DNA Replication Quiz Practice

During DNA replication, how is the leading strand built?

• Continuously, as nucleotides are added to the 3′ end

• Continuously, as nucleotides are added to both ends

• In short segments, as groups of nucleotides are added all at once

• In short segments, as nucleotides are added to the 5′ end

How are the leading and lagging strands built differently during elongation?

• The lagging strand is built toward the replication fork, while the leading strand is built away from the replication fork.

• An enzyme adds nucleotides to the lagging strand, but they spontaneously attach to the leading strand.

• Nucleotides are added to the 3′ end of the leading strand and to the 5′ end of the lagging strand.

• The lagging strand is built in short segments, while the leading strand is built continuously.

How is the lagging strand built during DNA replication?

• Continuously, as nucleotides are added to the 5′ end

• Continuously, as nucleotides are added to both ends

• In short segments, as nucleotides are added to the 3′ end

• In short segments, as groups of nucleotides are added all at once

What happens at the beginning of DNA replication?

• A group of enzymes attaches to the molecule and starts to build a new double helix.

• The two strands of DNA are separated to form a Y-shaped replication fork.

• RNA primers are removed and replaced with DNA nucleotides.

• The code in the sequence of bases is transferred to an mRNA molecule.

Which event must occur before nucleotides can be added to a new DNA strand during DNA replication?

• RNA primers must be added to the template strands.

• Hydrogen bonds must form between nitrogenous bases.

• A strand of mRNA must be built from the template strand.

• An enzyme must check the template strand for errors.

What role does primase play in the initial stages of DNA replication?

• It builds a strand of mRNA using the code in the template strand.

• It makes RNA primers and adds them to the template strand.

• It checks for errors and removes any RNA nucleotides.

• It adds nucleotides to RNA primers to build Okazaki fragments.

The model represents DNA replication. Where in this model are Okazaki fragments being built?

• To the right of enzyme 1

• To the right of enzyme 2

• Along structure 1

• Along structure 2

The model represents DNA replication. Which statement best describes structure 1?

• It is the lagging strand because it is behind enzyme 1.

• It is the leading strand because it is being built continuously.

• It is the leading strand because it is being built in the 3′ to 5′ direction

• It is the lagging strand because it uses RNA primers.

The model represents DNA replication. Which statement best describes structure 2?

• It is the lagging strand because it is being built in short segments.

• It is the leading strand because the 5′ end is closer to the replication fork.

• It is the leading strand because it is being built in the 3′ to 5′ direction.

• It is the lagging strand because it uses RNA primers.

How is the supercoiling of DNA corrected during the replication process?

• DNA ligase breaks bonds in the sugar–phosphate backbones to prevent supercoilin

• The entire DNA molecule is uncoiled prior to the start of the replication process.

• Topoisomerase clips and untwists small sections of supercoiled DNA molecules.

• Helicase separates the strands and snips them into smaller sections when supercoiling gets too tight.