Archaea and Eukarya

Question 1

What does common cellular ancestry mean?

Answer 1

Certain molecules are shared between all living organisms

Question 2

What molecules are shared within all living organisms?

Answer 2

transcriptional machinery, eg. ribosomal DNA

Question 3

How many phyla of archaea have been identified so far?

Answer 3

seven

Question 4

How many phyla of archaea can be grown in a lab?

Answer 4

5

Question 5

What are the 4 most known phyla of archaea?

Answer 5

1. Euryarchaeota
2. TACK
3. Asgard
4. DPANN

Question 6

What traits do archaea share with other domains?

Answer 6

Metabolic traits with bacteria, and core traits of DNA-RNA machinery with eukaryotes

Question 7

What domain does the gene regulation of of archaea resemble?

Answer 7

Bacteria

Question 8

What archaeal signature is found only in archaea and some bacteria that received this by horizontal gene flow from archaea?

Answer 8

ether-linked membrane lipids

Question 9

Where do archaea grow?

Answer 9

They are often associated with extreme environments, but do grow in temperate marine, soil, and freshwater environments

Question 10

What is the size of a typical archaea?

Answer 10

0.5 - 5 um

Question 11

What do archaea and bacteria share in structure?

Answer 11

They are prokaryotic- they have no nucleus

Question 12

What domains share the archaeal plasma membrane structure?

Answer 12

None of them, it is unique to to the archaea domain

Question 13

How can we describe the differences and similarities of archaeal cell membranes from other domains?

Answer 13

The membranes have different lipid constituents and chemistry, but are somewhat structurally similar

Some archaea have lipid monolayers

Question 14

What are fatty acids in the phospholipid bilayer replaced with in archaea?

Answer 14

Isoprene chains

Question 15

What are the sidechain and linkage differences between archaea and other domains?

Answer 15

Archaea and some bacteria have phytanyl sidechains where eukaryotes and most bacteria have straight fatty acid tails

Archaea have ether linkages instead of ester linkage in bacteria and eukaryotes

Question 16

What is the compositional difference in the cell wall of archaea vs that of bacteria?

Answer 16

There is no peptidoglycan layer in archaea, but they do have an S layer

Question 17

What are the sugars in pseudomurein?

Answer 17

It is a polysaccharide made of NAG and NAT (N-acetyltalosaminuronic acid)

Question 18

What kind of glycosidic bonds hold sugars together in archaeal pseudomurein vs bacteria?

Answer 18

Archaea use Beta-1,3 glycosidic bonds and bacteria use beta-1,4

Question 19

What is the stereochemistry of all of the amino acids in pseudomurein?

Answer 19

L-stereoisomers

Question 20

What kind of antibiotics are archaea immune to?

Answer 20

Lysozymes and penicillin

Question 21

What is the S layer of archaea made of and how does it differ from that of bacteria?

Answer 21

Archaeal S layers consist of proteins or glycoproteins, with some methanogenic Archaea having pseudomurein in their walls

Bacterial S layers are made of protein subunits

Question 22

Where is pseudomurein found?

Answer 22

Some methanogenic archaea have it in their cell walls

Question 23

What is the geometrical structure of archaeal s layers?

Answer 23

They are paracrystalline structures with symmetry eg. hexagons, tetragons, trimeric

Question 24

What are S layers usually accompanied by?

Answer 24

Other cell wall components like polysaccharides

Question 25

What is the advantage of an S layer instead of a peptidoglycan cell wall?

Answer 25

They resist osmotic pressure in extreme environments and are more flexible than peptidoglycan cell walls

Question 26

What comprises a cell wall in bacteria or archaea?

Answer 26

Bacteria cell walls are comprised of peptidoglycan layers and S layers Archaeal cell walls are composed of S layers and sometimes a pseudomurein layer

Question 27

On an archaeal cell, what are the grappling hook like structures and what type of structure do they help produce?

Answer 27

Hami can help to form biofilms

Question 28

What is the archaeal version of flagella?

Answer 28

Archaella

Question 29

Are archaella or flagella simpler?

Answer 29

Archaella

Question 30

What do archaella and flagella use as energy sources?

Answer 30

Archaella: ATP Flagella: proton motive force

Question 31

What is the difference in motion between an archaella and a flagella?

Answer 31

Archaella move in a rotating motion, and flagella use a whiplike motion

Question 32

What are inclusion bodies?

