DNA Structure, Replication, and Sequencing

Flashcards reviewing DNA structure, replication steps and enzymes, hydrogen bonding, and sequencing techniques such as PCR and sample sequencing.

Why does DNA have a negative charge?

Because of phosphate.

What is the sole purpose of DNA?

To store and transmit genetic information.

What are the three parts of a nucleotide?

5 carbon sugar (deoxyribose), Phosphate group, and Nitrogen base (4 types).

How are pyrimidines and purines categorized in the notes?

Pyrimidines are small (C + T) and Purines are big (A + G).

What is Chargaff's Rule?

In any DNA strand, the amount of A + T are equal as well as C + G.

What did Watson + Crick find in 1953?

Found double helix.

What occurs during the Initiation phase of DNA replication?

Helicase unwinds DNA, and single stranded binding proteins hold strands.

What occurs during Elongation in DNA replication?

DNA polymerase builds new strand following rules, and DNA Ligase seals strands together.

What occurs during Termination in DNA replication?

Nucleases proofread and repair mistakes and fill in gaps.

How many hydrogen bonds join Guanine and cytosine, and Thymine and adenine?

Guanine and cytosine have 3 bonds; Thymine and adenine have 2 bonds.

What is Polymerase Chain Reaction (PCR)?

A process that produces millions of identical copies of a DNA sequence.

How does Sample Sequencing differ from PCR?

Instead of making several copies of DNA, it makes fragments of DNA that vary in size by one letter.

What is the function of the primer used in PCR for pathogen detection?

It will only attach to bacteria/virus DNA so as PCR proceeds we only accept pathogen's DNA.

What happens once a fluorescently-tagged nucleotide is added to the DNA strand?

DNA polymerase stops building.

How does an automatic sequencer organize DNA fragments?

By size, where smaller fragments travel faster.

What does 'Denature' mean in the context of copying DNA?

To unwind + separate DNA into strands using the enzyme Helicase.