Wednesday, October 5, 2011

Scribe Post for Wednesday, 10/5

What we did in class today:
  • Egg Osmosis Demo
  • Normal and Plasmolyzed Cells Lab
  • Osmosis Worksheet
  • Mitosis Video
Homework for tonight:
  • Fill in your mitosis notes from Moodle
  • Read Chapter 8
  • Read mitosis lab- UP p. 53-60
Egg Osmosis Demo

This was the second day of our Egg osmosis demo, the first day we were just to observe a raw egg. Today, we observed a raw egg that had soaked in vinegar for 24 hrs. During the time it was soaking, the egg cracked. This was not part of the demonstration, so it was a little bit wacky, but there was still evident differences from the raw egg to the egg soaked in vinegar.

Some observations of the egg soaked in vinegar:
  • Pieces of shell are missing
  • Outside of what is left of the shell is soft
  • Rubbery to the touch
  • A few bubbles on the egg itself
  • No difference in size
Since I drew a diagram of the egg in vinegar, I found a picture of one.

As you can see here. The egg looks like it has lost some pieces of shell, also you can see some bubbles on it.

Normal and Plasmolyzed Cells Lab

Purpose: This lab was to show the effects osmosis can have on a cell, and to show the before and after of a cell when its surroundings are changed from an isotonic solution to a hypertonic solution.

  • microscope
  • microscope slides/cover slip
  • Elodea leaf
  • tap water
  • salt water
  1. Prepare two separate slides, one with an Edolea leaf and a wet mound with 3 drops of tap water ( 1 percent salt, 99 percent water), another one with an Edolea leaf and a wet mound with 3 drops of salt water ( 6 percent salt, 94 percent water)
  2. Wait 2 or 3 minutes for the reaction, if any, to happen.
  3. Under a microscope, carefully observe both slides and look at the position of the chloroplasts, cell wall, vacuole, and cell membrane
  4. Fill it what is seen on a diagram
Since I drew my own diagrams on the unit packet, I found pictures of what cells looked like in tap water and salt water on the internet.