CH 12 DNA Replication and Manipulation Reading Guide Flashcards Preview

Final Exam > CH 12 DNA Replication and Manipulation Reading Guide > Flashcards

Flashcards in CH 12 DNA Replication and Manipulation Reading Guide Deck (20):

Explain semi conservative and conservative DNA?

Semi conservative: one strand of the newly formed DNA will be from the parent and another strand will be brand newConservative both strands are from the parents no new strand is created


What method did me seldom and stahl up to identify parental and newly synthesized DNA strands?

They labeled the different strands with different isotopes of nitrogen


Explain the three main steps of the modelson and stahl experiment?

1 both strands of DNA are labeled with heavy nitrogen which forms a band of heavy DNA2 after one round of replication one strand contains heavy nitrogen and one strand contains light nitrogen therefore net lighter3. After two rounds of replication two strand of light nitrogen and one stand of heavy and one strand of light similar to step 2


How are the two daughter strands different after replication?

There anti parallel to one another


What is the enzyme called that is required to catalyze the addition of new nucleotides? Do they synthesize DNA from an existing template.

DNA polymeraseYes


Define leading strand

The daughter strand that has its 3' end pointing towards the replication fork


Define lagging strand

The daughter strand that has its 3' end pointing away from the replication fork


Define Okazaki fragments

Short pieces found within the lagging strand


Define a primer

Short stretch of RNA that serves as the starting point for a strand of DNA


What type of enzyme is primase?

A type of RNA polymerase


Why does DNA polymerase require a primer in order to do its job?

So that it knows where to start copying


What happens to DNA primers during the process of DNA replication?

Gets replaced by DNA nucleotides


What do DNA ligases do?

Joins the fragments of DNA together


Define proofreading

A process when DNA polymerase correct there own copying errors


How good is DNA polymerase at finding errors



Define a mutation in the context of DNA polymerase?

When mistakes slip past the proofreading process Some mistakes in coding may cause harmful changes to the genetic code


What is the function of helicase?

To unwind the parental double helix at the replication fork


What do topoisomerases do?

Removes stress associated wight the unwinding at the replication fork


What do single stranded binding proteins do?

Bind the resulting single stranded regions of DNA to prevent the template strands from coming back together


How are the deoxyribose sugars linked together in a DNA strand?

Phosphate group