Lab Practical 1 (Units 1-6) Flashcards Preview

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Describe the base units of the metric system



Explain what metric unit is used to measure volume, length, mass, and temperature

Meter= length/distance
Liter= volume
Gram= mass
Temperature= celsius


Know how to convert between metric units with the same base (move the decimal)

0.013 deciliters= 1,300,000 nanoliters
480,000 micrometers= .048 decameters


Know the metric prefixes, their abbreviations, and how much of the base unit they represent

T-Tera- 10^12
G- Giga- 10^9
M- Mega- 10^6
k- Kilo- 10^3
h- hecto- 10^2
da- Deka- 10^1
meters, liters, grams- 10^0
d- deci- 10^-1
c- centi- 10^-2
m- milli- 10^-3
u(kindof)- micro- 10^-6
n- nano- 10^-9
p- pico- 10^-12


Convert between different metric base units (1g=1ml=1cc) of water at standard conditions

freezing: 0 C = 32 F
Room Temperature: 21.1 C = 70 F
Body Temperature: 37 C = 98.6 F
Boiling: 100 C = 212 F

1 cc = 1 ml
1 ml = 1 g
1 liter = 1 kg
1 dm^3 = 1 liter

50 ml of water weighs 50 g
3 liters of water equals 3 kg

1 liter = 1000 ml


Describe how to convert from Fahrenheit to Celsius and how to convert from celsius to Fahrenheit

F to C
1. F-32
2. Multiply by 5
3. Divide by 9

C to F
1. C x 9
2. Divide by 5
3. Add 32


Identify all lab equipment used in unit 1

Graduated Cylinder
Erlenmeyer Flask
Triple Beam Balance
Digital Balance/Scale
Graduated Pipette (Pipette)
Weigh Boat
Hot/Stir Plate
Stir Bar
Pipette Pump
Beaker Tongs
Test Tube Tongs


Draw/define meniscus

When measuring the volume of a liquid in a graduated cylinder, you will observe a "meniscus."

The meniscus is the curved upper surface of a liquid in a tube. You measure the liquid/volume from the bottom of the curve
(which is in the middle) of the meniscus.


Know which lab items are most accurate when measuring volume (2)

Graduated Cylinder
glass pipette


Know how to appropriately measure the mass using both the electronic balance and the triple beam balance

Digital/Electronic Balance/Scale
1. Locate and place the weigh boat on the digital balance.
2. "Tare" the digital balance in order to reset the balance to "0" grams. This will ensure that you do not add the weight of the weigh boat to what you are weighing.

Triple Beam Balance
1. On the triple beam balance, you set the item on the metal pan without the weigh boat.
2. Make sure it is set to zero by using the adjustment knob underneath the pan.


Understand if something should be measured in grams or kg

Grams are smaller than kilograms, so something smaller would be measured in grams.??


Know how to appropriately measure length using rules and meter sticks

Something smaller would use a ruler to find the length.??


Predict if an item would be appropriately measured in mm, cm, m, or km

Depends on the size of the item??


Distinguish between weight and mass

Mass is a measure of how much matter an object has.

Weight is a measure of how strongly gravity pulls on that matter.


Write numbers in scientific notation

0.000554433= 5.54433 x 10^-4
457430= 4.57430 x 10^5


Take a number in scientific notation and write in long form

9.11 x 10^-4= 0.000911
8.992233 x 10^6= 8992233


Calculate the mean, median, and range of a set of numbers

Mean: an average of a group of measurements
add all values and divide by total number of values.

Median: the value that is in the middle of a group of measurements.
Arrange values in order from lowest to highest. Then pick the middle one.
If there are an even number of values, pick the two middle and add them together then divide that by 2.

Range: the difference between the smallest and the largest measurements.
Subtract the smallest value from the largest value.


Known the definition of deviation, variance, and standard deviation

Deviation: Measures hoe the measurements vary from the mean (+ or -). In other words, what is the difference between an actual measurement and the mean, or average, of the sample?

Variance: This measures how much difference, or variation, there is between the values you have obtained. The smaller the variance, the closer the values will be to the mean. Likewise, the larger the variance, the farther the values will be from the mean.

