Test 1 labs quiz
When utilizing the scientific method, there are two types of variables. They are
dependent and independent.
Which of the following liquids can be safety pipetted by mouth? (Select all that apply)
none
Which of the following steps are part of a thorough hand washing protocol? (Select all that apply)
removal of bracelets, watches, and rings lathering with soap, rubbing hands together for at least 20 seconds using a brush and wooden stick, clean well under finger nails
Select all of the following that are characteristics of a scientific result.
reproducible, systematic
Before you begin a scientific experiment, you should
state a hypothesis decide on a strategy To start an experiment you must have a hypothesis and a strategy. During the experiment you will record data collected and after you would report the results.
Which piece of equipment is routinely used for the decontamination of infectious laboratory waste?
steam autoclave infectious laboratory waste is routinely decontaminated by use of a steam autoclave.
]In the following figure, which cell exhibits the condition of plant cells that have been placed in a hypertonic environment?
C In the Tonicity in Elodea cells activity, the hypertonic 10% NaCl solution produced the shrunken Elodea cells and the hypotonic distilled water solution produced the swollen Elodea cells. Cells exposed to a hypertonic solution will cause the plasma membrane to pull away from the cell wall as the vacuole inside the plant cell loses water.
In the following figure, which cell exhibits the condition of plant cells that have been placed in an isotonic environment?
A -Plant cells exposed to an isotonic solution will have decreased turgor pressure, as the vacuole inside the plant cell neither loses nor gains water because the solution concentrations are equal.
When testing for tonicity of red blood cells, why were you unable to read the lab manual through the tubes containing hypertonic or isotonic solution?
Because the cells in those solutions remained intact, causing the solutions to be opaque. Both the hypertonic and the isotonic do not destroy the red blood cells (RBCs), so the light is blocked by the RBC and the tube looks opaque.
Vibrio cholerae is the bacterium responsible for cholera, a GI tract infection. Normally, it takes the ingestion of over one million bacterial cells to cause infection, but the consumption of antacids signficantly lowers this number. What does this tell you about the likely classification of V. cholerae in terms of pH preference?
It is likely an alkaliphile. Antacids increase the pH of the GI tract when taken to offset acidity. Therefore, since the environment becomes more basic, V. cholerae, an alkaliphile, flourishes.
Select all of the following that are required of a scientific result.
It must be open to revision in the light of new data. It has been tested using the scientific method.
Water freezes at _____ and boils at _____ temperature. (Select all that apply.)
0 degrees Celsius; 212 degrees Fahrenheit 32 degrees Fahrenheit; 100 degrees Celsius
How many pounds are in 1 gram?
0.0022
47.0 milligrams =
0.047 grams 4.7 centigrams 0.47 decigrams 0.00047 hectograms All of the answer
Assume you drink 250mL of soda out of a 1 liter soda bottle. How many liters are left?
0.75 liters
What is the freezing point of water on the Celsius temperature scale?
0ºC
Select the unit of weight that is heaviest.
1 kilogram
1. 1 meter = 2. 0.001 meter = 3. 0.515 meters = 4. 0.01 meter = 5. 0.015 meters =
1 millimeter 2 1000 millimeters 1 15 millimeters. 5 1 centimeter. 4 0.000515 kilometers. 3 Centi is hundredth from the base, milli is thousandth from the base, gram is the base, kilo is thousand from the base. 1 meter = 1000 millimeters, 1 meter x 1000 = 1000 millimeters (going from base to smaller unit of measurement, multiple) 0.015 meters = 15 millimeters, 0.015 meter x 1000 = 15 millimeters (going from base to smaller unit of measurement, multiple) 0.001 meters = 1 millimeter, 0.001 meters x 1000 = 1 millimeter (going from base to smaller unit of measurement, multiple) 0.01 mete = 1 centimeter, 0.01 meter x 100 = 1 centimeter (going from base to smaller unit of measurement, multiple) 0.515 meters = 0.000515 kilometers, 0.515 meters/1000 = 0.000515 kilometers (going from base to a larger unit of measurement, divide)
In the pillbug experiment, how many pillbugs did you need to use to get good information for the experiment?
10
How many centigrams are there in a gram?
100
How many centimeters are there in a meter?
100
The temperature outside is 40 degrees Celsius. What is this in degrees Fahrenheit?
104 degrees Fahrenheit
How long should hands be lathered while washing?
20 seconds The Center for Disease Control currently recommends 20 seconds of lathering under running water. This is about how long it takes to sing or hum the "Happy Birthday" song twice.
