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Questions and Answers
What type of chromosomes are present in the mitochondria of Saccharomyces cerevisiae?
What type of chromosomes are present in the mitochondria of Saccharomyces cerevisiae?
The hypothesis of endosymbiosis suggests that eukaryotic nuclei contain genes derived from archaea.
The hypothesis of endosymbiosis suggests that eukaryotic nuclei contain genes derived from archaea.
False
Name the two subunits of eukaryotic ribosomes.
Name the two subunits of eukaryotic ribosomes.
40s and 60s
The first cells to appear on Earth were __________.
The first cells to appear on Earth were __________.
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Match the type of ribosome with its classification:
Match the type of ribosome with its classification:
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Which of the following does tigecycline inhibit?
Which of the following does tigecycline inhibit?
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The transition of prokaryotic to eukaryotic cells involved the discovery of asexual reproduction.
The transition of prokaryotic to eukaryotic cells involved the discovery of asexual reproduction.
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What is the main function of the mitochondria in eukaryotic cells?
What is the main function of the mitochondria in eukaryotic cells?
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What is the primary function of tigecycline as described in the context?
What is the primary function of tigecycline as described in the context?
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Tigecycline binds to human 80S ribosomes at physiological concentrations.
Tigecycline binds to human 80S ribosomes at physiological concentrations.
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What are the two types of endosymbiosis discussed?
What are the two types of endosymbiosis discussed?
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The last eukaryotic common ancestor (LECA) is a key concept in understanding ________.
The last eukaryotic common ancestor (LECA) is a key concept in understanding ________.
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Match the following concepts with their descriptions:
Match the following concepts with their descriptions:
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Which of the following organisms are included in the secondary endosymbiosis?
Which of the following organisms are included in the secondary endosymbiosis?
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The divergence of red and green algae indicates they share a common ancestor.
The divergence of red and green algae indicates they share a common ancestor.
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Name the two major hypotheses discussed about the origin of eukaryotes.
Name the two major hypotheses discussed about the origin of eukaryotes.
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What type of organism is Giardia intestinalis?
What type of organism is Giardia intestinalis?
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Trichomonas vaginalis is a disease caused by a waterborne infection.
Trichomonas vaginalis is a disease caused by a waterborne infection.
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Name one characteristic of Parabasalids.
Name one characteristic of Parabasalids.
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The _____ is responsible for the mobility of Trichomonas.
The _____ is responsible for the mobility of Trichomonas.
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Match the following groups with their correct descriptions:
Match the following groups with their correct descriptions:
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Which of the following is NOT a characteristic of Euglena?
Which of the following is NOT a characteristic of Euglena?
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All dinoflagellates are non-toxic and safe for marine life.
All dinoflagellates are non-toxic and safe for marine life.
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Which of the following is a characteristic of ciliates?
Which of the following is a characteristic of ciliates?
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What is the primary role of alveoli in alveolates?
What is the primary role of alveoli in alveolates?
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Toxoplasma and Eimeria are classified as dinoflagellates.
Toxoplasma and Eimeria are classified as dinoflagellates.
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What is the function of the micronucleus in Paramecium?
What is the function of the micronucleus in Paramecium?
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Dinoflagellates are known to produce _____ that can be highly toxic.
Dinoflagellates are known to produce _____ that can be highly toxic.
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Match the following groups with their characteristics:
Match the following groups with their characteristics:
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Which of the following are included in the Stramenopiles group?
Which of the following are included in the Stramenopiles group?
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Apicomplexans have chloroplasts that are fully functional.
Apicomplexans have chloroplasts that are fully functional.
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What is an example of a ciliate mentioned in the content?
What is an example of a ciliate mentioned in the content?
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Which of the following is a characteristic of Gimnamebas?
Which of the following is a characteristic of Gimnamebas?
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Entamoeba histolytica is known for its role as a free-living protist.
