Both chloroplasts and mitochondria contain DNA and are double membrane-bound organelles having an inner membrane and outer membrane. Mitochondria occur in the cytoplasm of both plants and animal cells. A mitochondrion contains two chambers. The inner membrane forms mitochondrial cristae. The chloroplast is also a double membranous organelle but found only in plants. The membrane-bound matrix of chloroplasts is stroma and inside the stroma thylakoids are present which form grana.