Do plant cells have mitochondria, or only chloroplasts?

The click

Plant cells have both. Chloroplasts and mitochondria do opposite, complementary jobs, and a green plant cell needs both of them.

Chloroplasts carry out photosynthesis: they capture light energy and use it to make glucose from CO₂ and water. Mitochondria carry out aerobic respiration: they break down the products of glucose (pyruvate, from glycolysis) to release energy as ATP, which the cell spends on almost everything it does. The ATP made in the light reactions is used mainly inside the chloroplast to build sugars, so the rest of the cell still depends on mitochondria and glycolysis for its energy.

Not every plant cell has chloroplasts: root cells and cells deep inside stems usually lack them, since they get no light. But living plant cells have mitochondria. (Some cells, such as mature xylem vessels and tracheids, are dead at maturity and have no organelles at all.)

Both organelles have their own DNA, their own 70S ribosomes and a double membrane, which supports the endosymbiotic theory: mitochondria are thought to come from engulfed aerobic bacteria and chloroplasts from engulfed cyanobacteria. A useful summary for exams: plant cells have chloroplasts and mitochondria, animal cells have mitochondria but no chloroplasts, and prokaryotes such as bacteria have neither.