Question

multiple choice a vector is needed to introduce dna into human cells and not plant cells. genes to be expressed in human cells require a eukaryotic promoter, and genes to be expressed in plants dont. agrobacterium is commonly used as a tool to directly transform plant cells but not human cells. dna cannot be introduced into human cells.

Explanation:

1. Vectors are needed to introduce DNA into both human and plant cells, so the first option is incorrect.
2. Both human and plant cells are eukaryotic, and genes expressed in both require eukaryotic promoters, so the second option is incorrect.
3. Agrobacterium - mediated transformation is a common method for directly transforming plant cells, and it does not work for human cells as human cells are not natural hosts for Agrobacterium, so this option is correct.
4. DNA can be introduced into human cells through various methods like viral vectors, electroporation etc., so the fourth option is incorrect.

Answer:

C. Agrobacterium is commonly used as a tool to directly transform plant cells but not human cells.