Solutions
What is Aliivibrio fischeri (A. fischeri)? Right Ans - Rod shaped bacteria;
gram negative
Where does Aliivibrio fischeri (A. fischeri) live? Right Ans - In symbiosis
with many marine organisms.
What is special about Aliivibrio fischeri's (A. fischeri) chromosomal DNA?
Right Ans - Has the lux operon -> codes for proteins that are needed for
bioluminescence.
What is E. coli? Right Ans - Rod shaped bacteria; gram negative
Where does E. coli live? Right Ans - lower gut of warm-blooded animals
What is E. coli used for? Right Ans - Prokaryotic model organism for
biotechnology and microbiology as the host for working with recombinant
DNA.
Gram Negative vs. Gram Positive: Right Ans - External Lipopolysaccharide
layer w/ a single layer of peptidoglycan
How does gram staining work? Right Ans - Peptiodglycan layer -> gram
staining
Thin layer in neg. cells results in no staining
LPS can vary based on composition and length of O-antigen as well as
composition of core polysaccharides
What is an operon? Right Ans - genetic regulatory system; genes that are
coding for functionally related proteins are clustered w/ DNA.
This means proteins synthesis is controlled coordinately in response to
cellular needs.
,What is chromosomal DNA? Right Ans - Large circular DNA in bacteria.
What is restriction digestion? Right Ans - enzymatic reactions -> cut DNA
into smaller pieces.
has enzymes that cut the DNA at only specific sequences.
What are plasmids? Right Ans - small circular, usually double-stranded
DNA that is physically separate from chDNA.
carry "survival genes" -> antibiotic resistance
T/F: Plasmids are able to replicate autonomously within the cell and can be
transferred from one organism to another. Right Ans - True
How can plasmids be transferred from one organism to another? Right Ans
- Transformation, transduction, and conjugation.
What is ligation? Right Ans - enzymatic reaction -> pastes 2 pieces of DNA
together (from same or diff organisms).
What is recombinant DNA? Right Ans - When DNA from two sources comes
together -> chDNA + Plasmid DNA.
What is shotgun cloning? Right Ans - randomly digesting a large piece of
DNA to smaller pieces
Why is shotgun cloning done? Right Ans - so it can be ligated into plasmids
for transport to other organisms.
What is a genomic library? Right Ans - collection of cloned DNA fragments
from a genome where each part of the genome is represented in the library.
can use to screen for sequence of interest
What is a clone? Right Ans - A bacteria housing a recombinant plasmid that
contains a piece of genomic DNA
may or may not have gene of interest.
, Why is bioluminescence beneficial to fish? Right Ans - Communication
Attracting Prey
Hiding from predators
Attracting a Mate
Why is bioluminescence beneficial to bacteria? Right Ans - Reliable food
source
-Glucose
-Amino Acids
How is bioluminescence completed via cooperative development? Right
Ans - Infection by bacteria at birth → light organ maturation
Ex. Lophius piscatorius (angler fish)
What are some examples of species that host A. fischeri? Right Ans -
Monocentris japonicus (pinecone fish)
Euprymna scolopes (Hawaiian bobtail squid)
What are luciferins? Right Ans - are light emitting hetero-cyclic compounds
that undergo enzyme catalyzed oxidation
leads to emission of light upon decaying to a ground state
origination -> mechanism to deal with oxidative stress.
What are some dangerous photochemically generated oxygen species marine
animals are exposed to? Right Ans - superoxide anion (O2-) and hydrogen
peroxide (H2O2) -> Causes damage to DNA and initiates cellular lysis
With increasing ocean depth, there is a decrease in concentrations. How is the
pressure maintained? Right Ans - Symbiotic relationships maintain the
pressure to conserve bioluminescence.
What causes bioluminescence? Right Ans - Oxidation of luciferin catalyzed
by luciferase
Blue-green light emitted at 490 nm