microbio 1.2

Question 1

What is the role of the elongasome complex in cell division?

Answer 1

It includes proteins that assist in cell elongation during binary fission.

Question 2

What is MreB and its function in bacterial cell shape?

Answer 2

A small protein that polymerizes to guide peptidoglycan elongation, allowing the cell to form a rod shape.

Question 3

How is the number of cells in an exponentially growing population calculated?

Answer 3

Using the equation Nt = N0 * 2^n, where Nt is the cell number at time t, N0 is the initial cell number, and n is the number of generations.

Question 4

What is the generation time (g) in microbial growth?

Answer 4

The time it takes for the population of cells to double, calculated as g = t/n.

Question 5

What is the specific growth rate (k) in microbial growth?

Answer 5

Measured in hr-1, it expresses the rate at which the population is growing at any instant.

Question 6

How is the relationship between specific growth rate (k) and generation time (g) expressed?

Answer 6

k = (ln 2)/g, linking the rate of growth to the time taken for population doubling.

Question 7

What happens during the lag phase of bacterial growth?

Answer 7

Bacterial growth is limited as cells adjust to new nutrient conditions and prepare for growth.

Question 8

What characterizes the stationary phase of bacterial growth?

Answer 8

Cells stop growing and activate stress responses to maintain viability.

Question 9

What is the death phase in bacterial growth?

Answer 9

Cells die at a rate similar to radioactive decay, characterized by a ‘half-life’.

Question 10

How would a cell with a FtsZ mutation differ from one with a FtsK mutation?

Answer 10

A FtsZ mutation would affect the formation of the division ring, while a FtsK mutation would impact chromosome segregation.

Question 11

How does the presence of a cell division inhibitor affect FtsZ and DNA localization?

Answer 11

It would likely target MinCD, disrupting its function and allowing FtsZ to localize improperly.

Question 12

Calculate the number of generations for Sinorhizobium meliloti after 5 days if it reaches 10,000 cells.

Answer 12

Using Nt = N0 * 2^n, solve for n to find the number of generations.

Question 13

Which tube will have more bacteria after 2 hours: 1,000 bacteria doubling every hour or 10 bacteria doubling every 20 minutes?

Answer 13

The tube with 10000 bacteria will have more after 2 hours

Question 14

What is the role of a DNA motor protein in cell division?

Answer 14

It facilitates chromosome segregation by resolving chromosome dimers after replication.

Question 15

What are Class A and B penicillin-binding proteins (aPBP and bPBP)?

Answer 15

Proteins that synthesize new peptidoglycan during cell division.

Question 16

What is FtsZ and its role in cell division?

Answer 16

A protein that polymerizes to form a ring at the midline of the cell, marking where division will occur.

Question 17

What proteins anchor the FtsZ ring during cell division?

Answer 17

ZipA and FtsA anchor the FtsZ ring and assist in its stabilization.

Question 18

What is the function of Min proteins in bacterial cell division?

Answer 18

They regulate cell division by localizing FtsZ to the midline and preventing multiple division rings.

Question 19

What does MinE do in the context of cell division?

Answer 19

It oscillates from pole to pole, clearing MinCD from the midline, allowing FtsZ to form the division ring.

Question 20

What are the four phases of bacterial growth?

Answer 20

Lag phase, exponential phase, stationary phase, and death phase.

Question 21

What is the significance of the MinCD spiral in cell division?

Answer 21

It inhibits cell division by preventing the formation of the FtsZ ring at inappropriate locations.

Question 22

How many generations occur if the specific growth rate is 7 hr-1 over a period of time?

Answer 22

If 5 generations occur, it would take approximately 5 hours.

Question 23

What is binary fission?

Answer 23

A process where a cell divides in half after elongating, replicating its chromosome, and forming a division plane.

Question 24

What is the divisome complex?

Answer 24

A complex of proteins that play essential roles in bacterial cell division.