Dr Gilmour Flashcards
(33 cards)
What are the three high level divisions in the eukarya?
- Fungi and animals
- Primary endosymbiotic algae and plants
- Protists
What are the Opsithokonta?
- Animals, true fungi and microsporidia
- Named for backward pointing flagellum in animal spermatozoa and fungi zoospores
- Choanoflagellates similar to choanochytes in sponges
What are the primary endosymbiotic algae?
-Early eukaryote cells that had already acquired mitochondria used cyanobacterial cells as feedstocks. One of these was not digested and became the chloroplast
What are the Chlorophyta (Green algae)?
- Part of the primary endosymbiotic algae
- Unicellular, two anterior flagella that move the cell forward by a breast stroke swimming action
What are the Rhodophyta (Red algae)?
- Part of the primary endosymbiotic algae
- Many multicellular, but also filamentous and unicellular
- Coloured red by phycoerythrin
What are the protists?
-Mixture of groups previously divided into algae and protozoa
What are the secondary endosymbiotic algae?
- Part of the protists
- Have more than two membranes surrounding the chloroplast
- Widespread mixotrophy or heterotrophy, using many organic compounds
- Have more than two membranes surrounding the chloroplast
What are the diatoms?
- Part of the secondary endosymbiotic algae
- Frustules (Silica cell walls) produce diatomaceous earth
- Asexual cell division reduces cell size - Either centric with radial symmetry or pennate with bilateral
- Frustules (Silica cell walls) produce diatomaceous earth
What are the brown algae?
- Part of the secondary endosymbiotic algae
- Seaweeds
- Possess vacuoles of oily liquid (leucosin) for energy storage
What are the haptophytes?
- Part of the secondary endosymbiotic algae
- Coccolithophores produce an exo-skeleton of coccoliths made of CaCO3
What are the dinoflagellates?
- Secondary endosymbiotic algae
- Grouped in Alveolates as have alveoli
- Swim via spinning motion as have two flagella
- Can be toxic
What are the Alveolates?
- Part of the secondary endosymbiotic algae
- Have flattened vacuoles (alveoli) beneath outer membrane
What are the Apicomplexans?
- Parasites with an apicoplast derived from the endosymbiotic chloroplast. Used for fatty acid metabolism
- Have apical complex for entry to host
What are the amoebas and slime moulds?
- Amoebas move using pseudopodia which flow
- Slime moulds are amoebas that aggregate into a fruiting body
What are the Euglenozoa?
- E.g. Euglena: SEA but can lose flagella and grow heterotrophically
- E.g. Trypanosomes: Obligate parasites which produce major diseases
What are the Metamonada?
- Largely parasites
- Lost mitochondria (degenerative evolution)
What are the four theories on the origin of life?
- Chemical origin (Prebiotic Soup)
- Panspermia
- RNA world
- Hydrothermal vents
What are the earliest forms of life still existing on Earth?
Bacterial communities called stromatolites
What are stromatolites made of?
Layers of microorganisms, outermost organisms are photosynthetic and inner layers are anaerobic supporting sulphate-reducing bacteria
What are the requirements of life?
- Essential elements (C, H, N, O, Mg, Ca, Na, K, Fe): Available on early Earth, no free O2 in atmosphere
- Temperature: Between boiling and freezing points of water
- Source of energy: Reduced minerals, sunlight
What is the evidence of life?
- Stromatolites
- Isotope ratios: Limestone depleted of CO2 with 13 Carbon isotope
- Microfossils
How does limestone being depleted of 13CO2 provide evidence of life?
Carbon-12 is released from cells so if there is little Carbon-13, it shows more Carbon-12 is being released by decomposition
What is the evidence for O2 in the biosphere?
Fe2+ is soluble but Fe3+ is insoluble and forms precipitates of Fe2O3. Banded iron formations suggest periods of alternating oxygen-rich and anoxic conditions
What are the two functions a cell must have for reproduction and growth?
Coding functions and machine functions