Answer 32

Archaeal structures such as gas vacuoles or carbon storage

Question 33

In which molecules do archaea resemble bacteria?

Answer 33

Protein content ie. ribosomes and enzymes

Question 34

What domains do archaeal cytoskeletons resemble?

Answer 34

Both bacterial and eukaryotic cells

Question 35

What are archaeal cytoskeletons made of?

Answer 35

Proteins

Question 36

Do archaea form spores?

Answer 36

No

Question 37

Where is archaeal DNA found?

Answer 37

In the nucleoid (there is no nucleus)

Question 38

What are the archaeal and eukaryotic comparisons to FtsZ in bacterial cytoskeletons?

Answer 38

TubZ and tubulin

Question 39

What are the archaeal and eukaryotic comparisons to MreB in bacterial cytoskeletons?

Answer 39

crenactin and actin

Question 40

What are the archaeal and eukaryotic comparisons to CreS in bacterial cytoskeletons?

Answer 40

None for archaea and IF for eukaryotes

Question 41

What are the archaeal and eukaryotic comparisons to ESCRT in bacterial cytoskeletons?

Answer 41

There are no homologues to this

Question 42

What similarities do archaea share with bacteria genetically?

Answer 42

They are composed of singular circular chromosomes without a membrane bound nucleus - genomes resemble each other in size and density

Question 43

What archaeal DNA feature is shared with Eukaryotes?

Answer 43

The DNA is complexed with histones

Question 44

What does ESCRT stand for?

Answer 44

Endosomal Sorting Complex Required for Transport

Question 45

How do archaeal genetic pathways resemble those of eukaryotes?

Answer 45

tRNA genes are interrupted by introns, and DNA and RNA polymerases and transcription factors are similar to eukaryotes, and there are histones as well

Question 46

What is the unique feature of archaeal DNA?

Answer 46

Certain archaea possess a reverse gyrase enzyme

Question 47

What is the role of the reverse gyrase enzyme?

Answer 47

It introduces positive supercoils in chromosomes, protecting it against high temperatures

Question 48

What shape do archaeal histones form? How is this different from eukaryotes?

Answer 48

Archaeal histones are tetramers, and eukaryotic ones are octamers

Question 49

What is the added feature of the archaeal form of histones over eukaryotic ones?

Answer 49

The histones are able to stack and form superhelixes

Question 50

What is the potential role of a histone tail in archaea?

Answer 50

Epigenetic modification

Question 51

What is the metabolic process unique to archaea?

Answer 51

Methanogenesis

Question 52

What is methanogenesis?

Answer 52

Methanogenesis is the formation of methane to generate ATP. Chemolithotrophy

Question 53

What is the type of methanogenesis that generates ATP off of hydrogen and carbon dioxide?

Answer 53

Chemolithotrophy uses H2 and CO2 to produce ATP and methane

Question 54

What is chemoorganotrophy?

Answer 54

It is the formation of methane and ATP using methanol or acetate

Question 55

What type of metabolizer are haloarchaea? What does this mean?

Answer 55

Photoheterotrophs use light for energy and get their carbon from other life sources

Question 56

How do haloarchaea resipre?

Answer 56

Aerobically with oxygen, or anaerobically with nitrate

Question 57

How do haloarchaea supplement their usage of organic substrate for energy?

Answer 57

Light driven ion pumps

Question 58

Do haloarchaea fix carbon or product O2?

Answer 58

No

Question 59

What are the parts of the light driven ion pump in a haloarchaea? (3)

Answer 59

Bacteriorhodopsin Halorhodopsin Other rhodopsins

Question 60

What is the role of bacteriorhodopsin?

Answer 60

It pumps H+ out of the cell

Question 61

What is the role of Halorhodopsin?

Answer 61

It pumps Cl- into the cell

Question 62

What are the combined results of bacteriorhodopsin and halorhodopsin?

Answer 62

They both increase the proton motive force of the cell

Question 63

What is an archellum?

Answer 63

A molecular motor/filament on archaea

Question 64

What is the role of the other rhodopsins in the haloarchaeal ion pump?

Answer 64

They signal to the archellum to promote phototaxis

Question 65

Do archaeal enzymes resemble bacteria or eukaryotes?

Answer 65

Some of them resemble bacteria, but when they are linked to DNA replication, they tend to resemble eukaryotes