7c Flashcards
list the methods used by protists for obtaining food and for reproduction
Food (photosynthesis, absorption and predation)
Reproduction (asexual though fission and binary fission as well as sexual through syngamy and conjugation)
Describe in general the composition of the group known as ‘protists’ and their phylogenetic relationship to other living organisms;
Protists are mostly single celled and uses locomotion like amoeba, cilia and flagella. They occur whenever free water is available
Taxonomic groups: Excavates, Euglenozoans, Stramenopiles (chromists), Alveolates, Rhizarians, Amoebozoans, red algae and green algae.
describe general characteristics and an example of Diplomonads
Single celled with two nuclei (Excavate)
Giardia: , these can cause diarrhoea and fatigue.
describe general characteristics and an example of Parabasalids
It is anaerobic with no mitochondria.
trichomonas: infects both men and women and is an STI. Euglenoids - Euglena: Some are heterotrophs (via osmotrophy), many are photosynthetic (autotrophs)
describe general characteristics and an example of Kinetoplastids
Kinetoplastids generally have flagella, some are free living, some are parasitic and are important disease agents.
Trypanosoma: African sleeping sickness is an insect borne parasitic disease of humans and animals. The protozoan is transmitted by the bite of the tsetse fly. This fly is the host and vector.
describe general characteristics and an example of Stramenopiles
Variable nutrition modes (photosynthetic, heterotrophic. Variable cellularity (uni and multicellular) water nodes, diatoms and brown algae
P. cinnamomi: pathogen which is endangering native species (Wollemi Pine) around coastal Australia.
List representative organisms (or the maladies they cause) of the dinoflagellates and apicomplexans;
Dinoflagellates - cause of shellfish poisoning
Apicomplexans - Plasmodium spp (malaria): these hold small chloroplast, the drug(doxycycline) targets chloroplast and thus does not harm humans and effectively eliminates the parasite.
describe the life history of the apicomplexan Plasmodium, the causal agent of malaria
the life cycle rotates between humans and mosquitoes. The human is infected and the parasite enters the liver and undergoes mitotic reproduction causing the liver cells to rupture and merozoites are released. And then the cells invade blood cells to undergo an intraerythrocytic cycle.The merozoite produces gametocytes which mosquitoes ingest when biting humans. The Gametocytes mate and undergo meiosis; the result migrates through the midgut wall and forms oocyst which allow sporozoites to develop and infect a human when they are bitten.
Describe the structure of the acellular and cellular slime moulds
Structure (acellular) - contain many nuclei without separation, oozes through substrate, consumes bacteria and particles, when nutrients are scarce they form spores which re dispersed.
Structure (cellular) - free-living, haploid, when nutrients are scarce they form pseudoplasmodium which functions as a single cell though genetically different
describe the life cycle of cellular slime moulds
Life cycle(cellular) - when food is scarce the cells aggregate into pseudoplasmodium. A pseudoplasmodium migrates towards light and forms a fruiting body which produces spores.Singe amoeba-like cells emerge from spores and crawl and feed.
evolutionary connection between green algae and land plants
This idea is supported by the fact that they both share photosynthetic pathways using chlorophyll a and b. The evidence suggests that land plants evolved from a line of filamentous green algae that invaded land about 410 million years ago.
Describe the similarity between the red and green algae
Similarities - water inhabitants, multicellular, contains chlorophyll and has a double cell wall made from cellulose.
Describe differences between the red and green algae
green algae is in freshwater and can be unicellular, they also hold pectin in their cell walls. The red algae are photosynthetic and possess red pigment, the outer cell wall is composed of polysaccharides agarose and agaropectin that can be extracted from the cell walls by boiling down to produce agar. And do not hold chlorophyll a and b
