Molecular Genetics — Flashcards

Flashcard 11: What occurs during the denaturation step of PCR?

Answer: DNA is heated until the strands separate

Flashcard 12: What occurs during the annealing step of PCR?

Answer: as the denatured DNA is cooled, primers anneal to complementary target sequences

Flashcard 13: What occurs during the elongation step of PCR?

Answer: a heat-stable DNA polymerase replicates the DNA downstream of each primer

Flashcard 14: What are the assumptions of Hardy-Weinberg equilibrium?

Answer: 1. no mutation 2. no selection 3. no migration 4. random mating

Flashcard 15: mitochondrial

Answer: usually no, and in fact may transmit to every single child, but transmission may be obscured by low penetrance/variable expressivity

Extra: highly variabledefect in oxidative phosphorylationhighly variablenoyes; only transmitted through mother

Flashcard 16: cloning (lab technique)

Answer: production of self-perpetuating recombinant DNA

Flashcard 17: What are the steps of cloning eukaryotic DNA into a prokaryotic organism?

Answer: 1. Isolate mRNA from gene of interest. 2. Reverse transcribe mRNA into cDNA (no introns). 3. Insert cDNA into plasmid along with selectable gene (usually resistance gene). 4. Induce plasmid uptake by bacteria. 5. Use resistance gene to select for bacteria carrying cloned gene of interest.

Flashcard 18: What is RNA interference (RNAi) used for?

Answer: inducibly and reversibly silence expression of a target gene

Flashcard 19: Explain the steps of RNA interference (RNAi).

Answer: 1. dsRNA complementary to mRNA of interest is transfected into human cell 2. Dicer enzyme chops up dsRNA into fragments 3. dsRNA fragments direct RISC complex to chop up endogenous complementary mRNA

Flashcard 20: What is the Cre-lox system used for?

Answer: inducibly manipulate gene expression at specific timepoints; most useful for turning on/off genes fatal during development for study at a later developmental stage