2.General Informations Of Bacteria, Archaea, Viruses And Subviral Agents Flashcards
Does prokaryotic cell has an organelles
No
What do bacteria share with other cells
-plasma membrane-membrane surrounding the cell creating topological inside/outside
-rigid outer cell wall providing structural strength
-motion-dedicated organes(flagella)
-cytoplasm-acqueous solution of macromolecules and ions
-ribosomes-proteins-producing specialized organules
-nucleic acid molecule(DNA) containing genetic information
How were bacteria first called
Eubacteria; to be distinguished from archaebacteria
What is seperates bacteria from other cells
-no membrane-surrounded internal compartments: nucleus, mitochondria, chloroplasts
-no membrane organules: Golgi aparatus, endoplasmic reticulum
-specific systems for attachement and conjugation: pilus, fimbria
-genetic material is localized in the nucleoid (a region of a cell, not a compartment)
-different organization of genome(single chromosome, sometimes circular plasmids)
What’s some shapes that bacteria can have(morphology)?
Spheroidal-coccus
Twin-sphered- diplococcus
Rod-like -rod,bacillum
Comma-shaped- vibrio
Spiraling rod- spirillum
Coiled- spirochete
Some bacteria form chains or filments
Other are pleomorphic (can change shape)
What type of nutrituon do bacteria have?
•some are autotroph (food producers); producing complex organic conpounds from simpler ones. More specifically, they are chemoautotrophs ; using CO2 as their carbon source and as energy source- inorganic chemicals
• some are heterotroph (food producers) , using complex organic compounds produced by other organisms. They can be both photoheterotroph (using orgabic compounds as carbon source and light as energy source) and chemoheterotroph (organic compounds both as carbon source and energy source)
What are some other things( except morphology and nutrition) that bacteria heterogenous in?
•metabolism
•oxygen requirements
•ecology (ex: forming colonies, being endocellular parasites or symbionts)
•reproduction
•pathogenicity
•tinctorial properties: behavior when stained or dyied (ex: Gram positives/negatives)
What does bacteriology study?
Bacteria and archaea
What are archaea
They evolved independently from 2 domains: they have features conmon with bacteria, other similiar to eukaryotes, other distinctive.
What are some distinctive traits differentiating archaea?
Trait:
• carbon linkage of lipids:they use ether while both bacteria and eukarya use ester
• phosphate backbone of lipids: in archaea it’s glycerol-1-phosphate while in others is glycerol-3-phosphate
• metabolism : bacterial like
•nucleus: no
•organelles:no
•spliceosomal introns(non coding sequences of DNA removed during RNA splicing):no(like bacteria)
•telomeras:no
•chromosome shape:circular
•DNA replication: eukaryotic-like
•Transcription:eukaryotic -like
•Translation:eukaryotic-like
Where do archaea grow?
In extreme enviromental conditions
They are extremophiles
Can archaea live in animals?
Yes (ex:methanococci)
What are the names of fungi microorganisms?
Yeasts
Some are considered colonies: moulds(but there are also nonfungal moulds)
What can fungi do?
Form colonies, produce spores, be parasites of other organisms, be pathogenic. They are seperate kingdom
What branch of science studies fungi?
Mycology
What are protists and are they considered seperate kingdom?
The section was created for classifying very simple euekaryotic organisms, that were supposed to be the most ancient. But they aren’t considered as a seperate kingdom in all taxonomy models bc of their huge heterogeneity
What do protists include?
•Protozoa : they are heterotrophs like animals
•Protophylia: they are autotrophs like plants; also known as unicellular algae
Are protists related between each other?
They aren’t evolutionary or phylogenetically strictly related
Are viruses living beings?
No, and by that, they aren’t in the tree of life.
They don’t “live” outside another living being and are left out of systematic classification of living beings(but they apply to definition to nicroorganismsl
They are referred as infectious agents
What are differences between viruses and other living beings?
-they have acellular organisation
-they never have both nucleic acids in the same particle(virion)
-they can’t produce independently from other cells and can’t have any form of cell division
What is the main composition of a virus?
Proteins and nucleic acids (knowledge obtained by studying tobacco mosaic virus;first virus to be stuied)
What species can viruses be parasites of?
Both eukaryotic and prokaryotic but in specific way
What are bacteriophages?
Viruses infecting bacterial cells, usually abbriviated as phages. Some archaebacteria have their specific phages
Is infection always synonim for disease?
No. Many viruses can infect cells without harming them
How are viruses inside and outside host cells?
Inside host cells
Made out of specific nucleuc acid molecule(DNA or RNA) ready to be used as information source for producing viral proteins and replicating itself in collaboration with host cell elements
Outside host cells
They are packed as viral particles, virions, containing viral nucleic acid and some proteins in a proteic case (proteic or lipidic)
What are some elements of classification for viruses
Intrinsic:
• Virion structure: presence of lipidic membrane( envelope)
• Virion structure: geometry of proteic casing (capsid, lapid capsa(box))
•Type of nucleic acid: RNA or DNA
•Type of nucleic acid: double or single stranded (and in case, positive or negative polarity)
Extrinsic:
• Host species
• Cell/tissue tropism (ability of replicating)
• Transmission vectors
What are subviral agents
They are organisms smaller than viruses: viroids, satellites and prions
What are viroids
Viroids-circular ssRNA molecules(250-400 nucleotides), encoding no proteins. They infect plant cells and are responsible for plant diseases
What are satellites
Satellites- viral capsid+nucleic acids, without other proteins. They need another unrelated virus(helper) to replicate in co-infected cells. When a satellite is able to encode its own capsid, it’s called satellite virus
What are prions
Prions -proteinaceous infectious agents. They don’t contain any form of nucleic acid. They are made of a single kind of protein and are abnormal forms of the wild type protein.
Can prions infect smth
Yes, they can infect cells and “transmit” the protein alterations to host proteins. They are responsible for severe diseases ( “Mad cow” disease in animals )
Can prions bring some kind of inharitable information
Yes, even if they dont have any kind of genome
