BIOL 205 Exam Review: DNA Packaging, Manipulation, Replication, and Transcription

These flashcards cover key concepts related to DNA packaging, manipulation, replication, and transcription discussed in BIOL 205.

What is the percentage of adenine in puffer fish DNA if it contains 23% cytosine?

27% adenine.

Why does molecule A require less energy to separate than molecule B?

Because molecule A has a lower percentage of G:C pairs than molecule B, which has more stable G:C pairs requiring more energy to separate.

What would you expect to observe when digesting eukaryotic chromatin with micrococcal nuclease?

More undigested fragments of DNA, as sequences of DNA associated with nucleosomes would be protected from digestion.

What technique could be used to create a knockout mutation for the ACE2 gene?

CRISPR, with a guide RNA complementary to the ACE2 gene.

What effect does deleting the CRISPR locus from a bacterium have?

The bacterium becomes more susceptible to bacteriophage infection, as CRISPR serves as a defense mechanism against such infections.

Why is helicase not needed in PCR?

Because heat is used to separate DNA strands, eliminating the need for helicase.

Why is primase not required in PCR reactions?

Primase synthesizes primers during DNA replication, but in PCR, DNA primers are supplied in the reaction.

Which technique would you use to determine if a point mutation is present in DNA?

DNA sequencing, as it provides the sequence of DNA whereas PCR only creates copies.

What happens if you forget to add ddCTP in a DNA sequencing reaction?

You will be unable to determine the location of C bases, but could sequence the locations of the other three bases.

What is the effect of a mutation preventing general transcription factors from binding to DNA?

The cell would be unable to carry out transcription and would likely die.

What are some key differences between transcription in bacteria and eukaryotes?

1) Prokaryotes use RNAP core with sigma, eukaryotes use RNAP and general transcription factors; 2) Prokaryotes have simpler promoters; 3) Different termination mechanisms; 4) In prokaryotes, transcription and translation are coupled.

What is the RNA sequence transcribed from the DNA sequence 5’-ATCG-3’?

5’-UAGC-3’.