DNA REPLICATION TEST STUDYGUIDE

What type of macromolecule is DNA

Nucleic acid

Where is DNA located in eukaryotes?

In the nucleus

Where is DNA located in prokaryotes?

In the cytoplasm

What are the 3 parts of a nucleotide?

A phosphate group, a sugar, and a nitrogenous base.

What are the 5 possible nitrogenous bases?

Adenine, Thymine, Cytosine, Guanine, and Uracil.

What nitrogenous bases go with DNA?

Adenine pairs with thymine and guanine pairs with cytosine.

What nitrogenous bases pair with RNA?

Adenine pairs with uracil and guanine pairs with cytosine.

What type of force holds nitrogenous bases together in the DNA double helix?

Hydrogen bonds hold nitrogenous bases together in the DNA double helix.

Which scientist determined that adenine and thymine occur in roughly the same ammounts in DNA as do cytosine and guanine?

Erwin Chargaff

Which scientist coined the term transforming factor as a way to explain that the genetic material of one bacteria can be transferred to another?

Frederick Griffith

Which scientists determined that DNA is the carrier of genetic information- NOT protein- by using radioactive phosphorous in an experiment with bacteriophages and bacteria?

Hershey and Chase

Which scientist is famous for the x-ray diffraction photo B51 that turned out to be the last piece of the puzzle in Watson and Crick’s understanding of the structure of DNA?

Rosalind Franklin

How does the lagging strand differ from the leading strand in replication?

The lagging strand is synthesized discontinuously in short segments called Okazaki fragments, while the leading strand is synthesized continuously in the same direction as the replication fork.

What is the role of DNA helicase?

DNA helicase unwinds and separates the double-stranded DNA during replication, allowing the replication machinery to access the template strands.

What is the role of polymerase I

Polymerase I is responsible for removing RNA primers during DNA replication and replacing them with DNA nucleotides, ensuring the newly synthesized strand is continuous and accurate.

What is the role for polymerase III

Polymerase III is the primary enzyme responsible for synthesizing new DNA strands during replication, adding nucleotides to the growing chain in a 5' to 3' direction.

What is the role of DNA ligase?

DNA ligase functions to join Okazaki fragments on the lagging strand during DNA replication, ensuring the overall integrity of the newly formed DNA strand by sealing nicks in the sugar-phosphate backbone.

What is the role of primase?

Primase synthesizes short RNA primers that provide a starting point for DNA polymerase to begin DNA synthesis during replication.

What is the role of telomerase?

Telomerase is an enzyme that adds repetitive nucleotide sequences to the ends of chromosomes, called telomeres, which helps maintain chromosome stability and prevents degradation during DNA replication.

What are telomeres?

Telomeres are repetitive nucleotide sequences located at the ends of eukaryotic chromosomes that protect them from deterioration or fusion with neighboring chromosomes, ensuring the integrity of genetic information during cell division.

Why are telomeres important?

Telomeres are important because they protect chromosomes from deterioration and prevent the loss of vital genetic information during DNA replication and cell division.

Beginning with helicase explain what happens during DNA replication. Be sure to include the role of primase, RNA primer, DNA polymerase I, DNA Polymerase III, and ligase.

During DNA replication, helicase unwinds the double helix, creating replication forks. Primase synthesizes short RNA primers at the single-stranded template, providing a starting point for DNA synthesis. DNA polymerase III then extends the RNA primers, synthesizing new DNA strands in a 5' to 3' direction. DNA polymerase I replaces RNA primers with DNA nucleotides. Finally, ligase seals the gaps between Okazaki fragments on the lagging strand, completing the replication process.

What are Okazaki fragments?

Okazaki fragments are short sequences of DNA nucleotides synthesized on the lagging strand during DNA replication. They are formed discontinuously and are later connected by DNA ligase.