What would be most likely to happen to a plant that had working chloroplasts in its cells but had taken in a poison that kept mitochondria from working?

This plant would use its chloroplasts to do the work that mitochondria should have done.

Explanation:

Chloroplasts are organelles that are part of a group known as plastids. These organelles are surrounded by two lipoprotein membranes and internally have a complex membrane network. Usually plastids are classified according to the type of pigment they present. In the case of chloroplasts, the most commonly found pigment is chlorophyll, a green pigment. Chloroplasts, like mitochondria, have their own DNA, RNA, and ribosomes that synthesize a portion of their proteins. The other part is synthesized by cellular DNA.

If a plant's mitochondria ceased to function, chloroplasts would take over the functions of mitochondria, this would work in relation to protein production, but chloroplasts are important for the photosynthesis process and cannot promote cellular respiration like mitochondria, so , probably the plant would die.