The bacteriophage lambda genome can exist in either a linear form or a circular
ID: 40240 • Letter: T
Question
The bacteriophage lambda genome can exist in either a linear form or a circular form. The circular form occurs when the 20-bp cos sites (cohesive ends) anneal at their complementary base pairs and are ligated.
Part A - How many fragments will be formed by restriction enzyme digestion with XhoI in the linear form of the ? genome?
OPTIONS: 1, 2, 3, OR 4?
Part B - How many fragments will be formed by restriction enzyme digestion with XbaI in the linear form of the ? genome?
OPTIONS: 1, 2, 3, OR 4?
Part C - How many fragments will be formed by restriction enzyme digestion with both XhoI and XbaI in the linear form of the ? genome?
OPTIONS: 1, 2, 3, OR 4?
Part D - How many fragments will be formed by restriction enzyme digestion with XhoI in the circular form of the ? genome?
OPTIONS: 1, 2, 3, OR 4?
Part E - How many fragments will be formed by restriction enzyme digestion with XbaI in the circular form of the ? genome?
OPTIONS: 1, 2, 3, OR 4?
Part F - How many fragments will be formed by restriction enzyme digestion with both XhoI and XbaI in the circular form of the ? genome?
OPTIONS: 1, 2, 3, OR 4?
The bacteriophage lambda genome can exist in either a linear form or a circular form. The circular form occurs when the 20-bp cos sites (cohesive ends) anneal at their complementary base pairs and are ligated. Part A - How many fragments will be formed by restriction enzyme digestion with XhoI in the linear form of the ? genome? OPTIONS: 1, 2, 3, OR 4? Part B - How many fragments will be formed by restriction enzyme digestion with XbaI in the linear form of the ? genome? OPTIONS: 1, 2, 3, OR 4? Part C - How many fragments will be formed by restriction enzyme digestion with both XhoI and XbaI in the linear form of the ? genome? OPTIONS: 1, 2, 3, OR 4? Part D - How many fragments will be formed by restriction enzyme digestion with XhoI in the circular form of the ? genome? OPTIONS: 1, 2, 3, OR 4? Part E - How many fragments will be formed by restriction enzyme digestion with XbaI in the circular form of the ? genome? OPTIONS: 1, 2, 3, OR 4? Part F - How many fragments will be formed by restriction enzyme digestion with both XhoI and XbaI in the circular form of the ? genome? OPTIONS: 1, 2, 3, OR 4?Explanation / Answer
A. 2
B. 2
C. 3
D. 1
E. 1
F. 2
When restriction enzyme having a single recognition site on act on the linear molecule of bacteriophage lambda genome then the number of restriction fragments generated will be 2 since cleavage at one site would produce two fragments. Hence in a linear molecule the number of restriction fragments generated will be one more than the number of restriction sites it contains for single or multiple restriction enzymes.
When restriction enzyme having a single recognition site act on the circular molecule of bacteriophage lambda genome then the number of restriction fragments generated will be only 1 since it creates a cut in the circular molecule but cannot generate two fragments. Hence in a circular molecule the number of restriction fragments generated will be same as the number of restriction sites it contains for single or multiple restriction enzymes.