Exp 1:pr-prac - Replica Plating

Question 1

What is the name given to the agar that the bacteria originally grow on that will be used in replica plating?

Answer 1

Master (agar) plate

Question 2

During replica plating, what medium is the master plate transferred onto?

Answer 2

Velvet

Question 3

What analogy can be used to describe the process of replica plating?

Answer 3

like a printing block

Question 4

What is the outcome of phage resistant cells’ position in the spontaneous mutation model?

Answer 4

Resistant cells are transferred to the same place on each replicate

Question 5

What is the outcome of phage resistant cells’ position in the induced hereditary model?

Answer 5

Phage resistant colonies form at random positions

Question 6

Name two models used to describe the difference in position of phage resistant cells observed in replica plating.

Answer 6

Spontaneous mutation model
Induced heredity model

Question 7

Why, in the induced hereditary model of replica plating, are phage resistant colonies located at random positions?

Answer 7

Their position is not predetermined by whether there was a resistant cell in the existing master because there is random induction of phage resistant cells

Question 8

What concept of Dawinism was Lederberg’s replica plating results consistent with?

Answer 8

Pre-existing variation witin a population combined with natural selection drives evolution

Question 9

Why is velvet used for replica plating?

Answer 9

the fibres of velveteen act like hundreds of tiny inoculated needles

Question 10

What is the plot twist behind Joshua Lederberg’s Replica plating experiment?

Answer 10

It was actually his wife Esther who came up with the concept

Question 11

Replica plating is an indirect selective method of proving what idea?

Answer 11

The origins of spontaneous mutants with adaptive advantages such as resistance

Question 12

Why must you tap the master plate once on the velvet block during replica plating?

Answer 12

to allow for an even transfer onto the plate

Question 13

What important marking must be made during replica plating? and why?

Answer 13

marking the orientation of the master plate relative to the velvet block so that the orientation matches up when making replicas with minimal medium plates

Question 14

What type of plates are used for the replicas in replica plating?

Answer 14

minimal medium plates

Question 15

Why are minimal medium plates given their name?

Answer 15

THey have no amino acids and are therefore nutritionally restrictive

Question 16

In the Adenine pathway, what are the colours of the product when mutants block the pathway? What order do the colours come in?

Answer 16

White (first)
Red (second)