Organismal Biology: Lecture 10

Eukaryotes have a plasma membrane, cytoplasm, cytosol, organelles, inclusions, nuclei, endoplasmic reticulum (smooth through), golgi apparatus, mitochondria, cytoskeleton per peroxisome, lysosome, flagellum. Photosynthetic eukaryotes (plant cells) have both mitochondria and plastids (chloroplasts, chromoplasts, amyloplasts) Both originate from endosymbiosis. Eukaryotic cells include 1. animal cells: lack cell wall & chloroplasts 2. plant cells: have central vacuole, cell wall, plastids, sometimes flagella 3 fungi cells lack flagella, have cell wall made of chitin, syncytium Some eukaryotes have pseudopodia which is a cellular extension to help with movement A protist is any eukaryote that's not a plant, animal, or fungus Most are unicellular; they They ha have large diversity involving nutrition (photo autotrophs, heterotrophs, mixotrophs); also have large diversity involving reproduction and life cycles. Haplad reproductive gametes differ in size (anı sogamy). Sexual reproduction has its disadvantages -half of the genes are passed on, and reproductive out put is decreased by half for given sex (dilution of genes). Advantages include: -new genetic combinations and elimination of deleterious alleles → speed adaptation - Sexual reproduction breaks apart favourable gene combinations built by past selection (can be dele terious). •Life cycle refers to the sequence of events from haploid to diploid both undergo mitosis to produce multicellular organisms. Advantages of sexual reproduction - don't need to find a mate no gene dilution. - individuals from endangered species can reproduce frequently. Disadvantages of sexual reproduction: less diversity in genes - adaptation is slowed in possible new environments. Excavata live in anaerobic conditions (use H₂) and have a modified. mitochondria The SAR group originated from secondary endosymbiosis a eukaryotic cell engulfs a as already undergone. primary endosymbiosis; a cell that has alr results in 3 3 p plasma membranes (2nd membrane from the first eukaryotic cell of 3rd membrane from the second eukaryotic cell). - Examples from the SAR group: 1. Diatoms have a hard silica shell; unicellular photosynthetic, make up of sedentary rocks 2. Brown algae: photosynthetic; structures analogous to plants; multicellular, alleration of generations (heteromorphic); two multicellular phases in the haplodiplontic life cycle Sporophyte (2n) game tophyle (n) 3. Dinoflagellates two flagella; create a "red tide" ; unicellular: causes. bioluminescence to scare predators. 4. Apicomplexans parasites of animals: (haploid sporozoites); Ex Plasmodium/main life cycle. phase is haploid haplontic life cycle. [mast haplontic life cycles are unicellular] The incidence of malaria coincides with the distribution of sickle cell. allele Individuals with the allele have a malaria it inhibits infection.. survival advantage agaisnt Sickle cell anemia causes haemoglobin to attach to other hemoglobin. rather than oxygen. There is a heterozygate advantage the haemoglobin that's unable to carry of will be destroyed so if infected DESTROYED! before it can reproduce 5. Ciliates Ex Paramecium caudatum 6. Forams: Ex: for minifera Archae plastida are monophyletic group with plants; Ex red algae:- multicellular; alteration of generations; red pigment from phycoerythrin.. Green algae related to plants; paraphyletic group, intracellular des if symbiosis with Paramecium (algae lives in food and the Paramecium provides the Paramecium provides it with algae with movement protection); contains chloroplasts.