chapter 5

Question 1

replicon

Answer 1

region of the gene that contains the REPLICATION ORIGIN

Question 2

sigma factor

Answer 2

in transcription of RNA, it recognizes and guides the RNA from -30 and -10 sites to the +1 site to begin transscribing (promotor region)

Question 3

consensus sequence

Answer 3

each sigma factor knows which promotor to go to, to initiate transcription process

Question 4

3 types of termination of RNA during the end of transcription

Answer 4

1. intrinsic termintation - signals within the RNA transcript itself
2. Rho (p) protein uses ATP to pull it apart

3.

Question 5

wobble effect

Answer 5

happens in translation when you dont have enough anti codons (tRNA) for all the amino acids. so it just accepts the last anticode

ex: if it is supposed to be ATG then ATC will work just fine

this means you dont have to make so many tRNA’s and also decreases chances of heritable mutations

Question 6

chaperons

Answer 6

they are protines that help other protiens fold. they supress incorrect folding.

a chaperon called the Trigger Factor (TF) accociates with the ribosome and succesfully helps fold many protiens.

about 25% of proteins need help folding

Question 7

Translocation & Secretion (3types)

Answer 7

Translocation: moving proteins across plasma membrane

Secretion: out of cell into external environment (3 types)
Sec –> in all 3 domains and translocates Un-folded proteins across membrane
Tat –> only secretes folded protiens
YidC –> works with Sec

Question 8

Two-step and One-step secreting Systems

Answer 8

one-step: directly from cytoplasm to extracellular

two-step: cytoplasm –> periplasm –> extracellular (V, II, IX)

Question 9

inducers

Answer 9

makes repressor fall of operator

makes activator attatch to promoter

Question 10

co-repressors

Answer 10

makes repressor attatch to operator

Question 11

Inhibitor

Answer 11

makes activator attatch to promoter

Question 12

riboswitches

Question 13

attenuation

Answer 13

loops that form and either stop transcription or lets it continue.

Ex: trp operon.
continues in precnce of low trp
terminates it in precense of high trp

Question 14

riboswitches

Answer 14

part of an mRNA transcript 5’ molecule that can bind and target small molecules

during transcription if the end-product is abundant then it will bind to the riboswitch and transcription will stop

during transcription if the end-product is needed, it will continue transcription

–> in translation it has to do with shine delagarno sequences (SD)

Question 15

sRNA

Answer 15

less commonly used, sRNA regulates translation by trans-endoding and they can form stem-loop structures

Question 16

two-component sigal transduction (global regulation)