HORT 250 Fall 1999 Quiz 4

Select the most appropriate answer for each question from the selections provided.

 

1. Planting winter wheat after the "fly free day" is an example of which method to control damage from the Hessian fly:

  1. a genetic resistance
  2. a chemical control
  3. a cultural practice
  4. a physical entrapment
  5. none of the above

 

2. Which of the following is a potential problem in using insecticides to control insect populations in crops:

  1. contamination of groundwater
  2. loss of beneficial insects
  3. development of resistance in insect populations
  4. effective delivery of insecticide to site where insects are feeding
  5. all of these are potential problems
  6. none of these are potential problems

 

3. Proteins that block the action of digestive enzymes in the insect gut have been used to provide insect resistance in some crops. Which of the following is an example of this type of protein:

  1. EPSP synthase
  2. plasminogen activator
  3. protease inhibitor
  4. alkaline phosphatase

 

4. In order to express a protein only in the seed of transgenic plants, what modification must be made to the transgene that is introduced into transgenic plants:

  1. addition of a highly active promoter
  2. addition of a specific intron sequence
  3. addition of a promoter that is only active in seeds
  4. removal of aberrant codons

 

5. Bacillus thuringiensis produces a crystalline structure when it sporulates. This structure is composed of:

  1. kryptonite
  2. a single protoxin protein
  3. a small number of protoxin proteins
  4. a mixture of alpha-amylase inhibitors and protease inhibitors
  5. a small number of active toxin proteins

6. There are several steps required before Bt toxins can inhibit the growth of insects; which of the following is not involved in this process:

  1. release of the toxin from the protoxin
  2. synthesis of a chemical insecticide in the gut by Bt toxin
  3. recognition of the toxin by a receptor in the insect gut
  4. insertion of the toxin into the membrane of cells in the gut
  5. formation of a pore that leads to destruction of cells in the gut

 

7. Expression of Bt toxins in plants has a number of advantages over using conventional insecticides; which of the following is not an advantage of Bt toxins:

  1. the control is present throughout the growth of the plant
  2. the toxin can be targeted to specific tissues where insects feed
  3. this control is not dependent on the weather for application
  4. insects will not develop resistance to Bt toxins
  5. all of the above are advantages of the use of Bt toxins in transgenic plants

 

8. Farmers are encouraged to plant some of their corn or cotton acreage with varieties that do not express a Bt toxin because:

  1. seed companies do not have enough seed of Bt varieties available at the moment
  2. normal varieties have higher yields
  3. this allows populations of beneficial insects to survive
  4. this will slow down the development of insect populations with resistance to Bt
  5. this will spread their risk over different varieties

 

9. Ripening of tomato fruits:

  1. is an uncontrolled process of death and decay
  2. is regulated by the hormone ethylene
  3. does not involve changes in gene expression
  4. does not involve any changes in the composition of the fruit
  5. involves only the production of the red pigment lycopene

 

10. Crops that express Bt toxins are:

  1. immune from all insect damage
  2. very attractive to beneficial insects that prey on other insect pests
  3. resistant to a small number of insect pests
  4. resistant to microbial pathogens
  5. cheaper to buy than non-transgenic crops, in terms of cost of seed