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variable thats counted or measured or observed
variable thats being manipulated
other independent variables, that stay consistent
Level of Treatment
value set for the indepependent variable
same procedure repeated
benchmark, independent is held or omitted
How do you construct a table?
- All values of the same kind should be read down a column
- Omit information and results
- Headings should include units of measurement
- Tables numbered consecutively throughout labs
- Title located at top of table
- Capatalize first and important words (not a, an, the)
- When refering to table (Table 1.4) not "see the results in Table 1.4)
How do you construct a figure?
- Use graph paper and ruler to plot accurately
- Independent variable on x-axis (horizontal)
- Dependent variable on y-axis (vertical)
- Use appropriate numerical range
- Start with zero, to save space may use double tick marks between 0 and lowest #
- Label axes to indicate variable, and units of measurement
- Include legend with colors if needed
- Choice bar/line graph depending onnature of variable beign graphed
- Title below graph and numbered consecutively
- Only first word capital and end with period
- show changes in the quanity of chosen variable
- emphasize rise and fall
- use to present continuous quanitive data
- changes in dep. variable, weight, or measured over time
- vertical bars are drawn down to horizontal axis
- used for data to represent seperate or discontinuous groups or nonnumerical categories
- emphsize discrete differences between the groups
- when values on x axis are numerical but grouped together called histograms
- minimum of two magnifying lenses
- binocular or monocular microscopes
supports the two sets of magnifying lenses
- the lens in the eyepiece
- typically has a magnification of 10x
- distance between the eyepieces
- can be adjusted to suit your eyes
Feild of View
- is the circle of light that one sees in the microscope
- has a pointer to point to an object
- the three lenses on the revolving masterpiece
- shortest to longesxt lense; 4x, 10x, 40x
- clean lenses each time to avoid blurring or fogging of image
- always use lense paper
supports the stage and condenser lens
- used to focus the light from the lamp through the specimen to be viewed
- hieght can be adjusted by an adjustment knob
controls the the width of the circle of light and, therefore, the amount of light passing through the specimen
- if microscope has phase-contrast optics the condenser is housed here
- when set on 0 the normal optical arrangement is in place (called brightfeild microscopy)
- to use phase-contrast, turret settins must correspond to the magnifying power of the objective being used
- supports the specimen to be viewed
- a mechanical stage can be moved right and left and back and fourth
Stage Adjustment Knobs
two adjustment knobs for the stage
the slide is secured under stage clips and moved slightly by hand while vieing the slide
- adjustment for the distance between the stage and the objective
- can also use the fine focus adjustment knobs
Acts as a stand for the microscope and houses the lamp
Light Intensity Lever
adjusts the intesity of the light that passes through the specimen
Stereoscopic (Dissecting) Microscope
- low magnification of 7x to 30x
- for viewing and manipulation relatively large objects
- binocular feature creates the stereoscopic effect
- depth of feild is much greater than with the CM so objects are in 3 dimension
- the light source can be directed down onto as well as up through an object which permits viewing of objects too thick to transmit light
Reflected or Inciden Light
light directed down on the object
light passing through
distance between the specimen and the objective lens
How do you compute the total magnification of the spectrum being viewed?
multiply the magnification of the ocular lens by that of the objective lens
If you move the slide to the left which direction does the image in the ocular move?
to the right
How do you prepare a wetmount?
- place a drop of water and your specimen on the slide
- using a disecting needle, slowly lower a coverslip onto the slide
- be careful not to trsap air bubbles in the droplet
At what angle do you lower the coverslip onto the slide?
Place the coverslip at a 45 degree angle
How do you properly handle the microscope?
- with two hands
- one holding the arm
- the other supporting the base
How do you properly put away the microscope?
- rotate 4x objective into position
- remove slide from stage
- return phase-contrast condenser to 0 setting
- lower stage completely
- set light to lowest intesity
- turn off
- wrap the cord
- cover with dust jacket
cells swell and membranes burst
cells shrivel and appear bumpy
type of diffusion of water through selectively permeable membrane from region where it is highly concentrated to a region where its concentration is lower
large particles suspended in water in motion
What is the relationship between starch and iodine potassium iodide (I2KI)?
I2KI tests for presence of starch when it is added to an unknown solution
What was the permeability of the dialysis tubing?
It was permeable to the glucose but not the starch into the beaker, and the I2KI got into the tubing because of the size of the molecules
tests for presence of starch by turning purple or black when added to the unknown solution
- when reagent is added to unknown solution, solution is heated, if turns green, orange, or orange-red, a reducing sugar is present
- if no reducing sugar is present the solution remains the color of the Benedict's reagent (blue)
has a greater concentration of solutes that cannot cross the membrane (nonpenetration solutes) than the solution on the other side of the membrane greater osmolarity (solute concentration expressed as molarity)
has a lower conentration of nonpenetrating solutes, or a lower osmolarity, than the solution on the otherside of the membrane
when the two solutions are in equilibrium, the concentration of nonpenetrating solutes being equal on both sides of the membrane, the osmolarities are equal
the net flow of water is from the hypotonic solution to the hypertonic solution, when the solutions are isotonic, there is not net flow of water across the membrane
What happens to water when it moves into red blood cells (animal cells) placed in a hypotonic solution?
