527801
Description
Flashcards by sophietevans, updated more than 1 year ago
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Created by sophietevans
almost 11 years ago
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| Question | Answer |
| True or false: microbes are the earliest life form? | True! |
| List some environmental conditions that we depend on microbes for. | An aerobic atmosphere, carbon and nitrogen cycles, and water and soil quality. They are also the base of every food chain. |
| List some characteristics of eukaryotic microorganisms. List some types of microorganisms that fall within this category. | Membrane-bound nuclei, membrane-bound organelles, and usually larger. These include: algae, protozoa, fungi, and slime moulds. |
| List some characteristics of prokaryotic microorganisms. Which types of microorganisms fall into this category? | DNA not separate from cytoplasm, usually smaller, lack membrane-bound organelles. These include archaea and bacteria. |
| What can't viruses do without a host? | Replicate or produce metabolic energy. |
| Broadly describe the structure of a virus. | Viruses consist of a nucleic acid molecule (DNA or RNA), and a protein 'coat' or capsid. |
| What determines the specificity of a virus' interactions with its host? | The proteins (usually glycoproteins) that constitute its capsid. |
| What is a prion? | A misfolded protein that appears to act in an infectious manner. |
| What is unique about prion diseases? | They manifest as sporadic, genetic, and infectious diseases. |
| Name two prion diseases that occur in humours. | Creutzfeld-Jakob Disease (CJD) and kuru. |
| Other than disease, name a detrimental effect of microorganisms. | Spoilage of crops/food. |
| What is a mycelium? | A mass of branching, interlacing filaments (or 'hyphae') of a fungus. |
| What is a coenocyte? Why is a mycelium coenocytic? | A coenocyte is a multi-nucleated mass of continuous cytoplasm, which is possible in a mycelium as the hyphae exhibit cross walls but these are perforated and allow free passage of nuclei and cytoplasm. |
| What are mycelial fungi usually known as? | Moulds! |
| If yeasts do not form mycelia, why are they considered to be fungi? | Because of their sexual reproductive processes: they produce asexual reproductive structures called conidia). |
| What are the four groups that fungi can be subdivided into? | Zycomycotina (the phytomycetes), ascomycotina (the ascomycetes), basidiomycotina (the basidiomycetes), and deuteromycotina (the imperfect fungi). |
| Roughly how many microbes does 1 gram of soil contain? | 10^8. |
| How many body cells does an average human consist of? How many microbial cells are on or in a human being? | Humans consist of 10^13 human cells, but have 10^14 microbial cells living on and in us |
| Despite not being membrane bound, why is the DNA of prokaryotic organisms such as bacteria referred to as the nucleoid? | Because it exists in a certain area of the cell. |
| How do the purple bacteria generate metabolic energy? | They convert light energy to metabolic energy in the absence of oxygen. |
| Some organisms can use alternative electron acceptors to oxygen - such as? | NO3-, SO4-, or CO2. |
| How do consortia provide protection for prokaryotic communities against external agents? | Consortia, such as clone communities of up to 10^8 cells, provide physical protection by sheer numbers as a threat is unlikely to be able to physically reach all of them, and also a high cell number virtually assures the presence of a variant of any gene on the chromosome, so genetic variability, natural selection and evolution are all assured within a clone. |
| What are protozoa? | Unicellular, non-photosynthetic protists (protists also include fungi, algae and slime moulds). |
| If bacteria and archaea are prokaryotes, and fungi, protozoa, and algae are eukaryotes, what are viruses and prions? | Akaryotes. |
| What glycopeptide do bacteria characteristically possess at least one layer of in their cell envelope? | Peptidoglycan. |
| What accounts for the colour difference in Gram negative and Gram positive staining of bacteria? | The thickness of the peptidoglycan layer which holds the crystal violet dye. |
| The most commonly encountered bacteria have one of two shapes - what are these two common shapes? | Cocci and bacilli. |
| What are slime moulds characterised by? | The presence, as a stage in their life cycle, of an amoeboid multinucleate mass of cytoplasm (much like a fungal mycelium) called a plasmodium, in which the cytoplasm can flow in all directions (unlike in mycelium where it can only flow through the hyphae). |
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