BIOL110L Lab Report Module 1
Michael Rexach
BIOL110-12-Cell Biology
Guidelines for writing Lab Report #1
The written sections of this report must add up to be 9 pages long. Use double spacing
between lines. The document must have 1” borders and must use Arial font 12. All
pages should be numbered in the page footer, and your name must appear in the
header (as shown for this document). All scientific journals such as Cell, Journal of Cell
Biology, Molecular and Cellular Proteomics, etc. have a section in their webpage
entitled “Instructions to Authors” where you can find many pointers on how to best write
the various sections of a research report. As an example of how to write the various
sections in a scientifically-concise style, you may consult the research paper assigned
for Module #1: “Characteristics of ER-derived transport vesicles” by Rexach et al 1994,
and any other research article of a similar format.
______________________________________________________________________
Title: The title must be short and to the point, with no more than 120 characters
Authors (Authors and location where research was performed)
e.g. “Your Name, Your Lab Partner, Justin Yamada, and Michael Rexach, Biol110L Cell
Biology Laboratory; Thimann Labs 203; Molecular, Cellular and Developmental Biology
Department, UC Santa Cruz, CA 95064”
Summary: This should be a single concise paragraph of fewer than 200 words. The first
1-2 sentences should provide the general background for the scientific question
addressed (cellular compartmentalization). The next sentence or two should state the
purpose or importance (rationale) for the experiments conducted (characterize cell
proteome). The next 2-3 sentences should describe the methodology used (GFP
tagging, microscopy detection of GFP fusions, western blotting, HD exposure to explore
topology) and results obtained without extensive experimental detail. This section
should end with 1-2 sentences summarizing the conclusion reached and the
significance . References should not be cited in this section.
page 1
BIOL110L Lab Report Module 1
Michael Rexach
Introduction: This section must be 2-3 pages long without subheadings. It should
present the background information necessary to place the results that will be shown
into a biological context.
For example, the first paragraph should introduce the general topic of interest (e.g.
biological membranes, intracellular compartmentalization, and protein topology). You
could use your Alberts et al 2008 book for reference (I have some copies to lend) and/or
the lecture notes from my Module 1 Intro lecture, which are posted in the class website.
The second paragraph should focus on the specifics of the experimental system used.
For example, you could provide some info about the use of GFP-tagged proteins in
yeast as a way of studying cell compartmentalization and intracellular dynamics. Start
with something like: “Specific locations in cells can be highlighted for microscopic study
through the use of fluorescently tagged proteins that reside or visit often a specific
location or compartment in a cell. For example the plasma membrane of yeast can be
highlighted using proteins tagged with GFP such as ___(the one you used)”.
The third paragraph could introduce what is known about your GFP tagged protein, its
cellular residence, its topology on cell membranes if know, whether it has a
transmembrane domain, or is glycosylated, or has an auto proteolytic domain, etc. You
may find references for relevant information about your proteins at the SGD website
(http://www.yeastgenome.org/).
The fourth paragraph should establish a connection between the introduction and the
results. You could start the first 1-2 sentences by establishing the significance of the
experiments you are about to discuss. In the next 1-2 sentences, mention what you did
(in very general terms) and the experimental system you used… “Here, we
characterized the cellular location and biochemical fractionation of a GFP-tagged
proteins using a combination of microscopy and cell fractionation techniques.”
page 2
BIOL110L Lab Report Module 1
Michael Rexach
Results: This ~3-page section should be written in past tense, describing for each
subject what was done, why you did it, and how you did it. You should use short
subheadings for each subsection. Describe the results obtained providing additional
relevant information when needed. As you describe your specific results it is critical that
you specifically refer to the Figure(s) and/or Table(s) containing the relevant data (i.e.
see Figure 1).
Logistics of Results section: *Note that one figure (Figure 1) is different than what was
included in the oral presentations.
First, show AA sequence of (your protein) (Figure 1A). Then predict its molecular weight
based on AA composition. Then use hydropathy plot to predict the presence (or
absence) of membrane spanning domains (Figure 1B). Second, show the cellular
localization of your protein (Figure 2A) and the effect of HD on its localization (Figure
2B). Third, show the cellular fractionation of your protein (after cell fractionation) (Figure
3, left part), Fourth, show effect of salt, detergent and HD on the cellular fractionation of
your protein (Figure 3, right part). We will not be discussing the osmolarity experiments
on the report (Figure 1 of your oral presentations).
