Unit 4 Lesson 4 Practice Work

Examine the model. Select the option below that puts the steps of replication into the proper order.

.

A. Hydrogen bonds between nucleotides form.

B. Hydrogen bonds between nucleotides break.

C. Strands of DNA separate.

D. Free nucleotides are attracted to exposed bases on the loose strands of DNA.

• A,B,C,D

• B,D,C,A

• B,C,D,A

• C,B,A,D

What type of biological molecule is DNA helicase?

• carbohydrate

• lipid

• protein

• nucleic acid

What is the role of DNA helicase in the replication of DNA?

What rule is used to join the free nucleotides to the exposed bases of the DNA?

What sequence would DNA polymerase create if the template strand was GACCGTA ?

This image shows that DNA Replication is _______.

• Conservative
• Semiconservative
• Dispersive
• Spontaneous

This type of replication is called semi-conservative replication. Considering the meaning of these words (semi—half; conserve—to keep), explain why DNA replication is called semi-conservative.

DNA molecules can be tens of thousands of base pairs in length. Mistakes in DNA replication lead to mutations, which may or may not be harmful to an organism. How does semi-conservative replication help prevent mutations during DNA replication?