A C Close se-Up L Look ook a at PCR Polymerase Chain Reaction - - PowerPoint PPT Presentation

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Jan 20, 2024 33 likes •124 views

A C Close se-Up L Look ook a at PCR Polymerase Chain Reaction (PCR) and cellular DNA replication both result in synthesis of new DNA molecules Rev eview ew: DNA NA Rep eplic lication DNA r repl plication i is a semiconser

SLIDE 1

A C Close se-Up L Look

ok a

at PCR

Polymerase Chain Reaction (PCR) and cellular DNA replication both result in synthesis of new DNA molecules

SLIDE 2

Rev eview ew: DNA NA Rep eplic lication

DNA r repl plication i is a semiconser servative process

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New strands are built from complementary base pairing DNA m must b bec ecome s e sing ngle s e stranded ed i in n order der t to let new ew n nitrogen enous b s bases es bind nd to t the he old s d strand

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In replication, this occurs via a replication fork Repl eplication only occurs i in n the he 5’ to 3 3’ direc ection The c chemic ical b l bonds i in DNA are a as follo

llows:

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Phosphodiester bonds in the backbone are strong conservative bonds

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Bonds between the DNA bases are weaker hydrogen bonds.

Image courtesy of Madeline Price Ball, Wikiemedia Commons 2013

In a cell, all of the DNA is copied during the process of DNA replication!

SLIDE 3

During P g PCR m R many c copies o

a target r reg egion of DN DNA a are s e synthes esized ed

SLIDE 4

Imp mpor

rtan

ant V Vocabular ary

A heat stable version of DNA polymerase, Taq Polymerase, is used

to synthesize DNA

A dynamic, and complex process that involves repeated cycles of
Denaturation – “unzipping” the DNA to form single strands
Annealing – attaching the primers
Extension – synthesizing new DNA, starting at the primers

SLIDE 5

Lear arning Ob Objectives

Describe the role of a primer in PCR
Predict sequence and length of PCR product based on primer sequences
Recognize that primers are incorporated into the final PCR products and why
Identify covalent and Hydrogen bonds formed and broken during PCR
Predict the structure of PCR products after each cycle of the reaction
Explain why amplification proceeds exponentially

SLIDE 6

PCR: R: Wrap up

In order to amplify a particular region, we must first open (denature) the

DNA

Unlike cellular DNA replication, which uses helicase to unwind DNA, high

temperatures are used in PCR to separate the strands of DNA

Primers are crucial for specifying the region to be amplified and providing a

free 3’OH end for DNA polymerase.

The target region is amplified exponentially, resulting in billions of copies

after 30-40 cycles.

SLIDE 7

Cycle 1 Cycle 2 Cycle 3 Denaturation Annealing Extension

SLIDE 8

Cycle 1 Cycle 2 Cycle 3 Denaturation Annealing Extension

SLIDE 9