Prep for QUIZ 2
Quiz 2 (Monday, June 11) will cover the following material:
Lab- Ex. 3, 4, 5, 6A
#9-15 under History of Microbiology on the Study Guide for Lecture Exam 1
#1-9 under Biochemistry on the Study Guide for Lecture Exam 1. Note: for #9, we have only covered the carbohydrate group, so far.
If the answer is writtten in this color, it’s because it is not a subject we went over, but I looked up the answer just in case she still puts it on the quiz.
History of Microbiology
9. Be able to recognize the major discoveries/ contributions and approximate time period for each of
these early microbiologists:
a. Paul Ehrlich (1908) – Coined the term chemotherapy and popularized the concept of a magic bullet. “Magic Bullet” – chemical or agent that will kill a disease causing microbe w/o harming the host.
b. Alexander Fleming (early 1900s) – Discovered penicillin. Scottish biologist and pharmacologist. “It was a discovery that would change the course of history. The active ingredient in that mould, which Fleming named penicillin, turned out to be an infection-fighting agent of enormous potency. When it was finally recognized for what it was, the most efficacious life-saving drug in the world, penicillin would alter forever the treatment of bacterial infections. By the middle of the century, Fleming’s discovery had spawned a huge pharmaceutical industry, churning out synthetic penicillins that would conquer some of mankind’s most ancient scourges, including syphilis, gangrene and tuberculosis.” – Wikipedia
c. Hans Christian Gram – The work that gained him international reputation was his development of a method of staining bacteria. The stain later played a major role in classifying bacteria.
d. Robert Hooke (1665) – Created the word “cell” he observed cork material from plants under microscope.
e. Edward Jenner (1796) – First to perform a vaccination. (vaca – cow, from his work w/ small pox & cow pox)
f. Robert Koch – Examined blood of animals infected w/ bacillus anthracis, observing bacilli shaped microbes in the blood. From here he formed his postulates.
g. Anton van Leeuwenhoek (1870-80s)- Father of microbiology. First to observe living organisms which he termed “animacules.” This began many of the branches in biology today.
h. Joseph Lister ( 1860s) – Modified and advanced the idea of antispesis in health care settings. Used phenol on surgical wounds to reduce infection.
i. John Needham (mid 1700s) – Supported spontaneous generation after his experiments with boiling beef gravy & having life appear in the flasks. (Later Spalanzani did the same experiment but boiled the gravy over 1 hour and sealed the flasks better – no life formed)
j. Louis Pasteur (1861) –
- Rejected spontaneous generation. His experiment used swan neck flask allowing air to flow but no microbes to settle down.
- Experimented with fermentation, coming to the conclusion yeasts ferment and create alcohol.
- Proved some organisms do not need oxygen to stay alive (facultative anaerobes)
k. Richard Petri (late 1800s) – German bacteriologist who is generally credited with inventing the Petri dish while working as assistant to Robert Koch… invented the standard culture dish, or Petri plate, and further developed the technique of agar culture to purify or clone bacterial colonies derived from single cells. This advance made it possible to rigorously identify the bacteria responsible for disease. -wikipedia
l. Francesco Redi (late 1600s) – First to test spontaneous generation… Rejected it after an experiment w/ raw meat and 3 jars each covered or not covered examining if spontaneous generation would occur.
m. Ignaz Semmelweis (1848) – First to try to enforce handwashing after connecting deaths of women giving birth to doctors coming from autopsy rooms.
n. Lazzaro Spallanzani (1700s) – Rejected spontaneous generation after challenging Needham’s experiment by boiling the beef gravy for over an hour and sealing the flasks.
o. John Tyndall (mid/late 1800s) – prominent 19th century physicist. His initial scientific fame arose in the 1850s from his study of diamagnetism. Later he studied thermal radiation, and produced a number of discoveries about processes in the atmosphere
p. Rudolf Virchow (1860s) – a German doctor, anthropologist, pathologist, prehistorian, biologist and politician, known for his advancement of public health. Referred to as “the father of modern pathology,” he is considered one of the founders of social medicine. One of three credited for Cell Theory.
What are Koch’s postulates? List these postulates. Why are Koch’s postulates important?A series of steps that must be taken to prove the cause of any infectious disease.
- The suspected causative agent must be found in every case of the disease and be absent from healthy hosts.
- The agent must be isolated and grown outside the host.
- When the agent is introduced to a healthy, susceptible host, the host must get the disease.
- The same agent must be found in the diseased experimental host.