Suggested first paragraph… “In order to characterize (your protein) and study its cellular
location and fractionation, we tagged (your protein) with GFP. (Your protein) has a
predicted molecular weight of … based on AA sequence (Figure 1A). Based on the
hydropathy plot of … we determined that (your protein) has/has not transmembrane
domain(s) (Figure 1B). Elaborate on any posttranslational modification it may have that
could change its expected molecular weight.
The second paragraph… “To characterize the cellular location of (your protein) we
fused it to GFP and used microscopy to... The fusion protein has an expected molecular
weight of … and was seen to localize to…” Elaborate on localization pattern. “To study
the effect of aliphatic alcohols on (your protein) localization we exposed the cells to 1,6
% hexanediol… and observed…(discuss changes).
page 3
BIOL110L Lab Report Module 1
Michael Rexach
Next paragraph… “To characterize the biochemical fractionation of (your protein fused
to GFP), we… (did this, and did that)… and we observed that…” For example, this
could read something like: “We monitored the fate of GFP-X protein during fractionation
of perforated yeast spheroplasts using differential centrifugation and after extraction of
membranes with non-ionic detergents, high salt and an aliphatic alcohol.
Discussion: This 2-3 page section should be written in the past tense. You should
discuss each of your findings methodically, one per paragraph, delineating the
conclusions and/or lessons learned. It should only discuss the results, rather than
restate or reword what was has already said in the Results section. Discuss each
observation and its significance providing explanations for unexpected results. Make
conservative conclusions based on your observations as you discuss your findings and
their significance.
You could start by saying something like: “We expected to find that (your protein)
fractionates as a…. (e.g. integral membrane protein; or peripheral membrane protein, or
soluble protein) of the (ER, Golgi, Nuclear membrane, etc) given its function and its
content (or lack) of a transmembrane domain. Indeed, we observed that….” (if results
matched expectations)’ or could say “Surprisingly, we observed that…” (if your results
do not match your expectations). Or you may have to say “Unfortunately, we found
that…” if the results were unavailable or un-interpretable). Then end by saying, “Overall,
the result indicate that… (your initial conclusion).
Methods: In this 2-page section, include only the most relevant experimental
parameters and the reagents used. Provide a very brief summary of the protocols used.
Do not exceed 2 pages; the challenge here is to be as brief as possible without omitting
key steps or details.
A sample Methods section for Module 1 may have these subheadings:
Yeast strains, growth media and cell growth conditions
page 4
BIOL110L Lab Report Module 1
Michael Rexach
Light and fluorescent microscopy of yeast:
Preparation of yeast spheroplasts:
Cellular fractionation by lysis and differential centrifugation:
SDS-PAGE and Western blotting (do not describe how to pour an acrylamide gel)
References: Number the references used throughout the report; include any research
articles or review articles you may have used to gather information on the protein you
analyzed. Do not list my lecture notes or my presentation as a reference, or a source of
information. Instead you may (for example) list Alberts et al as a source for general
information.
Figure Legends: For each Figure (labeled Figure 1, Figure 2, etc) provide a concise
title and describe the experiment in it very briefly, but with enough detail such that
anyone can understand what you did and what is shown. Label panels as A and B when
appropriate. End each figure legend by highlighting the key finding and conclusion of
the figure. The three Figure Legends should fit in 1-2 pages.
An example Figure legend could be:
Figure 1: Cellular distribution of GFP-x in living yeast. Yeast expressing a GFP -X fusion
protein were grown to early log phase in rich media at 30°C. Cells were harvested at
low speed, resuspended in minimal media with glucose, and examined under a phase
contrast and fluorescence microscope using a 100x objective. Note the perinuclear
location of GFP-Hmg1, as expected for an ER resident protein.”
Figures and Tables: For figures, follow the format shown in the handout from last week.
Label each figure as Figure 1, Figure 2, etc. with subsections (panels A, B, C, etc)
when necessary. Label the figures with large-enough text to be visible in your computer
screen at a magnification of 50%. Make the Figures as tidy, big, and illustrative as
possible. Present one figure per page. For tables, provide a concise title for each table
and footnotes when needed. The data should be arranged in a column format with all
pertinent units shown.
page 5