LS7C Midterm 1 Exam
1. As cell size increases, what happens to the
surface area-to-volume ratio?: surface area to volume ratio
decreases
2. What kinds of molecules pass through a cell membrane
most easily through simple diffusion? What kind of receptor
do they bind to?: small hydrophobic (nonpolar) molecules;
i.e. estradiol and cortisone
bind to intracellular receptors
3. What kinds of molecules CANNOT pass through a cell
membrane easily through simple diffusion? What kind of
receptor do they bind to?: hydrophilic (polar) molecules; i.e.
acetylcholine, glucagon, adrenaline, PDGF
bind to cell-surface receptors
4. What happens to a signal after it binds the receptor?
A. It stays bound until the receptor is destroyed
,B. It eventually dissociates from the receptor
C. It is eventually destroyed by the receptor
D. It dissociates from the receptor when a termination signal
is received: B. It eventually dissociates from the receptor.
5. Based on the Week 1 Signaling Handout, which protein is a
phosphatase?-
: P2
6. Refer to the Week 1 Signaling Handout.
True or false: All of the proteins shown in the diagram are
active when they are phosporylated.: False
7. Refer to the Week 1 Signaling Handout. A mutation in P3
causes it to be active all of the time (even if it's
dephosphorylated). What would be the most likely
consequence of this mutation?
A. The cell will express genes regulated by TF1 in the
presence of signal
B. The cell will express genes regulated by TF2 in the
absence of signal
,C. The cell will express genes regulated by TF1 and TF2 in the
presence or absence of signal
D. The cell will fail to express any genes due to mixed
signals: A. The cell will express genes regulated by TF1 in the
presence of signal
8. Refer to the Week 1 Signaling Handout. Which of the
following would shut the TF2 pathway off the most quickly?
A. Activating phosphatase that targets the receptor
B. Activating a phosphatase that targets P2
C. Activating a phosphatase that targets P3: A. Activating
phosphatase that targets the receptor
9. Refer to Week 1 Stem Cell Handout. A cell in a chick
embryo is tested to determine whether it is a stem cell of
some kind.
The results of these tests find:
1. The SR receptor is present
2. DIV genes are on
, 3. The DIFF (skin) genes are blocked
4. TF of the neural pathway is in the cytoplasm
5. Transducer 2 of the skin pathway is not phosphorylated
True or false: The cell will no longer expresses ID genes.:
False
10. Refer to Week 1 Stem Cell Handout. A cell in a chick
embryo is tested to determine whether it is a stem cell of
some kind.
The results of these tests find:
1. The SR receptor is present
2. DIV genes are on
3. The DIFF (skin) genes are blocked
4. TF of the neural pathway is in the cytoplasm
5. Transducer 2 of the skin pathway is not phosphorylated
True or false: The skin signal is not present.: True
11. Refer to Week 1 Stem Cell Handout. A cell is determined
because it re- ceived the Self Renewal signal. Which genes
that were on, would be turned off if the cell then receives the
skin signal? (Assume the SR signal is still present.)
1. As cell size increases, what happens to the
surface area-to-volume ratio?: surface area to volume ratio
decreases
2. What kinds of molecules pass through a cell membrane
most easily through simple diffusion? What kind of receptor
do they bind to?: small hydrophobic (nonpolar) molecules;
i.e. estradiol and cortisone
bind to intracellular receptors
3. What kinds of molecules CANNOT pass through a cell
membrane easily through simple diffusion? What kind of
receptor do they bind to?: hydrophilic (polar) molecules; i.e.
acetylcholine, glucagon, adrenaline, PDGF
bind to cell-surface receptors
4. What happens to a signal after it binds the receptor?
A. It stays bound until the receptor is destroyed
,B. It eventually dissociates from the receptor
C. It is eventually destroyed by the receptor
D. It dissociates from the receptor when a termination signal
is received: B. It eventually dissociates from the receptor.
5. Based on the Week 1 Signaling Handout, which protein is a
phosphatase?-
: P2
6. Refer to the Week 1 Signaling Handout.
True or false: All of the proteins shown in the diagram are
active when they are phosporylated.: False
7. Refer to the Week 1 Signaling Handout. A mutation in P3
causes it to be active all of the time (even if it's
dephosphorylated). What would be the most likely
consequence of this mutation?
A. The cell will express genes regulated by TF1 in the
presence of signal
B. The cell will express genes regulated by TF2 in the
absence of signal
,C. The cell will express genes regulated by TF1 and TF2 in the
presence or absence of signal
D. The cell will fail to express any genes due to mixed
signals: A. The cell will express genes regulated by TF1 in the
presence of signal
8. Refer to the Week 1 Signaling Handout. Which of the
following would shut the TF2 pathway off the most quickly?
A. Activating phosphatase that targets the receptor
B. Activating a phosphatase that targets P2
C. Activating a phosphatase that targets P3: A. Activating
phosphatase that targets the receptor
9. Refer to Week 1 Stem Cell Handout. A cell in a chick
embryo is tested to determine whether it is a stem cell of
some kind.
The results of these tests find:
1. The SR receptor is present
2. DIV genes are on
, 3. The DIFF (skin) genes are blocked
4. TF of the neural pathway is in the cytoplasm
5. Transducer 2 of the skin pathway is not phosphorylated
True or false: The cell will no longer expresses ID genes.:
False
10. Refer to Week 1 Stem Cell Handout. A cell in a chick
embryo is tested to determine whether it is a stem cell of
some kind.
The results of these tests find:
1. The SR receptor is present
2. DIV genes are on
3. The DIFF (skin) genes are blocked
4. TF of the neural pathway is in the cytoplasm
5. Transducer 2 of the skin pathway is not phosphorylated
True or false: The skin signal is not present.: True
11. Refer to Week 1 Stem Cell Handout. A cell is determined
because it re- ceived the Self Renewal signal. Which genes
that were on, would be turned off if the cell then receives the
skin signal? (Assume the SR signal is still present.)