“These postulates must be satisfied before the cause of an infectious disease is proven.” – Bauman
What is the time period (years) for the Golden Age of Microbiology? Why is this time period
called the Golden Age of Microbiology? 1857 – 1914 ( just prior to the prohibition, not that long ago) Referred to as the “Golden Age” because it was the blossoming of the field of Microbiology and driven by four main questions (see below) that created a competition among scientists striving to be the first to answer them. These scientists and their research started new fields within Microbiology and their work continues to shape microbiologist research today.
” … a time when researchers proved that living things come from other living things, that microorganisms can cause fermentation and disease, that certain procedures and chemicals can limit, prevent and cure infectious diseases.” (Bauman, p. 17)
What four main questions were scientists attempting to answer during the Golden Age of
- Is spontaneous generation of microbial life possible?
- What causes fermentation?
- What causes disease?
- How can we prevent infection and disease?
Define the following terms related to the history of microbiology:
Biogenesis Theory – states that living things can only arise from living things and cannot be spontaneously generated.
Cell Theory –The Cell Theory states:
- All living organisms are composed of cells. They may be unicellular or multicellular.
- The cell is the basic unit of life.
- Cells arise from pre-existing cells.
The modern version of the Cell Theory includes the ideas that:
- Energy flow occurs within cells.
- Heredity information (DNA) is passed on from cell to cell.
- All cells have the same basic chemical composition.
Etiological agent – microorganisms and microbial toxins that cause disease in humans and include bacteria, bacterial toxins, viruses, fungi, rickettsiae, protozoans, and parasites. These disease-causing microorganisms may also be referred to as infectious agents
Germ Theory of Disease – Microorganisms can cause infectious diseases. (Pasteur – 1857)
“Magic bullet” – Paul Ehrlich search for chemicals that could be used to kill microorganisms without harming the host.
Pasteurization -A process of heating the grape juice just enough to kill most contaminating bacteria without changing the juice’s basic qualities, so that it could then be inoculated with yeast to ensure that alcohol fermentation occurred. (created the field of industrial microbiology)
Spontaneous generation (abiogenesis) hypothesis –” hypothetical process by which living organisms develop from nonliving matter; also, the archaic theory that utilized this process to explain the origin of life. According to this theory, pieces of cheese and bread wrapped in rags and left in a dark corner, for example, were thus thought to produce mice, because after several weeks there were mice in the rags. Many believed in spontaneous generation because it explained such occurrences as the appearance of maggots on decaying meat.” – Britannica
List and explain at least three different beneficial roles/uses of microorganisms.
- Microorganisms are beneficial in Industrial Microbiology – they are used for fermenting foods (wine, cheese etc.)
- Beneficial in defending animals & humans from pathogens for example as an immunization, or antibiotic such as penicillin
- Environmental uses- specific microbes are useful in soils, or cleaning up oil spills.
15. Define the following terms related to modern microbiology:
a. Bacteriology –the study of bacteria. This subdivision of microbiology involves the identification, classification, and characterization of bacterial species.
b. Mycology – Scientific study of fungi.
c. Parasitology – Study of parasites, their hosts, and the relationship between them. As a biological discipline, the scope of parasitology is not determined by the organism or environment in question, but by their way of life.
d. Immunology –Study of bodies specific defenses against pathogens in all aspects of the immune system in all organisms. It deals with the physiological functioning of the immune system in states of both health and diseases; malfunctions of the immune system in immunological disorders (autoimmune diseases, hypersensitivities, immune deficiency, transplant rejection); the physical, chemical and physiological characteristics of the components of the immune system in vitro, in situ, and in vivo.
e. Virology – Study of viruses and virus-like agents: their structure, classification and evolution, their ways to infect and exploit host cells for virus reproduction, their interaction with host organism physiology and immunity, the diseases they cause, the techniques to isolate and culture them, and their use in research and therapy.
f. Recombinant DNA technology – Type of biotechnology in which scientists change the genotypes and phenotypes of organisms.
1. List the six common elements in living things. CHNOPS – Carbon; Hydrogen; Nitrogen; Oxygen; Phosphorus; Sulfer
2. Define each type of chemical bond and know the relative strength of each (strongest, weakest):
- covalent bond – Strongest – chemical bonds made from shared pairs of electrons. (non-metals)
- ionic bond – Strong – Chemical bonds made from a cation + anion. Electrostatic attraction between these two entities forms the ionic bond, it is formed to attain stable octet structure.
