Mutations
A nucleotide substitution that does not change the amino acid produced due to redundancy in the genetic code.
Silent Mutation
The horizontal gene transfer process where a prokaryote uptakes 'naked' DNA from its environment.
Transformation
Which DNA fragments (large or small) move the furthest distance through the gel?
Small
What does PCR stand for?
Polymerase Chain Reaction
What are restriction enzymes?
Bacterial enzymes that cut DNA at specific nucleotide recognition sites.
A nucleotide substitution that changes an amino acid codon into a stop codon, ending translation prematurely.
Nonsense Mutation
Bacterial enzymes that cut DNA at specific nucleotide recognition sites.
Restriction Enzymes
Why does DNA migrate toward the positive electrode during gel electrophoresis?
DNA is negatively charged due to its phosphate groups.
What is the purpose of the Polymerase Chain Reaction (PCR)?
To amplify (make many copies of) a specific segment of DNA.
What are sticky ends?
short, single-stranded DNA overhangs created by staggered cuts from restriction enzymes.
A _____ mutation occurs when nucleotides are inserted or deleted, altering the reading frame of the genetic message.
Frameshift
The horizontal gene transfer process where a virus (bacteriophage) carries genetic material from one bacterium to another.
Transduction
On what two properties does gel electrophoresis separate DNA fragments?
Size and charge.
What are the three steps of a PCR cycle?
Denaturing (heating), Annealing (cooling), and Extending (heating).
Give an example of how restriction enzymes are used in biotechnology.
Answers will vary.
A nucleotide substitution that results in a different amino acid being incorporated into the protein.
What is a missense mutation?
The cell-to-cell transfer of DNA between bacteria using a structure called a pilus.
Conjugation
List 2 purposes for gel electrophoresis.
DNA fingerprinting for forensics/paternity tests, verifying PCR products, mapping restriction enzymes, analyzing protein structure/purity, and purifying nucleic acids for sequencing or cloning.
What is the purpose of Taq Polymerase in PCR?
It functions as DNA polymerase adding nucleotides to the new DNA strand.
Explain how restriction enzymes are used to produce insulin.
They cut the human insulin gene and bacterial plasmids at specific DNA sequences. The insulin gene is inserted into the plasmid for transformation.
What is nondisjunction?
The failure of chromosomes to separate properly during meiosis, resulting in an incorrect number of chromosomes in gametes.
How have bacteria evolved to avoid being infected by viruses?
Bacterial DNA is methylated. Restriction enzymes target the unmethylated DNA and splice it out of the bacterial DNA.
What is the purpose of a DNA ladder/Marker in Gel Electrophoresis?
Allows scientists to estimate the unknown lengths (in base pairs) of DNA fragments in their experimental samples by comparing their migration distance on the gel to the ladder's known-size fragments.
What is the purpose of the heat shock step of PCR?
It denatures the DNA, breaking the hydrogen bonds and causing the 2 strands to separate.
Name a restriction enzyme.
answers will vary