Ch. 19 Molecular Genetic Analysis

Question 1

forward genetics

Answer 1

phenotype –> mutation

• have mutant fly with white eyes (normally have red eyes) and look for the gene responsible for that mutation

Question 2

reverse genetics

Answer 2

mutation –> phenotype

-create a nonsense mutation in a target gene and trace the mutation through phenotype, if phenotype shows mutation then you have identified the gene responsible for it

Question 3

gel electrophoresis

Answer 3

used to separate nucleic acids based on their size

• nucleic acids are loaded into a gel matrix that is in a salt buffer
• electrical charge is passed through the gel
• nucleic acids travel to the positive pole (DNA is negative)
• small bands “run” faster than large ones do

Question 4

recombinant DNA technology (aka genetic engineering)

Answer 4

set of molecular techniques for locating, isolating, altering, and studying DNA fragments

• used to isolate, recombine, and amplify target DNA segments
• biotechnology uses these
• turn biology into tools

Question 5

PCR (polymerase chain reactions)

Answer 5

a method used to amplify a target region of DNA (DNA synthesis over and over again in a test tube)

components:
1. template DNA

2. Taq polymerase (thermal stable DNA polymerase)
3. dNTPS (A, T, C, G)
4. Primers (oligos) - used to prime the reaction by providing 3’ OH for Taq
5. buffers

Question 6

three stages of PCR reaction

Answer 6

1. denature (hydrogen bonds disrupted by heating) -95
2. Anneal (primers anneal to target sequences) - 55 to 60
   primers about 20nucleotides long
3. Elongation (Taq polymerase synthesizes new DNA)- 72

Question 7

restriction enzymes

Answer 7

endonucleases

• cuts dsDNA in a sequence specific way
• palindromic
• cuts either “blunt” or “sticky”/staggered ends

-like scissors cutting string (all fragments add up to length of original string length)

Question 8

vector (plasmid is a vector)

Answer 8

DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified

-many are derived from plasmids/bacteriophages/viruses

Question 9

essential components of a vector

Answer 9

• MCS
• ori
• selectable marker (plasmid)
• screenable marker (target DNA)