lab exam Flashcards
what was used as a natural colorimetric method for determining pH?
cabbage water
2 colorimetric methods used for pH
cabbage water and thymol blue
what substance was added to the unbuffered beaker?
calcium carbonate (0.1 g)
what substance was added to the buffered beaker?
baking soda
what substance is typically used to increase the acidity of a solution?
hydrochloric acid
how was the pH measured in the buffered and unbuffered beaker?
pH meter - take cap off
what is used to heat up solutions?
hot plate
what do you do between each measurement of pH with a pH meter?
rinse it with distilled water
what did the unbuffered/buffered procedure support?
that buffers accept hydrogen ions in order to resist a change in pH
color spectrum of thymol blue
acidic - more red
basic - more blue
color spectrum of cabbage water
acidic - more pink
basic - more blue/green
homeostasis
maintaining a constant internal environment within cells
internal pH of humans and other animals
about 7.2
acidity (pH)
measure of hydrogen ion concentration in a solution
p in pH
negative logarithm to the base 10
H in pH
hydrogen ion concentration
amphoteric
acting as either an acid or base
- water
product of H+ and OH-
1.0 x 10^-14
concentration of H+ in pH of 10
1.0 x 10^-10
OH - 1.0 x 10^-4
examples of acidic substances
battery acid, lemon juice, vinegar, black coffee, hydrochloric acid
examples of basic substances
baking soda, ammonia, bleach
what do buffer solutions contain?
a weak acid and its salt
different colorimetric methods for pH
litmus - red (acidic), blue (basic) - extracted from lichen
thymol blue
molarity/molar concentration
concentration of solution
- number of moles of a substance/solute dissolved per liter of solution
equation for molarity
concentration / molar mass
molar volume
volume that one mole of a substance takes up at a particular temperature/pressure
metabolism
sum total of chemical processes
catabolism
breakdwon
anabolism
synthesis and building up of molecules
enzyme
biological catalyst that accelerates chemical reaction without being consumed
activation energy
original input of energy necessary to initiate a reaction
- lowered by enzymes
factors on enzymatic activity
pH, concentration of substrate/enzymes, temperature, salinity
human enzyme temperature preference
37 degrees Celsius
optimal pH for enzymes
6-8
catalase
enzyme present in almost all organisms exposed to oxygen
- protects from oxidative damage
- breaks hydrogen peroxide into water and oxygen
bromelain
enzyme from pineapples
what enzyme was used in lab?
catalase (in yeast)
what substrate was used in lab?
hydrogen peroxide
what happens when enzymes get too hot?
denatured, not much of a reaction
which food had the most amount of catalase reaction?
carrot
- yeast was slightly less
what substances were used to create solutions of different pHs for testing catalase reactions?
soap solution, hydrogen peroxide
- hydrochloric acid and sodium hydroxide
- 5 mL of yeast then added
what did higher concentrations of substrate and enzymes yield?
more enzymatic activity
what vegetables were tested for enzymatic activity?
carrot, potato, cabbage
- control group: yeast
how was the amount of enzymatic activity determined?
measuring the amount of foam in cm
objective lenses from lowest to highest
scanning (4x), low (10x), high (40x)
equation for total magnification
objective magnification x ocular magnification
how to images appear in the microscope
upside down and reversed left to right
what unit was the field of view measured in
mm
what were the different protozoans examined in lab?
spirostonum, volvox gloater, blepharisma, stentor coeruleus, didinium
- didinium and paramecium caudata
- chaos carolina and paramecium caudata
spirostonum
long and snake-like, moved in circular motion
volvox globator
round and yellow, was pregnant, rolling movement
blepharisma
large and purple, moves quickly
stentor coeruleus
long/comb-like when attached to algae, circular when not attached, floats in circles, green
didinium
attaches to algae, moves quickly, light green
does food coloring distribute more/faster in hot, room, or cold temperature water?
hot
what dyes were used in the agar plate?
methylene blue, malachite green, potassium permanganate
were dialysis bags or glove material more permeable?
dialysis bags
what happened to the dialysis bag with higher concentrations of sucrose?
more water went in
when does Lugol’s solution turn blue
in the presence of starch
what was the positive control in the diffusion spot plate?
NaOH (Thymol blue) and starch (Lugol’s solution)
what was the negative control in the diffusion spot plate?
tap water with Thymol (green/yellow/brown) and Lugol’s (dark yellow/orange)
what did adding the NaCl solution to the plant cells do?
initiate plasmolysis
dialysis bag with NaOH and starch
external tap water had lots of NaOH and almost no starch
- diffusion occurred
glove bag with NaOH and starch
external tap water had no NaOH or starch
- no diffusion occurred
hypertonic solution
cell becomes crenated because water flow out of cell
hypotonic solution
cell becomes lysed because water flows into cell
diffusion of WATER in osmosis
high concentration of water to low concentration of water
diffusion of water in regards to SOLUTES in osmosis
low concentration of solutes to high concentration of solutes
what did lab 3 involve?
- enzymatic activity with pH and temperature
- enzymatic activity with concentration of substrate and enzyme
what did lab 4 involve?
microscopy of initials, onion slice, cheek cells, and threads
what did lab 5 involve?
measurement of field of view, protozoans
what did lab 6 involve?
diffusion
- temperature, membrane, molecular weight
what plants were observed with plasmolysis?
Elodea plant and red onion cell
what is the limiting factor of a compound light microscope?
resolution - can’t be used at a magnification greater than 2000X
what type of sucrose was used in lab 6
60% sucrose
