I'm so screwed Flashcards
What are two ways of determining the actual size of a specimen?
- proportion of field of view by the specimen -use the equation size of specimen=amount of field taken up (decimal)x field of view
- use an ocular micrometer- actual size of cell=# of ocular divisions x length of ocular division
How do you calculate magnification?
Magnification of drawing=size of drawing/ actual size of the specimen
What does reducing the amount of light change for your microscope?
The contrast
What does switch itching from a 40X objective lens (40/0.65) to 100X lens (100/1.25) do for your microscope?
Change in resolution and magnification
What does the use of immersion oil do for your microscope?
Change in Resolution
What does staining the specimen help with?
Contrast
What does changing the light source from a 400nm to a 500 NMR light help with for the microscope?
Contrast
What does changing the light source from a 500nm to a 400 nk light do for the microscope?
Helps with resolution
True or false a plant cell will become plasmolyzed when placed in a hypotonic solution.
False it will remain turgid
Hypotonic
There is less solute in the cell than the surrounding solution
Hypertonic
There is more solute in the cell than the surrounding solution
Isotonic
Net osmosis is 0
True or false- A hypertonic solution has a higher concentration of solutes than found in side the cell
True
Interpupillary distance
Distance between the centre of the pupils of the eyes
Ocular micrometer
A ruler on the eye piece of the microscope that can be used to measure the actual size of the specimen
Parfocal
When switching magnification the microscope stays in focus
Turgid
When the cell fills with water and swells
Plasmolyzed
When water leaves the cell and the plasma membrane pulls away from the cell wall
Flaccid
If to much water is lost the plant cell will wilt
You have been asked to test the 5 second rule. To do this you: place candies on the floor for 5 seconds, press the candies to the agar plates, incubate the plates and look for microbial growth
What is the independent variable, dependent variable, experimental group and constants? What’s missing from the exp?
Whether or not the candy touched the ground, the amount of microbial growth on the agar, pieces of candy touched the floor for 5 seconds, (time the agar is incubated and type of candy on the floor) there is no control group
Explain why grocery stores spray their products with water
So the plants don’t go into plasmolysis because they are dried out. The spray has little solute in it so it is hypertonic and water goes into the cell
Why was distilled water used as a blank?
.
For the experimental question “what is the effect of acetylcholine on heart rate in humans?”
a. independent variable
b. dependent variable
c. experimental group
d. control group
Ind. acetylcholine, dep. heart rate, exp group. Acetylcholine present control acetylcholine absent
The 10x, 40x and 100x objectives on the compound microscopes you used during the term are par focal. The fact that the microscopes are par focal implies:
a. When you look through both eye pieces, you only see one image
b. There are three lens systems on the compound microscope
c. the condenser lens must be focused before you use the microscope
d. you only need to adjust the fine focus when switching between objective lens
e. each of the objective lenses has a corresponding position on the annular condenser
D
Interpupillary distance on a microscope accounts for the differences between individuals who wear glasses and those that do not
False. Interpupillary distance accounts for the distance between individual’s pupils
True or false. An animal cell with an internal solute concentration of 0.25M will shrink when placed in a solution with a solute concentration of 1.0M
True
Your partner streaked an agar plate with a mixed bacterial culture. He placed a freshly flamed loop into a culture tube and made an initial streak on the surface of the agar. He then reclaimed the loop and without plunging the loop into the again streaked a portion of the first streak to make a second streak. Why did the bacteria not grow in the normal growth pattern?
Because the loop was still hot it killed the cells in the second streak
Choose the one correct order of signal transmission in the Spectronic 20 spectrophotometer.
a. light source, transmitted light, sample, incident light, meter
b. light source, photometer, transmitted light,sample, incident light, meter
c. light source, incident light, sample,transmitted light, photometer, meter
e. light source, incident light, sample, photometer, transmitted light, meter
C
In lab 2 why did you set the wavelength at 525nm to measure your samples?
Because betacyanin absorbs maximally at 525nm
In lab 2 what did you use to calibrate the meter on the spectrophotometer, why?
We used water as our blank because that was the solution the betacyanin was extracted in
A cell contains a red pigment in the cytoplasm and a blue pigment in the vacuole. After an irradiating treatment, the plasma membrane of the cells were damaged by that tonoplast remained in tasted what colour did the solution turn?
After the treatment the solution should appear red because the cell membrane was damaged the red would seep out however the blue in the vacuole would remain intact end because the vacuole remained intact
True or False. Absorb acne of light by pigment increases with concentration of pigment
True
What is the purpose of Safranin, what is the purpose of Gram iodine?
Safrine is a counter stain used to stain bacterial cells that were decolourized with ethanol during gram stain. Gram iodine forms a complex with crystal violet making it difficult to remove crystal violet stain from gram positive cells
In lab 8 during the alkali lysis mini prep procedure, it was critical not to vortex your tube after the addition of solution II (which contained SDS and NaOH) because vortexing will:
a. shear the plasma DNA causing it to denature
b. cause RNA to precipitate thus removing RNA from prep
c. break the bacterial genomic DNA into small pieces
d. beak the cells open causing the lays ate to become very viscous
e. cause RNA to remain in the solution, thus contaminating the plasmid DNA with RNA
C
In Lab 3 what characteristics did you use to identify the bacteria in the culture?
