Archaea

Question 1

Polymers in cell wall

Answer 1

• Pseudomurein: N-acetyl-talosaminuronic acid
• chondroitin sulphate (Gram-pos)
• glycoprotein or protein (Gram-neg)

Question 1

Cell Membranes

Answer 1

ether-linked, branched isoprene derivatives
- polar lipids: phospholipids, Sulpholipids and glycolipids
- non-polar lipids: sqaulene derivatives

Question 2

Genetics and Molecular Biology

Answer 2

• chromosome can be smaller than bacteria
• G+C content varies between 21% and 68%

Question 3

Metabolism

Answer 3

glucose broken down by Embden-Meyerhof pathway

Question 4

Gluconeogenesis

Answer 4

reversed Embden-Meyerhof in halophyles and
methanogenes

Question 5

Pyruvate oxido-reductase

Answer 5

oxidize pyruvate to acetyl CoA

Question 6

Tricarboxylic acid cycle

Answer 6

halophyles and extreme thermophiles

Question 7

Phylum Thaumarcheota

Answer 7

• soil and watery environments
• mesophillic ammonia oxidizers
• NB in nitrogen cycle

Question 8

Thermophiles and methanogenes

Answer 8

• glycogen as reserve
• autotrophs
• CO2 fixed by reductive acetyl CoA path

Question 9

Phylum Crenarcheota

Answer 9

• thermophiles
• acidophiles
• sulfate: electron acceptor
• H2S: electron donor
• anaerobes
• geothermically heated water or hot soil containing sulfur

Question 10

Pyrodictium

Answer 10

• thermophiles
• hydrothermal vents in seabed
• 84-100C

Question 11

Sulpholobus

Answer 11

• Gram-negative
• aerobe
• 70-80C
• pH 2-3
• lithotrophic growth on sulphur granules
• oxygen is electron acceptor, ferric iron used also
• thermoacidophiles

Question 12

Thermoproteus

Answer 12

• anaerobic
• 70-95C
• pH 2.5-6.5
• chemolithotrophic, then using H2 and S
• CO and CO2 as carbon source

Question 13

Phylum Euryarcheota

Answer 13

• lower temperatures
• sulfur-dependent metabolisms

Question 14

Methanogens

Answer 14

• anaerobes
• energy through conversion of CO2, H2, acetate TO methane or methane and CO2
• methanogenesis

Question 15

Methanogenes Coenzymes

Answer 15

• tetrahydromethanopterin (H4MPT)
• methanofuran (MFR)
• coenzyme M
• coenzyme F420
• coenzyme F430

Question 16

CO2-reducing methanogens

Answer 16

form CH4 from H2 and CO2

Question 17

Aceticlastic methanogens

Answer 17

cleave acetate to form CH4 and CO2

Question 18

Halobacteria

Answer 18

• aerobe, respiratory metabolism
• chemoheterotrophs
• motile or non-motile
• high salt environment: 3-4M NaCl

Question 19

Halobacterium salinarium

Answer 19

• produce purple membrane with archaerhodopsin when O2 low
• halorhodopsin: light energy to transport chloride ions
• photoreceptors to control the flagella

Question 20

Thermoplasms

Answer 20

thermoacidophiles with no cell walls

Question 21

Thermoplasma

Answer 21

• hot and acidic environment
• 55-59C
• pH 1-2
• diglycerol-tetra-ethers, lipopolysaccharides, glycoproteins
• histone-like proteins
• low temp: coccus
• high temp: filamentous

Question 22

Picrophilus

Answer 22

• S-layer on outside of membrane
• irregular cocci
• aerobe
• 47-60C
• pH 0-3.7

Question 23

Extremely thermophilic S-metabolizers

Answer 23

• thermophillic cocci with cell walls
• only one order

Question 24

Thermococcales

Answer 24

- anaerobe - flagella - 88-100C

Question 25

Sulphate-reducing Euryarchaeota

Answer 25

- Archaeoglobales - Gram-negative - irregular coccus - glycoprotein subunits - 83C - coenzymes F420 and Methanopterin - hydrothermal vents in ocean bed