Atomic Force Microscopy and Amino Acids Quiz
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Questions and Answers

What is the primary application of Atomic Force Microscopy (AFM)?

  • Studying large structures with low resolution
  • Analyzing chemical compositions
  • Examining details of specimens at an atomic level (correct)
  • Measuring large surfaces

    • Atomic Force Microscopy is capable of achieving resolution better than optical diffraction limits.

    True (A)

    What are the two modes of operation for AFM?

    Tapping mode and Scanning mode

    AFM detects the smallest of vibrations and must be operated away from __________.

    <p>urban areas</p> Signup and view all the answers

    Match the following components of Atomic Force Microscopy with their functions:

    <p>Silicon cantilever = Scans the surface of the specimen Laser beam = Reflects light to the photodiode Photodiode = Detects reflections from the cantilever Piezo crystal = Vibrates the holding stage of the cantilever</p> Signup and view all the answers

    Which of the following amino acids is capable of forming disulfide bonds?

    <p>Cysteine (B)</p> Signup and view all the answers

    Proline is an essential amino acid.

    <p>False (B)</p> Signup and view all the answers

    What is the primary role of non-polar amino acids in proteins?

    <p>They help to determine the 3-D structure and location of the protein.</p> Signup and view all the answers

    The amino acid __________ has a secondary amine structure due to its unique ring formation.

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

    Match the following amino acids with their characteristics:

    <p>Cysteine = Forms disulfide bonds Serine = Possesses a hydroxyl group Proline = Contains an imino group Alanine = Aliphatic non-polar side chain</p> Signup and view all the answers

    Which of the following amino acids has a net charge of zero at neutral pH?

    <p>Glutamine (D)</p> Signup and view all the answers

    The hydroxyl group in polar amino acids can only form hydrogen bonds with water.

    <p>False (B)</p> Signup and view all the answers

    What is unique about the side chain of Cysteine?

    <p>It contains a terminal thiol group.</p> Signup and view all the answers

    What does the FISH technique primarily detect?

    <p>Specific DNA sequences on chromosomes (C)</p> Signup and view all the answers

    FISH can be used to detect and localise specific RNA targets.

    <p>True (A)</p> Signup and view all the answers

    What is the role of DNA Polymerase I in Nick Translation?

    <p>To replace some nucleotides of a DNA sequence with labelled analogues</p> Signup and view all the answers

    The technique used to prepare a small probe for FISH is called _____ translation.

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

    Match the following components of FISH with their functions:

    <p>Fluorescent probes = Bind to specific DNA sequences Avidin = Bind to biotin Denaturation = Prepare chromatin for probing Fluorescence microscopy = Visualize bound probes</p> Signup and view all the answers

    What happens to the cell membrane during necrosis as described in the content?

    <p>It is compromised (A)</p> Signup and view all the answers

    In the early stages of apoptosis, the membrane remains intact and no PI staining occurs.

    <p>True (A)</p> Signup and view all the answers

    What temperature is mentioned for the denaturation of chromatin in the FISH process?

    <p>42 degrees Celsius</p> Signup and view all the answers

    What is a key advantage of electron diffraction over X-ray crystallography?

    <p>Fourier transform reconstruction occurs physically. (A)</p> Signup and view all the answers

    TEM requires specimens to be thicker than 100 nanometers.

    <p>False (B)</p> Signup and view all the answers

    What process is used to stabilize biological specimens for TEM?

    <p>Chemical fixation, dehydration, and embedding in polymer resin.</p> Signup and view all the answers

    Cryoelectronic microscopy involves rapidly freezing specimens to form ______ ice.

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

    What is one disadvantage of using TEM?

    <p>Specimens need to be very thin. (D)</p> Signup and view all the answers

    Match the following microscopy techniques with their characteristics:

    <p>TEM = Requires ultrathin sections for imaging STEM = Uses beam rastering for imaging Cryoelectronic Microscopy = Views samples in hydrated state without fixation Electron Diffraction = Avoids phase problem in imaging</p> Signup and view all the answers

    STEM acquires image data in parallel fashion.

    <p>False (B)</p> Signup and view all the answers

    What is the purpose of using heavy metal ion stains in biological specimen preparation?

    <p>To achieve the required contrast image.</p> Signup and view all the answers

    What is the primary purpose of centrifugation in fractionation?

    <p>To separate components based on size (B)</p> Signup and view all the answers

    A swinging bucket rotor allows for easier withdrawal of supernatant without disturbing the pellet than a fixed angle rotor.

    <p>True (A)</p> Signup and view all the answers

    What type of centrifuge separates components at high rotation speeds up to 80,000 rpms?

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

    During velocity sedimentation, components move through the salt solution in a series of distinct _____ based on their rates.

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

    Match the following centrifuge types with their properties:

    <p>Fixed angle = Short distance to travel before pelleting Swinging bucket = Allows better separation in density gradient centrifugation Ultracentrifuge = High rotation speeds up to 80,000 rpms Density gradient = Prevents convective mixing</p> Signup and view all the answers

    What is the function of the vacuum in an ultracentrifuge?

    <p>To reduce friction and prevent rotor heating (A)</p> Signup and view all the answers

    Re-suspending the pellet and repeating centrifugation can help remove contaminants.

    <p>True (A)</p> Signup and view all the answers

    What is the purpose of adding a gradient of sucrose in the centrifuge tube?

