Protists Flashcards
What is a protist?
A protist is a parapmpletic group of eukaryotes that are not fungi, land plants, or animals. They are diverse and can reproduce asexually or sexually.
Protists typically inhabit moist environments and impact human health and welfare.
Why study protists?
Studying protists is important due to their impact on agriculture and health, such as the Irish potato famine caused by the oomycete Phytophthora infestans, which leads to crop losses, and malaria caused by Plasmodium species.
Five different species of Plasmodium can infect humans.
What is the life cycle of malaria?
Malaria is caused by a complex lineage of Plasmodium that multiplies in red blood cells, causing fever and mitosis. The parasite can cause protein to stick to capillaries, leading to oxygen deprivation.
The Plasmodium is haploid, meaning it has one copy of each chromosome.
What are red tides?
Red tides are caused by blooms of algae that grow in high density, particularly dinoflagellates, which produce toxins that turn coastal water red.
These toxins can build up in shellfish, leading to paralytic shellfish poisoning.
What is the role of protists in ecosystems?
Protists play important roles in ecosystems as the foundation for aquatic ecosystems, including plankton and phytoplankton, such as diatoms, which are considered the grass of the ocean.
They also form symbiotic relationships, such as reef-building corals with zooxanthellae.
What is coral bleaching?
Coral bleaching occurs when corals release zooxanthellae, which can happen at a rate of 200 times.
This process negatively affects coral health and the ecosystems they support.
How do termites benefit from protists?
Termites host protists called Trichonymphs in their gut, which help digest cellulose through symbiotic relationships.
What type of organisms were the first eukaryotes?
unicellular
The first eukaryotes were single-celled organisms.
Did the first eukaryotes have a nucleus?
yes
The presence of a nucleus is a defining feature of eukaryotic cells.
What structures did the first eukaryotes possess?
Mitochondria, Cytoskeleton, Endomembrane system
These structures are important for cellular functions and organization.
Did the first eukaryotes have cell walls?
no
Unlike many prokaryotes, the first eukaryotes did not have cell walls.
How could the first eukaryotes move?
with flagellum-like structure
This allowed them to swim in their environment.
What is the nuclear envelope likely derived from?
infoldings of the plasma membrane
This infolding led to the formation of the nucleus and endoplasmic reticulum.
What does post-transcriptional processing allow?
enables alternate RNA splicing
This physical separation of transcription and translation is significant for gene regulation.
What is the theory of endosymbiosis regarding mitochondria?
mitochondria were small prokaryotes that began living inside another organism
This theory suggests a symbiotic relationship leading to the evolution of mitochondria.
What type of prokaryotes are believed to be the origin of mitochondria?
aerobic heterotrophic prokaryotes
These prokaryotes were capable of utilizing oxygen for energy.
What is the new hypothesis regarding the host of mitochondria?
archaean
This suggests that the host organism was a type of archaea.
What does the origin of chloroplasts involve?
endosymbiosis
Chloroplasts arose through a similar process as mitochondria.
When did chloroplasts acquire mitochondria?
after mitochondria
Chloroplasts evolved following the acquisition of mitochondria.
What is serial endosymbiosis?
occurs when endosymbiotic events happen repeatedly
This concept explains the acquisition of multiple organelles over time.
What is one characteristic of mitochondria that resembles bacteria?
Same size as average bacterium
Mitochondria are comparable in size to bacteria.
What replication method do mitochondria use?
similar to binary fission in prokaryotes
This method of replication is a characteristic of prokaryotic cells.
What type of DNA do mitochondria have?
single circular DNA not associated with histones
This structure is reminiscent of bacterial DNA.
Which gene sequences are related to mitochondria?
a-proteobacteria
The genetic material of mitochondria is closely related to that of a-proteobacteria.
