Christopher Rieger June 23, 2005 Lesson Length: 75 min
Trinity High School 10th Grade # of students: 18
AP Biology Ubiquitous Bacteria # of IEP students: 0
ACTIONS
1. Goal and Objectives
Goal:
Students will use both selective and differential agar plates to culture bacteria from prepared standards and sampled from their bodies and different objects from around the school. Through this laboratory session, students will understand the ubiquity of bacteria in the environment and how microbiologists use agar plates to identify different types of bacteria.
Objectives:
a. Students will use nutrient agar, blood agar, phenylethyl alcohol agar, eosin methylene blue agar, mannitol salt agar, and the gram stain procedure to identify both known and unknown bacterial samples.
b. Students will cooperate groups in perform the laboratory procedures and will record their test data in an organized table.
c. Students will develop communication skills as they discuss the questions included with the laboratory handout in their groups.
d. Students will understand the need for safety equipment when working with biological samples.
e. Students will understand the difference between pathogenic bacteria and how other bacteria can be useful to humans.
f. Students will understand how handwashing can affect the number of microorganisms carried on our skin.
2.
Connections
Kentucky Learner Goals and Academic Expectations:
1.3 – Students make sense
of the various things they observe.
1.10 – Students
organize information through development and use of classification rules and
systems.
1.16 – Students use computers and other
kinds of technology to collect, organize, and communicate information and
ideas.
2.1 – Students understand scientific ways
of thinking and working and use those methods to solve real-life problems.
3.5
– Students demonstrate self-control and self-discipline.
4.2 – Students use productive team membership skills.
5.1 – Students use critical thinking skills such as analyzing, prioritizing, categorizing, evaluating, and comparing to solve a variety of problems in real-life situations.
5.3 – Students organize information to develop or change their understanding of a concept.
6.2 – Students use what they already know to acquire new knowledge, develop new skills, or interpret new experiences.
6.3
– Students expand their
understanding of existing knowledge by making connections with new knowledge,
skills, and experiences.
Kentucky Core Content for Assessment, Grades 8-11. These requirements are tied to the National Science Teacher Association Content Standards:
SC-H-3.1.1 – Cells have particular structures that
underlie their function. Every cell is surrounded
by a membrane that separates it from the outside world. Inside the cell is a concentrated mixture of
thousands of different molecules that form a variety of specialized structures. These structures carry out specific cell
functions.
SC-H-3.1.2 – Most cell functions
involve chemical reactions. Food
molecules taken into cells react to provide the chemical constituents needed to
synthesize other molecules. Both breakdown
and synthesis are made possible by a large set of protein catalysts, called
enzymes. The breakdown of some of the
food molecules enables the cell to store energy in specific chemicals that are
used to carry out the many functions of the cell.
SC-H-3.1.4 – Cell functions are
regulated. Regulation occurs both
through changes in the activity of the functions performed by proteins and
through selective expression of individual genes. This regulation allows cells to respond to their internal and
external environments and to control and coordinate cell growth and division.
SC-H-3.4.3 – Biological
classifications are based on how organisms are related. Organisms are classified into a hierarchy of
groups and subgroups based on similarities that reflect their relationships. Species is the most fundamental unit of
classification. Different species are
classified by the comparison and analysis of their internal and external
structures and the similarity of their chemical processes.
S-HS-SI-3S – Students will use equipment (e.g., microscopes, lasers), tools
(e.g., beakers), techniques (e.g., microscope skills), technology (e.g.,
computers), and mathematics to improve scientific investigations and
communications.
S-HS-SI-4
– Students will use evidence,
logic, and scientific knowledge to develop and revise scientific explanations
and models.
S-HS-SI-5
– Students will communicate
designs, procedures, and results of scientific investigations.
S-HS-LS-1 –
Students will investigate cell structures, their functions (e.g., chemical reactions),
and how DNA guides their functions.
S-HS-LS-6 –
Students will examine diversity of organisms and biological classification.
S-HS-AC-3 – Students will explore the impact of scientific knowledge and discoveries on personal and community health.
S-HS-AC-7 –
Students will use science to investigate natural hazards and human-induced
hazards.
By drawing on Gardner’s multiple intelligences of logical/mathematical, interpersonal, and naturalist skills, students will cooperate in groups to discover how bacteria are ubiquitous in the environment and how scientist work with these microorganisms. The class discussion will include topics such as how bacteria can be both harmful and useful to humans and why handwashing is a critical measure to the prevention of disease. The testing methods used in this laboratory session incorporate authentic microbiological test methods and media to analyze the characteristics of the microorganisms in both stock cultures and samples taken from the students’ environment.