- hydrogen bond. – weak – Chemical bond between the most electronegative (F, O, N) & least electronegative (H) atoms. Requires molecules to be VERY POLAR.
3. Draw a simple diagram of a single water molecule, labeling each atom. Also show the partial
charges on each atom.
4. Draw a simple diagram showing a hydrogen bond between two water molecules. See above.
5. List four life-sustaining properties of water and explain how these properties are related to its
- 1. Water is liquid at room temperature & at 98.6°F, this chemical property enables it to carry materials around in the body.
2. Water is polar, so it dissolves many kinds of molecules, has surface tension, cohesion, and adhesion which support many life forms such as plants.
3. Water has a high specific heat (resists temperature change), giving a more constant environment for aquatic organisms.
4. Water expands when it freezes, so it breaks rocks into soil; it forms on the tops of bodies of water leaving a habitat underneath alive and well, and actually warmer from retaining the earth’s heat
6. Define the following terms:
a. Acid – Substances that release Hydrogen when added to water.
b. Base – Substances that release Hydroxide when added to water.
c. pH – A scale for measuring acid & base levels in comparison to water (7pH)
d. Buffer – Substances that resist pH changes.
7. Know the following information regarding the pH scale:
a. The values on the pH scale range from 0 (lowest value) to 14 (highest value).
b. A substance with a pH value between greater than 7 up to 14 is an acid and a substance with a pH
value between less than 7 down to 0 is a base. Neutral substances have a pH of 7.
c. Each unit on the pH scale represents a logarithmic change in pH. Correct, jumps up/down by powers of 10.
d. Practice- put the following liquids in order from strongest acid to strongest base:
i. Milk of magnesia (pH 10) 2
ii. Urine (pH 6) 4
iii. Vinegar (pH 3) 5
iv. Household bleach (pH 13) 1
v. Human blood (pH 7.4) 3
8. Define the following terms related to organic molecules:
a. Monomer – molecule that may bind chemically to other molecules to form a polymer; The most common natural monomer is glucose, which is linked by glycosidic bonds into polymers such as cellulose and starch. Most often the term monomer refers to the organic molecules which form synthetic polymers.
b. Polymer – a large molecule (macromolecule) composed of repeating structural units. These sub-units are typically connected by covalent chemical bonds.
c. Synthesis reaction – Building larger molecules from smaller molecules. (AKA combination RXN)
d. Decomposition (breakdown) reaction – Breakdown or catabolic RXN. A decomposition reaction is the opposite of a synthesis reaction – a complex molecule breaks down to make simpler ones. Catabolic RXN refers to the releasing of energy from a reaction.
e. Exchange/transfer reaction – (AKA Double replacement or displacement RXN) – Brahce wrote “exchanging phosphate or other functional groups.” From another source:” when the anions and cations of two different molecules switch places, forming two entirely different compounds.”
9. List the four major groups of organic molecules and know the following information for each
group: Carbohydrates, Lipids, Proteins, Nucleic Acid (All the following answers are based on Carbohydrates)
a. General function – Provide energy & structure.
b. General chemical structure/ properties – Consists of only C, H, O (C + water) 1C:2H:1O ratio. Structures: Open Chain; Haworth; Hemi-acetal.
c. Name of monomers or small/simple molecules (e.g. monosaccharides, disaccharides) Monosaccharides.
d. Examples of monomers – Glucose; Fructose; Galactose
e. Types of bonds that are formed between monomers – Glycosidic bond (type of covalent bond)
f. Name of polymers or large/complex molecules – Polysaccharides
g. Examples of polymers – Cellulose, Chiten, Amylose, Glycogen
h. Sub-groups (if applicable) N/A. Correct me if I am wrong.
Exercise 3: Culture of Microbes & Media Preparation
1. Define culture media. – Substance that contains nutrients for supporting the growth of microbes.
2. Who first discovered that agar is a useful medium for growing microorganisms? – Fanny Hess
3. Define agar and explain why agar is a useful medium for culturing microbes. – Agar is a gelatinous substance from a polysaccharide in red algae. It is useful because most microorganisms do not use agar as a nutrient source, therefore it retains its solidifying effect.
4. List the benefits and limitations for each of these media:
a. Broth media – Good for calculating cell concentrations. Also, organisms maintain their shape and can be extract to study cell morphology. Cannot study colony morphology.
b. Agar tubes (deeps) – Beneficial in studying the gas requirements of a microbe? Do they settle at the bottom, middle, top? Facultative anaerobes?
c. Agar slants (slopes) – Allow for longer storage times; more surface area for microorganisms than agar tubes. Wont dry out as quickly as streak plates.
d. Streak plates – (Petri dishes) Good for studying colony morphology; streak plates dry out quickly; distort cellular shape of microbe compared to broth.
