[OLD] DNA - Semi-Conservative Replication Experiment

Question 1

STEP 1

Answer 1

Bacteria were grown in a heavy 15N medium

Question 2

STEP 2

Answer 2

Bacteria were transferred to a 14N medium

Question 3

STEP 3

Answer 3

A sample of bacteria was removed after 1 generation

Question 4

STEP 4

Answer 4

DNA was extracted from the bacteria

Question 5

STEP 5

Answer 5

The DNA was centrifuged at high speed to separate the DNA by density. The lighter DNA collected above the heavier DNA

Question 6

STEP 6

Answer 6

The pattern of DNA was compared to parental bacteria grown in 15N medium and control bacteria grown in 14N medium

Question 7

STEP 7

Answer 7

Bacterial samples were also removed after 2 and 3 generations of growth and DNA was extracted

Question 8

STEP 8

Answer 8

Meselsohn and Stahl analysed their results to see if they were consistent with a model of semi-conservative replication