Lab 4: Cell Phone Biology and Antibiotic Resistance Notes
Lab 4: Cell Phone Biology and Antibiotic Resistance
Lab Activities Overview
In Lab 4, students participate in the following activities:
Mid-semester TA evaluation: This evaluation allows students to provide anonymous feedback on the Teaching Assistant's performance, contributing to improvements in instructional methods. The evaluation process helps in acquiring skills to articulate constructive feedback that can enhance teaching effectiveness and the learning environment.
Creating a Standard Curve: Students will create a standard curve to determine the concentration of unknown solutions using a spectrophotometer. This process is vital in quantitative analysis and helps in understanding the principles behind spectrophotometric measurements.
Examination of Cell Phone Imprints: This activity involves examining the bacteria present on cell phones after contact with skin, transferred onto agar plates. The examination highlights the role of everyday objects in bacterial transmission and the importance of hygiene in preventing infections.
Antibiotic Resistant Bacteria on Swabbed Plates: Students will examine bacterial cultures for antibiotic resistance, discussed in detail later in the lab. This assessment fosters awareness of the implications of antibiotic resistance in modern medicine.
Mid Semester TA Evaluation
The TA evaluation can be accessed through eClass, where students will receive feedback that contributes to their development as instructors. Completing the evaluation provides students with a benefit for their final lab exam preparation, including access to exam questions that are reflective of the curriculum covered.
Spectrophotometers and Standard Curves
Objectives
Create a standard curve to determine unknown concentrations. It integrates principles of analytical chemistry and helps solidify experimental design skills.
Measure absorbance using a spectrophotometer, enabling students to relate the absorbance values to concentration through calibration.
Understand absorption spectrum and its implications in biological systems, fostering a deeper appreciation for how light interacts with biological materials.
Importance of Spectrophotometry
Spectrophotometers are crucial for measuring light absorption across various wavelengths, which is essential for determining the concentration of solutions in biological research. By analyzing absorbance data, researchers can infer the presence and quantity of substances in a given sample. Incumbent Skills: Students will develop critical laboratory skills, including pipetting, spectrophotometry training, and data interpretation, which will be integral for their future labs and research projects.
Usage of Spectrophotometers
Mechanism: A light source passes through a prism to spread light into varying wavelengths, and the absorbance is measured by comparing incident and transmitted light.
Transmittance (T): The percentage of light transmitted through the sample, measured directly by the device.
Absorbance (A): The negative log of transmittance, which correlates with the concentration of solute, following Beer's Law, A = -log(T).
Measurement: The spectrophotometer is calibrated for accuracy, reading absorbance specifically at wavelengths correlating with the maximum absorbance of chromophores in the sample. Calibration with standards is crucial to ensure reliable results.
Creating a Standard Curve
The standard curve graphically represents the relationship between absorbance and concentration. It is crafted from a series of dilutions made from a known stock solution, allowing unknown concentrations to be determined based on their absorbance readings. Steps include preparation of a dilution series, measuring absorbance at predetermined wavelengths, and plotting results to establish a trendline for future reference. The slope of the line obtained can be used to calculate unknown concentrations in experimental samples efficiently.
Observations of Bacterial Growth Patterns
Objectives
To understand microbial diversity on everyday devices, such as cell phones, and to analyze antibiotic resistance, enhancing awareness of public health issues linked to microbial contamination.
To implement aseptic techniques in microbiology, ensuring that students are well-versed in practices that prevent contamination in scientific research.
Human Microbiota and Contamination
Human skin is a complex ecosystem where diverse bacteria thrive, influenced by environmental factors such as humidity and temperature. The relationship of bacteria on surfaces (like phones) demonstrates potential contamination pathways for pathogens, highlighting the need for regular cleaning of personal devices to minimize disease transmission.
Aseptic Techniques
To minimize contamination during microbial work, best practices such as sterilization, the use of personal protective equipment (PPE), and adhering to proper lab conduct must be followed. This practice ensures that experiments yield valid results and protect the health of individuals in the lab. Understanding these techniques is essential for all microbiology research.
Understanding Antibiotic Resistance
Antibiotic Mechanisms
Antibiotics work by targeting critical bacterial functions, such as protein synthesis or cell wall formation. However, antibiotic resistance is an increasing concern due to both natural mutations and horizontal gene transfer, which allows resistant genes to spread among bacteria. The importance of understanding these mechanisms lies in preserving the effectiveness of existing antibiotics and stimulating the development of new therapeutic strategies.
Lab Method for Assessing Resistance
In the lab, swabbed bacteria are cultured with antibiotic-infused discs to observe zones of inhibition, indicating sensitivity or resistance to specific antibiotics. This practical method reinforces the real-world implications of antibiotic use and resistance, emphasizing the need for responsible antibiotic prescribing practices in healthcare.
Safety and Cleanup Protocols
Students must follow strict safety protocols, particularly while handling cultures and antibiotics, to prevent contamination and ensure personal safety. Proper disposal methods are critical, such as autoclaving contaminated materials before disposal to prevent the spread of antibiotic-resistant bacteria in the environment.
Conclusion and Further Implications
This lab emphasizes interactions between human health, microbial biology, and the significance of antibiotics in treatment. Students are encouraged to consider the implications of antibiotic resistance in healthcare and everyday interactions. By fostering a proactive approach toward microbial safety and health awareness, students can contribute positively to public health discussions and practices.
