aerobic chemolithotrophs can perform CO2 production?
true
false - ANStrue
to begin transcription, RNA polymerase initially binds to which of the following sequences on
the DNA? - ANSpromoter
you isolate a mutated enzyme that no longer functions properly. One codon is changed from
5' UGU to 3' to 5' UGC 3.' Could this mutation be responsible for changing the function of
this protein? - ANSNO
which mutations can result in change in protein function? - ANSmissense, nonsense,
frameshift
you isolate a mutated enzyme that has one change codon due to a missense mutation. How
could proteins functions be affected? - ANSeither increase or decrease
UGG (Trp) to UGA (stop) is what type of mutation? - ANSnonsense because it affects
proteins function
base analogs - ANS-a base that is very similiar to the actual base
-it gets incorporated into DNA; base pair differently than the base replaced
-gets incorporated into DNA in place of T
-5-BU base pairs with A and G
- when it pairs with G --> mutations occur
if the mutagenic frequency is greater than 2, what does that tell us? - ANSthe plate is
mutagenic
number of revertants due to induced mutations= - ANS# of colonies on plate with suspected
mutagen - # of colonies grew on no mutagen one.
positive control plate represents - ANSplate with mutagen
negative control plate represents - ANSplate without mutagen
are antibiotic resistant strains spontaneous or nonspontaneous mutants - ANSspontaneous
because they are not caused by the antibiotic, they have a selective advantage in the
presence of the drugs
mutations occur in two ways: - ANSspontaneous: occur without cause or exposure to
external agents; usually the result of errors in DNA replication
induced: caused by a mutagen (generate mutations); can be physical or chemical agents
, mutagen - ANSA chemical or physical agent that interacts with DNA and increases the
frequency of mutations by at least 1000 fold
1. Imagine a bacterial cell that normally grows best in an isotonic environment now finds
itself living in a hypertonic environment. Which of the following is most likely to occur?
a. Solutes from the water environment will diffuse into the bacterial cell causing it to shrivel
up and die.
b. The cell will lose water and shrivel up and die.
c. The cell will explode due to decreased osmotic pressure.
d. The cell will burst open due to increased osmotic pressure.
e. Increased osmotic pressure will cause the cell to shrivel up and die. - ANSb. The cell will
lose water and shrivel up and die.
Which of the following molecules belongs to Gram-positive bacteria but NOT to
Gram-negative bacteria?
a. Lipopolysaccharide
b. Lipoteichoic acid
c. Braun's lipoprotein
d. Outer membrane
e. a and c - ANSb. lipteichoic acid
You have isolated a cell that possesses the following: 70S ribosomes, doublestranded DNA,
peptidoglycan, and a cytoplasmic membrane composed of a phospholipid bilayer. From this
information, into which domain of living organisms would you classify this cell?
a. Bacteria
b. Archaea
c. Eukarya
d. a and b
e. None of the above - ANSa.bacteria
Which of the following best describes lipopolysaccharide?
a. It is sloughed off when Gram-positive cells die
b. It is actively secreted by Gram-negative bacterial cells through type III secretion systems.
c. It is the same as endotoxin
d. It is an exotoxin.
e. a and c - ANSit is the same as an endotoxin
CD4 T cells recognize specific antigen presented on ____________ by professional antigen
presenting cells.
a. Class I MHC
b. Class II MHC
c. Both a and b - ANSClass II MHC
Cytotoxic T lymphocytes kill virally infected cells by secreting
a. Perforin
b. Granzyme
c. Interleukin-2
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