Old Midterm 2Key

Old Midterm 2Key - PLANT BIOLOGY 113 SPRING 2008 MIDTERM#2...

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PLANT BIOLOGY 113, SPRING 2008 MIDTERM #2 PAGE 1 MAY 22, 2008 NAME KEY MIDTERM #2 - 300 POINTS TOTAL. This is a closed book exam due at the end of class. You may use notes handwritten on one side of a 4" x 6" card. Put your name on the card and turn it in with your test. Please be sure that you have 6 pages. Good luck! QUESTION 1 (20 POINTS) : List two ways in which expression of the T-DNA opine synthase gene in a crown gall tumor benefits the bacteria. 1. Opine synthase genes encode enzymes that synthesize opines. Agrobacteria use opines as a food source (10 points) 2. Opines stimulate conjugation and recombination in Agrobacteria, increasing genetic diversity of the bacteria and fitness of the population (10 points). QUESTION 2 (25 POINTS) : Predict whether or not the T-strand will be formed during the infection process with Agrobacterium tumefaciens with a loss-of-function mutation in the following Ti plasmid genes. Briefly justify your answer. virA mutation: No T-strand formation. VirA is part of a two-component system that is required for Agrobacterium to recognize a wounded plant and induce Vir operons (5 points) virB mutation: T-strand would form. VirB proteins are required to form the T-transporter that is required to transport the T-complex out of the bacterial cell (5 points). virD2 mutation: No T-strand formation. VirD2 is required to excise the T-strand and is bound its the 5' end (5 points). virE2 mutation: T-strand would form. VirE2 is a single-stranded DNA binding protein that coats the T-strand in the plant cell (5 points) . tms mutation: T-strand would form. TMS acts in the plant cell, not the bacteria (5 points) .
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PLANT BIOLOGY 113, SPRING 2008 MIDTERM #2 PAGE 2 MAY 22, 2008 NAME KEY 3. You have isolated DNA fragments containing components of the wild type T-DNA, such as the left border and TMS locus. Each component is inserted into the indicated sites in T-DNA #1 and T-DNA #2. The modified T-DNAs are then transferred into plants. LB NPT II RB SITE RB T-DNA #1 LB TMS SITE OPINE SYNTHESIS RB T-DNA #2 QUESTION 3A (25 POINTS) : Why is the NPT II gene often inserted into the T-DNA? How is this bacterial gene expressed in plant cells? 1. NPTII (neomycin phosphotransferase II) is a gene that confers resistance to the bacterial protein synthesis inhibitor, kanamycin. A chimeric gene encoding NPTII is included in the T-DNA of plant transformation vectors so that transgenic plants can be selected on the basis of their resistance to kanamycin (13 points). 2.
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This note was uploaded on 06/23/2010 for the course PLB 113 taught by Professor O'neil during the Spring '09 term at UC Davis.

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Old Midterm 2Key - PLANT BIOLOGY 113 SPRING 2008 MIDTERM#2...

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