal medium (M) + arginine (A) + proline (P)

M + P + histidine (H)

M + A + H + P

but not on M or on M + A + H. The mutant requires

TLS Online TPP Program

#Question id: 5758

#Unit 8. Inheritance Biology

Consider a species with a diploid (2n) number of 28 chromosomes. How many chromosomes would be found in a monoploid body cell?

TLS Online TPP Program

#Question id: 5760

#Unit 8. Inheritance Biology

The fluctuation test of Luria and Delbruck (studying resistance to bacteriophge T1 infection) established that

TLS Online TPP Program

#Question id: 5761

#Unit 8. Inheritance Biology

E. coli cells were spread on an agar plate, producing 1000 colonies.  The colonies are replica plated on two agar plates containing the antibiotic kanamycin and one agar plate without antibiotics.  All of the colonies are able to grow on the agar plate without antibiotic but only 4 colonies are able to grow on each of the agar plates containing kanamycin.  You notice that the four colonies that grew on each of the kanamycin containing plates are in the exact same position.  This demonstrates