The results indicate that the organism prefers a pH of
7 The graph shows the most absorbance at pH 7 meaning that the most growth occurred in this tube.
Many bacteria that cause urinary tract infections must be able to withstand the conversion of urea to ammonia in the environment. Therefore, they must be at least tolerant of ________ conditions.
AKALINE The production of ammonia increases the pH, making the environment in the urinary tract more alkaline. Some bacteria are tolerant of this pH rise and can therefore cause UTIs.
If a sugar was allowed to ferment in a culture medium, what type of organisms would grow best?
Acidophiles Fermentation produces acid, resulting in lower pH values. This would favor the acidophiles.
Why is it recommended that hands be wet prior to adding soap? (Select all that apply)
Applying soap to wet hands will enable it to go into solution and produce more lather. Soap applied to dry hands may irritate the skin. -Hands should be wet prior to adding soap so that soap will go into solution and produce more lather. Also, applying soap to dry skin may irritate the skin.
In the metric system, gram, meter, and liter are _____ units.
Basic
Using your pH data from the pH enzyme lab, which statement(s) below are true? (Select all that apply.)
Catalase works best at pH7. Catalase works better in alkaline environments than acidic ones. The data from the lab shows that catalase reaction rate was the highest at pH7 and second highest at pH9. pH 9 is an alkaline environment. The acidic environments showed reduced reaction rates.
Beverages are allowed in the laboratory as long as the containers are covered.
F- Food and beverages are never allowed in the laboratory.
Which of the following are reasons for washing hands before and after lab activities? (Select all that apply)
Hands may be a source of contamination to the lab experiments. Hands may become contaminated with infectious bacteria during lab experiments. Hands may become stained during lab. Hands may be contaminated with irritating chemicals during experiments. Hands may become contaminated with infectious microorganisms, hazardous chemicals, or stains. Hands might also be a source of contamination to the laboratory experiments.
Jacob had just finished his lab work and went to the sink to wash his hands. He removed his watch, and added liquid soap to his hands. He then turned on the water and began to rub his hands together, lathering for 20 seconds and cleaning fronts and backs of hands, fingernails, and between his fingers. He then rinsed his hands in running water, dried his hands with paper towels, and used an additional paper towel to turn off the faucet. Which statement is correct?
Jacob should have wet his hands in running water before applying the soap. If soap is applied to the hands prior to wetting the hands, it will not dissolve and lather as well and it may cause skin irritation.
Identify the correct statements about lab coats.
Lab coats provide some protection against contamination with infectious microorganisms. Lab coats provide some protection against exposure to corrosive chemicals. Lab coats provide some protection against contamination with infectious microorganisms and exposure to corrosive chemicals. Lab coats should be decontaminated BEFORE they leave the lab.
What is the variable in these tubes?
PH lEVELS Each tube represents TSB Tryptic soy broth with a different pH but with the same organism growing for the same period of time
Water moved across a membrane, into the thistle tube
down its concentration gradient. The water moved across the selectively permeable membrane down its concentration gradient from an area of high water concentration (more water/less solute = beaker) to an area of low water concentration (less water/more solute = thistle).
Based on your procedure from the pH enzyme lab, how can you accurately measure how pH alone affects an enzyme's ability to function?
same amounts of enzymes and different pH values If you change two variables (amount of enzyme and pH values) at the same time, you cannot accurately measure how each one affects the reaction rate independently.
n the pillbug experiment, the substance used as the control was
sand
Where should glass slides, pipettes, and capillary tubes be disposed?
sharps container Each of these items pose a hazard for puncturing or cutting the skin and should be disposed of in a sharps container.
Suppose you study how speed affects the braking distance of a car. Match each part of the hypothesis phase with its output. 1 Formulate the hypothesis 2 Choose a scope 3 Make a strategy for testing the hypothesis
speed." 1 "We will focus on how braking distance depends on speed." 2 "We will brake at various speeds but keep the car and other factors constant." 3
Two solutions are made by mixing sugar and enough water to make a 1 liter solution. One contains 5% sugar and the other contains 10% sugar. Which solution contains more water?
the 5% sugar solution
What is meant by osmotic pressure?
the amount of pressure needed to oppose osmosis
What factors are responsible for the osmotic pressure of a solution?
the number and type of solute particles it contains
When determining the scope of an experiment, you need to consider:
the outcome you will investigate the factor that will vary. When determining how to test a hypothesis, you need to understand what outcome you are testing for; for example, in the pillbug experiment, you were testing to see if the pillbug would choose the chamber with the cornstarch. You also need to know what factors will vary; again, with the pillbug experiment, the variables were the cornstarch and the sand. Knowing the pillbugs weren't repelled from the sand you could surmise the movement to the cornstarch vs sand was caused by wanting to go into that chamber and not because they were repelled by the sand in the opposing chamber.