Gram stain reaction, colony morphology, cell morphology, O2 requirements, glucose fermentation, endosperm formation and mobility
Which of the following statements is false?
a. Iodine complexes with crystal violet
b. Safranin is the differential step in the Gram stain
c. Gram positive cells have a thick peptidoglycan layer
d. Safranin stains gram-negative cells pink
e. Ethanol washes crystal violet out of Gram negative cells
B
All of the following are cell morphology characteristics except for: a length b shape c edge d gram reaction e motile structures
C
You are concerned about bacterial contain inaction in the water from the drinking fountain opposite of the Bio 107 Labs, you get a sample of the drinking water from the fountain and streak it onto a PCA plate
a. What is the objective of streaking the cells onto solid medium
b. For colonies grow on the plate. Three colonies have identiacal colony morphology and one has different what can you conclude?
c. how would you confirm your answer in B?
A. To obtain single colonies
B.there are at least two diff species because diff characteristics means diff species. There could be more because identical cell morphology does not necessarily mean the same species.
C.preform further tests such as gram stain, determine cell morphology and various biochemical tests.
Your TA gives you a mixed culture of 2 bacteria in a liquid medium and asks you to preform a gram stain for each. What must you do at the beginning of the gram stain?
B. You notice that bacteria A is a negative bacillus but your stain for bacterium B has both gram negative A bacillus and Gram positive cocci. Explain the results.
A. Streak the cells on the plate to obtain isolated colonies
B. Possible contamination of bacterium B with cells of bacterium A, either due to shaking hands when picking up colony or improper isolation of colonies
True or False. The positive result for bacteria that produce endospores is turbid culture following following heating to 80C for 10 minutes and adequate incubation at optimal temperature
True
Turbid: cloudy
In one sentence briefly describe the purpose of using Detain
Impedes the movement of cells
Some you add cholchicine, a drug that effectively inhibits the function of microtubules to Pelomyxa Carolinensis. What effect would manipulation have on the mobility of this organism
No effect as the mobility of this organism is due to interactions between the microfilament cytoskeleton and the cytoplasm
Moltility via pseudopodia is achieved using which components?
I. Actin filaments II. Tubulidentata filaments III. Intermediate filaments IV. Flagellin V. Chromatin VI. Dynein
Tumblin filaments
Three ways to increase contrast in order to view a cell
Stain cell, adjust condenser diaphragm, use phase contrast microscope
True or false. The function of the contractile vacuole is single celled eukaryotic organisms is to pump waste particle out of the cell
False. The function of the contractile vacuole in single celled eukaryotic organisms is to pump water out of the cell
True or false. Enzymes are proteins that are composed of glucose molecules.
False enzymes are composed of amino acids
There were 2 controls in lab 6 photosynthesis. Describe what assumptions they were designed to test.
They were both dark controls-assumes that light is necessary for photosynthesis
True or false. Cellular respiration consumes oxygen and produces CO2
True
Glycolysis is a pathway that precedes:
I. Alcoholic fermentation II. The Krebs cycle III photosynthesis IV latic acid fermentation V the Calvin cycle
A.I, II,IV B.I,IV C.II only D.III,V E.All of the above F none of the above
A
Yeast in the Durham tube were undergoing anaerobic respiration
False fermentation
In lab 7 sugar metabolism in yeast you incubated yeast with glucose and varying amounts of ethanol inDurham tubes and obtained CO2 production. What do you think would happen to the rates of CO2 production if you incubated the tubes at 50C?
The rate of production would be less because the temp is much higher than the optimal temp of 30C
Bacteria genomic DNA:
a. Contains between 2 and 25 genes
b. Is a circular molecule anchored to the plasma membrane
c. is contained in the nucleus
d. exists in supercoiled conformation
e. is not necessary for the cell survival
B
True or False. Solution II (SDS and NaOH) is used in the plasmid mini-prep procedure to denature proteins disrupt the plasma membrane and cause hydrogen bonds in the DNA to re-form
False. Causes the hydrogen bonds to break
In lab 8 DNA extraction, when performing the mini-plasmid prep, after addition of which does plasma precipitate.
a. T buffer b. Solution II c. 70% ethanol d.95% ethanol e.solution III f.Solution I
D
You used micro pipettes as a tool to accurately measure small volumes of liquid
a. Briefly describe the function of the first two stops of the button on top of the pipettor
b. why is it important to touch the tip to the side of the receiving vessel when expelling liquid?
A. Stop 1 measures volume of the liquid in the selected window, stop 2 blows out the last few drops from the tip
B. The capillary action draws the last few drops out of the tip
In lab 8 during the alkali lysis mini-prep and during the preparation of HMW salmon sperm DNA, you precipitated the DNA with 95% ethanol, then washed the DNA pellet with 70% ethanol. What was the purpose of the 70% ethanol?
a. to remove lipids which will interfere with subsequently reactions
b. To remove salts and to add a bit of water to the pellet, making it easier to resuspend
c. to remove Mg2+ ions and therefore inhibit any DNAse activity
d. To remove medium and bacterial debris that inhibit the activity of restriction enzymes
e. to disrupt the plasma membrane and denature proteins
B
Gram positive cells
Have a thin layer of peptidoglycan and second phospholipid bilayer
Which of the following is true about plate count method?
I. It is an indirect way to determine cell count
II.it can be used to determine the # of competent cells in solution
III.it only considers plates between 30 and 300 to be accurate
IV. It takes into account the volume of the cells used
V.it I’d traditionally preformed using a petroff-hausser counting chamber
II,III, IV
