AP Biology Unit 6 Gene Expression

What does transformation involve in bacteria?

• the infection of cells by a phage DNA molecule

• assimilation of external DNA into a cell

Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism.

Approximately what percentage of the nucleotides in this sample will be thymine?

• 12%

• 24%

• 31%

• 38%

Why does the DNA double helix have a uniform diameter?

• Purines pair with pyrimidines.

• Deoxyribose sugars bind with ribose sugars.

In an analysis of the nucleotide composition of DNA, which of the following will be found?

• A = G and C = T

• A + C = G + T

Tags

NGSS.HS-LS1-1

What is meant by the description ʺantiparallelʺ regarding the strands that make up DNA?

• The 5ʹ to 3ʹ direction of one strand runs counter to the 5ʹ to 3ʹ direction of the other strand.

• One strand is positively charged and the other is negatively charged.

What determines the nucleotide sequence of the newly synthesized strand during DNA replication?

• the nucleotide sequence of the template strand

• the primase used in the reaction

You briefly expose bacteria undergoing DNA replication to radioactively labeled nucleotides. When you centrifuge the DNA isolated from the bacteria, the DNA separates into two classes. One class of labeled DNA includes very large molecules (thousands or even millions of nucleotides long), and the other includes short stretches of DNA (several hundred to a few thousand nucleotides in length). These two classes of DNA probably represent

• leading strands and Okazaki fragments

• lagging strands and Okazaki fragments.

Which of the following separates the DNA strands during replication?

• helicase

• DNA polymerase

• primase

Which of the following covalently connects segments of DNA?

• helicase

• DNA polymerase

• ligase

Which of the following synthesizes short segments of RNA?

• helicase

• DNA polymerase

• primase