In the tonicity in Elodea cells activity, the hypertonic 10% NaCl solution produced the shrunken Elodea cells and the hypotonic distilled water solution produced the swollen Elodea cells.
the solution was hypotonic and the cells had burst. If the blood becomes transparent then the red blood cells (RBCs) are not blocking the light, so the RBCs must have been destroyed if the solution is transparent.
When testing tonicity of red blood cells, if the solution became transparent after adding blood cells, you could assume
the solution was hypotonic and the cells had burst. If the blood becomes transparent then the red blood cells (RBCs) are not blocking the light, so the RBCs must have been destroyed if the solution is transparent.
This image illustrates what correct safety practices? (Select all that apply)
use of gloves and eye protection tying back of long hair wearing of the lab coat In this image, the technician is wearing the correct personal protection equipment, and her lab bench is clean and free of unnecessary clutter
What is the purpose of the sterile broth tube?
used to calibrate the spectrophotometer The spectrophotometer is calibrated using this sterile broth tube before measurements are taken with the growth samples.
A student was measuring the height of plants grown with different types of fertilizer or with plain water. What is the independent variable in this experiment?
what the plant was watered with Independent variables are variables that scientists select to change within the experiment like different types of fertilizer. Dependent variables are variables that scientists observe in relationship to the independent variable like plant height.
When should the chemical fume hood be used?
when using hazardous chemicals Chemical fume hoods do not provide protection from infectious microorganisms. If working with BSL-2 microorganisms, a biological safety cabinet should be used.
When testing tonicity in potato strips, you soaked potato strips in different solutions. You were then able to determine the tonicity of the solutions based on
whether the potato was crisp or limp. The lab strategy was to place potato strips into two different solutions with different tonicities to see which potato strip becomes limp or rigid.
What class of organisms is likely to inhabit the human body?
neutrophiles Human body pH is near 7, and therefore most bacteria that inhabit the body are neutrophiles.
The figure below reflects how animal and plant cells would respond in a(n) _______ environment.
hypertonic Since water is moving out of the animal cell and out of the plant cell in this image, they must be in a hypertonic environment with a high solute and low water concentration. This causes the water inside the cells to move outward into the solution.
What is the normal human body temperature at the Celsius temperature scale?
37ºC
An acidophile would likely grow best at which of the following pH values?
4 A value of 0-6 on the pH scale represents levels of acidity. Therefore, a pH of 4 would likely favor the growth of an acidophile.
At what pH will enzymes in human blood function best?
7.4
Place the following steps of the hand washing procedure in the correct order.
Thoroughly wet hands in running water. 1 Apply soap. 2 Lather for at least 20 seconds by rubbing hands together, paying attention to the back of hands, nails, and between fingers. 3 Rinse thoroughly in running water.4 Dry hands thoroughly and use a towel to turn off the faucet. 5.
Which properties of water contribute to the formation of the meniscus? Select all that apply.
cohesion adhesion
In the pillbug experiment, your hypothesis
was related to the environment pillbugs prefer
Some consider osmosis a special case of diffusion because it only involves the movement of what substance?
water
One gram is equal to 0.0022 pounds.
T
Some students consume large amounts of caffeinated drinks to help them stay alert when studying. You notice that many who engage in this practice seem to do poorly on exams. Suppose you want to investigate the relationship between caffeine consumption and exam performance. Which of the following statements would be an appropriate hypothesis?
Students who consume large amounts of caffeine while studying have lower exam scores than students that consume less caffeine while studying. A hypothesis is a tentative explanation for a phenomenon that can be tested and then supported or falsified based upon the results. To test the hypothesis, you would compare the exam scores of students who drink large amounts of caffeine while studying to those who do not. If the students who consume more caffeine have significantly lower scores, then your hypothesis is supported. Otherwise, the hypothesis is falsified. The statement that one should avoid consuming too much caffeine while studying is a recommendation, not a hypothesis. The statement that caffeine increases alertness but also increases anxiety would have to be tested more directly rather than looking just at exam scores. The statement that many students consume large amounts of caffeine caffeine while studying to try to improve their exam scores is an observation that could contribute to a hypothesis about why students are choosing to drink caffeine during study sessions, but it doesn't directly state a way to investigate the relationship between caffeine consumption and exam performance. Too much caffeine is harmful to your health is a conclusion that has been reached by some scientific studies; it is not, however, a hypothesis that is appropriate to this experimental design.
