Types of Microscopes Quiz

Types of Microscopes

• Microscopes are tools used to view tiny biological objects invisible to the naked eye.
• Different types of microscopes are available, each with unique features and applications.
• Light microscopes use light to illuminate and magnify specimens.
  • Compound light microscopes use multiple lenses to magnify specimens.
  • Binocular Dissecting microscopes (stereomicroscopes) provide a three-dimensional view of specimens.
  • Phase contrast microscopes enhance contrast between different parts of a specimen.
• Fluorescent microscopes use fluorescent dyes to illuminate and visualize specific structures within a specimen.
  • Confocal microscopes are a type of fluorescent microscope that uses lasers to scan and create images of very thin slices of a specimen.
• Electron microscopes use electrons to illuminate and magnify specimens.
  • Transmission electron microscopes (TEMs) create images of the internal structures of a specimen.
  • Scanning electron microscopes (SEMs) create images of the surface of a specimen.

Compound Light Microscope

• Compound light microscopes are the most common type used in biological research and education.
• They use two sets of lenses: objective lens and eyepiece lens.
• Light from a lamp is focused on the specimen by a condenser lens.
• The specimen is placed on a glass slide with a coverslip on top.
• The objective lens magnifies the specimen, and the eyepiece lens further magnifies the image.
• The total magnification is calculated by multiplying the magnification of the objective lens by the magnification of the eyepiece lens.
• Resolution is the ability to distinguish between two points that are close together.
• Compound light microscopes typically have a resolution of about 0.2 micrometers.

Learning Outcomes

• Define molecular biology methods and techniques.
• Explain DNA cloning techniques.
• Describe DNA and plasmid extraction.
• Describe the CRISPR-Cas9 system.
• Describe DNA synthesis and DNA microarray.
• Explain the different types of DNA mutation.

Molecular Biology Methods

• Used to study the molecular basis of biological activity.
• Goal to isolate and analyze cellular components, exploring cells, their characteristics, and processes.
• Commonly used methods include:
  • Nucleic acid methods
  • Protein methods
  • Immunostaining methods

Standard Practices in the Laboratory

• Gloves: Protect from contamination and chemicals, don't touch common surfaces outside of lab, use ungloved hand for common surfaces when leaving lab.
• Mouth: Don't put anything in mouth (food, drinks, chewing gum), don't pipette by mouth, avoid dangerous substance intake.
• Makeup: Don't apply makeup or adjust contact lenses.
• Benchtop: Keep clean, have only necessary lab materials, leave active experiments unattended.
• Disinfect: Benchtop before and after experiments to prevent contamination.
• Clean hands: Keep hands clean before and after lab experiments.
• Safety: Don't run in the lab, don't sit on laboratory benches.
• Unauthorized Experiments: Strictly forbidden, never work without supervision.
• Long Hair/Loose Clothing: Tie back long hair and secure loose clothing when working with open flames.
• Eye Protection: Goggles, safety glasses or face shields required when working with UV light and any procedure that could cause splashes.
• Footwear: Closed toed shoes required to protect from chemical spills and sharp objects.
• Safety Equipment: Know the location of safety equipment like eyewash, chemical shower, first aid kit, and fire extinguisher.

Laboratory Safety Equipment

• Chemical hygiene plans ensure lab worker safety from chemical hazards.
• Fume hoods or biosafety cabinets should be used as directed.

Lab Emergencies

• Notify instructor immediately for any spills, accidents, or injuries (chemical/biological spills, personal injuries, broken glass, equipment).

Biohazard Bin

• Properly labeled bins or bags for biohazardous waste (non-reusable items contaminated with infectious agents, body fluids, animal tissue).

Fluorescent Proteins and Stains

• Red Fluorescent Protein (RFP)
• Green Fluorescent Protein (GFP)
• DAPI (4′,6-diamidino-2-phenylindole): Fluorescent stain that binds to adenine-thymine rich regions in DNA.

Confocal Microscopes

• Laser Scanning Confocal Microscopes (LSCM):
  • Optical sections are produced by scanning the specimen point by point with a focused laser beam.
  • Pinhole removes fluorescence from above and below the focal plane.
  • Imaging structures at discrete levels within an intact biological specimen.

