Learning Outcomes
i. Define graticule, micrometer, and micrometry.
ii. Explain how to use a graticule and micrometer to measure microscopic structures.
iii. Describe the units used in micrometry.
i. Graticule: A graticule is a grid of lines that is etched into the eyepiece of a microscope. It is used to estimate the size of microscopic structures. The graticule is calibrated at a specific magnification, so it is important to know the magnification of the microscope when using the graticule to measure.
ii. Micrometer: A micrometer is a slide with a ruled scale that is used to calibrate the graticule and to measure microscopic structures directly. The micrometer is placed on the stage of the microscope and viewed through the eyepiece. The graticule is then aligned with the micrometer scale. The size of a microscopic structure can be measured by counting the number of graticule divisions that correspond to a known distance on the micrometer scale.
iii. Micrometry: Micrometry is the process of measuring microscopic structures using a microscope and a graticule or micrometer. Micrometry is used in a wide range of cell biology research and clinical applications.
iv. Units used in micrometry
The most common units used in micrometry are:
Micrometer (µm): A micrometer is one millionth of a meter.
Nanometer (nm): A nanometer is one billionth of a meter.
Ångström (Å): An ångström is one ten billionth of a meter.
How to use a graticule and micrometer to measure microscopic structures
To measure a microscopic structure using a graticule and micrometer, follow these steps:
i. Calibrate the graticule using the micrometer.
ii. Place the microscopic structure on the stage of the microscope.
iii. View the microscopic structure through the eyepiece.
iv. Align the graticule with the microscopic structure.
v. Count the number of graticule divisions that correspond to the microscopic structure.
vi. Use the calibration factor to convert the number of graticule divisions to the actual size of the microscopic structure.
Examples of how graticule and micrometer are used in cell biology
Here are some examples of how graticule and micrometer are used in cell biology research:
Measuring the size of cells and organelles: Graticule and micrometer can be used to measure the size of cells and organelles, such as the nucleus, mitochondria, and ribosomes. This information can be used to study cell growth and differentiation.
Measuring the distance between two structures: Graticule and micrometer can be used to measure the distance between two structures, such as the distance between two chromosomes during mitosis or the distance between two synapses in a neuron. This information can be used to study cell structure and function.
Measuring the rate of movement: Graticule and micrometer can be used to measure the rate of movement of microscopic objects, such as bacteria or microtubules. This information can be used to study cell dynamics.
Graticule, micrometer, and micrometry are essential tools for measuring microscopic structures in cell biology research. By understanding how to use these tools, students can gain a deeper understanding of cell structure and function.
