quiz 6 Flashcards
Which enzyme is involved in reducing supercoiling during DNA replication?
Question 1 Answer
a.
DNA topoisomerase
b.
DNA primase
c.
DNA helicase
d.
DNA ligase
a.
DNA topoisomerase
Which of the following cyclin-cdk complexes does p16 inhibit?
Question 2 Answer
a.
Cyclin B-cdk1.
b.
Cyclin A-cdk2.
c.
Cyclin E-cdk2.
d.
Cyclin D-cdk4.
d.
Cyclin D-cdk4.
Which of the following is TRUE regarding DNA synthesis (aka DNA replication):
Question 3 Answer
a.
DNA helicase joins the 3’ and 5’ ends DNA fragments after the RNA primers have been replaced with DNA.
b.
DNA ligase unwinds the double helix by breaking H-bonds.
c.
RNA primase is needed to build an RNA primer with a free 3’-OH group for elongation by DNA polymerase.
d.
DNA Polymerase adds DNA nucleotides in the 3’ to 5’ direction.
c.
RNA primase is needed to build an RNA primer with a free 3’-OH group for elongation by DNA polymerase.
Which of the following is TRUE regarding the role of RB in the cell cycle:
Question 4 Answer
a.
Active, hypo-phosphorylated RB prevents progression through the G2/M checkpoint.
b.
RB targets securin for proteolytic destruction to allow progression through the metaphase-to-anaphase checkpoint.
c.
RB initiates transcription of p21 to halt the cell cycle at the START transition (G1/S checkpoint).
d.
RB is inactivated by phosphorylation by an active Cyclin D-cdk4 (G1 cyclin-cdk) complex, releasing transcription factor, E2F.
d.
RB is inactivated by phosphorylation by an active Cyclin D-cdk4 (G1 cyclin-cdk) complex, releasing transcription factor, E2F.
P53 promotes the transcription of which Cdk inihibitor (CKI)
Question 5 Answer
a.
p21
b.
p16
c.
p27
d.
p57
a.
p21
A mutation in Myc was identified via genetic testing in your patient with breast cancer. How could a mutation in Myc increase the likelihood of developing cancer?
Question 6 Answer
a.
Myc promotes the proteolysis of p53.
b.
Myc promoted the transcription of cyclin D.
c.
Myc directly activates RB by phosphorylation.
d.
Myc phosphorylates PIP2, which is needed to activate AKT.
b.
Myc promoted the transcription of cyclin D.
Which of the following mutations would contribute the most significantly to genomic instability?
Question 7 Answer
a.
Gain of function mutation in Myc.
b.
Loss of function mutation in RB.
c.
Loss of function mutation in p53.
d.
Gain of function mutation in Ras.
c.
Loss of function mutation in p53.
Which of the following is most correct regarding anaplasia?
Question 8 Answer
a.
Anaplasia may include cellular pleiomorphism and loss of polarity.
b.
Anaplastic cells tend to have small, light-staining nuclei.
c.
Anaplasia is a hallmark of benign tumours.
d.
Anaplasia refers to cells that have reached a state of terminal differentiation.
a.
Anaplasia may include cellular pleiomorphism and loss of polarity.
Which of the following correctly describes metaplasia?
Question 9 Answer
a.
Replacement of one differentiated somatic cell for another
b.
Increase in number of cells
c.
Presence of pleomorphism and hyperchromatic nuclei
d.
Presence of abnormal cells
a.
Replacement of one differentiated somatic cell for another
If a neoplastic cell develops a gain of function mutation in cyclin D or cdk4, what cell cycle checkpoint will no longer effectively regulate division?
Question 10 Answer
a.
G2/M checkpoint
b.
G1/S checkpoint
c.
S/G2 checkpoint
d.
Metaphase-to-Anaphase checkpoint
b.
G1/S checkpoint
Choose the TRUE statement regarding Marfan’s syndrome:
Question 11 Answer
a.
The disorder is inherited in an X-linked dominant fashion
b.
The gene affected is the Type I collagen gene.
c.
Many individuals with Marfan syndrome will express some clinical features of the disorder but not others - this is an example of incomplete penetrance.
d.
The disorder is inherited in an autosomal dominant pattern.
d.
The disorder is inherited in an autosomal dominant pattern.
When a point mutation causes the formation of a stop codon which results in a shortened protein, this is known as a:
Question 12 Answer
a.
conservative missense mutation
b.
absence mutation
c.
nonconservative missense mutation
d.
nonsense mutation
d.
nonsense mutation
Choose the TRUE statement re: X-linked disorders
Question 13 Answer
a.
A father can pass an X-linked gene to his daughter, but not to his son
b.
Most X-linked disorders are expressed in women, since they have two X-chromosomes
c.
A mother can pass an X-linked gene to her son, but not to her daughter
d.
Most X-linked disorders are dominant
a.
A father can pass an X-linked gene to his daughter, but not to his son
Which of the following is NOT a function for the liver?
Question 14 Answer
a.
gluconeogenesis
b.
storage of bile
c.
production of bile
d.
production of proteins in the blood
b.
storage of bile
Which of the following is TRUE regarding the small and large intestine?
Question 15 Answer
a.
Only the small intestine has a lamina propria - the large intestine does not have a lamina propria, only a submucosa.
b.
Both the large and small intestine play important roles in the absorption of proteins and amino acids
c.
The epithelial cells of the large intestine lack microvilli, but those of the small intestine have many microvilli
d.
The muscular wall of the large intestine has a discontinuous longitudinal muscle layer - in the small intestine, all layers of the wall are continuous
d.
The muscular wall of the large intestine has a discontinuous longitudinal muscle layer - in the small intestine, all layers of the wall are continuous
