Lab 10: PCR and Electrophoresis Flashcards
Explain the PCR Lab.
In the PCR, Restriction Analysis, and Electrophoresis lab activity, DNA samples are amplified using PCR, then digested with restriction enzymes, and separated by gel electrophoresis. PCR amplifies specific DNA regions, restriction enzymes cut DNA at specific sites, and electrophoresis separates DNA fragments by size. This activity helps analyze DNA sequences and study genetic variations.
Explain how genotypes translate to phenotypes.
The genotype provides the genetic instructions that determine how traits develop and manifest in the phenotype.
Explain the structure of DNA.
DNA is a double-stranded molecule that carries genetic information. Its structure resembles a twisted ladder, with nucleotides forming the rungs. Each nucleotide consists of a phosphate group, a sugar molecule, and one of four nitrogenous bases: adenine (A), thymine (T), cytosine (C), or guanine (G). The two strands are held together by hydrogen bonds between complementary base pairs (A-T and C-G).
Describe the purpose and the three steps of PCR.
PCR, or Polymerase Chain Reaction, is a technique used to amplify a specific segment of DNA by making copies of it, which can then be analyzed or used in various experiments.
- Denaturation: DNA is heated causing the double-stands to seperate.
- Annealing: Temperature lowered to allow primers to bind to their complementary sequences
- Extension: Temperature raised again so a DNA polymerase enzyme synthesizes new DNA strands by extending from the primers along the template DNA.
What is restriction analysis?
Restriction analysis, also known as restriction digestion, is a laboratory technique used to cut DNA molecules into smaller fragments using restriction enzymes. These enzymes recognize specific DNA sequences (known as recognition sites) and cleave the DNA at or near these sites.
Describe the use and importance of restriction enzymes in DNA research.
Restriction enzymes are the enzymes that recognize specific DNA sequences and cleave the DNA at or near these sequences.
They are important for DNA research for fragmenting DNA, cloning, genetic engineering, and restriction mapping. They cut DNA at specific sequences, allowing precise manipulation and analysis of genetic material.
What is electrophoresis?
A laboratory technique used to separate molecules based on their size, charge, or other properties. In DNA electrophoresis, DNA fragments are separated by size as they migrate through a gel matrix in response to an electric field.
Explain how DNA fragments are seperated by electrophoresis.
Gel electrophoresis separates DNA fragments based on size and charge. DNA samples are loaded into wells, and an electric current is applied, causing DNA fragments to move through a gel towards the positive electrode. Smaller fragments move faster, resulting in separation by size. DNA bands are visualized using fluorescent dyes.
What is sickle-cell disease?
A genetic disorder that creates abnormal hemoglobin molecules in red blood cells caused by a mutation in the gene that instructs the body to make hemoglobin, resulting in the production of abnormal hemoglobin known as hemoglobin S. These molecules cause the cells to become rigid and assume a sickle shape, causing blood flow obstruction, decreased oxygen delivery, increased risk of infections and organ damage.
How can you determine the size of DNA fragments by comparison to marker DNA?
To determine DNA fragment sizes, run both sample and known-size marker DNA on a gel. Visualize the bands formed, then compare the migration distances of sample DNA to marker DNA. By plotting known marker DNA sizes against their migration distances, estimate sample DNA sizes based on their migration distances relative to the marker.
How do you interpret DNA banding patterns on an agarose gel?
