Chloroplasts are the organelles responsible for photosynthesis in plants and algae. They are found in the cells of plants and algae, specifically in the mesophyll cells of leaves and in the cells of green algae.

Here's a breakdown:

* Plants: Chloroplasts are most abundant in the mesophyll cells of leaves, which are specialized for photosynthesis. They are also present in other plant cells, but in lower numbers.

* Algae: Chloroplasts are found in all types of algae, which use them to produce their own food through photosynthesis.

* Animals and fungi: These organisms do not contain chloroplasts and cannot perform photosynthesis. They obtain energy by consuming other organisms.