PCB 3023 EXAM 4 QUESTIONS AND VERIFIED
ANSWERS; GET IT 100% ACCURATE
__________________ involve cadherin connections between
neighboring cells and are anchorage sites for actin filaments -
correct answer- Adherins Junctions
__________________ permit the passage of small molecules
from one cell to its adjacent cell. - correct answer- Gap
Junctions
__________________ prevent the leakage of molecules
between adjacent cells. - correct answer- Tight Junctions
___________________ can regulate the permeability of the gap
junctions - correct answer- Extracellular signals
A proto-oncogene can be converted into an oncogene via
various ways that lead to genetic changes such as... - correct
answer- -mutation in coding sequence
-gene amplification
-chromosome rearrangement
,A tumor suppressor gene can be lost via several genetic changes
such as... - correct answer- -loss of function mutation in
maternal chromosome, normal paternal.
-whole paternal chromosome lost
-region containing normal gene deleted
-gene silenced by epigenetic changes
A well known carcinogen, arsenic, causes: - correct answer-
skin carcinomas, bladder cancer
A well known carcinogen, asbestos, causes: - correct
answer- mesothelioma
A well known carcinogen, benzene, causes: - correct
answer- acute leukemias
A well known carcinogen, radium, causes: - correct answer-
osteocarcinoma
A well known carcinogen, vinyl chloride, causes: - correct
answer- liver angiosarcoma
,After acetylcholine is secreted from cells, it is long-lived, because
it has to reach target cells all over body. T/F? - correct
answer- False. Acetylcholine would be short-lived
All Cdks phosphorylate the same substrates. T/F? - correct
answer- False.
Bcl2 overexpression (amplification) is frequently observed in
cancers, therby preventing apoptosis. T/F? - correct
answer- True
Bcl2 releases cytochrome c from mitochondria. T/F? - correct
answer- False. It inhibits
Between Interphase and Mitosis, which takes the longest? -
correct answer- Interphase (~23 hours.)
Can a cell leave the G0 phase? - correct answer- Yes, if
the appropriate signals are received.
Can antibodies activate RTKS? GPCRs? - correct answer-
Yes because RTKs have two binding sites. GPCRs do not.
, Can cells lack gap phases? - correct answer- In some
organisms, yes. (e.g. frog embryos)
Cancer critical mutations fall into two distinguishable categories
- - correct answer- -dominant (oncogenes)/ gain-of-
function mutations
-recessive (tumor suppressor) loss-of-function mutations
Cdks must be bound to cyclins for activity. T/F? - correct
answer- True
Cyclin concentration gradually increases by transcription
(expression of cyclin genes). Does that mean the Cdk activity
gradually increases? - correct answer- No. The activity of
Cyclin-Cdk complexes switch on abruptly at the appropriate time
in the cell cycle
Cyclins are made (gradually/abruptly). Cdks are activated
(gradually/abruptly). Abrupt activity changes are possible
through ___________. - correct answer- Gradually;
Abruptly; Phosphorylation/dephosphorylation (post-
translational modification) switch allows
the acute activity changes.
ANSWERS; GET IT 100% ACCURATE
__________________ involve cadherin connections between
neighboring cells and are anchorage sites for actin filaments -
correct answer- Adherins Junctions
__________________ permit the passage of small molecules
from one cell to its adjacent cell. - correct answer- Gap
Junctions
__________________ prevent the leakage of molecules
between adjacent cells. - correct answer- Tight Junctions
___________________ can regulate the permeability of the gap
junctions - correct answer- Extracellular signals
A proto-oncogene can be converted into an oncogene via
various ways that lead to genetic changes such as... - correct
answer- -mutation in coding sequence
-gene amplification
-chromosome rearrangement
,A tumor suppressor gene can be lost via several genetic changes
such as... - correct answer- -loss of function mutation in
maternal chromosome, normal paternal.
-whole paternal chromosome lost
-region containing normal gene deleted
-gene silenced by epigenetic changes
A well known carcinogen, arsenic, causes: - correct answer-
skin carcinomas, bladder cancer
A well known carcinogen, asbestos, causes: - correct
answer- mesothelioma
A well known carcinogen, benzene, causes: - correct
answer- acute leukemias
A well known carcinogen, radium, causes: - correct answer-
osteocarcinoma
A well known carcinogen, vinyl chloride, causes: - correct
answer- liver angiosarcoma
,After acetylcholine is secreted from cells, it is long-lived, because
it has to reach target cells all over body. T/F? - correct
answer- False. Acetylcholine would be short-lived
All Cdks phosphorylate the same substrates. T/F? - correct
answer- False.
Bcl2 overexpression (amplification) is frequently observed in
cancers, therby preventing apoptosis. T/F? - correct
answer- True
Bcl2 releases cytochrome c from mitochondria. T/F? - correct
answer- False. It inhibits
Between Interphase and Mitosis, which takes the longest? -
correct answer- Interphase (~23 hours.)
Can a cell leave the G0 phase? - correct answer- Yes, if
the appropriate signals are received.
Can antibodies activate RTKS? GPCRs? - correct answer-
Yes because RTKs have two binding sites. GPCRs do not.
, Can cells lack gap phases? - correct answer- In some
organisms, yes. (e.g. frog embryos)
Cancer critical mutations fall into two distinguishable categories
- - correct answer- -dominant (oncogenes)/ gain-of-
function mutations
-recessive (tumor suppressor) loss-of-function mutations
Cdks must be bound to cyclins for activity. T/F? - correct
answer- True
Cyclin concentration gradually increases by transcription
(expression of cyclin genes). Does that mean the Cdk activity
gradually increases? - correct answer- No. The activity of
Cyclin-Cdk complexes switch on abruptly at the appropriate time
in the cell cycle
Cyclins are made (gradually/abruptly). Cdks are activated
(gradually/abruptly). Abrupt activity changes are possible
through ___________. - correct answer- Gradually;
Abruptly; Phosphorylation/dephosphorylation (post-
translational modification) switch allows
the acute activity changes.