5. Explain the difference between complex media and defined media. Complex media has an unkown quantity of nutrients whereas defined media has specified and known amounts of nutrients. Complex media nutrients fluctuate from batch to batch. Defined media is the same in each batch (harder to make)
6. Given a container of agar with instructions for making the agar, be able to calculate how much
agar is necessary for making specific volumes (e.g. 50 ml, 100 ml, 500 ml).
Exercise 4: Aseptic Technique & Streak Plate Preparation
1. List the steps for preparing a proper streak plate. streak in 3 sections to dilute out the colonies. A) streak the first section, flame the loop B) streak the second section by dragging through the first a few times, flame the loop C) streak the last section by dragging through the second section a few times.
2. Be able to recognize a properly streaked plate vs. improperly streaked plate.
3. Explain how to sterilize a wire loop. – sterilize the loop in a flame until it glows orange, at an angle allowing part of the “neck” of the loop wire to be in the flame as well.
4. Why is it important to allow the wire loop to cool briefly before obtaining bacteria with the loop? You don’t want to burn or kill the bacteria when transferring, or melt the agar.
5. List the items that should be included on the label of a streak plate. Name, date, microbe, agar type.
6. In what position should a streak plate be stored and why? Upside down, so condensation will not drip onto the colonies running them together.
7. List the scientific names of the bacteria in Mix A and be able to recognize each species growing
on a streak plate. What type of media was used for Mix A? Staphylococcus aureus – circular, shiny & white (smaller of the two) Klebsiella pneumoniae – irregular, glistening & off white (larger colonies)
8. List the scientific names of the bacteria in Mix B and be able to recognize each species growing
on a streak plate. What type of media was used for Mix B? Bacillus cereus – filamentous, flat, cloudy, white Serratia marcescans – Irregular, shiny, RED!
9. List two things you should do to practice aseptic technique when obtaining cells from a broth
tube. – sterilize your loop, pass tube through flame, do not set tube cap on counter.
Exercise 5: Pure Culture Technique
1. Define morphology. Defined as the science or study of form or external appearance (size, color, shape, etc.) w/o regard to function.
2. Be able to describe the characteristics (using correct terminology) of a pure bacterial culture,
including the following:
a. Colony forms (bottom of p. 49) Punctiform, Circular, Irregular, Filamentous, Rhizoid.
b. Colony margins (top of p. 50) entire, undulate, lobate, serrate, filamentous, curled.
c. Colony elevations (top of p. 50) Flat, Raised, Convex, Pulvinate, Umbonate.
d. Optical character (p. 50) Opaque, Translucent, opalescent, iridescent.
e. Pigment/ color (p. 50) Color
Exercise 6: Direct vs. Indirect Staining, including bacterial morphology and all stains completed during
1. Be able to describe or recognize the various cell shapes and arrangements of bacteria viewed
with a microscope (p. 59) Cocci – Round: diplococci (Pairs) , staphylococcus (Grape-like clusters), streptococci (chains) , tetrad (4), sarcinae (8); Bacilli – Rod-shaped: diplobacilli (pairs) , snapping (V-shape), coccobacilli (short rods), palisading(side-by-side); Spirilla – Spiral shaped: Vibrio (half turn)
2. Explain the difference between a direct stain and an indirect stain. Know which type of stain is
basic (contains cations) vs. acidic (contains anions) or neutral. Direct stains – dye the cell, they have have a positive charge and are attracted to the negatively charged cell walls. Indirect Stain – dye the background, they have a negative charge and are rejected by the cell’s negative charge so the dye is coloring the background.
3. Explain why basic stains attach to cell membranes. Basic stains attach to cell membranes because cell walls have a negative charge, forming a weak ionic bond.
4. List the steps for preparing a cell smear for direct staining. How does this differ from the steps for
preparing a cell smear for indirect staining? a) sterilize loop & put two loop fulls of water on slide b) sterilize loop and add “visible blob” of microorganisms and mix into water until consistency of skim milk c) allow to air dry d) heat fix w/ three swipes over flame e) apply methylane blue and let sit 60 sec f) rinse & air dry. The difference between the two is the heat fixing, you only gently heat fix w/ an indirect stain and you mix in a different stain with the water and microorganism while they are wet.
