Biology 13-2 and 13-3
Terms in this set (29)
making changes in the DNA code of a living organism
Is the following sentence true or false? Making changes to the DNA code is similar to changing the code of a computer program.
Scientists use their knowledge of the _________ of DNA and its ________ properties to study and change DNA molecules.
Structure and Chemical
List four steps that molecular biologists use to study and change DNA molecules.
a. Extract DNA from cells
b. Cut DNA into smaller pieces
c. Identify the sequence of bases in a DNA molecule
d. Make unlimited copies of DNA
Explain how biologists get DNA out of a cell.
The cells are opened, and the DNA is separated from the other cell parts.
Biologists use ___________ to cut DNA molecules at a specific
sequence of nucleotides to make smaller fragments.
process by which DNA fragments are separated and analyzed.
what is true about gel electrophoresis.
1.An electric voltage applied to the gel separates the DNA fragments.
2.Gel electrophoresis is used to compare the genomes of different organisms.
3.Gel electrophoresis can be used to locate and identify one particular gene in an individual's genome.
Identifying the DNA sequence enables researchers to
1.Compare genes with other organisms
2.Discover the functions of genes
3.Study specific genes
four "ingredients" added to a test tube to produce tagged DNA fragments that can be used to read a sequence of DNA.
a. Small, single-stranded pieces of DNA
b. DNA polymerase
c. Supply of the four nucleotide bases in DNA
d. One base labeled with a fluorescent dye
What does the reaction in the test tube generate when complementary DNA is made for reading DNA?
The reaction generates a series of tiny DNA fragments that are color-coded according to the fluorescent base that has been added at the very end.
what does the pattern of colored bands on a gel tell?
exact sequence of bases in DNA.
Enzymes that splice DNA together can also be used to join
How is recombinant DNA produced?
It is produced by combining DNA from different sources.
What is polymerase chain reaction (PCR)?
It is a technique that allows biologists to make many copies of a particular gene.
What is the role of the primers in PCR?
The primers are short pieces of complementary DNA sequences that provide a place for DNA polymerase to start working
what is the first step in the polymerase chain reaction.
The DNA is heated to separate its two strands.
What occurs during transformation?
A cell takes in DNA from outside the cell. This external DNA becomes a component of the cell's DNA.
what did Griffith's extract of heat-killed bacteria contain
circular DNA molecule found naturally in some bacteria.
Recombinant plasmids are mixed with bacterial cells. Some bacterial cells take in the recombinant DNA by the process of
Only cells that have been transformed survive, because only they carry a(an
Give two reasons why a plasmid is useful for DNA transfer.
It has a DNA sequence that helps promote plasmid replication, ensuring that the foreign DNA will be replicated.
It has a genetic marker—a gene that makes it possible to distinguish bacteria that carry the plasmid from those that don't
When researchers transform plant cells using a bacterium that causes plant tumors, how do researchers prevent plant tumors from forming in the transformed cells?
Researchers inactivate the tumor-producing gene.
transforming plant cells.
Many plant cells can be transformed by using a bacterium that will, in nature, insert a tumor-producing plasmid into plant cells.
Sometimes plant cells in culture will take up DNA on their own when their cell walls are removed.
what occurs in a successful transformation of cells.
The recombinant DNA is integrated into one of the chromosomes of the cell.
Describe how animal cells can be transformed by directly injecting DNA.
DNA can be directly injected into many egg cells. Once inside the nucleus, DNA repair enzymes may help to insert the foreign DNA into the chromosomes.
How is a DNA molecule constructed so that it will eliminate a particular gene?
The DNA molecule is constructed with two ends that will sometimes recombine with specific sequences in the host chromosome.
Is the following sentence true or false? Gene replacement has made it possible to identify the specific functions of genes in many organisms.