LESSON PLAN
Name: Jessica Hawkins
Title of lesson: Bacteria Lecture and Antibiotic Lab Preparation
Date of lesson: October 9, 2006
Length of lesson: 45 minutes
Description of the class:
Name of course: Biology
Grade level: 9th grade
Honors or regular: Honors
Source of the lesson:
http://science.education.nih.gov/supplements/nih1/diseases/guide/activity3-2.htm#labprep
http://www.belleville.k12.wi.us/bjhs/schmitz/bacteria.htm
TEKS addressed:
(1) Scientific processes. The student, for at least 40% of instructional time, conducts field and laboratory investigations using safe, environmentally appropriate, and ethical practices. The student is expected to:
(A) demonstrate safe practices during field and laboratory investigations; and
(4) Science concepts. The student knows that cells are the basic structures of all living things and have specialized parts that perform specific functions, and that viruses are different from cells and have different properties and functions. The student is expected to:
(A) identify the parts of prokaryotic and eukaryotic cells;
(8) Science concepts. The student knows applications of taxonomy and can identify its limitations. The student is expected to:
(C) identify characteristics of kingdoms including monerans, protists, fungi, plants, and animals.
Overview:
The students will have a general understanding on how to characterize
bacteria. They will know about their cell type, reproduction, shape,
motility, helpfulness, harmfulness, and oxygen needs. They will use
aseptic technique to start the antibiotic lab.
II. Performance or learner outcomes
Students will be able to:
-Describe characteristics of bacteria.
-Define cocci, bacillus and spirillum.
-Demonstrate their knowledge of aseptic technique.
III. Resources, materials and supplies needed
- petri dishes
- capped test tubes
- sterile 1-ml pipets
- pipet pumps or bulbs
- glass rod spreaders
- Bunsen burners
- alcohol (for sterilizing the glass spreaders)
- facilities for sterilizing and preparing growth media
IV. Supplementary
materials, handouts.
-Overheads of bacteria (pictures)
Teacher Does Probing Questions Student Does
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Engage: Streak plate a Petri dish with bacteria from the doorknob of the classroom. Show the class the Petri dish with the bacteria that has grown on it.
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What do you notice about the plate? Are they all the same type of bacteria? What makes the areas of growth different from each other? What are some ways we could group the different areas of growth? |
Expected Student Responses/Misconceptions
There are all different types of bacteria growing on the dish. The bacteria is different sizes, shapes and colors. Size, shape, color..etc. |
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Lecture: Bacteria can be classified by the type of the cell. We can use this property in the lab to classify certain types of bacteria through gram stains. We will learn more about gram staining later this week. Bacteria can be broken down by analyzing a number of different characteristics. Bacteria come in different shapes. The three shapes bacteria are found to look like are rod-like (bacilli-write on board) round (coccus-write on board) and spiral (spirillum-write on board). Draw pictures of the general shapes on the board. Show examples on overheads. Bacteria are sometimes motile, while some strains are not. They use flagella to whip themselves around or pilli may be used also. Show overhead of pilli and flagella. Bacteria can live in the presence of oxygen (aerobic) or without oxygen (anaerobic). Bacteria usually have a very short generation time. They reproduce in a matter of minutes at times. They use asexual reproduction to divide rapidly, however, they can also reproduce sexually. Some bacteria are harmful while others are helpful. Ask for examples from the students. These are just a few ways to classify bacteria further. We will use some of these characteristics later this week when we conduct labs with bacteria. These can be helpful when we have an unknown bacteria and want to find out what it is.
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Critical questions that will allow you to decide whether students understand or are able to carry out the assigned task (formative) What type of cells are bacteria? How do we characterize prokaryotes vs. eukaryotes? What are the three shapes of bacteria? Can bacteria move? How do they move? What is the name for organisms that need oxygen to live? What is the name for organisms who do not need oxygen to live? What type of cells are bacteria? How do bacteria grow? How is there reproduction so fast? Can you think of some bacteria that are helpful and some that are harmful?
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Expected Student Responses/Misconceptions Prokaryotic Cell Wall, no compartmentalization, nucleolus etc. Bacilli/Coccus/Spirillum Some can move. Flagella/Pilli Aerobes/Anaerobes Asexually/sexually Harmful bacteria – E.Coli infection Helpful- bacteria in our stomach
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ANTIBIOTIC PREPARATION: Teacher does this:
Prepare a solution of 25 mg/ml kanamycin in a test tube with water. Make sure it is sterile. Prepare nutrient broth medium as well as nutrient agar plates using the package’s instructions. With the medium containing kanamycin, add 2 ml of the stock kanamycin solution per liter of medium after allowing the medium to be cooled. Don’t wait until the agar solidifies. Dispense 5-ml portions of nutrient broth into capped test tubes, making sure they are sterile. 2 test tubes of nutrient broth and 1 test tube of nutrient broth with kanamycin for each team are needed. You need 3 nutrient agar plates and 3 nutrient agar plates containing kanamycin for each team also. Inoculate 1 nutrient broth tube with P. fluorescens for each group 2 days before you start the activity using a 0.1-ml inoculum. These cultures should be inoculated at 25°C. Student Instruction: (We will watch a video on aseptic technique the day before at the end of the lesson.) I will show aseptic technique by showing the Day 1 segment of Bacterial Growth Experiment on the Web site. This shows students doing the first four steps of the experiment and watching aseptic techniques. The video also shows students conducting safety practices. You should show students were to dispose of the materials. Tell the students that there are microbes present in the air. They should be careful to not contaminate any cultures with bacteria from the air. The P. fluorescens in the nutrient broth or agar will grow in 24 hours, but the cultures in kanamycin will take a couple of days.
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What does sterile mean? |
Expected Student Responses/Misconceptions Clean, properly prepared to prevent contamination. |