Egg-Speriment with a Cell

Question: What happens to a cell when it is put into different liquid environments?

Purpose: To find out how the membrane works and what it does to help the cell/egg survive.

Hypothesis: I think that the membrane will not allow most substances to pass, but some – like water, air, and some other elements will pass through tiny pores in the membrane.

Procedures:

Written procedures: When I first received the egg, I measured it by winding a piece of ordinary thread around the fattest section, or equator, of the egg. I cut the string at the point where the ends meet, then rechecked to see if I cut accurately. Then I placed the string on a ruler with millimeters, and recorded the length of the string, or circumference of the egg, without rounding. When I was finished with that, and recording what the egg looked like on the outside, I placed the egg in its first fluid – vinegar. I didn’t forget to always cover my cup with a lid to keep the liquid from evapourating. After an impatient two day’s wait, finally I poured the liquid out of the vessel that my egg was inside carefully into my sink, and took the egg out with a spoon. It still had the color of the shell, so I washed it and gently scrubbed away the remaining shell. I measured it like described earlier after bopping it dry with a paper towel. I kept repeating these procedures with the following:

Plain water	1 day
Salt water (as salty as possible)	1 day
Water with food coloring (3-4 drops)	1 day
Maple syrup	1 day

Materials list:

Spoon

Water

Vinegar

Maple syrup

Salt

Food coloring

Cup

Thread

Ruler

Paper towel

Lid

Notepad

Pen

Observations/Data:

Date	Fluid	Circum-ference, mm	Physical Appearance
5:37, November 6, 2002.	Normal egg state (no fluid)	148	It’s brown, like all other eggs in the box, it is hard, because of the shell, and has little stains on it.
6:18, November 8, 2002 – 9:37 November 11, 2002.	Vinegar and after	163	Soft, semi-transparent, has large white spots on its membrane, and is yellow. Yolk floating around inside.
Day 6; 8:24, November 13, 2002.		166	Dark green membrane on one side, light green on the other. On light side dark green stuff can be seen sloshing around inside.
Day 7; 7:31, November 14, 2002.			Still green but it shrunk greatly, and is all shriveled up like a deflated rubber ball.

Communication:

Illustration: See next page.

Graph:

Conclusion and Analysis: It is more than certain that the liquids went through the egg’s membrane, because the egg increased and decreased in size as it got placed into different liquids. In the graph above, it changes in size as it is placed into liquids wit different densities. And when I was holding the egg in its post food-coloring state, I wiped it with a paper towel, and water kept appearing on the membrane again. That is an example of diffusion (the movement of molecules from an area of higher concentration to an area of lower concentration)and osmosis (the movement of only water molecules from an area of higher concentration to an area of lower concentration)

New Questions: How does the diffusion process of a cell differ from the diffusion process of an egg? How does the membrane know which molecules are good, and which molecules are bad? What molecules does a nuclear membrane let through, and how can you test it?