Ameoba

Keith Foy

McDowell

Bio 101

04/09/2012

Amoeba

The amoeba falls under the classification Euklaryota. It is part of the Protista kingdom which is made up of the simplest known eukaryotes. These organisms are single celled with a membrane surrounding the nucleus. The amoeba genus has over 290 million species. The amoeba cell is described as riged with extending pseudopods located at the anterior side of the cell. The pseudopods are used to move the cell around. It also has extensions on the upper side. The pseudopods also are used ingest or even lure food in. Part of the outer layer of the pseudopods is a hyaline layer. This layer has the thickness of the enamel on a human tooth. The outer layer of the amoeba is referred to as the plasma lemma or the cell membrane. Even though the plasma lemma is thin, it is still semi permeable allowing some substances to pass through the membrane while keeping others out. Under the plasma lemma is the ectoplasm. Although it is transparent to the eye the ectoplasm is still semi solid. Closest to the nucleus is the endoplasm, also translucent to the eye and holds proteins. The contractile vacuole envelops water and food. Round in shape it can expand and contract to pull in nutrients. It has a condensation membrane on the inner side surrounded by endoplasm, accessory vacuoles, and mitochondria. The accessory vacuole aids in the formation of the main vacuole. The food vacuoles hold the nutrients and digest the intake. Lysosomes surround the food vacuoles and eliminate waste within the amoeba. The uroid excretes the waste. Some food sources for the amoeba are other bacteria. Amoebas even ingest dead organic material. The amoeba’s environment ranges in temperature and it can live in fresh or salt water. Amoebas are found in streams, soils, waste, sewage, free standing water, oceans, even drinking water. One effect on humans is a fresh water amoeba. This amoeba is referred to as PAM (Primary Amoebic Meningeoncephalitis). PAM enters the body through the nasal cavity while swimming, diving or boating in calm, warm waters. Three cases in 2011 proved to be fatal attacking the host’s brain. In most cases it showed up as meningitis causing upset stomach, nausea, diarrhea, vomiting, and when a person has been infected for a while it can cause hallucinations. Some amoebas have been known to cause cysts. Being swallowed by the host it then implants itself in the stomach or throat. Leaving infection of the liver, lungs, and heart. When an amoeba is coming from another species it is normally a parasite. One infection is Amoebiasis, which is a gastrointestinal infection. These amoebas can lay dormant for a while undetected. Contracting this infection is done thru dirty hands, fecal-oral route, or even a dirty doorknob. It attacks the colon or the gastrointestinal wall, even the liver. Most Amoebiasiss is found in countries with low or no sanitation. Symptoms of this infection can be blood or mucus in the stool and diarrhea. . When the parasite reaches the blood it can cause liver abscesses. It has killed an average of 70,000 victims per year. Amoebas are eukaryotes and its genus has over 290 million species. Amoebas seem to have a negative effect on the environment and species around them causing severe illnesses or even death.

Resources: http://en.wikipedia.org/wiki/Amoeba http://www.transtutors.com/biology-homework-help/amoeba/structure-of-amoeba/