TNS Flashcards
What is a forward genetic screen?
A screen used to identify genes important for a biological phenotype.
Tests for thousands of genes.
What is a reverse genetic screen?
An investigator selects an interesting gene and seeks to determine which phenotypes result from its absence.
Tests only for one gene.
What is BLAST?
Basic local alignment search tool used to compare nucleotide sequences of DNA or amino acid sequences of proteins.
Compares DNA or proteins to an entire library of known sequences.
What does a cDNA microarray screen measure?
Measures and compares gene expression profiles in biological samples.
Allows for simultaneous analysis of all genes in the genome.
How is RNA converted in a cDNA microarray screen?
RNA from the sample is converted into complementary DNA (cDNA) using reverse transcriptase and is incubated with the microarray to hybridize with the DNA sequences.
A computer scans the array to detect hybridization, revealing which genes were expressed.
What is RNA interference (RNAi)?
A technique used to reduce the expression of specific mRNA molecules.
Uses thousands of RNAi molecules to disrupt gene function in organisms or cultured cells.
What is the function of a restriction enzyme?
Used to cut specific DNA sequences at restriction sites.
The process of cutting pieces of DNA with restriction enzymes is a restriction digest.
What is PCR (Polymerase Chain Reaction)?
Targets and selectively amplifies specific sequences in the genome.
Uses temperature to amplify small DNA fragments.
What are the steps of PCR?
- Denaturation: DNA sample is heated to break down bonds between strands.
- Annealing: Temp is lowered for primers to bind to complementary sequences.
- Extension: Temp is raised for polymerase to synthesize a new DNA strand.
Repeat the cycle.
What is the purpose of cloning DNA and plasmid vectors?
Technique used to make copies of a specific DNA fragment by inserting genes into plasmids (vectors).
Vectors can replicate autonomously in the host.
What is gel electrophoresis used for?
Techniques used to isolate, identify, and characterize properties of DNA.
Separates DNA/RNA/etc. based on length.
What is a Southern blot?
Used to detect a specific DNA sequence within a complex mix of DNA fragments.
DNA is digested with restriction enzymes and separated by gel electrophoresis.
What is a Northern blot?
Used to analyze RNA and compare mRNA levels between different samples.
mRNA is separated using gel electrophoresis.
