Lectures 1, 2, 3

Question 1

What is the scientific method?

Answer 1

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

Question 2

What are the 3 variables in experiments (controlled, independent, dependent)

Answer 2

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

Question 3

What are positive and negative controls?

What is false positive and false negative?

Answer 3

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

Question 4

What is sensitivity, specificity, accuracy, and precision?

Answer 4

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

Question 5

What is the volume range of micropipettes?

Answer 5

10 to 0.0002 mL

Question 6

How do you find moles and molarity?

Answer 6

Moles = mass/molar mass
Molarity= moles/volume = M or mol/L

Examples on L2S4

Question 7

What is saying 1% of a substance the same as saying?

Answer 7

1%=1 gram/100mL

Question 8

What are acids and bases?

Answer 8

Acid- proton donor, releases protons when put into solution

Base- proton acceptor, increases hydroxyls in solutions

Question 9

What does water dissociate to give?

What happens when you add additional acid or bass to water?

Answer 9

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

Question 10

What is pKa?

What is the range of effectiveness of a buffer on pKa?

Answer 10

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

Question 11

What are buffers?

Answer 11

Reduce pH fluctuations
Counters pH change or pOH change
Higher concentration of buffer does more buffering

Examples on L2S9

Question 12

Study titration chart:
L2S10
L3S9
L3S11

Answer 12

Okay

Question 13

What is the Henderson hasslebach equation and the pH and pOH equations?

Answer 13

pH=pKa+log[base]/[acid]
pH=-log[H+]
pOH= -log[OH-]
pH+pOH=14

Example on L2S12-L3S3

Question 14

What happens when pH is less than pKa?

What happens if you flip acid and base volumes?

Answer 14

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

Question 15

What would you add to increase pH? Decrease pH?

Answer 15

Add base (like NaOH) to increase pH (more basic)
Add acid (like HCl) to decrease pH

Question 16

How do low pH and high pH affect ends of amino acids charged?

Answer 16

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

Question 17

What are tripotic amino acids?

Answer 17

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

Question 18

what is sterilization?

Answer 18

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)

Question 19

What is team sterilizing with an autoclave?

Answer 19

boiling point can be increased by pressure, higher boiling point gives hotter steam
look at L3S14 picture of autoclave

Question 20

What is filtration of heat labile compounds

Answer 20

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