Standard Deviation: Standard deviation gives you an idea of the widely spread your values are about the mean. The smaller the standard deviation, the closer your values will be to the average. If you were to graph data having a small standard deviation, you would expect a tall, thin bell shaped curve. On the other hand, if the standard deviation were large, your bell shaped curve would be wider.



Describe why a pencil looks yellow

A pencil looks yellow because the white light is hitting it and all of the colors are being absorbed, but the yellow light is being transmitted back out, which is what makes the pencil appear yellow.


Correlate colors of visible spectrum with their corresponding wavelengths or range of wavelengths

Red= 620-750 nm
Orange= 590-620 nm
Yellow= 570-590 nm
Green= 500-570 nm
Blue= 450-500 nm
Violet= 380-450 nm


Identify components of a spectrophotometer

Digital Display
Mode Button
Sample Holder
Wavelength Knob
0% T Knob
100% T Knob


Know how to calibrate the spectrophotometer to 0% and 100% transmission

1. Adjust the wavelength control knob until the digital display shows 540 nm. (Make sure the filter level is in the correct wavelength range.)
2. Make sure that you use the zero control knob to set transmittance to "0" before inserting your blank tube. Insert the "blank" into the sample holder and close the lid.
3. Adjust the meter reading 100% transmittance using the transmittance control knob.


What is the purpose of a blank tube?

A blank tube is a tube that is used in the spectrophotometry experiments that cancels out any unwanted molecules from absorbing light.


Describe the inverse relationship between transmittance and absorbance

As the amount of light transmitted by a solution increases, the amount
of light absorbed might be expected to decrease proportionally.
(((??the light absorbed by a solution depends on the absorbing ability of the
solute, the distance traveled by the light through the solution, and the concentration of the solution.??))

Transmittance measures how much light passes through the sample.
Absorbance measures how much light is absorbed by the substance.


What does it mean when there is nothing in the spectrophotometer and you are setting 0% transmission (think about absorbance)?

At this point, no light is shining on the detector. This step ensures that the measuring scale reads 0 under these conditions.


What does it mean when there is only the blank tube in the spectrophotometer and you are setting 100% transmission (think about absorbance)?

By setting the scale on the spectrophotometer to 100% transmittance using this “blank,” you can distinguish between light absorbed by your sample and light absorbed by your “blank” tube.


Define serial dilution and know how to create a serial dilution

A serial dilution is the repeated dilution of a solution to achieve a geometric dilution of the original solution.

To create a serial dilution you remove small amounts of an orignal solution to another container with a solution. Then you keep repeating and remove a small amount from that one to the next one, and then take a small amount from that one and then move to the next, and so on.


If given the starting concentration of a serial dilution, understand how to determine the concentration of each subsequent dilution

If you want to determine the concentration of a substance in a particular dilution, you multiply the original concentration times the dilution.
To illustrate consider the following:
Example 1:
You had a solution with 4 g of glucose per mL. You dilute this original solution by adding 1 mL of it to 9 mL of water. What is the dilution you prepared?
By adding 1 mL of solution to 9 mL of water, you have prepared a 1:10 dilution. Therefore:
4 g/mL x 1/10 = 4 g/mL/10 = 0.4 g/mL
Example 2:
If you had a 100 mg/dL solution of glucose and made a 1:5 dilution, what concentration of glucose is contained in the dilution?
100 mg/dL x 1/5 = 100 mg/dL/5 = 20 mg/dL


Describe the relationship between protein concentration and absorbance

Protein concentration and absorbance can be used to find one of those if you don't know the other one of a solution of something. They are proportional to each other.


Know how to construct a standard curve

Ton construct a standard curve, you plot the absorbance of each dilution on the Y-axis against the concentration of each dilution on the X-axis. You will draw a line of best fit using the data points you plot. By drawing a straight line from (a) to the curve at (b) and dropping from the curve to (c), the concentration of an unknown solution can be determined.


