Lectures 1, 2, 3 Flashcards
What is the scientific method?
Determines what can be studied by science and how it should be studied
Observation
Hypothesis- testable statement
Experiment/observations- hypothesis tested
Conclusion- results analyzed, hypothesis accepted or rejected
(Repeat hypothesis and experiment if needed)
Scientific theory
L1S13
What are the 3 variables in experiments (controlled, independent, dependent)
Controlled variables- don’t change, common to all treatments
Ex- paper airplane has same weight, same person throwing, same paper
Independent variables- what is being altered in the experiment
Ex- fold positioning
Dependent variables- what you are observing in the experiment, it should respond to changes in the independent variable
Ex- it flies better with better folding of the plane
What are positive and negative controls?
What is false positive and false negative?
Positive- an experimental treatment which will give the desired result
Negative- an experimental treatment which will not give the desired result
False positive- detected by negative control
False negative- detected by positive control
What is sensitivity, specificity, accuracy, and precision?
Sensitivity- how little we can detect
Specificity- measuring the right thing
Accuracy- how close one or more values is to the true value
Precision- how closely related two or more values are to eachother
What is the volume range of micropipettes?
10 to 0.0002 mL
How do you find moles and molarity?
Moles = mass/molar mass Molarity= moles/volume = M or mol/L
Examples on L2S4
What is saying 1% of a substance the same as saying?
1%=1 gram/100mL
What are acids and bases?
Acid- proton donor, releases protons when put into solution
Base- proton acceptor, increases hydroxyls in solutions
What does water dissociate to give?
What happens when you add additional acid or bass to water?
10^-7 mol/L H+
10^-7 mol/L OH-
Additional acid or base pushes equilibrium to more H+ or more OH- but [H+][OH-] will always equal 10^-14
OH- goes up, H+ goes down and vice versa
What is pKa?
What is the range of effectiveness of a buffer on pKa?
The pH value of 50/50 mix of acid and base where there’s equal amounts of the acid and conjugate base in solution
A buffer pair is only effective +/- 1 pH unit from the pKa
What are buffers?
Reduce pH fluctuations
Counters pH change or pOH change
Higher concentration of buffer does more buffering
Examples on L2S9
Study titration chart:
L2S10
L3S9
L3S11
Okay
What is the Henderson hasslebach equation and the pH and pOH equations?
pH=pKa+log[base]/[acid]
pH=-log[H+]
pOH= -log[OH-]
pH+pOH=14
Example on L2S12-L3S3
What happens when pH is less than pKa?
What happens if you flip acid and base volumes?
There is more acid, more acidic
If you flip acid and base volumes the pH will go up or down the same but opposite way from the pKa as it was supposed to
Ex: you wanted to go from 7.4 to 7.0, but instead the pH is 7.8, an equal change to what is desired but in wrong direction
What would you add to increase pH? Decrease pH?
Add base (like NaOH) to increase pH (more basic) Add acid (like HCl) to decrease pH
How do low pH and high pH affect ends of amino acids charged?
Amino and carboxyl ends of amino acid can act as an acid/conjugate base pair
At low pH, both ends are protonated and charge is +1
At high pH, both ends are deprotonated and charge is -1
At moderate pH, the amino end is protonated and the net charge is neutral
What are tripotic amino acids?
7 amino acids that have an R-group that can act as an acid/conjugate base pair
Can buffer at an additional pH
Still only has one pl (isoelectric point)
L3S11
what is sterilization?
storage of nutrient solutions
- high temps denature proteins which makes them non-functional
- heat killing is altered by temperature, time and conductance (if any of these is increased, another can be decreased to get the same killing effect)
What is team sterilizing with an autoclave?
boiling point can be increased by pressure, higher boiling point gives hotter steam
look at L3S14 picture of autoclave
What is filtration of heat labile compounds
for compounds that would be broken down boiling (can’t be heated)
- liquids can be passed through filters which contain holes too small for bacteria to pass (0.2 um)
L3S15
