Describe how plant genes can be manipulated using the ti plasmid carried by agrobacterium as a vector.

Agrobacterium tumefaciens is a bacteria that cause crown gall disease in plants. This bacterium enters in plant cell through the wound and releases Ti plasmid in bacteria cytoplasm. The T DNA present in the plasmid integrates into the plant genome and cause crown gall disease in plant.

Therefore this quality of Ti plasmid is used in genetic engineering to manipulate plant gene. A desired gene can be introduced in the place of T DNA of Ti plasmid and then this agrobacterium is used to infect a plant.

This will allow the bacterial Ti plasmid to integrate the desired DNA fragment in the host plant cells. So by this method plant genes can be manipulated.

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!