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Parabasalids

A second Excavata subgroup, the parabasalids, also exhibits semi-functional mitochondria. In parabasalids, these structures function anaerobically and are called hydrogenosomes because they produce hydrogen gas as a byproduct. Parabasalids move with flagella and membrane rippling. Trichomonas vaginalis , a parabasalid that causes a sexually transmitted disease in humans, employs these mechanisms to transit through the male and female urogenital tracts. T . vaginalis causes trichamoniasis, which appears in an estimated 180 million cases worldwide each year. Whereas men rarely exhibit symptoms during an infection with this protist, infected women may become more susceptible to secondary infection with human immunodeficiency virus (HIV) and may be more likely to develop cervical cancer. Pregnant women infected with T . vaginalis are at an increased risk of serious complications, such as pre-term delivery.

Euglenozoans

Euglenozoans includes parasites, heterotrophs, autotrophs, and mixotrophs, ranging in size from 10 to 500 µm. Euglenoids move through their aquatic habitats using two long flagella that guide them toward light sources sensed by a primitive ocular organ called an eyespot. The familiar genus, Euglena , encompasses some mixotrophic species that display a photosynthetic capability only when light is present. In the dark, the chloroplasts of Euglena shrink up and temporarily cease functioning, and the cells instead take up organic nutrients from their environment.

The human parasite, Trypanosoma brucei , belongs to a different subgroup of Euglenozoa, the kinetoplastids. The kinetoplastid subgroup is named after the kinetoplast    , a DNA mass carried within the single, oversized mitochondrion possessed by each of these cells. This subgroup includes several parasites, collectively called trypanosomes, which cause devastating human diseases and infect an insect species during a portion of their life cycle. T . brucei develops in the gut of the tsetse fly after the fly bites an infected human or other mammalian host. The parasite then travels to the insect salivary glands to be transmitted to another human or other mammal when the infected tsetse fly consumes another blood meal. T . brucei is common in central Africa and is the causative agent of African sleeping sickness, a disease associated with severe chronic fatigue, coma, and can be fatal if left untreated.

 The life cycle of  T. brucei begins when the tetse fly takes a blood meal from a human host, and inject the parasite into the bloodstream. T. brucei multiplies by binary fission in blood, lymph and spinal fluid. When another tsetse fly bites the infected person, it takes up the pathogen, which then multiplies by binary fission in the fly’s midgut. T. brucei transforms into an infective stage and enters the salivary gland, where it multiplies. The cycle is completed when the fly takes a blood meal from another human.
Trypanosoma brucei , the causative agent of sleeping sickness, spends part of its life cycle in the tsetse fly and part in humans. (credit: modification of work by CDC)

Watch this video to see T . brucei swimming.

Chromalveolata

Current evidence suggests that species classified as chromalveolates are derived from a common ancestor that engulfed a photosynthetic red algal cell, which itself had already evolved chloroplasts from an endosymbiotic relationship with a photosynthetic prokaryote. Therefore, the ancestor of chromalveolates is believed to have resulted from a secondary endosymbiotic event. However, some chromalveolates appear to have lost red alga-derived plastid organelles or lack plastid genes altogether. Therefore, this supergroup should be considered a hypothesis-based working group that is subject to change. Chromalveolates include very important photosynthetic organisms, such as diatoms, brown algae, and significant disease agents in animals and plants. The chromalveolates can be subdivided into alveolates and stramenopiles.

Questions & Answers

why are you insulting us my niggar?
Emmanuelfray Reply
what is deglutition
Nalumansi Reply
what is biology
Sierrah Reply
biology is a type of science that studies living things
xjuicy_editzz
viruses are composed of what
Daniel Reply
what are some disease caused by virus
Daniel
what are some disease caused by virus
Daniel
what are some disease caused by virus
Daniel
Ebola
Alhassan
Ebola,rabies,polio,hepatitis and small pox
Magoba
Corona (viral disease)
Musoke
viruses kinda in a sense not "living" what mean that a virus molecule that attaches to living organisms cells to destroy/kill them. so to answer your question they are composed/made up of molecules (please note that I am not 100% sure, please feel free to correct me :] )
xjuicy_editzz
what is meiosis
Koosono
what is evolution?
Emmanuelfray
what is the use of biology
Tarkaa Reply
To widen our reasoning abilities about the past and the present events in biology and life at large
Musoke
To understand our biography
Musoke
to study living things
Narh
Among all these which one is the major difference between platyhelminthes and coelenterates? 1. are multicellular 2. have developed a mesoderm 3. reproduce sexually 4. reproduce asexually
Habeeb Reply
what is evolution?
Emmanuelfray Reply
how can you define biology in terms of a burning fire in the bush?
Emmanuelfray
what is a cell
Kagelelo Reply
cell is a functional and unit of life
Sarita
it is the building block n basic unit of life
Narh
describe the process of testing the presence of starch in a leaf
Estel Reply
give me somes of examples.
Manu Reply
give example of what.
Ante
example of what
Elizabeth
what are chromosomes?
Ante
what is Biology
Darkoa
Biology is the study of animals and plants on their characters and death
Okol
No biology is the study of life (living thing's)
Achibiri
Chromosomes refers to one of the small parts like threads in the NUCLEI (central part )of plants and animals cell that carry the GENES
Estel
Yeah okol....Bio-means life and -logy means study/knowledge
Estel
Ecology is the study of
Abdul Reply
Ecology is the study of the interaction of organism in each other and their environment.
Ante
Ecology is the study of the interaction of organism in each other and their environment
Everlove
oh yes!!! exactly
Great
thank much
Ante
what is biome?
Ante
a geographical area with dinstic species
Francis
thanks much it very helpful
Ante
my pleasure
Francis
characteristics of living things
Jane Reply
excretion, movement, sensitivity, reproduction,growth, respiration,nutrition
Estel
what are there function
Ante
what are their function
Ante
what is the two type of reproduction?
Ante
sexual reproduction and asexual reproduction
Abdul
what are their function
Manu
Hi
Olufunmilokun
What is light independent reaction
Benjamin Reply
correct word or phrase. ______A____ uses carbon dioxide and _____B______ to make sugar during______C______. _____D______ traps light energy during this process. *
Andrea Reply
A_plant ,B_water,C_photosynthesis,D_chlorophyll
Abdul
Plant,sunlight,photosynthesis
Olufunmilokun
by which of the following feature c3 and c4 plant similar A .enzyme used to fix carbon dioxide B.cell where calvin cycle takes place C.cell where carbon dioxide fixation takes place
Kaleab Reply
correct word or phrase. ______A____ uses carbon dioxide and _____B______ to make sugar during______C______. _____D______ traps light energy during this process. *
Andrea

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Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
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