They include single-celled diatoms and multicellular seaweed. Like plants, they contain chlorophyll and make food by photosynthesis. Types of algae include red and green algae, euglenids, and dinoflagellates. Fungus-like protists are molds.

Protists are very small, eukaryotic organisms (meaning their cells are organized into specialized compartments) that are not plants, animals, or fungi. Diatoms are single-celled organisms but can often be found lumped together, and they live in both freshwater and marine water.

Diatoms are classified as eukaryotes, organisms with a membrane-bound cell nucleus, that separates them from the prokaryotes archaea and bacteria. Diatoms are a type of plankton called phytoplankton, the most common of the plankton types.

The living matter of each diatom is enclosed in a shell of silica that it secretes. When aquatic diatoms die they drop to the bottom, and the shells, not being subject to decay, collect in the ooze and eventually form the material known as diatomaceous earth (sometimes called kieselguhr).

Diatoms use it to build tough outer cell walls for themselves. The diatoms pop up to eat these excess nutrients. They usually go away on their own after a few weeks, but sometimes it can take several months. There are steps you can take to get rid of brown algae more quickly.

The neurotoxin domoic acid (DA) is produced by diatoms in the genus Pseudo-nitzschia and has a high affinity for glutamate receptors. In humans, it causes loss of short-term memory and is called amnesic shellfish poisoning.

A very common use for diatoms is for filtration. The fine structures of diatom shells trap foreign particles in fluids, such as dirt, lint, hair and some other microscopic organisms. Diatoms are often used to filter water, particularly water in hot tubs and swimming pools.

Diatoms are used in many manufactured products that we use every day. Diatoms are microscopic (to nanoscopic) bits of silica glass that are used as a fine abrasive in toothpaste to clean teeth. Another source of diatoms is tooth powder.

The diatoms are the unique organisms, because of their distinctive cell walls. The walls are embedded with silica and thus the walls are indestructible. It show sculpturing and ornamentation that why Diatoms are also called as ‘Pearls of Ocean’. Diatoms are the chief ‘producers’ in the oceans.

Kingdom Protista

Diatoms are microscopic and mostly unicellular algae and have the green pigment chlorophyll and the yellowish-brown pigment xanthophyll, which is responsible for the golden brown colour.

Diatoms are an enigma. Neither plant nor animal, they share biochemical features of both. Though simple single-celled algae, they are covered with elegant casings sculpted from silica.

Their predators include blue crabs, terrapins, fish, raccoons, and marsh birds.

Diatoms are usually referred to as golden-brown microalgae, due to the colour of their plastids and to their pigment composition, mainly carotenoids (fucoxanthin, diadinoxanthin, diatoxanthin), which mask chlorophylls a and c.

Explanation: The desmids are termed as golden-brown or golden algae as they have characteristic golden colored pigment named fucoxanthin. their color is also golden due to the presence of the oil droplets that they save as the source of food. This group have 33 genera and 1200 species in it.

As a plant containing chlorophyll, golden alga can make its own food using sunlight and inorganic nutrients found in the water. However, it’s also capable of preying on other organisms. Destroy cells of some organisms, causing them to release dissolved organic matter which then becomes food for the golden alga.

Bacteria has two domains, namely eubacteria and archaea. Eubacteria are also called true bacteria. They have rigid cell walls and flagella. Thus, the correct answer is ‘Eubacteria are also called false bacteria.

There is no peptidoglycan as in the bacterial cell wall. They are prokaryotes which do not have membrane-bound organelles. They have 16S rRNA genes which are genetically different from the other organisms. The lipids in archaebacteria form an S-layer with the amino acids and glycolipids.

Eubacterium, plural eubacteria, also called bacteria, term formerly used to describe and differentiate any of a group of prokaryotic true bacteria from the archaebacteria. Today, true bacteria form the domain Bacteria.

Desmids are a type of green algae. Prokaryotes are bacteria and archaea.

Desmid, (order Desmidiales), order of single-celled (sometimes filamentous or colonial) microscopic green algae, comprising some 5,000 species in about 40 genera. Desmids are sometimes treated as a family (Desmidiaceae) of the order Zygnematales.

Most dinoflagellates are autotrophic, others are heterotrophic or osmotrophic. Diatoms are unicellular, colonial, or filamentous autotrophic organisms that live in marine and freshwater habitats.

Desmids can be recognised by their symmetry. Two, mostly ornamented semi-cells are joined by a narrow connection called the isthmus. Many Desmids secrete mucilage from pores in the cell wall. With this they can move towards light or avoid too bright light.

An oligochaete worm with in its gut various algal species, among which the desmid Closterium moniliferum. There are also many uni-cellular organisms that feed on desmids: An Amoeba (Amoeba proteus) using two pseudopods (false feet) to capture Staurastrum brachiatum.

Desmids are primarily found in freshwater habitats, such as ponds, rivers, and lakes. There, they may live as phytoplankton, on the bottom as benthic dwellers, or on the submerged portions of plants. They may also be found in saline waters, or in snow or ice.