Suppose you have the speed on the x-axis and braking distance on the y-axis. Which graph would confirm the hypothesis "Braking distance is proportional to speed"? Multiple
Suppose you have the speed on the x-axis and braking distance on the y-axis. Which graph would confirm the hypothesis "Braking distance is proportional to speed"? Multiple
A major difference between red blood cells and Elodea cells, is that Elodea cells have a cell wall, which protects them from bursting. Group starts
T When a plant cell is placed in a hypotonic solution, the vacuole gains water and the plasma membrane pushed against the cell wall. The plant cell has a cell wall made from polysaccharides that prevents the cell from bursting.
Imagine that you wish to compare two different diets that will be fed to tadpoles raised in a lab. One diet is a meat-based fish food, and the other is the traditional diet of boiled lettuce. You want to see if the meat-based diet will be associated with an increase in the average weight of the tadpoles. In your experiment you keep all other factors, such as tadpole density per pan, temperature, pH, and the amount of food the same. The only difference between your control and experimental groups is the type of food the tadpoles receive. Which is a good hypothesis for this tadpole experiment?
Tadpoles will be larger if fed a meat-based diet. A good hypothesis is one that makes a prediction based on information known and predicts the behavior based off an independent (and testable) variable (there should only be one). The independent variable here is the type of food.
When Elodea leaves were placed in 10% NaCl, what was the result?
The cell membrane shrank away from the cell wall because the solution was hypertonic. -In the tonicity in Elodea cells activity, the hypertonic 10% NaCl solution produced the shrunken Elodea cells and the hypotonic distilled water solution produced the swollen Elodea cells.
When you receive fluid in the hospital, it is often 0.9% saline solution. What would happen if the nurse used distilled water instead?
The distilled water solution would be hypotonic to your blood cells, so they would gain water, swell, and possibly burst.
The distilled water solution would be hypotonic to your blood cells, so they would gain water, swell, and possibly burst.
The distilled water solution would be hypotonic to your blood cells, so they would gain water, swell, and possibly burst. -0.9% saline solution is isotonic compared to your red blood cells (RBCs) and distilled water is hypotonic to your RBCs. The distilled water solution would cause water to move down its concentration gradient from the solution across the selectively permeable membrane into the cell cytoplasm, which would cause the cell to swell and possibly burst.
How is enzyme activity influenced by pH?
The pH can alter how the substrate fits in the active site.
If we had done this same experiment with Saccharomyces (a yeast), how would the graph have appeared differently after plotting the spectrophotometer readings?
The peak would have been more to the left. Yeast are usually acidophiles, meaning that their growth would peak in the pH 4-6 range (on the left of the graph).
If you wanted to test whether or not a particular pain reliever was effective in the general population, you would need to design an experiment with an experimental group and a control group. What should be the only difference between these two groups?
Treatment: The experimental group should get the pain reliever, and the control group should get a placebo The control group is the group that received the independent variable. A placebo won't do anything to relieve pain, thus the group taking the placebo would be the control group because their pain levels would be unchanged.
Which of the following represent important safety procedures for microbiology students? (Select all that apply)
Wash your hands before and after laboratory procedures. Disinfect your lab bench at the beginning and end of the lab period. Take extra care around the flame of a Bunsen burner by tying up hair and keeping it from combustibles.
The pH can affect the activity of an enzyme-controlled reaction by (Select all that apply)
affecting hydrogen bonding changing the shape of the enzymes active site altering the interaction between the substrate and the enzyme active site changing the ionic state of either the enzyme or the substrate. pH can affect the hydrogen bonds between neighboring amino acids that create the folded shape of the protein (enzyme) as well alter the shape of the enzyme's active site. The ionic changes that can be caused by a non-optimal pH environment can affect the shape of the enzyme or the shape of the substrate, which could affect the ability of the formation of the substrate-enzyme complex.
The higher the pH the more ________ the environment.
alkaline Solutions with a pH above 7 are alkaline. The higher the pH, the more alkaline the environment.
