Examples of eukaryotic cells include plant, fungal, protist and animal cells. Myocytes (muscle cells) and human epithelial (skin) cells are both animal cells and are therefore eukaryotic. Parenchyma cells are plant cells that synthesize organic products, and are therefore eukaryotic. Examples of prokaryotic cells include bacteria. E. coli is a species of bacteria often found in the lower intestines of warm-blooded animals. All bacterial cells are prokaryotic, making an E. coli cell an example of a prokaryotic cell. 

Genetic recombination is one method by which the genome can change over time; the exchange of genetic material allows for the new combination of genes. Genetic recombination can be observed in both prokaryotic and eukaryotic cells. In eukaryotic cells, genetic recombination occurs during the crossing over event of meiosis, when homologous chromosomes exchange genetic material. In prokaryotes, genetic recombination occurs through the unilateral transfer of DNA. This includes transduction, transformation, and conjugation. Transduction the process by which DNA is transferred between bacterial cells by a virus. Transformation is the uptake of DNA from a bacteria's environment. Conjugation, or “bacterial sexual genetic recombination”, is the transfer of plasmid DNA between cells by physical contact, through a pilus.

Cells are encased in a semi-permeable phospholipid bilayer called the cell (plasma) membrane. Cell membranes serve to organize and protect the cell. Eukaryotic cells also have internal membranes, which enclose organelles, including the nuclear membrane. Plant, and fungal cells have an additional membrane, called the cell wall, outside of the cell membrane that offers additional support, protection, and rigidity. 

Eukaryotic DNA is separated from the rest of the cell in the nucleus, which is surrounded by a nuclear membrane. Bacteria and archaea are both prokaryotes, and thus do not have any membrane-bound organelles. Note that all cells have ribosomes, since they are not membrane-bound.

Protists consist of single celled eukaryotes and a few closely related multicellular organisms. Plantae contain multicellular eukaryotic organisms. Archaea and Bacteria are all prokaryotic. Examples of a single-celled eukaryotic protist are species of the genus Plasmodium, which cause malaria.

Nucleoids are found in prokaryotic cells. The nucleoid is the area of a cell that contains the DNA, and unlike the nucleus of eukaryotic cells, the nucleoid lacks a membrane to separate the DNA from the rest of the cell. The nucleolus is a structure within the nucleus of eukaryotic cells, and is the site of ribosome assembly.

The primary difference between prokaryotic and eukaryotic cells is that prokaryotic cells lack membrane-bound organelles and have circular DNA, while eukaryotic cells contain membrane-bound organelles and linear strands of DNA. Because prokaryotic cells lack membrane enclosed organelles, cells do not have nuclei. Rather, the cell’s DNA is located in the nucleoid, a nucleus-like region within the cell. Eukaryotic cells generally comprise more complex organisms, such as plants, humans, and animals. Prokaryotic cells generally comprise bacteria and smaller organisms. All cells have ribosomes.

Prokaryotes utilize binary fission for cellular division. Binary fission involves asexual reproduction of prokaryotes. First the cell grows and duplicates its genome, and any plasmids. The cell polarizes itself, then begins forming a cell wall to divide the cell into two slightly smaller cells. Eukaryotes use mitosis, and meiosis. Sexual reproduction occurs in some phyla of eukaryotes.

Prokaryotic cells do not have a nucleus. The genetic material for prokaryotes is concentrated in a region called the nucleoid but there is no membrane separating this region from the rest of the cell unlike in eukaryotic cells, which do have membrane-bound nuclei. Animal cells and plant cells are eukaryotes.  

All of these structures are organelles except the ribosome. The ribosome is found in both prokaryotic and eukaryotic cells. It is the site of protein synthesis (translation). Ribosomes may be free-floating in the cytoplasm, or attached to the endoplasmic reticulum in eukaryotes. Since ribosomes are not membrane-bound, they do not fit the classical definition of an organelle.