3.
Student Assessment
Students will be assessed in several ways during the course of this laboratory session. During the opening activities, students will be asked questions based upon the websites listed on the curriculum page they will be asked to read. Students will also be formatively assessed as part of the in-class activities and closing activities as they are asked to interpretive questions regarding the lab procedures. While the students are working on completing the laboratory procedures, they will be monitored to insure that the groups are working productively toward completing their tests. When the cultures are completed, the results from each group will be reviewed and a score will be assigned based on their findings on the control samples. Students will be summatively assessed by the questions included in the handout for the laboratory session. This assessment will be composed of fill-in-the-blank and short answer questions. Please refer to the assessment page for the structure of this scoring.
4.
Context
This lesson is designed to support the
chapters concerned with microorganisms.
Students will be studying the concept of pathogens and how both bacteria
and viruses can cause disease in other organisms. This activity allows students to work directly with some of the
organisms discussed in their texts to achieve a more personal understanding of
the concept of microorganisms. By
incorporating materials and methods used by microbiologists, students also gain
a sense they are doing “real” science as they culture items around the school
and their own bodies to see the bacterial flora that surrounds them.
Materials:
This lesson will be performed in the biology laboratory, as lab benches, gas for Bunsen burners, and water sources will be required. Each group will receive the equipment listed on the laboratory handout along with several stock cultures to use as positive controls for their plates. These stock cultures will be chosen to insure that the media the students are using is working properly. The students will also receive several cotton swabs to take samples from different objects around the school. Each student will receive a copy of the handout that details all of the discussion, procedures, and questions that will help them successfully complete the laboratory experiment.
Technology:
Each group will be using laboratory equipment to complete the procedures including agar plates, cotton swabs, sterile water, wire loops, Bunsen burners, incubators, microscopes, slides, stains, and soap for handwashing. Students will have access to water sources and gas outlets to support their equipment. An example setup will be placed at the teacher’s station so that a demonstration may be provided at the beginning of class. As part of their homework assignments, students will be asked to use a computer to view websites relating to the topics being discussed in class.
Resources:
This lesson plan was based upon a microbiology laboratory session completed during my Biology 321 class at Murray State University. This session was performed to help the class better understand the basic procedures in a microbiology lab while reinforcing the importance of handwashing as an important method of disease prevention. These procedures are based on authentic microbiological laboratory practices to determine the characteristics of microorganisms. Due to their relative ease of performance and accessibility to students, similar experiments are performed in both high school and college biology courses. Some of the material for the laboratory exercise was derived from A Photographic Atlas for the Microbiology Laboratory by Michael J. Leboffe and Burton E. Pierce and Biology, 4th Edition by Peter H. Raven and George B. Johnson.
Procedures:
Students will report to the classroom at the beginning of the period so
that the handout may be distributed and a brief reinforcement on laboratory safety
may be discussed. The teacher will
assign students into groups of three or four to complete the experiments to
insure a balance is maintained for students who may require academic, physical,
or behavioral considerations. After a brief opening activity, the groups will
report to the laboratory. The
procedures that will be performed are as follows:
·
Students will
arrive in the classroom at the beginning of the period.
·
Opening activity – Going around the room, each student will
be asked about the structure of bacteria.
Students will be called on the name different disease and determine
whether they think they are caused by bacteria or viruses. (4 min).
·
The laboratory
handout will be distributed and groups will be assigned (3 min).
·
The teacher
will present a brief restatement on laboratory safety to insure no student is
injured due to burns from hot equipment or exposure to the bacterial cultures
(3 min).
·
After
reporting to the laboratory, the teacher will provide a brief demonstration of
the experiment to be performed. (5 min).
·
In their
groups, the students will work through the procedures listed on the laboratory
handout. Each group will be provided
with four different known cultures to be included with their samples. Their
results will be recorded in the data table included with the handout. The teacher will be walking through the room
to answer any questions and render assistance as necessary. (50 min).
·
The students
will clean up their work areas and insure that all equipment has been cleaned
and put away properly. The teacher will
walk around the room to insure that all gas outlets are turned off (5 min)
·
Closing activity – The class will discuss their choices for
sampling and asked what types of bacteria they might expect to find in their
cultures. (5 min).
·
The students
will turn in their handouts at the end of the following period. Along with the
scores for answering the questions right, the students will receive a score for
their behavior in the laboratory session.
