Use of apparatus and techniques Flashcards
What apparatus is used to measure mass, time, volume, temperature, length, and pH in a biology practical?
Mass: Balance (e.g., electronic balance)
Time: Stopwatch
Volume: Measuring cylinder, pipette, burette
Temperature: Thermometer, digital temperature probe
Length: Ruler, vernier calipers, micrometer
pH: pH meter or pH probe
How do you calibrate a pH meter before use?
Rinse the electrode with distilled water.
Immerse it in a buffer solution of known pH (e.g., pH 7).
Adjust the meter to the correct reading.
Repeat with a second buffer solution (e.g., pH 4 or pH 10) for accuracy.
What instruments might you use to record quantitative measurements such as absorbance or transpiration rates?
Colorimeter: To measure absorbance or transmission of light in solutions.
Potometer: To measure water uptake in plants as a proxy for transpiration rates.
Describe how to set up a potometer.
Cut a plant shoot underwater to prevent air entering the xylem.
Assemble the potometer underwater to ensure it’s air-tight and water-filled.
Seal joints with petroleum jelly.
Introduce an air bubble and measure the distance it moves to calculate water uptake.
What is the purpose of serial dilutions, and which apparatus is typically used?
Purpose: To create a series of solutions with decreasing concentrations for experiments (e.g., enzyme activity).
Apparatus: Beakers, pipettes, test tubes, distilled water.
How do you focus a light microscope at high power?
Start with the lowest objective lens and focus using the coarse adjustment knob.
Switch to a higher objective lens.
Use the fine adjustment knob for precise focusing.
How do you use an eyepiece graticule and stage micrometer to measure cells under a microscope?
Calibrate the graticule using the stage micrometer at a specific magnification.
Measure the sample using the graticule units.
Convert the measurement using the calibration factor.
What are key features of a scientific drawing in biology?
Use a sharp pencil for clear lines.
Do not shade; use stippling for darker areas.
Include labels with straight lines.
Add annotations for key structures.
Indicate the magnification.
Name qualitative reagents used to test for biological molecules.
Reducing sugars: Benedict’s solution (heat required).
Non-reducing sugars: Benedict’s after acid hydrolysis.
Starch: Iodine solution.
Proteins: Biuret reagent.
Lipids: Ethanol and water (emulsion test).
What is the principle of chromatography, and how is it performed?
Apply a small sample to the baseline of chromatography paper.
Place the paper in a solvent, ensuring the sample doesn’t touch the solvent directly.
Allow the solvent to move up the paper, separating compounds by solubility.
Mark the solvent front and calculate
Rf values.
What precautions should you take when using agar plates in microbiology?
Sterilize all equipment (e.g., by autoclaving).
Work near a Bunsen burner to maintain sterility.
Use aseptic techniques (e.g., flaming tools before use).
Seal agar plates but allow air exchange to prevent anaerobic growth.
Dispose of cultures safely.
How do you safely dissect an animal organ?
Wear gloves and use disinfected tools.
Secure the organ with pins if necessary.
Cut carefully with a scalpel or scissors, avoiding injury.
Observe ethical guidelines and dispose of biological waste properly.
What sampling techniques are used in fieldwork?
Random sampling: Use a quadrat and random coordinates.
Systematic sampling: Use a transect line for studying changes across a gradient.
What ICT tools can be used in biological experiments?
Computer modeling: Simulate biological processes.
Data loggers: Collect environmental data (e.g., temperature, light).
Software: Process and analyze data (e.g., Excel, SPSS).
