What differentiates animals, plants and fungi?

Although there are some unicellular eukaryotes, such as amoebas, paramecia or yeasts, eukaryotes (Eukarya Domain) are the only ones that have developed multicellular organisms. There are no multicellular organisms among prokaryotes (Prokaryota Domain).

And within the multicellular eukaryotic organisms, There are three large groups: floors (Kingdom Plantae), mushrooms (fungi kingdom) Y animals (Animalia Kingdom).

In this article we are going to see what are the main differences at the cellular and biochemical level between fungi, animals and plants, and a bit of their common evolutionary history.

Animals, plants and fungi: common evolutionary line

All available data and evidence suggest that fungi, animals and plants would have evolved from an ancient common ancestor, a primitive eukaryotic organism from which all current eukaryotes would arise.

Evolutionary cladogram of animals, fungi and plants
Evolutionary cladogram of animals, fungi and plants

They all present cells with a complex structure where membranous cell organelles appear, such as the nucleusthe mitochondriathe Golgi apparatus or the endoplasmic reticulumorganelles that are not present in prokaryotic cells (bacteria, archaea).

Although many fungal structures may resemble plant structures at the macroscopic level, from an evolutionary point of view fungi and animals are closer to each other than plants and fungi among them, although they are different enough that each forms its own biological kingdom.

This makes fungi and animals share some characteristics at the cellular and biochemical level that do not appear in plants.

For example, amino acid sequences in ribosome proteins have high similarity between animals and fungi. In both you can also find chitina substance that is not found in any plant.

Another common feature between fungi and animals is their position in the food chain. Neither fungi nor animals are primary producers, since both need to obtain food from the environment, while plants are photosynthetic organisms and present plastidsorganelles that do not appear in fungi or animals.

Fungi: lomasomes, chitin and ergosterol

The mushrooms they are organisms eukaryotes, multicellular (except yeasts which are unicellular) and heterotrophs.

Fungal cells have a cell wall. chitin cellunlike the cell wall of plant cells that is made of cellulose and animal cells that do not have a cell wall.

Also, fungal chitin is unique. Some animals produce an exoskeleton of chitin, like insects, but it is a different type of chitin, and in any case, the exoskeleton of insects is not a cellular structure.

The lomasomas They are bags with vesicular material formed by invaginations of the cytoplasmic membrane. These structures are often described as typical fungal cell organelles.

The structure of the cytoplasmic membrane is very similar between animals, plants and fungi. In all of them appear sterols that stabilize the double lipid layer, although in each group the sterol is different.

In fungi it appears ergosterolwhile cholesterol appears in animals and phytosterol in plants.

Fungal cells, like animal cells, use glycogen as a reserve carbohydrate, while plant cells use starch.

Plants: plastids, cellulose and phytosterols

Plant cells differ from animal cells and fungal cells in several ways.

One of the most notable is the presence of plastidscellular organelles that contain pigments. They highlight the chloroplasts that contain chlorophyll and perform the photosynthesis.

Through photosynthesis, plants synthesize their own food. That is, they are organisms. autotrophsunlike fungi and animals that are heterotrophs.

In addition, plants use starch as a reserve carbohydrate, while animals and fungi use glycogen.

Plant cells have cellulose cell wallunlike animal cells that do not have a cell wall and fungi that have a chitin cell wall.

The sterol of the cytoplasmic membrane in plants is the phytosterol, which contains cycloartenol. Ergosterol (fungi) and cholesterol (animals) contain lanosterol.

Animals: centrosome and cholesterol

In the cytoskeleton of animal cells, the centrosome, a cellular structure or organelle formed by the grouping of centrioles. Neither fungi nor plants have centrosomes.

The sterol of the cytoplasmic membrane is the cholesterol. animal cells do not have a cell wall.

Animals are all heterotrophic organisms and use glycogen as a carbohydrate for energy reserves, just like fungi.

Key Differences Between Fungi, Animals, and Plants

  • Cellular wall: Plant cells and fungi have a cell wall. In plants it is made of cellulose and in fungi it is made of chitin. There is no cell wall in the animal cell.
  • Sterols: Cholesterol appears in the cytoplasmic membrane of animal cells, in fungi ergosterol and in plants phytosterol.
  • organelles: Plants have plastids, including chloroplasts where they carry out photosynthesis. Centrosomes are typical of animal cells and lomasomes of fungi.
  • Reserve carbohydrates: plants are autotrophic and use starch as a reserve carbohydrate. Animals and fungi are heterotrophs and use glycogen.
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