    <p>To prevent convective mixing and distort separation.</p> Signup and view all the answers

    What does the 'pulse' in Pulse Chase Autoradiography refer to?

    <p>Addition of a measured dose of a radioactive tracer (D)</p> Signup and view all the answers

    Tritiated thymidine can be incorporated into both DNA and RNA.

    <p>False (B)</p> Signup and view all the answers

    What is the purpose of the chase phase in Pulse Chase Autoradiography?

    <p>To push the pulse using unlabelled chase compound</p> Signup and view all the answers

    In Pulse Chase Autoradiography, _____ is a commonly used radioactive label.

    <p>3H Thymidine</p> Signup and view all the answers

    Which of the following isotopes is NOT commonly used in Pulse Chase Autoradiography?

    <p>40K (A)</p> Signup and view all the answers

    Match the following isotopes with their primary use in autoradiography:

    <p>3H = Incorporation into DNA 14C = Metabolite tracing 32P = Nucleic acid labeling 35S = Protein labeling</p> Signup and view all the answers

    Photographs taken during the pulse chase can show the movement of chemical compounds.

    <p>True (A)</p> Signup and view all the answers

    What material is used to cover the labelled tissue on a glass slide in autoradiography?

    <p>Glycerine and AgBr photographic emulsion</p> Signup and view all the answers

    Study Notes

    Prokaryotic Cells

    • Prokaryotic cells lack a defined nucleus but have a region containing genetic material.
    • Two major groups: Eubacteria and Archaea.
    • Archaea are extremophiles adapted to extreme environments.
    • Prokaryotic cells possess a cell wall and plasma membrane but do not have mitochondria or other membrane-bound organelles.

    Endosymbiotic Theory

    • The endosymbiotic theory proposes that prokaryotic cells clustered together to form eukaryotic cells.

    Eukaryotic Cells

    • Eukaryotic cells have a true nucleus, where genetic material is enclosed within a circular structure (the nucleus) surrounded by a nuclear envelope (membrane).
    • Eukaryotic cells are further divided into plant and animal cells.
    • Plant cells typically have a cell wall surrounding the cell membrane, whereas animal cells do not.

    Viruses

    • Viruses are infectious particles that only replicate inside a living host cell.
    • Viruses can infect all forms of life.
    • Viruses are generally 20-300 nanometers across.
    • Viruses consist of a head region (protein coat) housing genetic material (single or double-stranded RNA or DNA)
    • Some Viruses are bacteriophages that infect bacteria.

    Viroids

    • Viroids are plant pathogens composed of short, circular, single-stranded RNA molecules.
    • They do not code for any protein.
    • They cause distorted growth and stunting in plants by using the rolling circle mechanism using the enzyme RNA polymerase I.

    Prions

    • Prions are misfolded proteins that cause brain degeneration diseases, such as encephalopathies, Alzheimer's, Creutzfeldt-Jakob, fatal familial insomnia and kuru.
    • Prions are protease-resistant and can transmit disease.
    • Prions lack nucleic acids.

    Cell Biology Tools

    • A variety of tools have been developed over the past 50 years to assist in understanding cell structures and organizational processes.
    • Tools include electron microscopy, confocal fluorescence microscopy, atomic force microscopy, flow cytometry and DNA analysis tools.

    Microscopy Techniques

    • Microscopy: Enables the visual observation of cells and cell components at varying magnifications.
    • Units of measurement: mm (millimeter), μm (micrometer), nm (nanometer) and angstrom units.
    • Light Microscopy:
      • Uses visible light and phase contrast.
      • Creates contrast images using alterations in light amplitude.
    • Confocal Fluorescent Light Microscopy: Shows clear images of nucleus, chromosomes, actin cytoskeleton filaments using stains like phalloidin-FITC (f-actin, green) and Hoechst 33342 (nuclear stain, blue).
    • Electron Microscopy: Uses an electron beam (much shorter wavelength than light) to magnify images at even higher magnifications than light microscopy with resolving power of 0.1 nanometers.
      • Transmission Electron Microscopy (TEM): Uses an electron beam passing through a thin sample section.
      • Scanning Electron Microscopy (SEM): Scans a focussed beam of electrons over the surface of a sample.

    Limitations of light Microscopy

    • Optical thickness of the specimen
    • Light intensity of image quality

    Staining Techniques

    • Haematoxylin and eosin (H&E): Stains nuclei and cytoplasm.
    • Fast green and Safranin: Stains cellulose and lignified walls.

    Fluorescent Stains

    • Fluorescent dyes can be used to visualize specific cellular structures.
    • Appropriate wavelength of excitation and observation light is required for the fluorescence process to appear.
    • Fluorescent dyes are used to mark, highlight, label or visualise parts.
    • Commonly used dyes include DAPI (blue), GFP (green), FITC (fluorescent isothiocyanate), Texas Red, and Cy3.

    Propidium Iodide and Cell Cycle Analysis

    • Propidium iodide intercalates between DNA bases, allowing for measurement of DNA content and cell cycle analysis, e.g. G₀, G₁, S, G₂ and M phase.

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    BIO1010 Practice Document PDF

    Description

    Test your knowledge on Atomic Force Microscopy (AFM) and the characteristics of various amino acids. This quiz covers the applications of AFM, the functions of amino acids, and techniques like FISH. Dive into the details of protein structures and their biochemical properties.

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