Electron Microscope

• Uses a beam of electrons magnified and focused by electron magnetics.
• Views smaller objects compared to light microscopes with greater detail.
• Transmission Electron Microscope (TEM): Analogous to compound light microscope.
• Scanning Electron Microscope (SEM): Analogous to dissecting light microscope.
• Specimen preparation is extensive, potentially introducing artifacts.

Microscope Use

• Keep both eyes open when using the microscope.
• Never touch the eyepiece with your eyelashes.
• Lowest power objective should be in position at the beginning and end of use.
• Don't clean lenses with regular paper tissue.
• Don't tilt the microscope when viewing.
• Don't remove parts of the microscope.
• Locate small objects first with the naked eye or under low power.
• Always begin focusing with the scanning power objective (4x).

Focusing the Microscope

• Lower stage with coarse adjustment knob. Place slide on stage and secure with clip.
• While looking through eyepiece, slowly raise the stage until the object comes into view.
• Fine adjustment knob sharpens focus if needed.

Laboratory Safety

• Laboratories present various hazards, including corrosive chemicals, sharp objects, and open flames.
• Microorganisms are categorized into four biosafety levels (BSL) based on their transmissibility and pathogenicity.
• BSL-1 organisms, commonly used in undergraduate labs, are generally not harmful to healthy individuals.
• BSL-4 organisms, requiring specialized labs, include highly dangerous pathogens like Marburg and hantaviruses.
• Lab coats are crucial for protecting against contamination.
• Always wear gloves to safeguard hands from chemicals and microorganisms, but avoid touching surfaces outside the lab with them.
• Never consume food, drink, or chew gum in the lab.
• Avoid applying makeup or adjusting contact lenses within the laboratory.
• Always keep the lab bench clean and organized, removing personal belongings (e.g., cell phones, bags).
• Never leave experiments unattended, especially those involving heat or reactions.
• Disinfect the lab bench before and after each experiment.
• Maintain hand hygiene before, after, and whenever contacting potential hazards.
• Never run in the laboratory.
• Do not sit on lab benches.
• Unauthorized experiments are strictly prohibited.
• Always work under supervision.
• Tie back long hair and secure loose clothing, especially when working with open flames.
• Wear goggles or face shields when using UV light or during procedures that generate aerosols or splashes.
• Wear closed-toe shoes to protect against chemical spills and sharp objects.
• Familiarize yourself with the location of safety equipment (eyewash station, chemical shower, first aid kit, fire extinguisher).
• Utilize fume hoods or biosafety cabinets as instructed.
• Report any spills, accidents, or injuries immediately to the instructor.
• Dispose of biohazardous waste (non-reusable items, animal tissue) in properly labeled bins or bags.
• Use sharps containers for broken glass, needles, scalpel blades, and other sharp objects.
• Place non-contaminated waste paper or trash in regular trash cans.
• Sterilize reusable materials in an autoclave before discarding, while non-sterile materials can be washed in the sink.
• Always keep chemical containers tightly closed to prevent vapor escape.
• Never use unmarked or unidentified reagents; consult your instructor if uncertain.
• Use appropriate carrying methods for chemicals, avoiding contact with your body.
• Always face chemical bottle labels upward when pouring to prevent damage.
• Never add chemicals to bottles other than their intended contents.
• Dilute acids by slowly pouring acid into water, stirring continuously.
• Properly dispose of chemicals according to institutional guidelines.
• Wash hands thoroughly before and after each experiment.
• Removing jewelry is important for proper handwashing.
• Apply soap and lather for at least 20 seconds, rubbing hands together thoroughly.
• Rinse hands thoroughly under running water.
• Dry hands with a clean towel or air dryer.
• The SI (International System of Units) is the standard system of measurement used by scientists.
• The SI system prefixes are based on the number 10, simplifying calculations.
• All measurements require a number and a unit.

Explore the various types of microscopes used in biology through this quiz. Test your knowledge on light, fluorescent, and electron microscopes along with their unique applications and features. Perfect for students and enthusiasts in the field of microscopy.