2.General Informations Of Bacteria, Archaea, Viruses And Subviral Agents

Question 1

Does prokaryotic cell has an organelles

Answer 1

No

Question 2

What do bacteria share with other cells

Answer 2

-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

Question 3

How were bacteria first called

Answer 3

Eubacteria; to be distinguished from archaebacteria

Question 4

What is seperates bacteria from other cells

Answer 4

-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)

Question 5

What’s some shapes that bacteria can have(morphology)?

Answer 5

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)

Question 6

What type of nutrituon do bacteria have?

Answer 6

•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)

Question 7

What are some other things( except morphology and nutrition) that bacteria heterogenous in?

Answer 7

•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)

Question 8

What does bacteriology study?

Answer 8

Bacteria and archaea

Question 9

What are archaea

Answer 9

They evolved independently from 2 domains: they have features conmon with bacteria, other similiar to eukaryotes, other distinctive.

Question 10

What are some distinctive traits differentiating archaea?

Answer 10

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

Question 11

Where do archaea grow?

Answer 11

In extreme enviromental conditions
They are extremophiles

Question 12

Can archaea live in animals?

Answer 12

Yes (ex:methanococci)

Question 13

What are the names of fungi microorganisms?

Answer 13

Yeasts
Some are considered colonies: moulds(but there are also nonfungal moulds)

Question 14

What can fungi do?

Answer 14

Form colonies, produce spores, be parasites of other organisms, be pathogenic. They are seperate kingdom

Question 15

What branch of science studies fungi?

Answer 15

Mycology

Question 16

What are protists and are they considered seperate kingdom?

Answer 16

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

Question 17

What do protists include?

Answer 17

•Protozoa : they are heterotrophs like animals
•Protophylia: they are autotrophs like plants; also known as unicellular algae

Question 18

Are protists related between each other?

Answer 18

They aren’t evolutionary or phylogenetically strictly related

Question 19

Are viruses living beings?

Answer 19

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

Question 20

What are differences between viruses and other living beings?

Answer 20

-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

Question 21

What is the main composition of a virus?

Answer 21

Proteins and nucleic acids (knowledge obtained by studying tobacco mosaic virus;first virus to be stuied)

Question 22

What species can viruses be parasites of?

Answer 22

Both eukaryotic and prokaryotic but in specific way

Question 23

What are bacteriophages?

Answer 23

Viruses infecting bacterial cells, usually abbriviated as phages. Some archaebacteria have their specific phages

Question 24

Is infection always synonim for disease?

Answer 24

No. Many viruses can infect cells without harming them

Question 25

How are viruses inside and outside host cells?

Answer 25

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)

Question 26

What are some elements of classification for viruses

Answer 26

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

Question 27

What are subviral agents

Answer 27

They are organisms smaller than viruses: viroids, satellites and prions

Question 28

What are viroids

Answer 28

Viroids-circular ssRNA molecules(250-400 nucleotides), encoding no proteins. They infect plant cells and are responsible for plant diseases

Question 29

What are satellites

Answer 29

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

Question 30

What are prions

Answer 30

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.

Question 31

Can prions infect smth

Answer 31

Yes, they can infect cells and “transmit” the protein alterations to host proteins. They are responsible for severe diseases ( “Mad cow” disease in animals )

Question 32

Can prions bring some kind of inharitable information

Answer 32

Yes, even if they dont have any kind of genome