Frederick Griffith’s transformation experiment showed that
A chemical component of cells could introduce a new trait to a cell
In Avery, MacLeod and McCarty's experiment, what enzyme was present in the mixture of R & S Strain that when injected into the mice did not result in death?
DNase
If Hershey and Chase phage experiment, what finding led to the conclusion that DNA is the genetic material?
The presence of radioactivity in the bacteria when 32 P was used
What would be the outcome of Hershey-Chase experiment if protein (and not DNA) was the carrier of genetic information?
The infected bacteria would be positive for 35 S radioactive labeling, and not 32 P
This molecule is most likely found on ___. It has a(n) ___ ring
RNA; purine
Which of the following is not included in the Watson-Crick model of D N A structure?
The strands run parallel
Which of the following is not consistent with Erwin Chargaff’s findings?
(C + G) = (A + T)
The virus phi X 174 infects Escherichia coli. Its base composition is
as follows:
A = 24.0 %
G = 23.3 %
C = 21.4 %
T =
31.3 %
What conclusions can you draw about phi X 174
It has a single-stranded D N A genome.
If you heated a sample of D N A from 30°Ceto 100°C while you measured the A 260 , which of the following graphs would you expect to see?
(A)
In the Meselson–Stahl experiment, if DNA had been replicated conservatively, after two rounds of replication, there would be _____
one old, heavy band and one new, light band
All known bacterial D N A polymerases _____.
have 5′ to 3′ polymerization activity
What activity provides D N A pol III the ability to proofread?
D N A pol III has 3′→5′ exonuclease activity
What protein is functioning at the point marked with the large arrow?
D N A polymerase III
What enzyme will replace the R N A primers found in the newly synthesized strand
D N A pol I
Okasaki fragments are a consequence of
the inability of the DNA polymerase to polymerize in the 3′ to 5′ direction
Is there any role for an R N A polymerase in D N A replication?
Yes, to generate primers.
What does the term “processive” mean in the context of D N A replication?
that length of D N A that is replicated by the core enzyme before it detaches from the template
Telomerase _____.
a. contains its own R N A template
b. is a reverse
transcriptase
c. extends one strand of the telomere
d. is
responsible for helping to maintain chromosome size
e. all of the above
How do bacteria package their D N A
by supercoiling the D N A
If there were six bases in D N A and still only 20 amino acids, how long would a codon need to be in order to specify an amino acid?
Two bases
The wobble hypothesis predicts that codons coding for the same amino acid _____
may differ at the third position
Nobel Prize in Physiology or Medicine 2024
Victor Ambros and Gary Ruvkun
In humans, the phenylalanine hydroxylase gene is 90,000 (90 k b) bases long, yet the mRNA is only 2,400 (2.4 k b). What explains this difference?
Presence of introns in DNA
The sigma subunit of bacterial R N A polymerase _____.
binds to a bacterial gene’s promoter
An aminoacyl tRNA synthase Valine is mutated so that it now attaches the amino acid glycine to the tRNA Valine instead of valine. What will happen at translation?
There will be glycines at all glycine positions and at all valine positions
During the elongation phase of translation, charged tRNAs enter the ribosome at the ______.
A site
Which of the following will most likely result in frameshift mutations
Acridine orange dye
Which of the following will more likely result in double stranded breaks? Select all that apply
Ionizing radiation, transposable elements, and oxidizing damage
Which of the following will likely result in thymine dimer?
UV
Constitutive genes ____
are expressed continuously
The lac operon is optimally expressed _____
in the presence of lactose and the absence of glucose
Which of the following is a trans-acting element?
a. Lac O
b. T r p R protein
c. Lac I protein
d. C A
P
e. b, c, and d
Attenuation in the E. coli t r p operon _____.
results from the formation of secondary structures in the t r p m R N A
Eukaryotic regulation of gene expression occurs at the level of _____
a. transcription
b. splicing and processing
c. m R N A
degradation
d. translation
e. all of the above
What is an interchromatin compartment?
D N A-free area of the nucleus located between chromosomes
Where might you most likely find the histone variant H2A.Z?
In promoters and enhancers of expressed genes
A protein causes the acetylation of histones. What effect do you think this will have on a gene in that region?
It will cause an increase in expression
What is the role of D N A methylation in eukaryotes?
To aid in silencing transcription
What is the difference between the Initiator element (I n r) and the TATA box?
R N A P binds to the TATA sequence and then initiates transcription downstream at I n r
An enhancer sequence _____.
can be inverted without altering its functional ability