AP Biology: Genetics & Evolution

What is the law stating that two alleles for a heritable character separate during gamete formation and end up in different gametes?

The Law of Segregation

Which enzyme is responsible for unwinding the DNA double helix at the replication fork?

Helicase

What is the primary mechanism of evolution where organisms with favorable traits are more likely to survive and reproduce?

Natural Selection

Which laboratory technique is used to amplify a specific segment of DNA into millions of copies?

Polymerase Chain Reaction (PCR)

In an RNA molecule, which nitrogenous base replaces the thymine found in DNA?

Uracil

What are anatomical structures in different species that are similar because of common ancestry?

Homologous structures

In a dihybrid cross between two individuals heterozygous for both traits (AaBb x AaBb), what is the expected phenotypic ratio?

9:3:3:1

What is the specific DNA sequence where RNA polymerase binds to initiate the process of transcription?

The promoter

How does the lac operon respond when lactose is present and glucose is absent in the environment?

The allolactose inducer inactivates the repressor, allowing high levels of transcription.

In gel electrophoresis, why do DNA fragments migrate toward the positive (anode) end of the gel?

DNA is negatively charged due to its phosphate groups.