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Bio ch. 27
| Question | Answer |
|---|---|
| peptidoglycan | A polymer composed of modified sugars cross-linked by short polypeptides. In most bacterial cell walls. |
| capsule | a sticky layer of polysaccharide or protein that surrounds the cell wall of many prokaryotes. It is called a capsule if it is well organized, and called a slime layer if it is not well organized. |
| endospore | a thick-coated, resistant cell produced by some bacterial cells when they are exposed to harsh conditions. |
| fimbriae | A short, hair-like appendage of a prokaryotic cell that helps it adhere to the substrate or to other cells. |
| pili | In bacteria, appendages that pull two cells together prior to DNA transfer from one cell to the other; also called a sex pilus. |
| taxis | An oriented movement toward or away from a stimulus. |
| flagella | the most common way prokaryotes move |
| What is the difference between prokaryotes and eukaryotes? | eukaryotes have a nucleus |
| nucleoid | A non-membrane, non- enclosed region in a prokaryotic cell where its chromosome is located. |
| plasmid | a small, circular, double-stranded DNA molecule that carries accessory genes separate from those of a bacterial chrosome |
| what are the three factors that give rise to high levels of genetic diversity in prokaryotes? | rapid reproduction, mutation, and genetic recombination. |
| what are the three mechanisms of genetic recombination in prokaryotes? | transformation, transduction, and conjugation. |
| transformation | a change in genotype and phenotype due to the assimilation of external DNA by a cell. When the external DNA is from a member of a different species, transformation results in horizontal gene transfer. |
| transduction | A process in which phages (viruses) carry bacterial DNA from one bacterial cell to another. |
| conjugation | when DNA is transferred between two prokaryotic cells (usually of the same species) that are temporarily joined. |
| F factor | In bacteria, the DNA segment that confers the ability to form pili for conjugation and associated functions required for the transfer of DNA from donor to recipient. May exist as plasmid or be integrated into the bacterial chromosome. |
| F plasmid | The plasmid form of the F factor. F+ functions as DNA donors during conjugation and F- functions as the DNA recipient. |
| R plasmid | (R for resistance) A bacterial plasmid carrying genes that confer resistance to certain antibiotics. |
| obligate aerobes | must use oxygen for cellular respiration and cannot grow without it. |
| obligate anaerobes | poisoned by oxygen. Most live by fermentation; others extract chemical energy by anaerobic respiration where sulfate or nitrate ions accept electrons at the "downhill" end of the electron transport chain. |
| Facultative anaerobes | uses oxygen if present but can also carry out fermentation or anaerobic respiration in an anaerobic environment. |
| What are the 5 major clades of Bacteria? | 1) Proteobacteria 2) Chlamydias 3) Spirochetes 4) Cyanobacteria ((5) Gram positive bacteria) |
| What are the 4 major clades of Archae? | 1) Korarchaeotes 2) Euryarchaeotes 3)Crenarchaeotes 4) Nanoarchaeotes |
| extremophiles | An organism that lives in such extreme environmental conditions that few other organisms can live in. |
| extreme halophiles | An organism that lives in a highly saline environment, such as the Great Salt Lake or the Dead Sea. |
| extreme thermophiles | An organism that thrives in hot environments (often 60-80 degrees Celsius or hotter) |
| methanogen | An organism that produces methane as a waste product of the way it obtains energy. All known methanogens are in domain archaea. |
| decomposers | (chemoheterotrophic) |
| nitrogen fixation | The conversion of atmospheric nitrogen (N2) to ammonia (NH3). |
| symbiosis | An ecological relationship between organisms of two different species that live together in direct and intimate contact. |
| parasitism | an ecological relationship in which a parasite eats the cell contents, tissues, or body fluids of its host. |
| pathogens | parasites that cause disease, many of which are prokaryotic. |
| Exotoxin | A toxic protein that is secreted by a prokaryote or other pathogen and that produces specific symptoms, even if the pathogen is no longer present. |
| Endotoxin | A toxic component of the outer membrane of certain gram-negative bacteria that is released only when the bacteria die. |
| antibiotics | target prokaryote traits. (read slide) Use of antibiotics=strong selection for resistance |
| bioremediation | using bacteria to break down sewage, chemical spills, etc. |
| genetic engineering | use cellular machinery to make chemicals we can use (vitamins, antibiotics, etc.) |
| Genes for the resistance to antibiotics are usually located _____. | on plasmids |
| Which statement is true about obligate anaerobes? | They are poisoned by O2. |
| How are archaeans most similar to bacteria? | the shape of their chromosomes and plasmids |
| An ecological relationship between organisms of different species that are in direct contact can best be described as _____. | symbiotic |
| Bioremediation is _____. | the use of organisms to remove pollutants from the environment |
Created by:
evie_mcintyre