Understand how to use a standard curve to find the concentration of an unknown protein solution (Fig 3.1)

You can find the concentration of an unknown solution if you know the protein concentration and absorbance of some solutions. To find the unknown solution's concentration, you plot the absorbance of each dilution on the y-axis against the protein concentration of each dilution on the x-axis. Then you draw a line of best fit using the data points you plotted. Then you take the absorbance of the unknown and plot it on the y-axis, and then draw a straight line from that point to the curve/line of best fit that you drew through the points plotted. Then you draw a straight line down from the point where the line hit the line of best fit (which ends up looking like a squareish object). Then where the line hits on the x-axis will give you the protein concentration of that solution.


Know the flow of the scientific method (Sup Fig 1)

Observe ---> hypothesize ---> experiment ---> analyze/conclude


Define independent and dependent variable

Independent Variable: The variable in an experiment that is being manipulated by the researcher.

Dependent Variable: The variable in an experiment that has the potential to change in response to the experimental conditions altered by the researcher. The dependent variable is often times is defined as the variable that changes in response to the independent variable. It depends on the independent variable.


Identify the independent and dependent variable in scientific protocols

Independent: the value you are manipulating
Dependent: products produced by the reaction


Define hypothesis

A hypothesis is not an educated guess, but instead is a statement based off of previously supported data. A hypothesis must be falsifiable, and therefore must provide a means to test and either support or nullify the hypothesis. Note that one does not "prove" a hypothesis as being true, but instead determines whether or not the hypothesis is supported by the data obtained from experiments.


Describe the relationship between H+ concentration and pH

The pH of a solution is defined as the negative logarithm (base 10) of the hydrogen ion concentration. pH= -log [H+]

pH declines as the H+ concentration increases.


Explain what an acid or a base does to the H+ concentration of a solution

An acid is a substance that increases the H+ (hydrogen ion) concentration of a solution.

A base is a substance that reduces/decreases the H+ (hydrogen ion) concentration of a solution.


Describe what it means that pH is based on a log scale

The pH scale compresses the range of H+ and OH- concentrations by employing logarithms. The pH of a solution is defined as the negative logarithm of the hydrogen ion concentration.
Each pH unit represents a tenfold difference in H+ and OH- concentrations. It is this mathematical feature that makes the pH scale so compact. A solution of pH 3 is not twice as acidic as a solution of pH 6, but a thousand times (10 x 10 x 10) more acidic. When the pH of a solution changes slightly, the actual concentration of H+ and OH- in the solution changes substantially.


If the concentration of the H+ ions is 10^-5 what is the concentration of the OH- ions and what is the pH of the solution?

Concentration of H+ Ions= 10^-5
Concentration of OH- Ions= 10^-9
pH of the solution= 5


List the advantages and disadvantages to using anthocyanins, pH paper, and pH meters to determine pH

Anthocynanin advantage: they change color in response to changes in pH.


Define anthocyanin

plant pigments


Describe what must be done first before using anthocyanins to determine pH

The pigments in anthocynanins are responsible for some of the color variations found in fruits and flowers.
These anthocyanins, were extracted from red cabbage by boiling the red cabbage for three minutes and then filtering the cabbage extract.


Identify the relative colors of acids/bases/neutral substances when using cabbage anthocyanins

Acid- Red
Neutral- Blue
Base- Green/Yellow


Describe what numerical values correspond to acidic, neutral, and basic solutions

Acid= 0-6
Neutral= 7
Base= 8-14


State how to use anthocyanins to determine pH

You place some buffer into a test tube. Then you put some of the anthocyanin (cabbage extract) into the test tube and mix it well. Then there should be a color change, and you match the color to the standards of pH levels to figure out what the pH of the solution is.


Describe what must be done first before using a pH meter to determine pH

1. take off safety cap
2. calibrate pH meter


Define alkalized

alkalized:turn basic and less acidic; "the solution alkalized"

alkaline: of, relating to, containing, or having the properties of an alkali or alkali metal : basic; especially of a solution : having a pH of more than 7.

A new technique utilized by some alternative medicine approaches is one where solutions consumed are alkalized (pH is raised to 9.5 which is thought to be optimal). These alkalized solutions may be a contributing factor in observed health improvements in some cancer patients.


Determine how alkalized a solution is based on pH values

If the pH is 8 or higher than it is alkalized, and the higher the number the more alkalized it is.



