What Is Kingdom Protista?

Kingdom Protista consists of unicellular eukaryotes. They act as a bridge between prokaryotic organisms and multi cellular eukaryotes and complex organisms including fungi, virus, plants and animals. It was discovered by Ernest Haeckel in 1866. They mostly occur in aquatic environment. Some of them act as a parasite. Their cell structure is in contrast with Prokaryotes. They have cell membrane with outer covering of sub cellular walls. They also contain membrane bound organelles such as mitochondria, endoplasmic reticulum, Golgi complex. Ribosome is 80S. Some of them have chloroplast which helps in photosynthesis. Nucleus is compact and has nuclear covering. It is not naked. They also have cilia and flagella which occur in variety of forms.