Wednesday 1/30/13

EQ: Why must cells divide?

VOCAB:

HOMEWORK:
-Finish the two questions on the back of your graphic organizer called "Why cells divide"

CLASS RECAP:  Today students started class by reviewing the class activity from yesterday titled "the size is right!".  Students discussed why smaller cells have a more efficient surface area to volume ratio.

Students then set up the first part of a demo involving potato cubes.  The class put three different sizes of potato cubes into iodine solution to observe how quickly diffusion would occur in different sized cells. 
We investigated a :
-  2cm x 2cm cube
-  1cm x 1cm cube
-  1/2cm x1/2cm cube

We observed that the smaller cube showed the greatest % volume affected by diffusion.

Students then participated in the Showcase showdown from yesterday.  Contestants had to estimate the mass and volume of three different sized "cells".  Winners of the showcase showdown won a fabulous vacation!

Towards the end of class students filled out a graphic organizer with reasons that cells divide.

- growth
- development
- healing injuries
- uncontrolled growth (cancer)
- to maintain a small cell size
- to replace dead or dying cells
- to maintain homeostasis 

Students were to complete the last two questions on the back of their graphic organizer for homework tonight.  It will be graded and handed in tomorrow.