DNA

 If 35% of an organism’s DNA is thymine, what is the percentage of guanine?

• 15%

• 35%

• 50%

• 42%

Chargaff's rules of base pairing are explained by which structural feature of DNA?

• Each strand of DNA contains a phosphate and sugar backbone.

• DNA is double stranded, and covalent bonds between identical nucleotides hold the two strands together.

• DNA is double stranded, and hydrogen bonds between base pairs hold the two strands together.

• All of theses

• None of these

The model of the double-helix model of the DNA molecule resembles a twisted ladder.

What makes up the rungs, or steps, of the twisted ladder?

• paired phosphate groups

• paired nitrogenous bases

• paired sugars

What aspects of the structure of DNA are explained by this model? Select three answer choices.

• Paired nucleotides are held together by covalent bonds

• Adenine is paired with thymine and guanine is paired with cytosine

• Paired nucleotides are held together by hydrogen bonds

• The two strands of DNA each have phosphate-sugar backbones

How does the double-helical structure of DNA explain how the molecules can be copied or replicated?

• Because of base pairing, each strand has all the information to serve as a template for the synthesis of the other strand.

• Each strand receives the information from the DNA polymerase attached to the replication fork.

• The nitrogenous bases on one strand are copied to the other strand.

• All of these

• None of these

When must DNA replication occur during the cell cycle for each daughter cell to receive a complete copy of DNA?

• DNA replication must occur before mitosis.

• DNA replication must occur during mitosis.

• DNA replication must occur during G₂.

• Any of these times

• None of these times

The sequence of nitrogenous bases on a portion of a strand of DNA is shown in the diagram. From left to right, what is the corresponding sequence of the complementary strand?

• C C A C T G A

• G G U G T A T

• T T A G A T C

• A A U A C G C

Which of the following labels should NOT be added to the model?

• DNA polymerase

• Replication fork

• RNA polymerase

• All of these should NOT be added to the model

• All of these should be added to the model