Entamoeba histolytica is known for its role as a free-living protist.
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What do mucilaginous fungi produce for reproduction?
What do mucilaginous fungi produce for reproduction?
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The color of red algae is primarily due to the presence of __________.
The color of red algae is primarily due to the presence of __________.
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Match the following algae with their characteristics:
Match the following algae with their characteristics:
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Which of the following is NOT a type of amoebozoan?
Which of the following is NOT a type of amoebozoan?
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All green algae are unicellular.
All green algae are unicellular.
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Name one characteristic that distinguishes mucilaginous fungi from other fungi.
Name one characteristic that distinguishes mucilaginous fungi from other fungi.
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Study Notes
Origin of Eukaryotic Cells
- The first cells that appeared were prokaryotes (before the nucleus).
- Originated 1500 to 2000 million years ago.
- Evolutionary transition involved morphological complexity, incorporating genomes, discovering sexual reproduction, and leading to multicellular organisms.
Endosymbiotic Hypothesis
- The eukaryotic nucleus contains genes derived from bacteria.
- Ribosomes, organelles and their phylogeny suggest a shared origin with prokaryotic ribosomes.
- Antibiotic specificity supports the theory.
Endosymbiotic Hypothesis: Antibiotic Specificity
- Tigecycline is an antibiotic used to treat bacterial infections.
- It inhibits bacterial protein translation by blocking the ribosomal A-site.
- While cytotoxic to human cells, its mechanism of inhibition is unclear.
Endosymbiotic Hypothesis: Hidrogenosomas
- Phylogenetic analyses associate them with prokaryotes.
Primary and Secondary Endosymbiosis
- Primary Endosymbiosis: A cell of Eukarya acquires a mitochondrion and a nucleus.
-
Secondary Endosymbiosis: A cell from a cyanobacterial lineage of Bacteria acquires a chloroplast from red algae, leading to:
- Dinoflagellates
- Apicomplexans
- Stramenopiles.
- A cell from a green algae lineage acquires a chloroplast from green algae leading to:
- Green Algae
- Euglenida
- Chlorarachniophytes.
Eucariogenesis
- Eukaryotes originated from a prokaryotic ancestor.
- LECA (Last Eukaryotic Common Ancestor) is a key point in eukaryotic evolution.
- Debates on the origin of LECA from Bacteria or Archea.
- Monophyletic origin of Eukaryotes.
Eucariogenesis: Phylogeny
- A comparison of 3D and 2D phylogenetic trees shows the relationship between Bacteria, Archaea, and Eukarya.
Diplomonads and Parabasalids
- Diplomonads:
- Two nuclei of the same size.
- Mitosomes.
- Compact genome with few introns.
- Giardia intestinalis causes diarrheal disease transmitted through water.
- Parabasalids:
- Parabasal body supporting the Golgi complex.
- Hidrogenosomas.
- Found in the gastrointestinal and urogenital tracts.
- Trichomonas vaginalis is a sexually transmitted disease.
Trichomonas
- Trichomonas is a flagellated protozoan with a parabasal body and hidrogenosomas.
- It's a human pathogen that causes sexually transmitted infections.
Euglenozoa
- A diverse group of unicellular flagellated eukaryotes.
- They can be free-living or parasitic.
- Some are pathogenic and have a kinetoplast (DNA in the unique mitochondrion).
- Euglenids are mobile, non-pathogenic, and phototrophic or chemotrophic.
Euglenozoa: Kinetoplastids and Euglenids
- Kinetoplastids:
- Kinetoplast.
- Unique mitochondrion.
- Aquatic environments. Some are pathogenic (e.g., Trypanosoma brucei, T. cruzi, Leishmania).
- Euglenids:
- Non-pathogenic.
- Chemo- or phototrophic.
- Found in freshwater or saltwater environments.
- Phagotrophic (feeding on bacteria by phagocytosis).
Alveolates
- Characterized by alveoli, cytoplasmic sacs below the plasma membrane.