When testing osmosis by measuring thistle tube height, what is the first step in the procedure?
apply membranes to the thistle tubes
Laboratory instruments are sterilized prior to reuse by __________.
autoclaving (steam autoclave) It is customary to use the autoclave to sterilize infectious waste prior to disposal. While there are other means to sterilize this waste, the steam autoclave is the most practical.
Why do scientists put so much effort into documenting their experiment and analysis?
because other researchers must be able to repeat the experiment in order to check the results
A disinfectant is used on your work surface
before the beginning of lab procedures, after all work is complete, and after any spill of live organisms. Explanation:The lab bench is disinfected prior to and at the end of each lab exercise. It is also important to use appropriate disinfection in the case of a culture spill.
Goggles or appropriate safety glasses protect the eyes from (Select all that applY
chemical splashes UV exposure when using UV radiation in the laboratory
Imagine that you wish to compare two different diets that will be fed to tadpoles raised in a lab. One diet is a meat-based fish food, and the other is the traditional diet of boiled lettuce. You want to see if the meat-based diet will be associated with an increase in the average weight of the tadpoles. In your experiment you keep all other factors, such as tadpole density per pan, temperature, pH, and the amount of food the same. The only difference between your control and experimental groups is the type of food the tadpoles receive. What is the independent variable for the tadpole diet experiment?
diet The independent variable is the group that is being examined
Which of the following items can be washed in the sink after use in the laboratory? (Select all that apply)
dissection tools glassware that was not used with hazardous chemicals dissection trays Glassware that was not used with hazardous chemicals, dissection tools, dissection trays, and staining trays can all be washed in the sink in the laboratory after use. Agar plates and broth culture tubes pose an infectious hazard and are not washed in the sink. Culture plates are discarded in the biohazard bag. Culture tubes are autoclaved prior to discarding the contents, washing, and reusing. Inoculating loops are generally not washed, but are sterilized in the Bunsen burner flame or in a bench top incinerator.
pounds is equal to 10 kilograms.
f
After testing tonicity in the lab, the items that have been contaminated with blood can be disposed of in the trash can.
f - Items contaminated with blood should be disposed of in the biohazard container, not the regular trash can in order to adhere to lab safety protocols.
in the metric system, the base unit of weight is the
gram.
Match the action to the appropriate phase of the scientific method 1 document results 2carry out the strategy, collect measurements 3 formulate a hypothesis and create a strategy 4 draw graphs, evaluate the hypothesis
hypothesis 3 experiment 2 analysis 4 report 1 - The scientific method starts with a hypothesis and an idea of how to test that hypothesis. During the experiment, you could carry out the formed strategy and collect measurements/data. In analysis, data is examined, and graphs can be used for a visual representation of the findings. Documenting the results would occur when you report your findings.
When a person requires intravenous administration of fluids which type of you expect to most commonly use?
isotonic
Which of the following should be worn at ALL times in the lab? (Select all that apply)
lab coat closed-toed shoes A lab coat and closed-toe shoes should be worn at all times. It may be advisable to where protective goggles, a face mask, and gloves in some instances. Instructions regarding personal protective equipment for each lab activity will be provided by your instructor.
The spectrophotometer measures the transmittance of growth. More light transmittance would mean ________ growth in the sample tube.
less If more light can transmit through the sample, it is less cloudy (turbid) with bacterial growth.
In the pillbug experiment, an important part of the experimental strategy was to
make observations at regular intervals. In order to have enough data to graph and draw conclusions, it is important that you take several measurements at regular intervals throughout the experiment.
Which of the following units is the metric basic unit of length?
meter
In the length unit exercise, what tool did you use to measure the circles?
metric ruler
Which prefix means 1/1000 or 0.001?
milli
The organism in the video experiment would be classified as a
neutrophile - The organism grew best at a pH of 7 so it would be classified as a neutrophile.
In which circumstance is food and/or beverage allowed in the laboratory?
never
How does pH negatively affect the metabolism of microorganisms?
pH changes can denature enzymes pH changes can change the charges on amino acids in proteins and result in denaturation and loss of activity.
According to the results of the pillbug experiment,
pillbugs tend to prefer cornstarch over sand.
When graphing your data, it is important to
place the dependent variable on the Y-axis.
When graphing your data, it is important that you
place the independent variable on the X-axis.
Suppose you have the speed on the x-axis and braking distance on the y-axis. Which graph would confirm the hypothesis "Braking distance is proportional to speed"?
points on a straight line through (0,0) progressing upward and to the right
