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BIOL 240 > Module 3 > Flashcards

Module 3 Flashcards

Archaea

1
Q

features archaea have in common with bacteria

A

molecules in the cytoplasm (mRNA, tRNA, ribosomes, and DNA)
can have inclusion bodies - gas vacuoles, vesicles, etc
most have a single circular chromosome
lack a membrane-bound nucleus

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2
Q

features archaea have in common with eukaryotes

A

have a polymerase in common, they’re homologues
have histone proteins

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3
Q

how do histone proteins differ in archaea vs eukaryotes

A

eukaryotic histone proteins form an octamer, archaea: tetramer

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4
Q

definition: nucleosome

A

DNA wrapped around histone proteins

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5
Q

what keeps nucleosomes together

A

histone proteins are positively charged
DNA is negatively charged

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6
Q

what is typically in the cell envelope of archaea

A

cell membrane
cell wall
no outer membrane

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7
Q

what are some differences with archaea plasma membrane

A

the polar head groups are glycerol 1-phosphate instead of glycerol 3-phosphate (mirrored)
there is a phytanyl chain instead of fatty acid tails

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8
Q

what is the structure of a phytanyl chain

A

4 repeated isoprene units (a 5-carbon compound)

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9
Q

what is the benefit of the phytanyl chain being linked by an ether linkage as opposed to an ester one

A

beneficial for cells inhabiting high temperatures
brings additional stability

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10
Q

definition: biphytanyl chain

A

two sets of phytanyl chains covalently linked in the middle
stronger than those is a bilayer

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11
Q

when will the proportion of biphytanyl chains increase

A

in higher temperatures

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12
Q

what is a tetraether layer

A

another name for the monolayer that archaea will form

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13
Q

what are some differences in the archaea cell wall

A

has beta-1,3-glycosidic linkages
has NATs instead of NAMs
there are no D-amino acids present

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14
Q

describe: S-layer

A

surface layer/slime layer
protects against predation and viruses
mediates adhesion to existent biofilm

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15
Q

describe: cannulae

A

they are tubes made up of sugars and proteins
form complex networks
function is not well understood

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16
Q

compare archaea flagella to bacterial flagella

A

assembled from the base outwards
simpler
more solid
more narrow
made up of more than one type of protein

17
Q

what are the 2 major phyla of archaea

A

Euryarchaeota
Crenarchaeota

18
Q

what is the main feature of Crenarchaeota

A

they are extremophiles
temperature, pressure, acid, etc.

19
Q

having increased proportions of arginines and tyrosines is a feature of which archaea

A

thermophiles (and other extremophiles)

20
Q

what is a way that thermophiles increase their stability in terms of metabolism

A

they possess reverse DNA gyrase
increases the extent of DNA supercoiling

21
Q

what is the main feature of Thaumarchaeota

A

they are intermediate/lower temp loving (mesophilic)
many are found in the ocean

22
Q

where in the ocean are there more archaea than bacteria

A

lower down

23
Q

what is the main feature of Euryarchaeota

A

contains all known methanogens

24
Q

what are some features of halophiles

A

require very high salt concentrations
have high concentrations of potassium to combat high salinity

25
Q

having increased proportions of genomic guanine and cytosine is a feature of which archaea

A

halophiles
G and C pairs have 3 hydrogen bonds

26
Q

what causes the red colour in halophiles

A

it is caused by a light-harvesting pigment, retinal
produced in low-oxygen conditions
helps supplement the high requirements for ATP

27
Q

where are methanogens found

A

in environments that don’t have any oxygen
methanogens are strict anaerobes
e.g. large intestines, sediments, wastewater sludge, rice paddies, landfills

28
Q

what do many methanogens require and what do they produce

A

CO2 and H2 - parts of the end products of fermentation (+ acetic acid)
they produce methane

29
Q

what do methanogens use as an electron acceptor

A

CO2
H2 gets oxidized

30
Q

what are some types of methanogens

A

hydrogenoclastic - take in H2
acetoclastic - take in acetate, CH3CO2
methylotrophic - use one-carbon compounds, like methanol (CH3OH)

31
Q

what are some suitable electron acceptors of methane

A

oxygen, nitrate, or sulphate

32
Q

what is the main feature of Nanoarchaeota

A

the only member is Nanoarchaeum equitans

33
Q

what is Nanoarchaeum equitans found in association with

A

Ignicoccus hospitalis

34
Q

what do Nanoarchaeum equitans lack

A

metabolic genes
ability to make ATP, AA’s, nucleotides
ability to make lipids

35
Q

Ignicoccus features

A

extended periplasm
ATP synthases are housed in the outer membrane
lots of vacuoles in the periplasm

BIOL 240 (12 decks)

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