- Alveoli may help maintain osmotic balance.
- Three main groups:
- Ciliates (e.g., Paramecium)
- Dinoflagellates (photosynthetic, some toxic; e.g., Gonyaulax - red tide)
- Apicomplexans (e.g., Toxoplasma, Plasmodium, Eimeria).
Alveolates: Ciliates, Dinoflagellates and Apicomplexans
- Ciliates:
- Have cilia at some point.
- Use them for movement and feeding.
- Have a food vacuole.
- Micronucleus for genetic recombination.
- Macronucleus for basic cell functions.
- Examples: Balantidium coli, Paramecium
- Dinoflagellates:
- Phototrophic freshwater organisms.
- Secondary endosymbiosis.
- Flagella with spinning motion.
- Free-living or symbiotic.
- Some produce neurotoxins (e.g., Gonyaulax, Pfiesteria).
- Apicomplexans:
- Non-phototrophic.
- Obligate parasites of animals.
- Produce sporozoites, the transmission stage of the parasite.
- Apicomplexan refers to their specialized organelles at the sporozoite's end.
- Degenerate chloroplasts (fatty acids, isoprenoids, heme group).
- Examples: Plasmodium, Toxoplasma, Eimeria (coccidia).
Paramecium
- Micronuclei function in genetic recombination.
- The macronucleus controls cellular activities.
- Specialized cellular structures: Contractile vacuole, Anal pore, Pellicle, Oral groove, Digestive vacuole, Trichocyst, Fibrils, Alveolus, Cilium, Cilia, Alveoli.
Stamenopiles
- 'Stramen' refers to the straw-like hairs (pili) on their flagella.
- Includes chemotrophs (heterotrophs) and phototrophs (autotrophs), from micro- to macro- organisms.
Stamenopiles: Diatoms, Oomycetes, Crisophytes and Brown Algae
- Diatoms:
- Unicellular, photosynthetic.
- Oomycetes:
- Aquatic fungi.
- Filamentous and coenocytic (multinucleate) growth.
- Crisophytes:
- Chrysophytes or golden-brown algae.
- Brown Algae:
- Large and multicellular.
Amoebozoa
- Gymnamoebas:
- Free-living protozoa.
- Use pseudopods (false feet) for movement (e.g., Amoeba)
- Entamoebas:
- Parasites of vertebrates and invertebrates.
- Found in the oral cavity or gastrointestinal tract.
- Entamoeba histolytica is a human parasite.
- Slime Molds:
- Form fruiting bodies with spores.
- Mobile, moving over solid surfaces.
- Two types:
- Plasmodial (multinucleate)
- Cellular (individual cells)
Amoebozoa: Amoeba, Slime Molds and Entamoeba
- Amoeba
- Slime Molds
- Entamoeba
Red and Green Algae: General Properties
- Photosynthetic.
- Contain chlorophyll a.
- Red algae:
- Do not have chlorophyll b.
- Contain phycobiliproteins, giving them a reddish color due to phycoerythrin.
- Lack flagella.
- Used in agar and sushi production.
- Some live acid hot springs.
- Green algae:
- Have chlorophyll a and b, giving their characteristic green color.
- Closely related to plants.
- Unicellular (e.g., Chlamydomonas, Dunaliella, Ostrococcus tauri) or macroscopic (e.g., Chara, Volvox).
Red and Green Algae: Organisms
- Red algae:
- Polysiphonia
- Cyanidium
- Galdiera
- Green algae:
- Chlamydomona
- Dunaliella
- Ostrococcus tauri
- Chara
- Volvox
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Description
Explore the origin of eukaryotic cells and the endosymbiotic hypothesis in this quiz. Learn about the evolutionary transition from prokaryotes to complex multicellular organisms and how antibiotic specificity supports this theory. Delve into the significance of ribosomes and organelles in understanding cellular evolution.
