Biology Lab Final
Under what circumstances is a pie chart appropriate?
When you want to illustrate how each part fits into the whole. In other words when you want to indicate percents.
Leukemia cells were treated with cladribine, subiolsamide, or no drugs in the presence of radioactive nucleotides. Radioactivity was measured in cmp/ul. Label the axes and provide a caption (stating the pattern of results) for the graph below.
X-axis: Time (hours) Y-axis: cmp/ul Caption: Leukemia Cells treated with Cladribine or Subiolsamide divide less than untreated cells, as measured by radioactive nucleotide incorporation.
Examine figure 2. Which photo (a or b) shows cells in a hypertonic solution?
a
Which cells (figure 2) have undergone plasmolysis
a
A plant cell with an osmolarity of .8M will undergo plasmolysis if placed in
a solution greater than .8M
Consider the data table below. (Enzyme lab part 1) Which of the following best accounts for the result in the 20 minute tube?
between 15 and 20 minutes the enzyme is not operating at a maximum rate because most of the substrate has been used up.
How do you calculate the diameter of a single cell, given the field diameter of the objective used
f you know the field diameter for an objective, you can estimate how many cells will fit across the diameter, then divide the diameter by the estimated number of cells.
If a dialysis tube is filled with a 20% sucrose solution and placed in pure water it will
increase in volume
Examine the data table below. These results support the hypothesis that the rate of osmosis
increases with concentration.
Two dye molecules equal in size and charge may have different migration rates through an agarose gel because of their difference in _________.
shape
Lactase catalyzes the conversion of
Lactose to glucose and galactose
In preparation of their blank a pair of students accidently combined the enzyme and substrate before adding NaCO3. How would this mistake affect their subsequent absorbance readings
ONP would accumulate in their blank and therefore their readings would be inaccurately low.
Why was it important to use an extremely high concentration of ONPG for this experiment? (Figure 6)
Only one variable can be tested at a time. The experimental variable is Enzyme concentration, therefore substrate concentration must be kept high enough so that the rate of the reaction is independent of the substrate concentration. In other words all enzymes must be saturated for the results to be valid.
The cellular content of a leukemia patient's blood is 82% red blood cells, 4% functioning leukocytes and 16% nonfunctioning leukocytes. Which of the following would best illustrate this finding?
Pie chart
Examine figure 3. Which of the following best accounts for the surprising difference in the results between the 20 and 30% bags
The area of the 20% bag was much greater than the area of the 30% bag.
Under what circumstances is a bar graph appropriate
When independent variables are discrete (no values fall between them). For example to illustrate the relationship between cell length and species.
Calculate the osmotic pressure (in atm) for the 20% bag. See figure 4 for formula and conversion factors. Assume room temperature = 22 degrees C. Show your work. (No credit will be given without work show
(.58mol/liter) (.082liter x atm/K x mole) (295 K) = 14 atm
Considering the results shown in figure 6, what would you estimate the concentration of enzyme to be in a sample with an absorbance reading of .653? (Assume the sample was subjected to the same experimental conditions.
.075 units/m
For the results shown above, 10ul of .8ug/ul plasmid solution was added to 250ul CaCl2 and after heat shock 250ul of LB broth was added. 100ul of this mixture was plated. Calculate the transformational efficiency (in transformants/ug).
10ul)(.8ug/ul) = 8ug 8ug/510ul = .016ug/ul ( .016ug/ul)(100ul) = 1.6ug 34 transformants/1.6 ug = 21 transformants/ug
Calculate the rate of osmosis (mg/min/cm2) for the 10% bag
3000mg/60min/30cm2 = 1.67mg/min/cm2
Calculate the % cells transformed (transformants/cells plated).
34/2000 = .017 transformants/cell plated = 1.7 %
What is the osmotic pressure of a 2 mol/liter solution of sucrose? Osmotic pressure = CRT R=0.082 (liter atm)/(K mol) T=293 K
48 atm
Examine figure 6. The result shown for the .5units/ml sample was flashing and therefore inaccurate. If it was possible for the spectrophotometer to read a concentration of ONP this high, what absorbance reading would you expect?
5 x .902 = 4.51
Consider the data table above. What is the cumulative weight gain for the 30% bag after 20 minutes?
7.9 g (27.9 - 20 = 7.9g)
Examine figure 1. The dialysis bag shown in the photo contains a 10% sucrose solution and the beaker contains a 10% NaCl solution. Which of the graphs (A,B,C or D) shows the expected results
A. The Molecular weight of NaCl is 58g/mol and therefore a 10% NaCl solution has a much higher molar concentration than a 10% sucrose solution. In addition, NaCl dissociates into Na+ and Cl- ions.
Why don't the cells in plate A fluoresce?
Arabinose is required to turn on the GFP gene and it is not present in the growth media.
What is the most likely role of PARP-1 in WBCs
Cladribine is effective at slowing cell reproduction (Study I) and increases the concentration of cladribine. We can therefore hypothesize that PARP-1 is an inhibitor of cell reproduction.
Examine the results of the DNA analysis for an STR for 5 individuals in the figure. If Mom (A) has a child (C), which of the 3 other individuals (B, D & E) could be C's father? How could we use STR's to determine definitively which man is C's father?
D & E could be C's father, but B could not. We cannot tell by looking at one STR, since many people may have the same number of repeats for one particular STR. We would have to look at multiple STRs in order to tell which man was C's father.
Successful transformation requires that the bacteria be heat shocked. Why is this necessary?
Heat shock provides the stress needed to get the bacteria to take up materials from their surroundings.
Compare the rate of the reaction (figure 5) in the first 10 minutes with the rate in the last 10 minutes. Does the rate increase, decrease, or stay the same? Are these results expected
In the first 10 minutes the rate is .516/10 = .0516 in the last 10 minutes the rate is .634/10 = .0634. The rate increases in the last 10 minutes. It is expected to stay the same (as long as substrate is in excess).
Most students found ONP production in tubes incubated at 100 degrees C. Does lactase function at this temperature? Explai
Lactase would be completely denatured. The extreme temperature increased the spontaneous breakdown of ONPG into ONP. It is non-enzymatic.
What would happen if you removed the ORI sequence from the plasmid?
The plasmid would not be able to initiate DNA replication, so any transformed bacteria would not be able to replicate their plasmids during cell division and the resultant colonies would not glow.
What was the purpose of study II
To determine the effect of cladribine and subiolsamide on the concentrations of 5 cellular proteins.
What was the purpose of Study III?
To determine the effect of cladribine and subiolsamide on the health of neuronal cells.
What was the purpose of Study 1
To determine the effect of cladribine and subiolsamide on the rate of cell reproduction.
Why is ampicillin added to plates A and B?
To kill all cells that haven't been transformed.
Which of the following shows the correct order in preparing the blank for the enzyme lab?
enzyme → Na2CO3 → ONPG
The migration rate of DNA fragments is directly related to their __________.
length
What could added to these cells to reverse plasmolysis?
pure water