5. What are two functions of heat-fixing bacterial smears? Kills living organisms, therefore reducing chance of spreading pathogens, and adheres cells to slide.
6. Indirect stains such as nigrosin provide a more accurate view of cell shape and size than direct
stains. Explain why this is so. Gently heat fixing means less distortion to the cells. The background being stained provides a higher contrast to view cell shape.
Prep for QUIZ 1
1. Define microbiology. The study of living things that are too small to be seen w/ the naked eye.
2. List the major categories of microbes included in this microbiology course.
- Prokaryotes – Organisms with prokaryotic cells & no true nucleus or organelles: Archaea & Bacteria
- Eukaryotes – Organisms with eukaryotic cells and a true nucleus & organelles: Fungi, Algae, Protozoa, Multicellular parasites & vectors (animals)
3. Define or explain these properties of living things:
- Archaea – Extremophile: live in acidic, hot or salty environments. No true nucleus.
- Bacteria – No nuclei.
- Fungi – Unicellular or multicellular, sometimes opportunistic pathogens
- Protozoa – “first animals” Unicellular organisms with mobility.
- Algae – Unicellular or colonial, antotrophs (self-feeder; photosynthetic)
- Multicellular Parasites & Vectors – Animal that can caryy pathogens from one host to another (eg. insects)
a. Metabolism – The ability to convert energy from one form to another
b. Evolutionary adaptation – The ability (ex. bacteria) for bacteria to become stronger against life threats, such as sanitizers. Killing off weak organisms and evolving into strong strains.
c. Regulation – (General Characteristic of living things) organisms ability to control its internal/intracellular conditions. (homeostasis in animals)
d. Growth/development – (General Characteristic of living things) Organisms ability to mature. Or in bacteria this could mean ability to divide and replicate.
e. Structural organization (including cells = smallest units of life) (General Characteristic of living things) All organisms have structural organization based on cells.
f. Reproduction – (General Characteristic of living things) Ability to pass DNA on via asexual or sexual reproduction.
g. Response to environmental stimuli – (General Characteristic of living things) An organisms response to its environment
4. List the three domains of life and be able to recognize organisms from each domain. Eukaryotic, Bacteria, Archaea
5. Define prokaryote. – Organisms that have prokaryotic cells and no true nuclei or organelles
6. Define eukaryote. – Organisms that have eukaryotic cells and a true nuclei & organelles
7. Viruses, viroids, and prions are not included in the domains of life. Explain why this is so. They are technically not living because they do not have any cells (acellular) but are made of proteins , acids or RNA only. Cell is the smallest unit of life.
8. Explain how to write the scientific name of a species, according to the scientific nomenclature
system. Also define binomial. Who developed this binomial system for naming living things? Start with the genus, followed by specific epithet. Binomial meaning 2 names. This system of nomenclature was designed by Carolus Linnaeus in 1758 (approx 100 years before Semmelweis and his handwashing)
1. Know how/where to dispose of contaminated slides, streak plates, and glassware (beakers or test
tubes). Bench w/ Shelves in front of room
- Top Shelf: Lab supplies, non-contaminated items
- Middle Shelf: Contaminated glassware, slides, test tubes in “50 test tube rack”
- Bottom shelf: Paper, plastics, petri dishes, autoclave items.
2. Explain why it is important to wait for instructions before proceeding with lab exercises. To insure that you are handling materials properly, doing the lab correctly and following safety precautions.
3. Define aseptic.
” aseptic technique is the effort taken to keep patients as free from hospital micro-organisms as possible (Crow 1989). It is a method used to prevent contamination of wounds and other susceptible sites by organisms that could cause infection. This can be achieved by ensuring that only sterile equipment and fluids are used during invasive medical and nursing procedures. Ayliffe et al. (2000) suggest that there are two types of asepsis: medical and surgical asepsis. Medical or clean asepsis reduces the number of organisms and prevents their spread; surgical or sterile asepsis includes procedures to eliminate micro-organisms from an area and is practised by surgical technologists and nurses in operating theaters and treatment areas. In an operating room, while all members of the surgical team should demonstrate good aseptic technique, it is the role of the scrub nurse or surgical technologist to set up and maintain the sterile field”. – Wikipedia
A more concise explanation from the text : “…describes an environment or procedure that is free of contamination by pathogens.
