Animal Cells

Animal cells are eukaryotic cells, so their DNA is enclosed in a nucleus. All the subcellular structures in the animal cell are contained by a cell membrane. Unlike the cells of plants and fungi, animal cells do not have a cell wall.

Under an electron microscope, an animal cell will look similar to the diagram below.

Diagram of an animal cell showing key components including the nucleus, mitochondria, ribosomes, cytoplasm, and cell membrane

Under a light microscope, only the cell membrane, cytoplasm and nucleus can be seen. This visibility is due to the size of the organelles.

Mitochondria are visible under a light microscope, however, they can only be seen in detail under an electron microscope. Whereas, ribosomes are only visible under an electron microscope.

Structures in an Animal Cell

The table below describes the function of different structures in an animal cell.

NucleusContains the genetic information of the cell in the form of DNA.

A gene is a functional unit of DNA. Information about every feature of the cell and the whole organism can be found in the genes.

The nucleus also controls the activities that occur within the cell, such as the substances that the cell produces and what goes in and out of the cell.
CytoplasmA jelly-like material where most of the chemical reactions in the cell occur.

The organelles of the cell move around in this substance. Important molecules, such as enzymes (which catalyse many metabolic reactions), are also found in the cytoplasm.
MitochondriaOrganelles found within the cytoplasm which are responsible for providing energy by carrying out aerobic respiration.

The enzymes for respiration are found in the mitochondria.
RibosomesVery small organelles that are responsible for the synthesis (production) of proteins such as enzymes.

There are millions of ribosomes located in the cell.
Cell membraneEvery cell has a cell membrane which controls what moves in and out of the cell.

It is the boundary between the cytoplasm and the cell’s surroundings, keeping the organelles locked within the cell.

There are different ways that substances can move across the cell membrane, such as diffusion and active transport.