microscopes

• Light/Optical Microscopes have poor resolution due to the wavelength of light and can use living samples, resulting in a color image.
• Transmission Electron Microscopes have higher magnification and resolution, but electrons must pass through the specimen to create the image.
• Scanning Electron Microscopes use electrons to bounce off the surface to create a 3D image.
• Laser Scanning Confocal Microscopes have high resolution and 3D, and use laser light to create the image.
• Resolution is the minimum distance between two objects that can still be viewed as separate.
• Light microscope resolution is determined by the wavelength of light.
• Electron microscope resolution is determined by the wavelength of electron.
• Magnification refers to how many times larger the image is compared to the actual object.
• Slide preparation includes four types: dry mount, wet mount, squash slide, and smear slide.
• Dry mounts involve thin slices or whole organisms placed on a slide with a cover slip.
• Wet mounts involve specimens added to water or stain before a cover slip is lowered on top.
• Squash mounts are wet mounts with a cover slip pushed down to create a thin layer of cells.
• Smear mounts involve samples smeared across a slide with a cover slip on top.
• Eyepiece graticule is a scale inserted in the eyepiece of a microscope used to measure the size of an object being viewed.
• Different lenses cause different magnifications.
• Calibration is done with a stage micrometer, a glass slide with a ruler.
• Staining is used to make some cell components easier to see under a microscope without stain.
• Differential staining involves using different chemical stains to stain different parts of a cell different colors.
• Crystal violet and methylene blue are positively charged stains.
• Nigrasin and Congo red are negatively charged stains that create a stained background.
• Gram staining differentiates gram-positive and gram-negative bacteria.
• Crystal violet is added, then iodine to fix the stain, then alcohol to wash any unstained parts.
• Gram-positive bacteria appear blue or purple due to their thick peptoglycan cell wall.
• Gram-negative bacteria cannot absorb Crystal Violet stain due to their thin peptoglycan wall, so a saffronin counter stain is used to turn them red.
• Differential staining is important in determining which antibiotic to use for bacterial infection.
• Scientific drawings are different from artistic drawings as they have a complete set of rules and are used to show the size, location, proportion, and labeling of structures.
• Pencil should be used and the lines should be solid without any gaps or overlaps.
• No coloring or shading should be added.
• Electron microscopes have a higher resolution than light microscopes and can use living samples, but they cannot be used with wet mounts.
• Transmission Electron Microscopes (TEMs) and Scanning Electron Microscopes (SEMs) are two types of electron microscopes.
• Laser Scanning Confocal Microscope is a type of fluorescent microscope that uses high light intensity to illuminate the specimen and combines the benefits of high resolution Optical Imaging with depth selectivity.