Busy Day!

Hey, Anka here! Today was a busy day in biology class!

For starters we learned about catalysts. A Catalyst is a substance that speeds up a chemical reaction because it decreases the amount of energy a cell needs to use during a chemical reaction.

To demonstrate the effect of a catalyst

during chemical reaction, our teacher poured a small amount of hydrogen peroxide into a graduated cylinder. Hydrogen peroxide is known to turn into water after a certain amount of time. Well, to speed up the process, a catalyst solution was added to the hydrogen peroxide. Adding the catalyst caused a crazy reaction that made the hyrdrogen peroxide bubble up. The catalyst was speeding up the transformation of hydrogen peroxide into water! Cool, right?!

After learning about catalysts, we conducted a lab comparing normal and plasmolyzed cells. A cell is plasmolyzed when a plant cells protoplast is forced to shrink due to water loss.

• To begin the experiment, we prepared a wet mount with 3 drops of TAP water and added one elodea leaf to the water. Then, we wait 3 minutes. After 3 minutes, we observed the leaf under low and high power on a microscope. We then picked one particular cell to observe. The cell was green and contained a cell wall and chloroplasts. We noted that the chloroplasts were randomlyspaced out, as you can see in the picture to the right.
• Next we prepared a wet mount with 3 drops of SALT water and added one elodea leaf to the water. After 3 minutes of waiting, we picked one single cell and observed it under high and low power. The cell was also green and contained a cell wall and chloroplasts. HOWEVER, the chloroplasts were sort of clumped together in the center of the cell.

This was caused by osmosis. Osmosis is when areas of high water concentration move to areas of low concentration. This happened because if you apply salt water to an elodea leaf the

balance of the water outside the cell and inside the cell is changed. The addition of salt to water causes the water concentration to diminish but the salt to increase. In other words, more water molecules were leaving the cell rather than going into the cell and more salt molecules were going into the cell. This caused chloroplasts to clump together, which means this cell was plasmolyzed. This is why plasmolyzed cells are different from normal cells.

And that's basically what we did in class today! The next scribe will be Sarah! (: