Hi. In this video, we're going to talk about protists, which are essentially the category of eukaryotes that include everything that isn't a plant, an animal, or a fungus. So it's kind of like a biological grab bag or potpourri. It's a real mixture, and as you'll see there aren't really a lot of unifying themes that tie protists together. So let's begin our discussion by talking about eukaryotic cells. Right? Protists are eukaryotes. So what are eukaryotes? Well, you might recall that eukaryotes have a nucleus, they have membrane-bound organelles, and these include a cytoskeleton. Now, the unifying theme of eukaryotes, if you will, is the nucleus. And let's use a little fancy terminology here. The synapomorphy, right? The derived character that is shared between the organisms in a clade, the synapomorphy that unifies eukaryotes is the nucleus. Right? Now, eukaryotes also tend to be much larger than prokaryotes. Right here we've got some little prokaryotic cells. Here we have our eukaryotic cell, I should say, just one cell. A eukaryote tends to be a lot larger, it's got this nucleus, you can see all these membrane-bound organelles, we have mitochondria here, these are Golgi apparatus, right? There are our centrioles and, you know, here we're really showing the same thing, you know, now you can see the rough ER and the smooth ER. And if you want to review these concepts, go back and check out the video on cells. Before we dive into Protists, I also want to revisit the idea of endosymbiotic theory. And that is because endosymbiotic theory is actually going to play into Protists in kind of a unique and pretty darn cool way. So if you recall, the basic idea of endosymbiotic theory is that as prokaryotic cells, which were the first form of cells, got bigger, they faced this problem, the surface area to volume ratio issue that cells and organisms in general run into as they get larger. And so, these infoldings, these membrane infoldings, appeared to help counteract, or to help maintain rather a surface area to volume ratio that was ideal for the organism. Eventually, these infoldings become the nucleus and the endomembrane system and, ultimately, now we're going to get to the endosymbiotic part, ultimately what's going to happen is these cells are going to engulf a Proteobacterium. And it's worth noting that a lot of these single-celled organisms, you know, that act as hunters will literally just engulf their prey like this but instead of digesting this bacterium, what happened is these two organisms, essentially became reliant on each other. They formed a symbiotic relationship where they were helping each other. You know, for example, the larger cell that engulfed the proteobacterium, was like offering protection, probably feeding nutrients to the proteobacterium, and in exchange, the proteobacterium is going to generate a bunch of ATP, by oxidative phosphorylation. So eventually, these proteobacterium, through what is called symbiogenesis, write that down. So through symbiogenesis, these proteobacterium that were engulfed by prokaryotic cells will eventually become a eukaryotic cell, and those proteobacterium are going to become mitochondria. There's a lot of evidence for this. We're not going to cover it now, other than saying that like prokaryotes, mitochondria have a double membrane, which is unlike other membrane-bound organelles. And the reason I'm mentioning that, will become significant later. So in addition to this, there was also another symbiogenesis event where cyanobacterium were engulfed and eventually became chloroplasts. Right? So these are both instances of symbiogenesis. We have proteobacterium becoming mitochondria and cyanobacteria becoming chloroplasts. Now with that, let's flip the page and talk about how protists experience some unique forms of endosymbiosis.
Table of contents
- 1. Introduction to Biology2h 40m
- 2. Chemistry3h 40m
- 3. Water1h 26m
- 4. Biomolecules2h 23m
- 5. Cell Components2h 26m
- 6. The Membrane2h 31m
- 7. Energy and Metabolism2h 0m
- 8. Respiration2h 40m
- 9. Photosynthesis2h 49m
- 10. Cell Signaling59m
- 11. Cell Division2h 47m
- 12. Meiosis2h 0m
- 13. Mendelian Genetics4h 41m
- Introduction to Mendel's Experiments7m
- Genotype vs. Phenotype17m
- Punnett Squares13m
- Mendel's Experiments26m
- Mendel's Laws18m
- Monohybrid Crosses16m
- Test Crosses14m
- Dihybrid Crosses20m
- Punnett Square Probability26m
- Incomplete Dominance vs. Codominance20m
- Epistasis7m
- Non-Mendelian Genetics12m
- Pedigrees6m
- Autosomal Inheritance21m
- Sex-Linked Inheritance43m
- X-Inactivation9m
- 14. DNA Synthesis2h 27m
- 15. Gene Expression3h 20m
- 16. Regulation of Expression3h 31m
- Introduction to Regulation of Gene Expression13m
- Prokaryotic Gene Regulation via Operons27m
- The Lac Operon21m
- Glucose's Impact on Lac Operon25m
- The Trp Operon20m
- Review of the Lac Operon & Trp Operon11m
- Introduction to Eukaryotic Gene Regulation9m
- Eukaryotic Chromatin Modifications16m
- Eukaryotic Transcriptional Control22m
- Eukaryotic Post-Transcriptional Regulation28m
- Eukaryotic Post-Translational Regulation13m
- 17. Viruses37m
- 18. Biotechnology2h 58m
- 19. Genomics17m
- 20. Development1h 5m
- 21. Evolution3h 1m
- 22. Evolution of Populations3h 52m
- 23. Speciation1h 37m
- 24. History of Life on Earth2h 6m
- 25. Phylogeny2h 31m
- 26. Prokaryotes4h 59m
- 27. Protists1h 12m
- 28. Plants1h 22m
- 29. Fungi36m
- 30. Overview of Animals34m
- 31. Invertebrates1h 2m
- 32. Vertebrates50m
- 33. Plant Anatomy1h 3m
- 34. Vascular Plant Transport2m
- 35. Soil37m
- 36. Plant Reproduction47m
- 37. Plant Sensation and Response1h 9m
- 38. Animal Form and Function1h 19m
- 39. Digestive System10m
- 40. Circulatory System1h 57m
- 41. Immune System1h 12m
- 42. Osmoregulation and Excretion50m
- 43. Endocrine System4m
- 44. Animal Reproduction2m
- 45. Nervous System55m
- 46. Sensory Systems46m
- 47. Muscle Systems23m
- 48. Ecology3h 11m
- Introduction to Ecology20m
- Biogeography14m
- Earth's Climate Patterns50m
- Introduction to Terrestrial Biomes10m
- Terrestrial Biomes: Near Equator13m
- Terrestrial Biomes: Temperate Regions10m
- Terrestrial Biomes: Northern Regions15m
- Introduction to Aquatic Biomes27m
- Freshwater Aquatic Biomes14m
- Marine Aquatic Biomes13m
- 49. Animal Behavior28m
- 50. Population Ecology3h 41m
- Introduction to Population Ecology28m
- Population Sampling Methods23m
- Life History12m
- Population Demography17m
- Factors Limiting Population Growth14m
- Introduction to Population Growth Models22m
- Linear Population Growth6m
- Exponential Population Growth29m
- Logistic Population Growth32m
- r/K Selection10m
- The Human Population22m
- 51. Community Ecology2h 46m
- Introduction to Community Ecology2m
- Introduction to Community Interactions9m
- Community Interactions: Competition (-/-)38m
- Community Interactions: Exploitation (+/-)23m
- Community Interactions: Mutualism (+/+) & Commensalism (+/0)9m
- Community Structure35m
- Community Dynamics26m
- Geographic Impact on Communities21m
- 52. Ecosystems2h 36m
- 53. Conservation Biology24m
27. Protists
Introduction to Protists
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