1010 Unit 2 - Techniques, Measurements, and Microscopes
61 Questions
4 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What does a higher concentration of a colored solution result in regarding light transmission?

  • More light passes through the solution
  • Transmittance remains constant
  • Less light passes through the solution (correct)
  • Absorbance decreases

    • According to Beer’s Law, how is absorbance related to concentration?

  • Absorbance is independent of concentration
  • Absorbance is directly proportional to concentration (correct)
  • Absorbance is inversely proportional to concentration
  • Absorbance varies randomly with concentration

    • Which part of the spectrophotometer is responsible for detecting transmitted light?

  • Galvanometer
  • Light Source
  • Photo-Detector (correct)
  • Cuvette

    • In constructing a standard curve, where is absorbance plotted?

    <p>Y-axis (vertical)</p> Signup and view all the answers

    What happens to % transmittance as concentration increases?

    <p>It decreases</p> Signup and view all the answers

    Which element in a spectrophotometer is used to isolate a specific wavelength of light?

    <p>Monochromator</p> Signup and view all the answers

    What criteria defines a good standard curve?

    <p>The line is straight</p> Signup and view all the answers

    What is the role of the galvanometer in a spectrophotometer?

    <p>To measure and record electrical current</p> Signup and view all the answers

    What does the Y-axis represent in a hemoglobin standard curve?

    <p>Absorbance</p> Signup and view all the answers

    What is a criterion for a good standard curve?

    <p>The line connects all data points</p> Signup and view all the answers

    What is the calculated protein concentration for a patient with an absorbance of 0.3 on the standard curve?

    <p>1.5 mg</p> Signup and view all the answers

    Which point represents a blank sample in the hemoglobin standard curve?

    <p>0 absorbance</p> Signup and view all the answers

    What is the intercept of the standard curve on the axes?

    <p>It connects at the origin.</p> Signup and view all the answers

    What is the primary function of a spectrophotometer?

    <p>To determine the concentration of colored solutions</p> Signup and view all the answers

    Which of the following best describes Beer’s Law?

    <p>The relationship between absorbance and concentration of a solution</p> Signup and view all the answers

    What is the role of the monochromator in a spectrophotometer?

    <p>To filter a specific wavelength of light</p> Signup and view all the answers

    What should be avoided when caring for cuvettes?

    <p>Using abrasive materials for cleaning</p> Signup and view all the answers

    Which component of the spectrophotometer would detect light after it passes through a sample?

    <p>Photoelectric cell</p> Signup and view all the answers

    If a sample has a higher absorbance, what can be inferred about its concentration?

    <p>The concentration is higher</p> Signup and view all the answers

    What does a standard curve help with in spectrophotometry?

    <p>Reporting results based on concentration</p> Signup and view all the answers

    Which technique measures the wavelengths of light?

    <p>Spectrophotometry</p> Signup and view all the answers

    Which system of measurement is based on the decimal system (meaning a base-ten system) and is traditionally used in clinical laboratories?

    <p>Metric System</p> Signup and view all the answers

    What is the correct SI unit for measuring mass?

    <p>Kilogram</p> Signup and view all the answers

    Which of the following prefixes represents a factor of $10^{-6}$ in the SI system?

    <p>Micro-</p> Signup and view all the answers

    When converting Fahrenheit to Celsius, what is the first step in the formula?

    <p>(F°-32)</p> Signup and view all the answers

    Which of the following is a non-SI unit commonly used in clinical laboratories to measure volume? Select all that apply.

    <p>Liter</p> Signup and view all the answers

    What temperature scale is primarily used for recording temperatures in clinical laboratories?

    <p>Celsius</p> Signup and view all the answers

    Which of the following measures enzyme activity in a laboratory setting?

    <p>International units (IU)</p> Signup and view all the answers

    What is the primary purpose of reporting lab results in SI units?

    <p>To ensure consistency in mass concentration</p> Signup and view all the answers

    What is the total magnification achieved with a 10x ocular and a 40x objective?

    <p>400x</p> Signup and view all the answers

    Which adjustment control should be used for achieving fine focus at higher magnifications (40x and 100x)?

    <p>Fine adjustment</p> Signup and view all the answers

    Which of the following represents a common function of the body tube in a microscope?

    <p>Directs light to the ocular</p> Signup and view all the answers

    What is the primary reason for using specific cleaning supplies for the microscope?

    <p>To prevent damage to optics</p> Signup and view all the answers

    Which type of objective is used primarily for oil immersion to achieve the highest magnification?

    <p>100x objective</p> Signup and view all the answers

    What is the impact of failing to use fine adjustments on a 100x objective lens?

    <p>Possible damage to the slide</p> Signup and view all the answers

    Which component is responsible for primary image formation in a microscope?

    <p>Objectives</p> Signup and view all the answers

    What should be avoided when cleaning the lenses of a microscope?

    <p>Using paper towels</p> Signup and view all the answers

    What is the first step to take when cleaning a microscope?

    <p>Wash hands</p> Signup and view all the answers

    What should be used to avoid fingerprints when replacing the microscope bulb?

    <p>A tissue</p> Signup and view all the answers

    When setting Koehler illumination, what is adjusted to achieve the optimal focus?

    <p>The condenser</p> Signup and view all the answers

    What should you avoid doing after the Koehler illumination is set?

    <p>Changing the condenser position</p> Signup and view all the answers

    What is the purpose of racking up the stage to its highest position during the Koehler illumination setup?

    <p>To center the specimen under the objective</p> Signup and view all the answers

    What is the result of excessive rubbing while cleaning optical surfaces?

