Archaea

Question 1

Through common cellular ancestry, certain molecules are ______ between all living organisms like molecules of transcription.

Answer 1

shared

Question 2

Archaea share bacterial _____ traits and eukaryotic ___ - ___ machinery and _______ _______.

Answer 2

metabolic traits

DNA RNA machinery and transcriptional factors

Question 3

Membrane lipids contain ester linkages for archaea (T/F).

Answer 3

False, they are ETHER linkages. Bacteria + eukaryotes have ESTER linkages.

Question 4

Archaea can form spores and have inclusion bodies (T/F).

Answer 4

False, they can’t form spores but they do have inclusion bodies.

Question 5

While the cytoskeleton of archaea has bacterial + eukaryotic properties, archaeal protein content is similar to ?

Answer 5

Bacteria

Question 6

Instead of unbranched fatty acids, archaea have
_________ ______ on their membranes.

Answer 6

Isoprene chains

Question 7

(T/F) All archaea have lipid monolayers.

Answer 7

False, only some do.

Question 8

What are the similar features an archaea genome shares with bacteria?

Answer 8

• single, circular DNA
• no nucleus; DNA is within the nucleoid

Question 9

What are the similar features an archaea genome shares with eukaryotes?

Answer 9

• DNA bound by histones
• DNA replication enzymes look similar

Question 10

What are the four different structures can the archaeal cell wall be composed of instead of peptidoglycan?

Answer 10

1. Pseudomurein
2. S-layer
3. Methanochondroitin
4. Protein sheath

Question 11

Match the following terms to their definition:
1. Pseudomurein
2. S-layer
3. Methanochondroitin
4. Protein sheath

A. Covers multiple cells forming a chain instead of a single cell.
B. Consists of glycoprotein with a paracrystalline structure of various symmetry: hexagonal, tetragonal, or trimeric. Resists osmotic pressure.
C. Similar to connective tissues in animals
D. Polysaccharide which consists of NAT and NAG. Has b-1,3 glycosidic bonds. All L-stereoisomer amino acids.

Answer 11

Pseudomurein - Polysaccharide consisting of NAT and NAG. Has b-1,3 glycosidic bonds. All L-stereoisomer amino acids.

S-Layer - Consists of glycoprotein with a paracrystalline structure of various symmetry: hexagonal, tetragonal, or
trimeric. Resists osmotic pressure.

Methanochondroitin - Similar to connective tissues in animals

Protein sheath - Covers multiple cells forming a chain instead of a single cell.

Question 12

What are the differences between peptidoglycan and pseudomurein?

Answer 12

Peptidoglycan:
- b-1,3 bonds
- destroyed by lysozyme + penicillin
- NAG (n-acetyl-glucosamine) & NAM (-muramic acid)
- can have L or D stereoisomers amino acids
- found in bacteria

Psuedomurein:
- b-1,4 bonds
- immune to lysozyme + penicillin
- NAG and NAT (…-talosaminuronic)
- all L stereoisimers amino acids
- found in archaea

Question 12

(T/F) Psuedomurein is the most common cell wall type in archaea.

Answer 12

False, S-layer is the most common cell wall type.

Question 13

What is a Hami?

Answer 13

A cell surface structure of archaea. Archaea’s version of fimbrae (surface attachment) which form BIOFILMS.

Question 14

While bacterial flagella use proton motive force, archaella use ___. Instead of having a whip like motion, they have a ______ motion.

Answer 14

ATP

Rotating

Question 15

(T/F) All prokaryotes are capable of methanogenesis (methane production).

Answer 15

False, archaea are the only organisms responsible of methane production.

Question 16

Which molecule do archaea use to use light for ATP production without doing photosynthesis?

Answer 16

Bacteriorhodopsin

Question 17

(T/F) Bacteriorhodopsin is structurally similar to the rhodopsin found in vertebrate eyes.

Answer 17

True!

Question 18

Match the following steps regarding on how bacteriorhodopsin produces ATP:

Step 1
Step 2
Step 3
Step 4
Step 5

A.Retinal changes conformation from Trans to Cis
B. Retinal transformation coupled to one proton being pumped outside of the cell
C. ATP synthase uses proton gradient to produce ATP
D. Bacteriorhodopsin absorbs light
E. Retinal is excited by light

Answer 18

Step 1: Bacteriorhodopsin absorbs light

Step 2: Retinal is excited by light

Step 3: Retinal changes conformation from Trans to Cis

Step 4: Retinal transformation coupled to one proton being pumped outside of the cell

Step 5: ATP synthase uses proton gradient to produce ATP

Question 19

Retinal is a pink molecule.

Answer 19

False, it is purple.

Question 20

(T/F) Genomes of archaea resemble those of bacteria in gene size and density.

Answer 20

True!

Question 21

How does the genome structure of archaea resemble eukaryotic genome?

Answer 21

1. Certain tRNA genes have introns
2. DNA and RNA polymerases and transcription factors are similar to those of
   eukaryotes
   - Both have TATA box, BRE (b-recognizing element), and formation of pre-initiation complex.
3. Archaea contain histone homologs

Question 22

What is a unique feature of the archaeal genome?

Answer 22

Some thermophiles have a reverse gyrase to introduces positive supercoils in DNA, to protect against high temperatures.

Question 23

Briefly describe the chromatin structure of archaea.

Answer 23

Histones form TETRAMERS to wrap DNA. This allows stacking of units, or superhelix. Histone tails may allow some modifications.

Question 24

(T/F) Stacking of units (superhelix) is found in all organisms.

Answer 24

False, eukaryotic histone OCTAMERS prevent this. Only done in archaea.

Question 25

(T/F) 40% of archaea’s genome has no homology to any living organisms.

Answer 25

True!

Question 26

What is the guanosine analog of archaea?

Answer 26

Archaeosine

Question 27

Archaeal activators and regulators resemble more that of _______ DNA binding proteins than _____ transcriptional factors.

Answer 27

Bacterial

Eukaryotic

Question 28

(T/F) Cell division of archaea is well studied.

Answer 28

False! It’s hard to recreate environment in labs.