Question

Cristae are found in?

Answer 1

Chloroplasts are usually found in green plants and algae. Chloroplasts are also found in photosynthetic tissues that do not appear green in color, such as brown blades of giant kelp or the red leaves of certain plants. chloroplast is a pigment based on plastid types. Chloroplasts contain chlorophyll and carotenoid pigments that are essential for photosynthesis to trap light energy.

Complete answer:
Like mitochondria chloroplasts are also double membrane organelle. One of the membranes is the inner membrane which is less permeable. The space limited by the inner membrane of the chloroplast is called the stroma. A number of organized flattened membranous sacs called as thylakoids are present inside the stroma. Thylakoids are arranged in stacks like the piles of coin shaped known as grana. Also, there are flat membranous tubules called the stroma lamellae which connects the thylakoids of different grana. The stroma of the chloroplast contains many enzymes which are required for the synthesis of carbohydrates and proteins. The membrane of thylakoids is enclosed by a space which is called lumen.
The stroma also contains small, double stranded DNA molecules and ribosomes. The ribosomes of chloroplasts are smaller than the cytoplasmic ribosomes.
In them are two chambers: mitochondria and chloroplast; in mitochondria, stroma and thylakoids in Chloroplast, both have two matrix and crista. Mitochondria's inner membrane is folded to the crystals and a chloroplast membrane into flattened sacs.
Cristae is a fold in a mitochondria's inner membrane. It gives the internal membrane its wrinkled shape characteristics which provide a wide surface area for chemical reactions. The interior membrane is plied to form crystals to increase the ability of the mitochondria to synthesize ATP.

Hence, Cristae is found in ‘mitochondria’.

Note:
As we discussed the function of cristae and its purpose in both chloroplast and mitochondria. The chloroplast DNA nucleoids are clustered in the chloroplast middle of primitive red algae, while the nucleoids are spread throughout stroma in green plants and green algae. Chloroplasts are not present in all cells of a multicellular plant. Chloroplast without grana is found in mesophyll cells of all plants. Also, leucoplast is the plastid which has unpigmented organelle.