Know the definition of buffer, and buffering capacity

Buffer: A substance that minimizes changes in the concentrations of H+ and OH- in a solution.

Buffering Capacity: Buffering capacity is measured by how much the solution resists change in its pH when acid or base is added to the solution.


Describe the difference between solutions with low buffering capacity and high buffering capacity

Low buffering capacity: A solution has a low buffering capacity when it is observed that pH changes fairly quickly when acid or base is added.

High buffering capacity: A solution has a high buffering capacity when it is observed to resist changes in pH when an acid or base is added.


Identify solutions as buffers based on data (graph)

You can tell whether a solution is a buffer if there is very little change in pH when looking on a graph or at data.


Know how to read/interpret the buffer graph generated in experiment 3.4

Little change in pH means the solution is a buffer.??


Identify visually positive and negative results for the four detection tests (know colors)

a. Lipid test
Positive Color- bright red
Negative Color-

b. Reducing Sugars Test
Positive Color-
+++ burnt orange
++ yellow
+ green
Negative Color- blue

c. Starch Test
Positive Color- black
Negative Color- orange/brown

d. Proteins Test
Positive Color- purple
Negative Color- very light blue


List the positive and negative controls for each experiment

a. Lipid Test (Sudan IV Dye)
Positive Control- Vegetable Oil
Negative Control- Water

b. Reducing Sugars Test (Benedict's)
Positive Control- Glucose Solution
Negative Control- Water

c. Starch Test (Iodine)
Positive Control- Starch Solution
Negative Control- Water

d. Proteins Test (Biuret)
Positive Control- Egg Albumin
Negative Control- Water


Know which detection reagent tests for which macromolecule

a. Lipids
Reagent- Sudan IV dye

b. Reducing Sugars (Carbohydrates)
Reagent- Benedict's

c. Starch (Carbohydrates)
Reagent- Iodine

d. Proteins
Reagent- Biuret's


Differentiate between testing for reducing sugars (Carbohydrates) and starches (carbohydrates)

When testing for reducing sugars, you add glucose solution to it. You also have to heat them for 3 minutes at 100 C.

When testing for starch, you had starch solution to it. You do NOT have to heat it though.


Provide examples of reducing sugars

monosaccharide- glucose
disaccharide- sucrose
polysaccharide- starch


Compare and contrast the 4 test reagent protocols

The Lipids test with Sudan IV is the only one that had the addition of an emulsifier.

The reducing sugars test is the only one that needed the third factor of heat added.


List the names of the four detection reagents

Sudan IV
Benedict's Reagent


Describe Sudan IV solubility in water

Sudan IV is not soluble in water, so it can detect water insoluble substances. You use this dye to detect if lipids are present in water.


Define emulsifier

An emulsifier is a substance that has both hydrophobic and hydrophilic properties on different portions of the molecule.


What is the effect of an emulsifier on a lipid/water solution?

When an emulsifier is added to a lipid/water solution, it makes it able to absorb the lipid substances that are normally insoluble.


Understand orientation of slides under the microscope

When you look at the specimen through the microscope, the image appears inverted (upside down).


Describe how to determine what is on the upper surface of the slide v. the bottom layer of the slide

The upper surface of the slide will have the part with the name/writing on it. and will also have the specimen on that side.


Identify and know the function of microscope parts

-Stage: is the black part that the slide sits on.
-Power Switch: turns the microscope off and on
-Ocular Lens: what you use/look through to see the specimen. magnify by power of (10x)
-Objective Lenses: these are lenses used to look at the specimen in different magnifications. There are 4: 4x-scanning, 10x-low, 40x- high dry, 100x-oil immersion.
-Base: The bottom part of the microscope that it all sits on.
-Irisdiaphrahm lever: used to regulate how much light comes up through the opening
-Coarse focus knob: moves the stage up and down to bring the specimen into focus.
-Fine focus knob: changes the clearness/focus
-Light Source: is under the stage and is where the light comes from that allows you to view the specimen.
-Condenser: contains a series of lenses that focus light onto the specimen.


Know how to use/focus the microscope

You use the coarse focus knob to move the stage up and bring the specimen into focus.
Then you use the fine focus knob to change the clearness/focus of it.


