Quiz · DNA Replication and Its Proofreading Machinery

Question 1What is the main focus of the lecture?

How a single enzyme copies genetic material How diseases damage the double helix How cells copy DNA with remarkable accuracy How scientists first discovered DNA structure

Question 2What did later work show about how DNA strands are copied?

Both strands are copied at the same speed The machinery moves without ever pausing Errors cannot be corrected once inserted One strand is assembled in separate fragments

Question 3What was the unexpected outcome of the experiment mentioned?

It revealed a second repair system It confirmed the predicted error rates It proved helicase worked alone It showed replication never makes errors

Question 4What is the specific role of helicase during DNA replication?

It unwinds the double helix by breaking bonds between paired bases It joins the small fragments into one complete new strand It measures the error rate during the copying process It reverses direction whenever a mistake appears

Question 5What does DNA polymerase do when an incorrect base is inserted?

It pauses, reverses, and removes the error It ignores the error and continues copying It destroys the entire newly built strand It signals the helicase to stop unwinding

Question 6Which quality most defines DNA polymerase, according to the speaker?

Its remarkable overall working speed Its accuracy, although it achieves both well Its ability to function entirely alone Its resistance to very high temperatures

Question 7What eventually happens to the fragments of the new strand?

They are checked and then discarded They are joined together by another enzyme They are stored inside the cell nucleus They are copied once more by helicase

Question 8How did the fragments of the new strand get their name?

From the shape they form under pressure From the scientist who discovered them From the enzyme that finally removes them From the disease they help to prevent

Question 9Why does proofreading matter, according to the example given in the lecture?

Because errors tend to speed up cell division Because repair systems consume most of the energy Because unrepaired errors can accumulate and trigger disease Because perfectly accurate DNA prevents all mutation

Question 10Which idea is closest in meaning to describing replication as a coordinated molecular machine?

A single enzyme acting extremely quickly Random chemical reactions inside the nucleus Equipment built by scientists in laboratories Many components working together in an organised way