Chapter 13 Flashcards
recombinant DNA technology
is technology used by scientists to combine genes from different organisms or species
plasmids
small, circular DNA molecules that are separate from the much larger bacterial chromosome
how do biologists use plasmids?
to move genes into bacteria
restriction enzyme
“cuts” a DNA molecule into fragments at specific points
how do bacterial cells reproduce and make a clone/identical copies of a desired gene?
1) the restriction enzyme “cuts” a DNA molecule into fragments at specific points
2) Another enzyme “pastes” a fragment carrying a particular gene into a plasmid
3) Then the plasmid is put back into a bacterial cell. Then when the bacterial cell reproduces, it creates clones/identical copies, of the desired gene
genomic library
the complete collection of cloned DNA fragments from an organism
nucleic acid probe
a molecule that has been labeled with radioactivity, making it easy to detect
Genetically Modified Organism (GMO)
any organism that has acquired one of more genes by artificial means
transgenic
if the new genetic material came from a different species
how do u genetically modify a plant?
researchers inset a plasmid containing the desired gene into a plant cell
how do u genetically modify a mammal?
the desired gene is inserted j to a fertilized egg. the egg is then returned to a female animals body
how can plants be cloned?
from cuttings
how can animals be cloned?
replacing the nucleus of an egg cell with another cell’s nucleus
polymerase chain reaction (PCR)
a technique that makes billions of identical DNA molecules in just a few short hours. it is used to produce large enough samples of DNA for further analysis
Gel electrophoresis
a technique for sorting DNA fragments by length
Genetic markers
particular stretches of DNA that vary from person to person
DNA fingerprint
each persons DNA fragments produce a particular pattern of banding
operon
prokaryotes
a cluster of genes along with its two control sequences
promoter
prokaryotes
(one control sequence) is a binding site for an enzyme needed in DNA transcription
operator
prokaryotes
(one control sequence) switches the promoter on and off
repressor
(prokaryotes)
a protein that turns the operator off by binding to it
gene expression
eukaryotic cells
the transcription and translation of genes into proteins
transcription factors
eukaryotic cells
are proteins that regulate promoter sequences. told by chemical signals in the cell.
cellular differentiation
when individual cells become more specialized in structure and function as the organism develops
stem cells
cells that remain able to differentiate into various other types of cells
Homeotic genes
are master control genes that produce proteins that regulate the expression of other genes
biotechnology
the use of organisms to perform tasks for humans
what is one way that recombinant DNA technology can benefit farmers?
using this technology, a gene that provides resistance to specific weed-killing chemicals has been developed. When farmers use chemicals, they kill weeds withou killing crops
how can recombinant DNA technology be used to treat the disease diabetes?
using this technology, scientists can insert the human gene that directs the production of human insulin into the bacterium E Coli, which can produce large quantities of human insulin, insulin is used to treat diabetes
what is the role of the restriction enzyme?
they can recognize a specific base sequence in DNA, attach themselves to the DNA, and cut the two nucleotide strands
why do scientists keep a set of restiction enzymes?
because they can cut DNA where they want, eliminate a gene, and replace it with another
why might scientists want to insert a new gene into bacteria?
bacteria reproduce rapidly and could make many copies of a new gene. Bacteria could also produce large quantities of a gene product
what is the role of the DNA ligase?
DNA ligase pastes the sticky ends to a new complementary sequence
why did the scientists first chose to clone a mouse with brown fur, but the egg from a mouse with white fur?
they could tell by the fur of the newborn if the brown mouse was cloned
what is the role of heat in the first step of PCR?
heat breaks the hydrogen bonds between the complimentary DNA strands, allowing the strands to separate
when there is no lactose, what prevents EColi from producing lactose-processing enzymes?
the repressor binds to the operator and prevents RNA polymerase from starting the process of transcription and translation
what is the role of the RNA polymerase?
RNA polymerase is the enzyme that copies the DNA code into RNA
why is it important for the Ecoli to turn on and off the enzyme making machinery?
to conserve energy; it’s a bad strategy for the organisms to produce a very “expensive” set of proteins if they are not needed