Gardner’s
multiple intelligences:
Logical-Mathematical Intelligence – The laboratory session engages the students in deductive thinking as they analyze the results of the cultures. Their findings will be recorded in data tables and then be used to construct answers to the questions included in the handout.
Naturalist Intelligence – This laboratory session allows students to analyze the diversity of microorganisms that live all around them. This session is designed to support class readings concerning prokaryotic organisms by allowing students to investigate the presence of these organisms in their environment and on their bodies.
Body/Kinesthetic – This laboratory session allows students to handle different laboratory equipment skillfully to perform the procedures. As the equipment is fragile and may contain live cultures of bacteria, the students will need to be careful as they manipulate the equipment.
If Clostridium botulinum was
present in the canned soup you just had for lunch, what might be the effects?
This question asks students to review the handout and respond that this
organism is the source of botulism, a severe form of food poisoning. This draws on their existing knowledge that
food poisoning often causes vomiting along with other symptoms.
Comprehension
How
does the cell wall structure differ between Gram-positive and Gram-negative
organisms?
This question
asks students to explain why the Gram stain procedure works due to the lipid
content between the two types of cell walls.
This question helps verify that students understand how this procedure
is effective in classifying different types of bacteria.
Application
Pathogenic bacteria may be present on any surface
we touch. What methods would you
suggest to reduce the numbers of pathogens to which you might be exposed?
This question asks students to think about the different products on
the market designed to reduce potential pathogens and determine how they may be
used to prevent disease transmission.
As students may have already found potential pathogens in their unknown
samples, this helps them connect the experiment to the real world.
Synthesis
What process would you use to separate the
strains of a Gram-negative bacilli and a Gram-positive cocci present in a
contaminated culture?
This question requires students to evaluate the
media they have used to determine a method of separating the different
strains. Students should suggest a
method of using stains and the appropriate media to separate the strains.
Why is important to insure sterility of the media
when setting up bacterial cultures?
This question asks students to explain why is important to insure that
the media is not contaminated before it is inoculated with the desired
sample. This helps students the better
understand the procedures they have just completed.
This lesson will require students to use their cognitive abilities to
determine whether their cultures have tested positively or negatively for the
different media. As they work to
perform the procedures, students will engage their psychomotor abilities as
they samples bacteria from different sources and perform other actions related
to completing the lab. The affective
hierarchy can be engaged as students employ the safety rules for this
laboratory to insure no injury occurs to themselves or their peers.
Adaptations for Special Needs:
As students will be working in groups of three or four, this provides a
support structure for any students who may be having difficulty with the
session. The groups will be assigned by
the teacher to insure that any special needs students will have an individual
who can physically assist them in being engaged with the experiment. A translation of the laboratory procedures
can be provided to ESL students by the use of online translation services or
they can be partnered with another student who is more fluent in English.
Designer Elements:
Choice – Students will be asked to collect unknown
samples of bacteria from around the school and off of their bodies in order to
understand the diversity of bacteria present in the world. As this opens up countless opportunities for
students to examine the microbiological world around them, students will have
the opportunity to study the objects that they believe may be interesting.
Authenticity – As the students are using real laboratory
equipment along with procedures based on microbiological testing methods, this
laboratory session is very representative of experiments performed by
scientists. By allowing students to
culture common objects they touch every day along with taking samples from
their bodies, they will draw an understating of the ubiquity of bacteria in the
environment. This laboratory will
include discussions that explain how bacteria can be helpful to humans and how
pathogenic bacteria can cause disease.
Novelty – As this activity involves the growth of
microorganisms on different media, the results can be very surprising and
builds interest in students due to the “ick” factor of the cultures. The bright colors and complex colonies that
result on the agar plates provide students a very visual perspective of the
microbial world around them. Some of
these procedures may relate to television shows and movies students have
watched that concern diseases, so this lab provides a real-world connection to
involve students.
Student
Diversity – Diversity will be
approached in this laboratory session by explaining to students that although
bacteria are ubiquitous, many variants can be found around the world and this
is often to source of disease for travelers.
As people become accustomed to the flora in their particular region,
they develop resistance to those strains of bacteria. This will lead into discussions of how epidemics can be started
by individuals bringing pathogens into a new area where other organisms have
never been exposed to these diseases.
One topic that may be engaged is how European explorers greatly harmed
indigenous populations in the New World.
IMPACT
Reflection/Analysis of Teaching and Learning:
Not required at this time.
REFINEMENT
Lesson/Extension Follow-up: