Mitochondria are only found in eukaryotic cells. This is also true of other membrane-bound structures like the nucleus and the Golgi apparatus more on these later. One theory for eukaryotic evolution hypothesizes that mitochondria were first prokaryotic cells that lived inside other cells. Over time, evolution led to these separate organisms functioning as a single organism in the form of a eukaryote.
Eukaryotes are organisms whose cells have a nucleus and other organelles enclosed by a plasma membrane. Organelles are internal structures responsible for a variety of functions, such as energy production and protein synthesis. While most eukaryotes are multicellular organisms, there are some single-cell eukaryotes. Within a eukaryotic cell, each membrane-bound structure carries out specific cellular functions.
Here is an overview of many of the primary components of eukaryotic cells. Other common organelles found in many, but not all, eukaryotes include the Golgi apparatus, chloroplasts and lysosomes. Further Exploration Concept Links for further exploration plasmid cell genome chromosome conjugation prokaryotes transformation prokaryotes transduction prokaryotes eukaryote archaea eubacteria.
Related Concepts You have authorized LearnCasting of your reading list in Scitable. Do you want to LearnCast this session? Fimbriae and pili can often be found on the surface of bacterial cells. Fimbriae are short, hair-like projections that attach a bacterium to a substrate or other cells. Pili are similar structures that can serve many functions, including helping the bacterium move or helping it transfer DNA to another bacterium. Many bacteria have a whip-like flagellum or flagella, if they have more than one that aid in movement, or locomotion.
In bacterial cells, genetic material is usually clustered together in a region called the nucleoid, which floats in the cytoplasm. Some bacteria contain plasmids —small, circular strings of DNA that can replicate independently from the rest of the DNA in the cell. Ribosomes , which are essentially little protein factories, can be found scattered throughout the cytoplasm.
See more from our free eBook library. An introduction to bacteria from the Microbiology Society. Chapter 1: Scientific Inquiry. Chapter 2: Chemistry of Life. Chapter 3: Macromolecules.
Chapter 5: Membranes and Cellular Transport. Chapter 6: Cell Signaling. Chapter 7: Metabolism. Chapter 8: Cellular Respiration. Chapter 9: Photosynthesis. Chapter Cell Cycle and Division. Chapter Meiosis. Chapter Classical and Modern Genetics. Chapter Gene Expression. Chapter Biotechnology. Chapter Viruses. Chapter Nutrition and Digestion. Chapter Nervous System. Chapter Sensory Systems. Chapter Musculoskeletal System. Chapter Endocrine System.
Chapter Circulatory and Pulmonary Systems. Chapter Osmoregulation and Excretion. Chapter Immune System. Chapter Reproduction and Development.
Chapter Behavior. Chapter Ecosystems.
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