Lab Activities Overview
In Lab 4, students take part in several important activities:
Mid-semester TA evaluation: In this evaluation, students can give anonymous feedback about their Teaching Assistant’s performance. This feedback helps improve how teaching is done. Students also learn how to give constructive feedback, which can help make the learning atmosphere better.
Creating a Standard Curve: Students will learn how to create a standard curve. This curve helps them figure out the concentration of unknown solutions using a device called a spectrophotometer. This skill is very important in doing quantitative measurements and helps students grasp the basic principles behind spectrophotometric measurements.
Examination of Cell Phone Imprints: In this activity, students will look at the bacteria that are found on cell phones after they’ve touched our skin. They will transfer these bacteria onto agar plates to observe them. This exercise highlights how everyday items can transmit bacteria and shows the importance of keeping things clean to avoid infections.
Antibiotic Resistant Bacteria on Swabbed Plates: Students will study bacterial cultures to check for antibiotic resistance. This part of the lab is discussed in detail later and emphasizes how antibiotic resistance is an important issue in today’s medicine.
Mid Semester TA Evaluation
Students can access the TA evaluation through eClass. By completing this evaluation, they help their Teaching Assistants improve as instructors. Additionally, students benefit from this evaluation since it aids in preparing for the final lab exam, including gaining access to exam questions that reflect the material they have learned in class.
Spectrophotometers and Standard Curves
Objectives
Create a standard curve: This helps in finding out unknown concentrations, linking to key ideas in analytical chemistry and enhancing experimental design skills.
Measure absorbance: Using a spectrophotometer allows students to connect the absorbance values to concentration through a method of calibration.
Understand absorption spectrum: Learning about how light absorption works and its effects on biological systems helps students appreciate how light interacts with living materials.
Importance of Spectrophotometry
Spectrophotometers are vital tools for measuring how much light is absorbed at different wavelengths. This measurement helps determine the concentration of solutions in biological research. By evaluating absorbance data, scientists can figure out what and how much of substances are present in a sample. Skills Developed: Students will learn important lab skills such as pipetting, using a spectrophotometer, and interpreting results, which will be essential in their future experiments and research.
Usage of Spectrophotometers
Mechanism: A light source sends light through a prism to spread it into different wavelengths, while the device measures how much light makes it through the sample versus how much is blocked.
Transmittance (T): This is the percentage of light that goes through the sample, which the device measures directly.
Absorbance (A): This is calculated as the negative logarithm of transmittance, which relates to the concentration of the substance being measured, following Beer's Law: A = -log(T).
Measurement: The spectrophotometer has to be calibrated to ensure it gives accurate readings when measuring absorbance at specific wavelengths that correspond to the maximum absorbance of the substances in the sample. Calibration with known standards is very crucial for reliable results.
Creating a Standard Curve
A standard curve is a visual graph that shows the link between absorbance and concentration. It is made from a series of dilutions using a known stock solution. By measuring the absorbance of these dilutions, students can plot the results to create a trendline that helps in determining the concentrations of unknown samples. The slope of the trendline allows students to efficiently calculate the concentrations in experimental samples.
Observations of Bacterial Growth Patterns
Objectives
To comprehend the diversity of microbes on common items like cell phones and look into antibiotic resistance. This enhances awareness of public health issues associated with bacterial contamination.
To learn and use aseptic techniques in microbiology, ensuring students are skilled in methods that keep experiments free from contamination.
Human Microbiota and Contamination
The human skin is a complex ecosystem where various bacteria live, influenced by factors such as humidity and temperature. The bacteria found on surfaces like cell phones can lead to contamination risks and diseases. This highlights the importance of regularly cleaning personal devices to help reduce the chance of spreading infections.
Aseptic Techniques
To avoid contamination during microbiological work, students should follow best practices, such as sterilizing equipment, using personal protective equipment (PPE), and maintaining proper laboratory conduct. These methods ensure that the experiments provide reliable results and help protect everyone's health in the lab. Understanding these practices is vital for all microbiology studies.
Understanding Antibiotic Resistance
Antibiotic Mechanisms
Antibiotics function by targeting key processes in bacteria, such as producing proteins or forming cell walls. However, antibiotic resistance is a growing concern, primarily due to natural mutations and the ability of bacteria to share resistance genes. It is crucial to grasp these mechanisms to help maintain the effectiveness of current antibiotics and to motivate the creation of new treatment strategies.
Lab Method for Assessing Resistance
In the lab, students will culture swabbed bacteria with antibiotic disks to observe zones of inhibition, which show areas where bacteria are sensitive or resistant to specific antibiotics. This hands-on experience highlights the real-world consequences of antibiotic use and the challenges of resistance, stressing the importance of responsible antibiotic prescribing in healthcare.
Safety and Cleanup Protocols
Students must adhere to strict safety rules, especially when handling bacterial cultures and antibiotics, to prevent contamination and keep themselves safe. Proper disposal of materials, such as autoclaving contaminated items before disposal, is crucial for preventing the spread of antibiotic-resistant bacteria in the environment.
Conclusion and Further Implications
This lab focuses on the relationships between human health, the biology of microbes, and the crucial role of antibiotics in treatment. Students are encouraged to think about what antibiotic resistance means in healthcare and daily life. By promoting safe microbial practices and health awareness, students can positively influence public health discussions and actions.