Lab Exam Flashcards
equipment
distance: 15 cm ruler
weight: electronic balance
volume: graduated cylinder
- pipette - come in 10 ml, 2 ml, and 1 ml
- micropipette - to measure 1 ml or less
2-20 uL
20 - 200 uL
100 - 1000 uL
microscope
accuracy
measure of how close measured values come to true value
precision
measure of consistency and sometimes referred to as reproducibility
formula using a dry solute & a solvent
g solute needed = g/mole x mole/L x Liter
units of measurement - m
deci = 0.1 centi = 0.01 milli (m) = 0.001 micro (u) = one millionth 0.0001 nano (n) = one billionth 10-9
parallel dilutions
making different dilutions of different concentrations with no relationship to each other
C1V1 = C2 V2
nearly always solve for V1
serial dilutions
- using a dilute solution to an even more dilute solution
- making several dilutions where there is a constant dilution factor
- OR where diluted solution is much, much less concentrated than the stock
V1 + V2
________ = dilution factor
V1
spectrophotometer
will register:
1. transmittance - light passing thru the sample (ex. 630 nm)
OR
2. absorbance - like absorbed by the sample (range 0.00 - 1.99)
independent variables
- those the scientist chooses (concentration of potassium; dosage of Rx, etc)
- plotted on x-axis
dependent variable
- results of the experiment
- dependent on the experiment
- plotted on y-axis
pH
percentage of H+ and OH- ions
acid
proton donor
base
proton acceptor
- can decrease the [H+] in 2 ways
1. dissociate to form OH- (H+ decreases b/c they combine w/OH- for form H2O)
2. combine directly w/H+ ions (e.g. NH3 combines w/H+ to form NH4
buffers
- release or mine H+ in order to keep a (relatively) constant pH; not keep it neutral
- most consist of a weak acid (release H+) and a weak base (bind to H+))
why is it important to keep pH stable?
- most biochemical processes proceed normally only when pH stays w/in a fairly narrow range
- excess of H+ or OH- can interfere w/structure and activity of many biomolecules, esp. proteins (e.g. human blood)
3 buffer systems in body
- bicarbonate buffer system
- phosphate buffer system
- protein buffer system
buffering range
- pH range where buffer is effective to maintain pH even the adding acid or base
- beyond its range, can no longer stabilize pH
- can have more than one range
buffering capacity
- ability of buffer to resist changes in pH when acid or base is added
Brightfieqld microscopes
- a compound microscope
- magnify & provide resolution
prokaryotic cells
- has a cell wall
- no nucleus
- no endomembrane system
e. g. bacteria
eukaryotic cells
- nucleus & organelles
- much bigger than prokaryotic cells
- no cell wall
4 main groups:
1. protists - mostly unicellular
2. plants
3. fungi
4. animals
similarities between prokaryotic and eukaryotic cells
Both have: 1. plasma membrane 2. ribosomes 3, cytosol 4. DNA
what affects diffusion rate
3 factors
- size of molecule
- temperature
- heated = faster diffusion
- gas move faster than liquid
- liquid moves faster than solid - medium through which they are moving
simple diffusion
- non polar molecules that will diffuse thru plasma membrane
oxygen
carbon dioxide
lipids
facilitated diffusion
- molecules still go down the concentration gradient, but membrane proteins regulate coming and going
