Biology Practice Exam Questions

[Irving4Prez]

Couldn't manage to get my head around these 2 questions,

[Russ]

Question is testing your understanding of the concept of semi conservative DNA replication. Every replication cycle the cell needs to get N from its environment in order to double the amount of DNA it has. After 1 replication there will be equal amounts of each isotope and after X cell cycles there will be an overwhelmingly larger amount of the environmentally supplied isotope.

Does that help?

(alternatively, I'm wrong, it's been a while -.-)

[Irving4Prez]

Question is testing your understanding of the concept of semi conservative DNA replication. Every replication cycle the cell needs to get N from its environment in order to double the amount of DNA it has. After 1 replication there will be equal amounts of each isotope and after X cell cycles there will be an overwhelmingly larger amount of the environmentally supplied isotope.

If that were the case, after one cycle the test tube should appear as test tube 5 because equivalent amount of isoptopes are being used. However the answer for Q 2 was, C

For question 3, the answer was C, not too sure if that corresponds with your explanation...