the cells swell and the membranes burst, or undergo lysis
What happens when the water moves out of red blood cells (animal cells) placed in a hypertonic solution?
the cells shrivel and appear bumpy or crenate
Hypotonic solution in plant cells
- as water moves into the cell and the cell's central vacuole, the cell's protoplast expands
- the cell wall restricts the expansion, resulting in turgor pressure
- a high turgor pressure will prevent further movement of water into the cell
Hypertonic solution in plant cells
- water moves out of the cell
- the protoplast shrinks and pulls away from the cell wall call plasmolysis
- the cell is then described as plasmolyzed
- biological catalysts, compounds that speed up a chemical reaction without being used up or altered in the reaction
- a small amount of enzyme can alter a relatively enormous amount of substrate
- the material with which the catalyst reacts
- modified during the reaction to form a new product
- active site of an enzyme that will bind with the substrate forming the enzyme-substrate complex
- site where catalysis takes place and when complete dissociates into enzyme and product or products
In the potato experiment what was the role of the catechol?
catechol is a phenolic compound found in plant cells and is converted to benzoquinone, a pigment product by catechol oxidase
What did the potato extract represent, or what did it contain that was important to this expirement?
the extract is to test for the presence of catechol oxidase
- phenylthiourea is the specific inhibitor
- known to combine with the copper in catechol oxidase and inhibits its enzymatic activity
What was the enzyme in the potato extract experiment?
catechol oxidase and amylase
What was the substrate in the potato extract expirement?
Why was the concentration of catechol increased in excersize 4.2?
adding additional substrate (catechol) will not reverse the inhibition if it is a noncompetitive inhibition
Name three variables that may affect the activity of amylase.
enzyme concentration, pH, and temperature
Effect of temperature on Amylase
(expirement we used)
- chemical reactions accelerate as temperature rises, however high temperatures denature the protein
- After conducting an expirement at four different temperatures, in four different test tubes, the results yeilded that between 22 and 37 degrees the reaction time is the quickest, where as it slows down at higher temperatures of 80 degrees
- the inhibitor binds to a part of the enzyme that is not the active site, in so doing it changes the nature of the enzyme so that its catalytic properties are lost
- 1) either the NI itself physically blocks the acces to the active site
- 2) it causes a conformational change in the protein, thus inactivating the active site
- the inhibitor can become unbound, reversing the inhibition
- unlike competitive inhibition, adding additional substrate will not reverse the inhibition
- when a molecule structurally similiar to the substrate for a particular reaction competes for a position at the active site on the enzyme
- tieing up the enzyme so that it is not available to the substrate
- competitive inhibition can be reversed if the concentration of substrate is raised to sufficiently high levels while the concentration of the inhibitor is held constant
capable of utilizing only organic materials as a source of food
strands of cytoplasm that extend through plant cells to connect to other cells
- circulation of cytoplasm caused by shortening and lengthening of "microfilaments" of actin
- motion of the chloroplasts (and other organelles) around the periphery of the cell
circular, cannot distinguish any structures
(a ton of tiny circles with cell walls-the dark outside)
red pigmentation, does not move out of cell with water
(looks like red bricks, the outline of each is cell wall, the nucleus is the dark circles, and the cytoplasm is the area inbetween)
be able to label the cell wall, cytoplasm, chloroplasts, and plasma membrane
- utilizing oxygen
- includes cellular respiration, krebs, and electron transport chain
- without oxygen
- include fermentation and glycolysis
What is the difference between cellular respiration and fermentation?
cellular respiration is aerobic and gives greater yield of ATP, and fermentation is anaerobic
Independent Investigation of fermentation
beer and wine yeast
We predicted that beer yeast will ferment faster than wine yeast, and we experimented having 4 different tests tubes with different amouts of yeast and glucose solution. There was a control tube for each yeast, and the results supported the hypothesis
- absorption pattern for a particular pigment, showing the relative absorbance at different wavelengths of light
- can be determined with a spectrophotmeter or colorimeter
- a graph that illustrates the efficacy of different wavelengths of light in promoting photosynthesis
- the efficacy of various wavelengths of light is measured by the production of oxygen and the clustering of bacteria
Which colored filters allow for the greatest photosynthesis activity?
blue because black absorbs all wavelengths even white
What was the purpose of dropping I2KI on the boiled geranium and Coleus leaves?
- Because it stains starch purple-black
- a change fromthe yellow-amber color of the iodine solution to a purple-black solution is a positive test for starch production which determines photosynthesis
How do different polarities affect the rate of movement of compunds on chromatography paper?
The most polar will travel the slowest up the chromatography paper compared to the least polar will travel the highest on the chromatography paper over the same amounts of time
Analyzing an abosorbtion spectrum
- Use a spectrophotometer or colorimeter
- List the pigments extracted and the optimum wavelengths of light for each
- Decide which pigment is most important in photosynthesis (the one that has a higher abosorbion at more wavelengths)