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29 Cards in this Set
- Front
- Back
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Why is it thought that prokaryotes are an ancient group?
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The structure of stromatolites is very similar to the layered mats formed by colonies of photosynthetic prokaryotes today. Fossils resembling photosynthetic prokaryotes have been found in stromatolites that are 3.5 bya
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What are the 3 domains of life and what makes them different?
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Archaea, Bacteria, and Eukarya
Archaea:live in the most extreme environments on earth.RNA polymerase is more complex.Have introns.Do not have peptidoglycan. Bacteria:RNA polymerase is small and simple.Don't have introns.Cell walls contain peptidoglycan.Certain antibiotics kill bacteria and not archaea. Eurkarya:Not a prokaryote. Consists of protists, fungi, plants and animals. |
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What three main groups are archaea classified in?
hint: they are all known as "extremophiles" |
1) halophiles - salt loving
2) Thermophiles - heat loving 3) Methogens - menthane users or makers |
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What are the three shapes of bacteria and what are they called?
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1) Bacilli - rod shaped (E.coli)
2) Spirilli - Spiral shaped 3) Cocci - Sphere shaped |
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Describe the structure of a bacterium
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Cell wall
1) most peptoglycan 2) less pept.and additional outer membrane -flagellum:used for locomotion -Pili:used for attachment -Plasmid:small,circular sequences of DNA, used in "swapping genes" -Ribosomes |
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What is peptidoglycan?
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polymer which consists of sugars and short polypeptides
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What is a pathogen?
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a disease-causing organism or virus
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How does gram stainging distinguish between types of bacteria?
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Stain bacteria with violet colored dye.The violet dye is then rinsed off stain second time with pink dye.
Gram Positive: bacteria with extra thick peptidog. cell wall absorb a lot of the purple. Gram negative: bacteria with a thin peptidoglycan wall, masked by an outer membrane, absorbe little of the purple and become pink. |
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Why is gram staining useful?
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Some antibiotics only work against Gram-positive bacteria. Doctors use Gram staining to identify bacteria in order to prescribe the correct antibiotics.
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How do prokaryotes reproduce?
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Binary fission - the replication of DNA and the division of one bacterium into two cells.
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How do bacteria mix genes?
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Conjugation - the copying and swapping of genes between cells, especially when an environment is unfavorable. Is considered sex, biologically.
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What are 3 examples of pathogenic bacteria?
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lyme, cholerae, and tuberculosis
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What do you know about lyme disease from the video?
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-Is airborn is it spreads quickly.
-Variety of untreatable TB strains -Prisoners weren't taking the full cycle of antibiotics, which left a little of surviving, more resistance bacteria still. That resistance bacteria reproduced into a new strain that could not be treated with the same antibiotics. |
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What are antibiotics?
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chemicals that inhibit or destroy bacteriam often by distruping the peptidog. in the cell wall.
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Describe the nitrogen cycle
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1)nitrogen fixing bacteria convert N2 from the air to an organic form (NH3), unusable by some plants
2)Nitrifying bacteria convert NH3 to NO3m which can be used as a fertilizer by plants to make protein 3)Assimilation - plants suck up nitrates from the soil 4)Decomposing bacteria break complex organic nitrogen in dead organisms back to NH4 5)Denitrifying bacteria break organic nitrogen in dead organisms back into N2 gas. |
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What are some characteristics of viruses?
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-they are non living,infectious particles(can't reproduce on their own and can't obtain energy or feed in any way)
-1/000 size of bacterium -Vary in structure and shape -All organisms can be infected by them |
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What is a protein capsid?
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the coat of protein around a virus
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Why can't viruses be treated with antibiotics?
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They lack a peptidog. cell wall.
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What is the structure of a virus?
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a protein capsi. nucleic acid (RNA or DNA), and some means of attaching to and entering a host.
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Describe the lytic cycle of a virus
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The virus enters into the host cell and it's DNA or RNA uses the cellular machinery of the host cell to replicate itself, than the cell ruptures and the new viruses are released.
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Describe the lysogenic cylce
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replicates the phage genome without destroying the host cell. However, the virus is capable of entering the lyctic cycle at any time. Virus hangs out in the cells for a while, reproducing when the cell does.
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Why does HIV have so many resistant strains?
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HIV is RNA-based. It uses an enzyme called reverse transcriptase to copy its RNA into DNA in order to start transcription. THe extra step in reproducing gives more of a chance for mutations and therefor genetic variation.
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What does AIDS stand for?
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Aquired Immune Defiency Syndrome, and is caused by HIV (aids is not the virus)
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What does HIV stand for?
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Human Immunodefiency Virus
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What is a retrovirus?
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RNA based viruses that use reverse transcriptase to copy their RNA into DNA before starting transcriptase (ex: HIV)
Causes cancer and aids |
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What are three examples of pathogenic viruses?
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Retrovirus, Herpes viruses, and Pox Viruses
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What is the base of Herpes and Pox viruses
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DNA
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What does herpes viruses cause?
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chicken pox
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what does pox virus cause?
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small pox
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