Section 3

Question 1

differences of archea (4 things)

Answer 1

1- diff phospholipids
2- pseudopeptidoglycan + S Layer rather than peptidoglycan cell wall
3- transcription promotors and RNA pol is more similar to eukaryotic
4- extremophiles

Question 2

diff of archeal viruses (7 things)

Answer 2

1- encode pesudopeptidoglycan specific lysin enzyme
2- have NO RNA viruses
3- have on ss DNA virus (rest are dsDNA)
4- have circular dsDNA packed in virion
5- many have envelopes
6- released without lysis
7- not pathogens and extremophiles so hard to research

Question 3

Model Archeal virus:

Answer 3

Sulfolobus spindle-shaped virus (SSV-1)
lemone shaped

Question 4

SSV-1 virus encodes the enzyme ________

Answer 4

reverse gyrase

Question 5

Function of SSV-1 reverse gyrase:

Answer 5

introduces positive supercoils into DNA protecting it at higher temperatures (common in hyperthermophiles)

Question 6

SSV-1 is a temperate virus:

Answer 6

1- integrates into host genome
2- gets induced for replication by UV damage or stress
3- goes through round of replication to make and release visions
4- goes back into lysogenic state

Question 7

SSV-1 type of DNA and times of transcription:

Answer 7

dsDNA CIRCULAR (takes 6 hours to transcribe late genes)

T-ind (immediate early)
T5 and T6 (early after 1 hr)
T9 (late early 5 hrs)
Late gene after 6 HOURS

Question 8

Shape of SSV-1 capsid protein

NEVER SEEN BEFORE 1

Answer 8

4- stranded helices (4 strands of protein come together as one cable)
THEN 6 of these cables wrap around outer surface of the virion capsid and tail)

Conserved

Question 9

Another archaeal virus :

Answer 9

Acidianus two tailed virus (ATV)
also lemon shaped

Question 10

ATV grow tails (elongate outside of the cell when temperature is above 75 degrees)

NEVER SEEN BEFORE 2

Answer 10

Finishes growth and maturation OUTSIDE host cell

Question 11

ATV infects at ____ degrees (host optimal growth temp) and integrates into host chromosome

Answer 11

85

Question 12

if ATV infects at suboptimal temp, it leads to

Answer 12

Viral replication and lysis

Question 13

Lambda
Good conditions —-> replication and lysis
Bad conditions—–> integrate and wait
V.S
ATV
Good conditions (85 deg) —->
Bad conditions (suboptimal temp) —->

Answer 13

ATV
Good conditions —-> integrate 85 deg
Bad conditions ——-> replicate and lyse

Question 14

Another archaean virus (#3)

Answer 14

sublolobus islandicus rod-shaped virus

Question 15

sublolobus islandicus rod-shaped virus structure

Answer 15

helical shaped structures with tails at the end

Question 16

sublolobus islandicus rod-shaped virus shape UPON infection

NEVER SEEN BEFORE 3

Answer 16

viral protien makes unusual pyramid structure on cell surface which open to make holes (like a gate) that the virus is released through

Question 17

Another archaean virus (#4)

Answer 17

Acidianus filamentous virus 1 (AFV-1)

Question 18

AFV-1 structure

NEVER SEEN BEFORE 4

Answer 18

hook structure at the end of visions that claws to attach to host cells plius

Question 19

Another archaean virus (#5)

Answer 19

Sulfolobus turreted icosahedral virus (STVI)

Question 20

STVI facts

Answer 20

• tightly packed structure
• high proline content
• increase in electrostatic interactions in capsid proteins
• increased polar surface

evolutionary adaptations

Question 21

Why do archeal cells get released without lysing cells?

Answer 21

due to cell wall structures having a wide diversity of structures (don’t have rigid peptidoglycan) so can get out by budding they don’t have to lyse

Cytoplasmic membrane
Surface layer (S-layer)
Protein sheath
glycocalyx
lipoglycan
methanochondrotin
peseudomurein

Question 22

are there RNA archeal viruses

Answer 22

metagenomic evidence from acidic hot springs has isolated nucleic acids and looked for high amounts of RNA and found RdRp enzyme sequences