You discovered that a species of bacteria can break down StyrofoamTM (polystyrene) products due to an
enzyme it produces, polystyrenase. You wish to study the gene that codes for this enzyme.
Agarose Gel Electrophoresis
Your amplicon from PCR was subjected to AGE for analysis. You are shown the image of the gel loaded
with the following lanes: (A) negative control, (B) size ladder (1, 2, 3, 4, 6, and 10 kb), (C) gDNA extract, (D)
PCR amplicon. However, due to mishaps while loading the gel with the samples, you are not sure which lane
is which. You are shown a diagram of the obtained gel below.
a. Label each lane of the gel. Write only the corresponding letters in the wells above.
b. Above each band in the size ladder, write its size (in kb).
c. Approximate the size (in kb) of the polystyrenase gene. Write your answer above the band
corresponding to the gene.
Bonus: If you wish to identify the bacterial species in this scenario, what gene is most commonly and
routinely sequenced?
Answer
You discovered that a species of bacteria can break down StyrofoamTM (polystyrene) products due to an
enzyme it produces, polystyrenase. You wish to study the gene that codes for this enzyme.
Polymerase Chain Reaction
After purifying the gDNA extract, you want to isolate and amplify the polystyrenase gene. You perform PCR
using the appropriate gene-targeted primers. What is the purpose of the following PCR components? Answer
briefly but completely.
a. DNA polymerase isolated from Thermus aquaticus
Answer: __________________________________
b. Deoxynucleotide triphosphates (dNTPs)
Answer: __________________________________
c.Forward and reverse primers
Answer:
You discovered that a species of bacteria can break down StyrofoamTM (polystyrene) products due to an
enzyme it produces, polystyrenase. You wish to study the gene that codes for this enzyme.
Task 1: DNA Extraction
To begin work on the bacterium, you begin by extracting its genomic DNA (gDNA). What is the purpose of
the following procedures? Answer briefly but completely.
b. Adding RNase A and Proteinase K during extraction
Answer: __________________________________
c. Adding ethanol before recovering the DNA extract
Answer: __________________________________
Can Nonsense mutation be reversed by hydroxylamine? Why or why not?
What mutations are produced by ionizing and UV Radiation?
When round and yellow seeded pea plants (YYRR) are crossed with green wrinkled
(y y r r) seeded pea plants the F1 are yellow and round seeded plants (Yy Rr).
What will be the results when this F1 is crossed with round and yellow seeded parents?
In a mating between two individuals that are heterozygous for a recessive lethal allele
that is expressed in utero, what genotypic ratio (homozygous dominant: heterozygous:
homozygous recessive) would you expect to observe in the offspring?
Imagine you are performing a cross involving garden pea plants. What F1, F2 offspring
would you expect if you cross true-breeding parents with green seeds and yellow
seeds? Yellow seed color is dominant over green.
What will be the appearance of (a) F1 and (b) F2 progenies when a pure (homozygous)
tall pea plant is crossed with a pure (homozygous) dwarf pea plant?
What observations led Mendel to conclude that traits were inherited as particles from
each parent?