Section 2 pt 2 B

Question 1

Phage λ: After infection and circularization of the DNA genes ____ and _____ are expressed

Answer 1

N and cro

Question 2

Phage λ: N and cro allows expression of gene ____

Answer 2

cII

Question 3

Phage λ: if lysis, activates expression of ____ and __ genes

Answer 3

structure & lysis

Question 4

Phage λ: if lysogeny: expresses genes ___ and ___

Answer 4

cI and int

Question 5

Immediately after infection, only the cro and N genes get transcribed because only the ___ and ____ are bound by the host’s RNA pol

Answer 5

PL and PR

Question 6

transcription stops after cro and N because of the terminators

Answer 6

TL1 and TR1

Question 7

After N and Cro get translated, they bind to DNA and RNA pol at ___ sites

Answer 7

nut

Question 8

nut sites are named for N utilization as N is a ____ _______ protein

Answer 8

anti-terminator

Question 9

N is an anti-terminator so it leads to continuous RNA pol transcription past terminator to make __ gene

Answer 9

cll

Question 10

If cll is acted upon by proteases and inactivated, it means the cell is well growing and active and the _____ cycle occurs

Answer 10

lytic

Question 11

If cll is not inactivated, It means the cell is in poor state, and the _____ cycle occurs

Answer 11

lysogenic

Question 12

When cll gets degraded, activates replication and lysis genes and inhibits cl

Question 13

early lytic genes: (2)

Answer 13

1- DNA replication genes “rolling circle replication” that makes linear concatemers
2- another anti terminator Q: activates transcription of late Luton genes (works PR’)

Question 14

Late lytic genes: (3)

Answer 14

heads, tails, lysis

Question 15

Rolling cycle replication makes concatermer by:

Answer 15

DNA replication makes copies of DNA with small gaps at the end, those are later recombined to form concatermer

Question 16

Lambda packages one genome length into the head between ___ sites of the concatermer called ___ ____ packaging

Answer 16

cos

Pac site packaging

Question 17

packaging done by terminase enzyme complex through: (4 steps)

Answer 17

1- binds to DNA
2- recognizes cos site
3- cuts it at cos
4- uses ATP to pomp that DNA inside until next cos site

Question 18

Lysis of the cell needs to be carefully controlled to ensure that the cell doesn’t lyse before the new viruses are assembled, this is done by the genes ___, _____ and _____ that act as molecular clocks

Answer 18

S, R, Rz/Rz1

Question 19

S: holin:

Answer 19

Puts a hole in the CM

Question 20

R: endolysin:

Answer 20

degrades peptidoglycan

Question 21

Rz/Rz1:

Answer 21

span from inner to outer membrane to disrupt outer membrane

Question 22

____ protein accumulates in the CM overtime and eventually reaches a critical concentration (S-105 more than S-107), changes confirmation, membrane depolarizes and it DISRUPTS the PMF, makes hole in CM

Answer 22

holin

Question 23

lambda ____ protein is a transglycolyase that breaks bonds between sugar chains in peptidoglycan

Answer 23

endolysin

Question 24

__ is In the IM and __ is a lipoprotein attached to the inner side of the OM

After holin opens the IM, the lysin can get into the periplasm to degrease the peptidoglycan and then Rz and Rz1 interact to disrupt OM

Answer 24

Rz
Rz1 is a lipoprotein