Describe how to observe a specimen with the light microscope. What is the sequence of objective lens that one uses? What/when do you use the different adjustment knobs?

You turn on the microscope, and normally set the brightness to the highest. Then you place the slide on the stage under the stage clip and center the specimen so it is directly above the light and centered.
Then you start with the 4x objective lens.
You use the coarse focus knob to move the stage up and down so that you can bring the specimen into focus.
Then you use the fine focus knob to change the clearness/focus of it.

You always start with the 4x objective lens, then you use the 10x, then 40x, then 100x.

4x- scanning
10x- low
40x- high dry
100x- oil immersion


Visually identify plant v. animal cells from the specimens viewed in class



Describe the relationship between magnification and field of view

As magnification increases, the field of view decreases.


Describe the relationship between magnification and resolution

Magnification and resolution go together. Magnification would be meaningless without resolution because the image wouldn't be clear and it would be pointless. As you increase the magnification, you also have to increase the resolution.


Describe the relationship between magnification and depth of focus

Higher magnification decreases the depth of focus.


Define magnification, resolution, field of view, and depth of focus

Magnification: is the ratio of an object's image size to its real size.

Resolution: is a measure of the clarity of the image; it is the minimum distance two points can be separated and still be distinguished as two points. (amount of detail).

Field of View: the diameter of the field, or area of the slide that you are able to observe under a given magnification. 4x has the largest field of view.

Depth of Focus: the thickness you can see. how much the focus knob(s) can be moved while still keeping the image in focus. If the depth of focus of an objective lens is high, then the focus knob(s) must be moved more to observe a change in focus of the image. Greatest depth of focus is with the 4x lens.


Know what structures could and couldn't be visualized in the Elodea, onion, and cheek cells



Identify the following structures in an Elodea Cell
a. cell wall/plasma membrane
b. cytoplasm/vacuole
c. chloroplast
d. CAN'T visualize (nucleus, nucleoli)



Identify the following structures in an onion cell
a. cell wall/plasma membrane
b. cytoplasm/vacuole
c. nucleus
d. nucleoli
e. NOT THERE- chloroplasts- not found in non-green plant tissue



Identify the following structures in a cheek cell
a. plasma membrane
b. cytoplasm
c. nucleus
d. HARD TO VISUALIZE (nucleolus)
e. NOT THERE- cell wall, vacuole, chloroplast- these structures aren't found in animal cells



Differentiate between eukaryotic and prokaryotic cells

-Kingdoms: Plant, Animal, Fungi, protista
-Much larger than prokaryotic cells
-Has a "true nucleus" (membrane around nucleus)
-Has multiple types of organelles

Prokaryotic Cells:
-Domains: Bacteria, Archaea
-Very small
-Has a nucleoid
-Has one type of organelle --> Ribosomes


list the part(s) of the microscope that we be used to change the amount of light (contrast) of the specimen

The irisdiaphragm level is an adjustable light barrier built into the condenser that regulates the amount of light passing through the specimen. This helps with contrast.


Draw what the letters FGZ look like when viewed in the microscope

The letters will look inverted, which means it will appear to have rotated 180 degrees. And look upside down.


Define diffusion and osmosis

Diffusion: The spontaneous movement of molecules or particles in solution along (down) a concentration gradient (i.e. from areas of high concentration to a low concentration) until there is an equilibrium.

Osmosis: The diffusion of water molecules through a selectively permeable membrane from a region of low solute concentration to a region of high solute concentration


Describe the effects of temperature and molecular size on the rate of diffusion

Temperature: The warmer it is, the faster something will diffuse.

Molecular Size: The smaller the molecule, the quicker it will diffuse.


Predict the movement of water between two substances separated by a selectively permeable membrane

Water moves across the membrane from the region of lower solute concentration (higher free water concentration) to that of higher solute concentration (lower free water concentration). [[high water concentration to low water concentration]]


Define selectively permeable

Selectively permeable is a property of biological membranes that allows them to regulate the passage of substances across them.


