DNA Replication Simulation (Chapter 11)

Section Title

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Tutorial Comprehension Quiz

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After you've completed the tutorial, click the button below to answer questions about what you've learned.

Tutorial Comprehension Quiz

Question 1 of 7

Question

Of the components of the replication fork, which does not have direct contact with DNA?

polymerase

helicase

clamp loader

primase

clamp

Correct.

Incorrect.

Question

What and where are the chemical bonds that helicase breaks to unwind the DNA?

It does not break any bonds.

covalent/phosphate backbone

hydrogen/between base pairs

covalent/between base pairs

hydrogen/phosphate backbone

Correct.

Incorrect.

Question

Which result would be a consequence of having a nonfunctioning clamp loader in a DNA replication reaction?

The helicase complex would not unwind the DNA molecule.

The polymerase would dissociate from the DNA.

Only the lagging strand would be affected.

The polymerase would bind to the wrong area of the DNA.

Primers would not be formed.

Correct.

Incorrect.

Question

Why is primase not continually needed in the replication of the leading strand?

Single-stranded DNA–binding proteins bind to the single-stranded DNA of the leading strand and protect it until the polymerase can replicate that portion.

The clamp acts as the primer in the elongation of the leading strand.

The DNA of the leading strand does not actually unwind. This results in the polymerase being able to bind at any point and continue elongation.

Once the initial primer is made and the polymerase bound, replication of the leading strand occurs in continuous elongation by the polymerase, since the leading-strand DNA is being unwound in the 3’→5’ direction.

The polymerase that replicates the leading strand differs from the polymerases that replicate the lagging strand in that it can bind single-stranded DNA.

Correct.

Incorrect.

Question

In the DNA Replication simulation, you were asked to build a replication fork without polymerase on the lagging strand. What was the resulting DNA conformation for both the lagging and leading strand?

lagging strand = double-stranded/leading strand = single-stranded

lagging strand = single-stranded/leading strand = double-stranded

lagging strand = single-stranded/leading strand = single-stranded

lagging strand = double-stranded/leading strand = double-stranded

There would be no differential effect of this replication fork.

Correct.

Incorrect.

Question

DNA is replicated in the 5’→3’ direction due to the functioning of DNA polymerase. Because of this, the lagging strand is replicated in several fragments and then connected together by ligase. Given this information, in which direction does the lagging strand run and in which direction is it replicated?

3’→5’, 5’→3’

3’→5’, 3’→5’

5’→3’, 5’→3’

5’→3’, 3’→5’

The lagging strand runs in the same direction as the leading strand and is also replicated in the same direction.

Correct.

Incorrect.

Question

The replication of DNA is said to be semiconservative. Looking at the two newly formed DNA molecules from the simulation, what do you think “semiconservative” means?

There is both DNA and RNA in the resulting molecules.

Only some of the original genetic information is retained.

Each newly synthesized molecule has one strand from the original molecule.

The two newly formed DNA molecules are actually complementary to the original molecule.

There are many mutations introduced by the replication process that must be fixed later on.

Correct.

Incorrect.

Chapter 1. DNA Replication Simulation (Chapter 11)

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