Cell
Biology
Biology
308: Review 2 November 2000
The
review is due Monday
November 13, 2000 at 3:00pm
This
is a closed-book, closed-note review. There is no time limit for taking the
review. All answers must be typed. You may use a calculator if
calculations are required. However, the steps behind any calculation must be
included to receive full credit (can be hand-written). Any figures or graphs
may be hand-drawn.
The
questions are yours to keep. This page must be the first page of your answer
packet. Fill out the information at the bottom and attach this page to the ones
containing your answers. The top of each additional page in the packet should
contain only your initials and the page number.
Your
review period does not begin until you read any question within this packet.
Any
questions about the review should be directed to me at kabernd@davidson.edu, 894-2889
(o), or XXX (h). Any calls to my home must occur before 9:00pm.
Name:
____________________________________
(print)
Signature:
_________________________________
My
signature indicates that I have completed this review following the Honor Code.
This
review was completed in ________hours
Question 1
(parts 1-4, 19pt)
The
unpredictable and cyclic nature of Bipolar disorder makes it both fascinating
and frustrating to study. Initially efforts could only focus on characterizing
symptoms. More recently theories have been proposed to explain the molecular
basis of this disorder.
1) Provide a well-labeled diagram of a
neuron indicating its major structural parts. (6pt)
2) What is the Catecholamine theory of
affective disorder? (4pt)
3) What is an inhibitory response at a
synapse Include the role of ions in this process. (3pt)
4) Would neurotransmitters and
neurotransmitter receptors be predicted to contain ER signal sequences? (why or
why not) (6pt)
Bonus:
Suicide is the second highest cause of death of college students. What ranks
first as a cause of death on college campuses? (1pt)
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Question 2
(parts 1-4; 15pt total)
A friend from
another school calls you. Their Cell Bio lab is also studying mating (using
brewer’s yeast) and they have performed a number of experiments but the
lab manual isn’t clear and he doesn’t know how to interpret his results.
He has to finish his project and write a lab report. He is beginning to panic
and needs your help.
They have 3
yeast strains: KKB1 wt
strain (a, -his); KKB2
wt strain (alpha, -trp);
RGN 1
nonmating strain (a –his)
A
complementation test between KKB2 and RGN1 resulted in colony growth on
–HIS, YEPD, -TRP, and (-HIS,-TRP) plates.
They then
performed serial dilution of log phase cultures of KKB1 and RGN1. They mixed
equal amounts of each dilution and undiluted KKB2 cells, plated 100ul of the
mixture on the plates indicated and counted colonies after 2 days of growth at
30°C. He emails you a table of the mixtures and the number of colonies seen
in each growth condition.
Platesà |
-HIS |
-TRP |
-HIS-TRP |
10-3KKB1/KKB2 |
>4000 |
>4000 |
>4000 |
10-3RGN1/KKB2 |
>4000 |
>4000 |
>4000 |
10-4KKB1/KKB2 |
>4000 |
2897 |
2362 |
10-4RGN1/KKB2 |
>4000 |
3002 |
960 |
10-5KKB1/KKB2 |
>4000 |
324 |
258 |
10-5RGN1/KKB2 |
>4000 |
310 |
105 |
10-6KKB1/KKB2 |
>4000 |
40 |
32 |
10-6RGN1/KKB2 |
>4000 |
25 |
8 |
His report needs
an introduction including background information on yeast and his professor is
a stickler for Latin names. When your friend was working in lab he accidentally
spilled his Nalgene water bottle on his notebook and now he can’t read
the introductory information that tells him about his yeast and yeast mating.
1) What is the Latin name of the organism he
is studying? (3pt)
2) If he had followed all laboratory safety
rules he would know the background material. What safety rule did he break?
(2pt)
3) What is the mating efficiency of RGN1?
