Part 2 – Obtaining energy and repoduction Microbes Part 2 – Obtaining energy and repoduction

Bacterial reproduction Reproduction in prokaryotes is primarily asexual and takes place by binary fission. Prokaryotes usually have a single circular chromosome. Prokaryotes don’t undergo mitosis, rather the chromosome loop is replicated, and the two resulting copies attached to the plasma membrane move apart as the cell grows. The now enlarged prokaryotic cell pinches in at its equator resulting in two cells. The two new daughter cells are clones of the parent cell. Binary fission does not provide an opportunity for genetic recombination.

Prokaryotes can alter there genetic make up in three ways. Transformation: the cell takes in DNA found in its environment that is shed by other prokaryotes, alive or dead. The cell may then take on characteristics found in the new DNA that it has recently acquired. Transduction: bacteriophages (the viruses that infect bacteria) move DNA from one bacterium cell to another. Archaea have a different set of viruses that do the same thing and translocate genetic material from on individual to another. Conjugation: DNA is transferred from on prokaryote to another my means of a pilus that brings the organisms into contact with one another. The DNA transferred is usually a plasmid.

Spore formation: when growth conditions become unfavourable, many prokaryotes form structures called spores. Endospore: formed when a prokaryote produces an internal capsule that encloses its DNA and a portion of cytoplasm. The endospore can remain dormant for months or even years. When growth conditions improve the endospore will open and the prokaryote will begin to grow again. This characteristic enables them to survive conditions that would otherwise kill them. Many bacterial diseases are the result of ingesting an endospore

https://www. britannica https://www.britannica.com/science/binary-fission/images-videos/Many- prokaryotic-organisms-such-as-bacteria-reproduce-by-the-process/107076

Obtaining energy All organisms require energy to survive. The process we use to produce energy is known as cellular respirations. Prokaryotes are very versatile and can utilize different ways to produce energy. Heterotrophs: Organisms that obtain their energy by taking in organics molecules and then breaking them down and absorbing them.

Heterotrophic organisms can be aerobic, anaerobic and obligate anaerobes. Aerobic: organisms that require oxygen to survive Anaerobic: organisms that can survive without oxygen. Obligate anaerobic: organisms that must live in oxygen free environment. Oxygen is lethal to these organisms

Autotrophic organisms make their own food from an energy source. Photosynthetic: uses the energy from the sun to make food Chemotropic: able to break down inorganic substances, such as hydro sulphuric acid, to produce energy to survive.

Resident Human Microbiota Many species of bacteria live on and in our bodies. Some are not harmful while other are. Harmful bacteria are known as pathogenic, or virulent. A pathogen refers to any organisms that is harmful. The degree of virulence is determining by two factors: Invasiveness: the ability to invade and multiple within human tissue Toxigenicity: the ability of a pathogenic organism to produce injurious substances that damage the host. Eg. Botulism toxin – a byproduct of the anaerobic bacterium Clostridium botulinum bacteria that can invaded the body through consumption of tainted/no sterile food itmes (cans, jars, packages). 1g and kill half of the US population. There are no known pathogenic Archaea in humans or any other organism. Pathogenic organism evolved alongside humans.

Beneficial Bacteria Not all prokaryotes are pathogenic. On the contrary, pathogens represent only a very small percentage of the diversity of the microbial world. In fact, our life and all life on this planet would not be possible without prokaryotes. Humans have used prokaryotes to create products before the term biotechnology was even coined. And some of the goods and services are as simple as cheese, yogurt, sour cream, vinegar, cured sausage, sauerkraut, and fermented seafood that contains both bacteria and archaea.

Using Prokaryotes to Clean up Our Planet: Bioremediation Microbial bioremediation is the use of prokaryotes (or microbial metabolism) to remove pollutants. Bioremediation has been used to remove agricultural chemicals (pesticides and fertilizers) that leach from soil into groundwater. Certain toxic metals, such as selenium and arsenic compounds, can also be removed from water by bioremediation.