Drexel BIO 221 - MT1 Questions with Complete Solutions Definition of a cell - Correct Answer A dynamic entity that forms the fundamental unit of life.Six features/properties of cells (living organisms) - Correct Answer Metabolism: Chemical transformation of nutrients Tons of important actions in a cell require having a metabolism
Reproduction: Generation of two cells from one
Differentiation: Synthesis of new substances or structures that modify the cell Only in some microbes Communication: Generation of, and responding to, chemical signals Only in some microbes Ex: quorum sensing Movement: Via self propulsion, many forms in microbes Flagella in euks and proks, cilia only in euks
Evolution: Genetic changes in cells that are transferred to offspring
Microbial communities - Correct Answer Populations in which microorganism exist in where they interact Habitat - Correct Answer The environment in which a microbial population lives in Ecosystem - Correct Answer All living organisms plus physical and chemical constituents of their environment How microbes can change the properties of their habitat - Correct Answer Consumption of resources and excretion of metabolites Examples of beneficial and harmful effects of microbes on humans presented in the lecture - Correct Answer Microbial disease agents: most are no longer relevant since we have a better understanding of how to avoid them Influenza and pneumonia Tuberculosis Gastroenteritis Infant diseases Diphtheria 1 / 2
Microorganisms for good Microbes in agriculture: Nitrogen fixing bacteria Cellulose-degrading microbes in the rumen Regeneration of nutrients in soil and water Human body Synthesize vitamins and other nutrients Compete with pathogens for space and resources Energy: Biofuels Bioremediation Time line of important evolutionary events - Correct Answer 3.8-3.9 BYA: First cells Mostly anoxic atmosphere
- BYA: Novel group: cyanobacteria Atmosphere becomes oxygenated Now we can harness O2 and
make a lot more ATP
1 BYA: Life becomes not exclusively microbial Three domain system below
Three domain system, what it is and how we put it together - Correct Answer We used to organize based on physical characteristics, this changed to the use of phylogenetic information: Evolutionary relationships between organisms Relationships can be deduced by comparing genetic information in the different specimens Ribosomal RNA (rRNA) is excellent for determining phylogeny Relationships can be visualized on a phylogenetic tree Robert Hooke - Correct Answer First to describe microbes Illustrated fruiting structures of molds Antoni van Leeuwenhoek - Correct Answer First to describe bacteria Further progress required development of more powerful microscopes Louis Pasteur (4) - Correct Answer Discovered that living organisms discriminate between optical isomers Discovered that alcoholic fermentation was a biologically mediated process (used to be considered chemical) Disproved spontaneous generation
- / 2