(show calculations—hand written is ok) (5pt)
4) They were told that RGN1 is a mating
mutant. Are the results of the complementation test and the mating efficiency
test consistent with that description? (Be sure to mention the results of both
tests in your answer) (5pt)
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Question 3
(parts 1- 14; 61 points)
You have
identified a free-swimming algae that regulates its internal temperature by
concentrating or dispersing pigment filled vesicles. Enthralled, you decide to
study these vesicles and their movement. Early research indicates that the
vesicles are derived from the trans
Golgi network (TGN) and travel along microtubules. When the algae are in a warm
environment the pigment vesicles (abbreviated PV) are moved to the center of the algae.
When the temperature is cooler the PV are moved to just under the plasma
membrane so that they can help to capture solar energy. The motors appear to be
the same as those used in mammalian systems.
You set up an in
vitro assay to study the
motor involved in PV movement
1) Microtubules are polymers. What is the
basic unit of unit of this polymer? (3pt)
2) Name the compartments of the cell where
microtubule genes are transcribed and the resulting message is translated.
(3pt)
3) In mammals what are the minimal
components needed to study (+) end directed movement in an in vitro assay? (You may assume you have access to
purified proteins) (5pt)
4) You decide it would be prudent to add a
drug to stabilize the microtubules in your algae PV movement assay. What drug
do you add? (2pt)
Bonus:
what drug could you add to destabilize microtubules? (2pt)
5) Briefly describe how a microtubule
stabilizing drug would effect mating in yeast. (3pt)
6) Microtubules are not static structures.
Discuss the role of nucleotides in the process of dynamic instability. (4pt)
These algae have
a unique mechanism for dealing with extremes in heat. Since the dark pigment
helps retain heat, under extreme conditions the algae secrete the pigment and
thus turn a much ‘cooler’ clear color. The release of the pigment
covers the cells with a brown color that is then washed away. In lakes
containing large populations of these algae, this can cover the surface of the
lake with a distinctive ‘brown ooze’.
7) Pigment release is an example of what
type of exocytosis? In your answer provide a definition of that type of
exocytosis and an example of that type of exocytosis from mammalian
cells. (5pt)
8) Is it reasonable to predict that TAP
would have a role in the exocytosis of pigment? (why or why not) (4pt)
You are interested in the interactions
that allow a particular motor to interact with a specific vesicle. A current
hypothesis states that the vesicle must contain a protein that acts as a
molecular marker or ‘ZIP code’. You think that you have identified
such a protein in the membrane of the pigment vesicle. You name the protein
Vrom (for vesicle receptor onto motor). As seen in
the diagram the cytoplasmic portion of Vrom is predicted to interact with a
motor protein. You begin gathering data about Vrom, its synthesis, localization
and function.
Vrom
9) Name 2 agencies you could apply to for
grant money to support this research project. (3pt)
10) Transcription of the gene encoding vrom
reveals no surprises. However its processing is slightly unusual. Vrom mRNA has
a poly(A )tail that is very short. What is a poly(A) tail and what consequences
might result from an mRNA having a very short one? (5pt)
11) Analysis of the 5’ end of the mRNA
shows that it contains two start codons. How does the cell know which one to
use to begin translation and what cellular components are necessary to form the
initiation complex? (5pt)
12) As indicated, Vrom is part of a pigment
vesicle membrane. How could you determine if its translocation occurred using
an SRP-mediated or a Sec mediated pathway? (Be sure to describe the 2
translocation pathways in your answer) (9pt)
13) Name all of the cellular compartments
that the Vrom protein will pass through before it is incorporated into a
pigment vesicle? (4pt)
Data suggests
that the last 6 amino acids of Vrom (KRLVDE) are important for the interaction
between the vesicle and their motor protein.
14) How can you demonstrate that the KRLVDE
region is both necessary and sufficient for vesicle/motor protein interaction?
(6pt) (theoretical explanation is enough, experimental design is not needed)
Question 4:
(1 part 5pt)
Every once and a
while a student will approach me saying “Dr Bernd, if you had only asked
X. I know all about that but you didn’t ask me”. Here is your
chance. Write and answer your own short answer question. It must relate to a
topic we have covered in this section and cannot repeat any of the questions
that appear above. My advice—keep it simple and straight forward and
don’t ask yourself to write a book. (5pt)