CBT QUESTIONS AND ACCURATE PASSED ANSWERS 2023/2024
Which one of the following statements correctly describes what happens after Wnt ligand binds to Frizzled and LRP?
a. RAR-RXR heterodimers are formed and associate with HDAC co-repressor complexes, silencing target genes.
b. Axin and APC fo...
CBT EXAM 2 HW + SUPP
Which one of the following statements correctly describes what happens after Wnt
ligand binds to Frizzled and LRP?
a. RAR-RXR heterodimers are formed and associate with HDAC co-repressor
complexes, silencing target genes.
b. Axin and APC form a complex with CKI and GSK3β which then modifies β-catenin for
degradation.
c. Axin is recruited to the phosphorylated co-receptor LRP and this disrupts the APC,
CKI, GSK3β complex.
d. Patched inhibits Smoothened and the pathway is suppressed. - correct answer C)
Correct. The disruption of this complex allows β-catenin to escape degradation, move
into the nucleus and act as a co-activator for Tcf/LEF.
Incorrects:
A)Feedback: Incorrect. These are interactions between retinoic acid receptors and
HDAC that occurs in the absence of retinoic acid.
B).Feedback: Incorrect. This process occurs in the absence of Wnt and the modification
is the addition of ubiquitin which acts as a molecular flag for β-catenin degradation. It is
not the next step after ligand binding.
D)Feedback: Incorrect. These are events in the Hh pathway in the absence of Hh.
Patched and Smoothened are transmembrane proteins. Binding of Hh to Patched
relieves Smoothened inhibition and the signal is transduced into the cell.
Which one of the following statements about the Bcl-2 family is false?
a. Pro-apoptotic members of the Bcl-2 family are Bax and Bak.
b. The release of important apoptosis mediators from the mitochondria is mediated by
the pro-apoptotic members only.
c. Pro-apoptotic and anti-apoptotic members of the Bcl-2 family can interact with each
other via protein-protein interactions
d. Anti-apoptotic factors are Bcl-2 and Bcl-xL. - correct answer B
Which one of the following statements about apoptosis is false?
a. The aim of conventional chemotherapies is to inhibit apoptosis.
b. In the absence of apoptosis, conventional chemotherapies lead to the accumulation
of mutations.
c. For chemotherapy to be successful, cells must be able to trigger apoptosis.
d. Gene mutations that inhibit apoptosis lead to drug resistance - correct answer A)
This statement is false. The aim of conventional chemotherapies is to induce apoptosis.
Most conventional chemotherapies induce extensive DNA damage in order to trigger
apoptosis. True or False? - correct answer True
, Gene mutations that inhibit apoptosis lead to drug resistance. True or False? - correct
answer True) These mutations serve to uncouple drug-induced damage from
apoptosis and therefore these tumor cells are resistant to the drug.
Which one of the following statements about the apoptosome is correct?
a. Cytochrome B, caspase-9, ATP and Apaf-1 are components of the apoptosome.
b. Cytochrome C, procaspase-9, ATP and Apaf-1 are components of the apoptosome.
c. Bcl-2, ATP, caspase-8 and caspase-9 are components of the apoptosome.Feedback:
d. Procaspase-9, Bax, cytochrome C and Apaf-1 are components of the apoptosome. -
correct answer B
Bax resides in the _______ and allows the release of several components of the
_______ into the cytoplasm. - correct answer mitochondrial membrane and
apoptosome
Which one of the following statements about apoptosis is false?
a. It is an important tumor suppression mechanism.
b. It may be triggered by extracellular death signals that act via the extrinsic pathway.
c. It may be triggered by internal stimuli such as DNA damage
d. It is unregulated cell death characterized by cell swelling - correct answer D)
Apoptosis is regulated cell death characterized by cell shrinkage. Cell death
characterized by swelling is called necrosis.
Which one of the following statements is false?
a. Most anti-apoptotic genes are proto-oncogenes.
b. Mutations in Fas receptors have been found in skin cancer.
c. Oncogenic activation of Bcl-2 is associated with lymphoma
d. Gain of caspase-8 expression is linked with lung cancer. - correct answer D)Loss of
caspase-8 expression is linked with lung cancer.
Which one of the following statements correctly explains why direct apoptotic inducers
may be a better drug strategy than conventional chemotherapy?
a. They bypass the need to be mutagenic and avoid therapy related leukemias.
b. They target a host mechanism and not the tumor.
c. They all involve gene therapy
d. They will target tyrosine kinase activity in order to induce apoptosis. - correct answer
A)
Direct apoptotic inducers will target the _____. Anti-angiogenic therapies target
_______. - correct answer Direct apoptotic inducers will target the tumor. Anti-
angiogenic therapies target a host mechanism.
All direct apoptotic inducers depend on gene therapy. True or False - correct answer
False
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