4. List at least four things that can be done during lab to practice aseptic technique. Place our samples in plastic bags, wipe our counters down with the supplied disenfectant, wash our hands, clean equipment thoroughly (autoclave).
5. Explain what you should do if you accidently spill a broth culture on the bench or floor. Notify the people around you, notify the teacher, clean thoroughly with disinfectant or have teacher clean properly.
6. Explain what you should do if you accidently drop and break a non-contaminated beaker. Notify the people around you, notify the teacher, dispose of the glass in the broken glass trash bin in the back of the classroom.
7. Explain what you should do if you accidently get a cut or burn during lab. Notify the teacher and take the appropriate steps for the injury according to teachers direction.
8. Know where the eyewash and body shower are located and how to use each. Located in the back of the room. To use body shower, pull large lever and stand under. For eyewash use foot pedal and flush eyes for 15 min.
9. Explain why it is important not to eat or drink in the lab. To lessen the chance of ingesting microbes into the body, considering we are in an environment where they are more present.
10. List two things you should do to help prevent a fire or burns when using a Bunsen burner Notify people next to you that your bunsen burner is on & make sure it is not near anything that can catch fire & keep an eye on it.
11. Where is the fire extinguisher in our lab? Front of the room on the side of teacher’s desk.
12. Explain the procedure for evacuating the building, including the meeting location outside the
building. Evacuate together as a class, through the double doors to the left. Meet together on the grass so teacher can take roll.
13. Fill in the blanks in the following sentence. _______Does anyone know this one?_____ _______________ Data
Sheets provide specific information about the potential health hazards of chemicals that we use
Exercise 1: Effectiveness of Handwashing
1. Define normal microbiota (normal flora). Also explain why normal microbiota are important. Microbes that are found on the outside and inside of the human body on a permanent basis. They are important for a couple reasons: they literally crowd out transient microbiota, support our immune system, digestive tract and help many other functions in our bodies.
2. Define transient microbiota (transient flora). Temporary microbes acquired from the environment.
3. Draw a diagram of the nutrient agar plate (quadrants) and explain how each quadrant was treated
during lab. Be able to interpret the results shown in a picture or actual plate. Quadrant 1: Stamped finger. Quadrant 2: Stamped finger w/ transient microbes on it. Quadrant 3: Stamped finger after we used sanitizer. Quadrant 4: Stamped finger after washed, scrubbed and air-dried. Waiting on results.
4. Explain how the widespread use of antibacterial soaps is affecting bacterial populations. The antibacterial soaps are killing off weaker bacterial populations leaving the stronger strains behind that then reproduce resistant bacterial populations.
5. What are the most effective handwashing agents/methods, based on what you learned during this
lab? Waiting on results.
Exercise 2: Microscopic Technique & Measurement
1. Be able to identify parts of the microscope and explain the function of each part. Be sure you
know the name, individual magnification, and total magnification of each objective lens. See Monday notes.
2. When initially viewing microorganisms, you should start with the scanning objective lens.
Always use the Coarse focus knob first with this lens.
3. Define magnification. – Makes specimen appear larger.
4. Define resolution. – Clarity/sharpness of image
5. Define parfocal – when the specimen is in focus using one objective lens it is in focus in all objective lenses (w/minor adjustments w/fine focus knob)
6. Define working distance. Which objective lens has the greatest working distance? – Working distance is the space between the end of your objective lens and the stage/slide. The scan lens allows the largest working distance.
7. What happens to depth of field as magnification is increased? ” increasing the magnification, either by moving closer to the subject or using a lens of greater focal length, decreases the DOF; decreasing magnification increases DOF.” -Wikipedia
8. What happens to the field of view as magnification is increased? Decreases
9. Explain how to add oil to a slide so that you do not get oil on lenses other than the oil immersion
lens. – push the nosepiece up to increase your working space, place the oil drops directly on slide, with nosepiece pushed up, turn to oil immersion lens then slowly drop back down and into the oil.
10. How should you clean the oil immersion lens after using oil? With lens papers only
11. Memorize the ocular micrometer calibration values for each objective lens (recorded on the
bottom of p. 37 in the lab syllabus). Be able to estimate the size of an object or cell based on
these calibration values. Scanner: 22µm Low: 10µm High: 2.2µm Oil: 1µm
12. List the things that should be done to your microscope before you put it away in the cabinet after
using it. Wipe down stage. Clean immersion lens with lens papers if needed. Put scanning lens in place. Turn light off. Wrap cord through ocular lenses and under stage. No slides left on stage.
First quiz here we go…..