Describe the physical property of dialysis tubing that allows it to function as a selectively permeable membrane

The dialysis tubing serves as a selectively permeable membrane because it acts like a membrane with pores that can restrict certain molecules or particles to diffuse through its microscopic holes. Larger particles aren't able to fit through the microscopic holes in the dialysis bag.


Identify what process governs the movement of a solute across a selectively permeable membrane

Facilitated diffusion- when transport proteins speed the passive movement of molecules across the plasma membrane.

Transport proteins.
Channel proteins and carrier proteins.


Describe what types of molecules can cross a selectively permeable membrane based on size and what molecules cannot cross the membrane

1. Small polar molecules (H2O)
2. Hydrophobic molecules

1. Large polar molecules
2. Ions


Know the solutions used to detect the presence of Cl-, SO4^2-. glucose, starch, and protein

Cl- (Chloride): Silver Nitrate
SO4^2- (Sulfate): Barium Chloride
Glucose: Benedict's
Starch: Iodine
Protein: Biuret


Explain why the Cl- results for experiment 6.3 were very clear, but the results for SO4^2- and glucose were only slightly positive

The positive outcome for Cl- (Chloride) is milky white.
The positive outcome for Sulfate (SO4^2-) is precipitate (cloudy looking with stuff in it) so it would be harder to see clear positive results for Sulfate because you have to agitate the tube to see if there are any visible, minute particles.


Recognize what blood cells/animal cells look like when placed in solutions of various tonicities

Water enters the cell faster than it leaves so the cell ends up swelling and bursts (lyse).

The cell is stable because water diffuses across the membrane into and out of the cell at the same rate.

It is shriveled (crenate) because the cell loses and loses water, then shrivels and the cell will probably die.


Recognize what plant cells look like when placed in various tonicities

The uptake of water is balanced by the wall pushing back on the cell, so the cell is normal and turgid (firm).

There is no net tendency for water to enter, and water goes in and out of the cell, so the cell becomes flaccid (limp).

The cell loses water to its surroundings and starts to shrink. As it shrivels, the plasma membrane pulls away from the wall. This is called plasmolysis, which causes the plant to wilt and can lead to plant death.


Use appropriate scientific terminology to describe plant and animal cells placed in different tonicities (Fig 7. 15)

Animal cell
Hypotonic: Lyse = (burst)
Isotonic: Normal
Hypertonic: Crenate = (shrivel)

Plant cell
Hypotonic: Turgid = (very firm)
Isotonic: Flaccid = (limp)
Hypertonic: Plasmolyzed


State whether osmosis occurs in plant cells and justify your reasoning

Osmosis does occur in plant cells because osmosis is the movement of water across a selectively permeable membrane. Plants need water to survive; without enough water plant cells become flaccid. If plant cells don't get enough water then it starts to shrivel and the plasma membrane pulls away from the cell (plasmolysis) and it will cause the plant to wilt and lead to the plants death.


Define and differentiate between the following terms:

-Plasmolysis- happens in plant cells in hypertonic solutions. Its when the cell loses water to its surroundings and shrinks. As it shrivels the plasma membrane pulls away from the wall, causing the plant to wilt and lead to its death. This is a lethal effect usually.

-Turgor- happens in plant cells in hypotonic solutions. It is when the cell becomes full and swollen but doesn't explode because of the cell wall, so it is very firm (turgid). Plant cells love to be turgid and in hypotonic environments.

-Flaccid- happens in plant cells in isotonic solutions. It is when water goes in and out. There is no net tendency for water to enter, and the cell becomes limp and may wilt.

-Lysed- happens in animal cells in hypotonic solutions. It is when water enters the cell faster than it leaves, so the cell swells and bursts (lyse).

-Normal- happens in animal cells in isotonic solutions. This is when there is no net movement of water across the membrane, but instead the water diffuses across the membrane at the same rate in both directions, so its normal and nothing happens. The cell is stable and we want cells in this isotonic environment.

-Shriveled- happens in animal cells in hypertonic solutions. This is when the cell loses and loses and loses water and shrivels (crenate), and probably dies.


Know what stains were used for each slide created in class.

(unit 5: microscopy and cytology)

Elodea leaf:

Onion cell:

Cheek cell:
methylene blue