Chapter 20 Flashcards
What is genetic engineering?
Direct manipulation of genes for practical purposes
How is genetic engineering done?
DNA sequencing, gene cloning, gene therapy, etc.
What is DNA sequencing?
A scientific process by which a specific strand of each fragment is immobilized, and the complementary strand synthesized one nucleotide at a time
How is DNA sequencing done?
A specific strand of each fragment is immobilized, and the complementary strand synthesized one nucleotide at a time
What is a plasmid? How is plasmid used in recombinant DNA research?
Small, circular DNA molecules that replicate separately from the bacterial chromosome
What is gene cloning?
Process by which scientists prepare well-defined DNA segments, usually a single gene, in multiple identical copies
What are some uses of gene cloning?
Useful for amplifying genes to produce a protein product for research, medical, or other purposes.
Describe how restriction enzymes are used to cut DNA molecules.
used to cut the sugar-phosphate backbone of DNA in order to make a recombinant DNA fragment
Where do restriction enzymes cut DNA molecules?
Restriction sites
What are restriction fragments?
Fragments of DNA made during the cutting process
How can restriction fragments be inserted into strands for foreign DNA?
Sticky ends can bond with complementary sticky ends of other fragments; DNA ligase is an enzyme that seals the bonds between restriction fragments which allows researchers to join two DNA fragments from different sources
Describe the CRISPR-Cas9 technology.
Scientists can use it to edit genes by inserting an RNA strand for the DNA sequence they want to find and remove
How is CRISPR-Cas9 technology being used to address insect-borne disease?
They can alter genes in the insects so they cannot transmit the disease and engineer the new allele so that it is favored for inheritance over the wild type allele
What role can gel electrophoresis play in visualizing restriction fragments?
To separate and visualize the fragments produced to check that recombination has taken place
What does PCR stand for?
Polymerase Chain Reaction
Describe how PCR works.
1) the DNA is heated leading to denaturation (untwisting and separation) of the DNA strands
2) The DNA is cooled during the annealing process which allows the attachment of DNA primers
3) the DNA is replicated during the extension process.
What useable product do you end up with at the end of PCR?
Clones of a specific segment of DNA
Why might you want to produce many copies of a segment of DNA?
The segments can be inserted into other organisms, can be used to compare DNA between species to assess evolutionary relationships, can be used to amplify DNA found at a crime scene, etc.
Can PCR be used to clone genes? Explain your answer.
Yes, it is a way to quickly replicate the DNA with few errors and can be used even if the researcher only has a small sample of the DNA.
What is organismal cloning?
A process that produces one or more organisms genetically identical to the “parent” that donated the single cell
How is nuclear transplantation accomplished?
the nucleus of an unfertilized egg cell or zygote is replaced with the nucleus of a differentiated cell
Will cloned animals always look and behave the same as the original organism?
no
What are stem cells?
A relatively unspecialized cell that can reproduce itself indefinitely, or under certain conditions can differentiate into one or more types of specialized cells
Totipotent
a cell that can generate an entirely new organism and is used for cloning in plants
