Describe how the number of weed species resistant to herbicides has altered since 1960.
Explain how resistance to a herbicide develops in a weed species.
The gene coding for the ALS polypeptide has no non-coding sections (introns). The first amino acid in the completed polypeptide is methionine. State the number of base pairs in the gene that codes for an ALS polypeptide.
Explain why resistance to ALS inhibitor herbicide can arise from substitutions of amino acids that are widely separated in the primary sequence.
Genetic modification is one route used to create herbicide resistance in crop plants. Other routes are: method 1: crossing a crop plant with a herbicide-resistant wild plant from the same genus and then applying the herbicide method 2: inducing mutations in the crop plants and then applying the herbicide. State two advantages of using method 1 and two advantages of using method 2 to develop herbicide resistance in crop plants.