Molecular Micro. Ch.3 Bacterial Chromosomes & Cell Division

What helps the bacterial cell determine the center for cell division?

FtsZ ring

What is FtsZ made of?

Tubulin

What two systems help regulate FtsZ formation?

Min and Noc

Which regulatory system oscillates and ensures that FtsZ forms in the middle?

Min

What regulatory system inhibits FtsZ formation until daughter chromosomes are properly segregated?

Noc

In the Min system, which protein binds to the cell membrane at the poles?

MinD

In the Min system, which protein binds to MinD and inhibits FtsZ formation?

MinC

What must MinD be bound to in order to bind to the cell membrane?

ATP

In the Min system which protein acts as the engine that causes MinCD to oscillate between the poles?

MinE

How was the Min system discovered?

Mini-cells

What does MinE stimulate to cause MinD to be released from the cell membrane?

ATPase

What is the written out name of the Noc system?

Nucleoid occlusion system

What do Noc proteins inhibit?

FtsZ formation

Where do Noc proteins bind?

DNA

What is the other name for Noc proteins found in B. subtilis?

SlmA

What is the name of the revolutionary system used to study bacterial cell cycle by having mother cells attached to a membrane and subsequent daughter cells be “dropped” below?

Baby Machine

Who invented the “Baby Machine”?

Charles Helmstetter and Steve Cooper

How long does chromosome replication take?

40 minutesH

How long does cell division take?

20 minutes

In the “ICD” terminology, what does the “I” stand for?

Time between initiation of last round of replication and the initiation of a new round of replication

In the “ICD” terminology, what does “C” stand for?

Time to replicate an entire chromosome

In the “ICD” terminology, what does “D” stand for?

Time between completion of chromosome replication and cell division

In the “ICD” terminology, what 2 processes always occur in the same time frame?

C and D

In “ICD” terminology, which process is variable and is dependent on how fast the cell grows?

I

Presence of nutrients and temperature would affect which process in the cell cycle (ICD)

Time between last and new round of replication

After DNA replication, which protein is diluted due to the presence of 2 oriC sites?

DnaA

After chromosome replication, what site sequesters DnaA and competes with oriC for DnaA binding?

datA site

What sites does E. coli methylate DNA at?

GATC

Which specific nucleotide does E. coli methylate in DNA?

Adenine

Immediately following DNA replication, the daughter strand is unmethylated.

True

How many times does the GATC sequence appear in the oriC region?

11 times

Where else do GATC sites exist besides oriC?

dnaA promoter region

What must me done in order for dnaA transcription?

GATC methylation in the dnaA promoter

What protein binds the hemimethylated oriC to the membrane, preventing further initiation and methylation?

SeqA