AP Biology Chapter 15
What is the process for the polymerase chain reaction?
1. DNA is denatured by heat in which the DNA separates into single strands. 2. Primers attach to a primer binding site on each DNA strand. 3. Each DNA strand acts as a template for DNA synthesis catalyzed by Tag DNA polymerase. The number of DNA molecules doubles each time the cycle is repeated.
What is the process for Restriction Fragment Length Polymorphism?
1. Restriction enzymes are used to cute the DNA from two or more individuals. 2. The fragments are separated by gel electrophoresis. 3. Shorter fragments migrate farther than longer fragments. 4. Researchers make a Southern Blot. 5. RFLP analysis
What is a vector molecule?
A carrier capable of transporting the DNA fragment into a cell.
How does a bacterium protect its own DNA when using restriction enzymes as a defense against infection?
By adding a methyl group to one or more bases in each restriction site so that the restriction enzyme does not recognize and cut the bacterial DNA.
What do restriction enzymes enable researchers to do?
Cut DNA into manageable segments.
What is RFLP used to determine?
How closely related different members of a population are. They result from random DNA mutations and recombinations in different individuals.
What does gel electrophoresis do?
It separates DNA fragments by length.
Explain what a genetic probe is.
It's a radioactively labeled segment of single-stranded DNA that can attach, through pairing base pairs, to the target DNA. It is used to detect specific DNA sequences of interest. The probe itself is a segment of DNA that is homologous to part of the sequence of interest.
What are examples of vector molecules?
Plasmids and Bacteriophages
Where do restriction enzymes come from?
They are produced by bacteria.
What are restriction enzymes do?
They cut DNA molecules only in specific places.
Which charge do the fragments migrate towards? Why?
They migrate towards the positive pole because their phosphate groups make DNA molecules negatively charged.
What is a plasmid?
A separate, much smaller, circular DNA molecules that may be present and replicate inside a bacterial cell (such as e.coli).
Why do bacteria produce restriction enzymes?
Because during infection a bacteriophage injects its DNA into a bacterial cell. The bacterium can defend itself if it has restriction enzymes that can attack the bacteriophage DNA.
What is transformation?
The method by which researchers introduce plasminds into bacterial cells (the uptake of foreign DNA by cells).