MCAT Biology

Prokaryotic Cells

MCAT Biology > Cells > Prokaryotic Cells


Prokaryotes are simple organisms that contain no membrane bound organelles. These simple organisms are commonly known as bacteria, viruses and bacteriophages. A few specific examples of prokaryotic cells cyanobacteria and archaebacteria. Prokaryotic cells only contain a small amount of DNA

Prokaryotic Cells - Prokaryotic Cell

They may also contain plasmids, which is a small ring that contains a few genes that may offer antibacterial resistance. The plasmid replicates independently of the genome and is not a vital structure. This allows prokaryotic cells such as bacteria to have a high degree of genetic variation and adaptability.

Prokaryotic Cells - Plasmid

Prokaryotes also have 50s/30s subunit ribosomes and have locomotion through their flagella

Asexual Replication

See Asexual Replication

Simple prokaryotic cells such as bacteria and viruses replicate asexually which means that they do not require a partner to make an offspring. Prokaryotic cells have many methods of creating genetically identical copies of themselves, and methods vary by organism. A few examples tested on the MCAT are:

  • Binary Fission
  • Budding
  • Regeneration
  • Parthenogenesis

Asexual vs. Sexual Replication

There are many key differences between asexual and sexual reproduction that you should know for the MCAT exam. Use the following table to learn the concepts for what is on the MCAT

Feature Asexual Reproduction Sexual Reproduction
Parents Required One Parent Two Parents
Type of Replication Binary Fission, Budding, Regeneration, Parthenogenesis Meiosis
Occurs In Lower Organisms Invertebrates and Vertebrates
Genetic Variation Identical (only some mutations) Unique Genetic Material (Fundamental for Evolution)
Sex Cells Required or Formed? No Yes (Gametes)
Time Efficient Yes No
Energy Required Small Amount More Energy Required
Number of Offspring Produced 2+ 1+


See Bacteria

There are two types of bacteria, spherical (cocci) and rod shaped (bacilli). Instead of having a nucleus, prokaryotes have a nucleoid region, which is simply DNA supercoiled around histones floating together in the cytoplasm.

A common example of a bacteria is the cyanobacteria.

Bacteria can be classified into 2 main types based on their morphology. These are bacilli and cocci. Bacilli bacteria have a more oval and oblique shape while cocci bacteria have a more spherical and rounded shape.

Bacterial Genetics

See Bacterial Genetics


See Plasmids


See Viruses


See Bacteriophages

Bacteria vs. Viruses

See Bacteria vs. Viruses

There are many differences between bacteria and viruses. Use this table to see a side by side comparison.

Click here to see the differences between prokaryotic and eukaryotic cells.


Click here to move onto eukaryotic cells.

Prokaryotic Cells

Prokaryotic Cells Topics

MCAT Biology

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