THANATOCHEMISTRY
CRYOGENY
Cryogenics: A How-To Manual
• 1) Remove head
• 2) Immerse head in
hypertonic glycerol
bath
• 3) Place head in liquid
nitrogen until ???
• 4) Place head in
distilled water
• 5) Enjoy!
Why doesn’t cryogenics work?
TONICITY
• Def: Relative measure of
dissolved particles
(solute) in the solution
surrounding the cell
membrane
• Measurement is always
compared to
interior/cytoplasm of cell
• Water does not have a
tonic classification as it is
invariably the solvent
PLASMOLYSIS
• DEF: Loss of water
and turgor due to
placement of cell in
HYPERTONIC
environment
• Water leaves cell via
osmosis, causing
vacuole to shrink, or
cytoplasm to lose
volume (crenation)
CYTOLYSIS
• Def: Cells placed in
HYPOTONIC
environments may
undergo cytolysis/cell
rupture as water
enters the cell
• Loss of the lipid
bilayer ultimate
causes cell death
TURGOR
• In plants, the cell wall
resists cytolysis in
hypotonic
environments
• This turgor pressure
allows the plant to
resist gravity
Lab: Semipermeable Membranes
and Osmosis
• Purpose: To analyze the movement of
solutes and water across a selectively
permeable membrane
• Method: Tracking movement of solutes
and water achieved by use of organic
indicators and qualitative description of
turgor (rigidity of fluid filled container)
Dialysis
• Loss of kidney
membrane
permeability due to
disease or damage
requires dialysis
• Wastes are removed
from body by passing
blood through an
artificial cell
membrane
Protocol #1
• Fill beaker 2/3rds full with tap water
• Add Lugol’s solution until mixture is amber
Protocol #2
• Open wet dialysis tube using fingers and glass rod.
Tie one end off with string
• Using seral pipettes fill tube with starch and glucose
solutions
• Tie off open end. Do NOT leave space for air
• Trim the strings and excess tubing
Protocol #3
• Immerse “cell” in iodine-water bath
• Allow to sit for 20 minutes while doing
Protocol #4
• After 20 minutes, qualitatively assess color
of bath, cell and turgidity of cell
• Retest water with Tes-Tape to check for
presence of Glucose
Protocol #4
• Observe Elodea cells in fresh water (premade slide) and sketch
• Make a 2nd slide using one Elodea leaf
and a drop of 6% NaCl solution
• Sketch the 2nd slide, noting any changes
between the fresh water and salt water
Lab: Semipermeable Membranes
and Osmosis
• Purpose: To analyze the movement of
solutes and water across a selectively
permeable membrane
• Method: Tracking movement of solutes
and water achieved by use of organic
indicators and qualitative description of
turgor (rigidity of fluid filled container)
Protocol #1
• Fill beaker 2/3rds full with tap water
• Add Lugol’s solution until mixture is amber
• Test water with Tes-Tape to determine if glucose
is present in the bath
Protocol #2
• Open wet dialysis tube using fingers and glass rod.
Tie one end off with string
• Using seral pipettes fill tube with starch and glucose
solutions
• Tie off open end. Do NOT leave space for air
• Trim the strings and excess tubing
Protocol #3
• Immerse “cell” in iodine-water bath
• Allow to sit for 20 minutes while doing
Protocol #4
• After 20 minutes, qualitatively assess color
of bath, cell and turgidity of cell
• Retest water with Tes-Tape to check for
presence of Glucose