    <p>Scratches on the surface</p> Signup and view all the answers

    What should be done immediately after unplugging the microscope before replacing the bulb?

    <p>Allow the bulb to cool</p> Signup and view all the answers

    What is an important consideration when removing objectives from the microscope?

    <p>Excessive force can damage them</p> Signup and view all the answers

    Which part of the brightfield microscope system is responsible for directing and focusing the beam of light onto the material being examined?

    <p>Condenser</p> Signup and view all the answers

    What component is primarily used to control the amount of light passing through the material in a brightfield microscope?

    <p>Aperture Iris Diaphragm</p> Signup and view all the answers

    Which of the following systems makes up the brightfield microscope?

    <p>Illumination, Magnification, and Focusing</p> Signup and view all the answers

    What is the primary function of the ocular lens in a microscope?

    <p>To magnify the image formed by the objective</p> Signup and view all the answers

    In fluorescence microscopy, what technical advancements have increased its usage in biomedical analysis?

    <p>Fluorochrome stains and monoclonal antibody techniques</p> Signup and view all the answers

    What role does the field diaphragm play in microscopy?

    <p>It determines the area of the circle of light in the field of view</p> Signup and view all the answers

    Which component is involved in controlling the light intensity in a microscope?

    <p>Rheostat</p> Signup and view all the answers

    What is the main focus of using a compound microscope in clinical laboratories?

    <p>To examine minute objects such as bacteria and cells</p> Signup and view all the answers

    What is the purpose of adjusting the oculars for interpupillary distance when using a microscope?

    <p>To achieve a single circle of light</p> Signup and view all the answers

    What should be done first when troubleshooting a microscope that shows a black field?

    <p>Ensure the microscope is plugged in</p> Signup and view all the answers

    When adjusting for the 40X objective after initially focusing at 10X, which action is necessary regarding the light?

    <p>Keep the light intensity unchanged</p> Signup and view all the answers

    What is a possible reason for a microscope showing only partial illumination of the field?

    <p>Objective not clicked into position</p> Signup and view all the answers

    What should be checked if a microscope image is blurry at both 10X and 40X magnifications?

    <p>Clean the objective lens</p> Signup and view all the answers

    When should the fine adjustment knob be used during microscopy?

    <p>After achieving focus at 10X</p> Signup and view all the answers

    If a microscope slide field appears to have a ground glass appearance, what is a likely cause?

    <p>Condenser positioned too high</p> Signup and view all the answers

    What is a common troubleshooting step if it is difficult to focus with the 40X objective?

    <p>Ensure the correct plane of focus is engaged</p> Signup and view all the answers

    Study Notes

    Chapter 7: Basic and Contemporary Techniques in the Clinical Laboratory

    • PowerPoints are general overviews of video lectures, only.
    • PowerPoints do not include details for unit exams.
    • Students are responsible for reading the textbook to answer unit objectives.
    • Unit objectives are the study guide, not the PowerPoint.
    • Test questions are based on unit objectives found in the textbook, not the PowerPoint.

    Chapter 8 Objectives

    • Describe absorbance spectrophotometry's principles and components.
    • Define Beer's Law.
    • Compare visible spectrum colors to wavelengths.
    • Describe proper cuvette care.
    • Prepare a standard curve using concentration and optical density readings.
    • Demonstrate spectrophotometer use and standard curve preparation.
    • Define key terms: meniscus, absorbance, %T, reagent, standard, blank, photoelectric cell, monochromator, diffraction grating, galvanometer.

    Measurement Techniques

    • Most measurement techniques fall into four categories: Spectrometry, Luminescence, Electroanalytical methods, and Chromatography.
    • Spectrometry is the focus of this course.
    • Other categories are covered in Immunology.

    Absorbance Spectrophotometry

    • Light is radiant energy that travels in waves; wavelength is the distance between waves
    • Light visible to the human eye includes wavelengths bordering those

    Spectrophotometer

    • Instrument that determines the concentration of colored solutions.
    • Works by passing a light beam through the solution.

    Spectrophotometer Principle

    • The instrument passes a beam of light through a sample, measuring light intensity reaching the detector.

    Observed Colors of the Visible Spectrum

    • Table shows approximate wavelengths (nm) and corresponding colors.

    Spectrophotometer

    • %Transmission (%T) is the portion of light passing through a colored solution.
    • Absorbance is the light not passing through the solution.
    • Concentrated solutions transmit less light than dilute ones.
    • For most colored solutions, increased concentration results in increased absorbance. (Linear relationship)

    Spectrophotometer (continued)

    • Beer's Law states the absorbance of a colored substance is directly proportional to its concentration.

    Spectrophotometer and Standard Curves

    • Standard curves graph absorbance versus known solution concentrations
    • Use linear graph paper to plot these concentrations on the y-axis and absorbance on the x-axis
    • Standard curves help determine the concentration of unknown samples using Beer's Law.
    • Known concentrations are used to create the curves to which unknowns are compared.

    Standard Curve (Preparation and Use)

    • Criteria for a good standard curve:
      • Straight line
      • All plotted points fall on or near the line.
      • Line intersects origin or an appropriate point

    Postamble

    • Use the textbook and unit objectives as a study guide.
    • Textbook material is the basis for test questions, not the PowerPoint.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    U2 Ch7 - Basic and Contemporary Techniques in Clinical Laboratory PDF
    Chapter 5 Systems of Measurement, Laboratory Equipment, and Reagents PDF
    Microscopes PDF - Chapter 4

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser