2. Indiana Standard 6.4.7 Explain that about two thirds of the mass of a cell is accounted for by water. Understand that water gives cells many of their properties.
3. Purpose You will be able to explain that about two-thirds of the mass of a cell is accounted for by water.
6. Pre-Activity Questions 1. What are all living things made up of? 2. What do you think cells are made up of? 3. How much water makes up a cell? 4.How much of an organism is made up of water?”
7. Pre-Activity Answers 1. Cells- All organisms are composed of cells The cell is the structural unit of life - units smaller than cells are not alive Cells arise by division of preexisting cells - spontaneous generation does not exist 2. Plasma membrane - separates the cell from the external environment Cytoplasm - fluid-filled cell interior Nuclear material - genetic information stored as DNA
8. Pre-Activity Answers Cont. Within cells there is an intricate network of organelles that all have unique functions. These organelles allow the cell to function properly. Click here
9. Pre-Activity Answers Cont. 3. A human cell is approximately 75% water. 4. An organism is made up of approximately 60%-90% water.
10. Activity When you water a plant, where does it go? The water moves from the roots through the internal structure to the cells of the plant. How could you use a scale to determine how much water a plant had in it? Weigh your plant to see how much it weighs and record your findings. Place your plant on a paper towel and dry it with a hair dryer, or lay it by a heat vent, or in the sun.
11. Activity (cont) Let your plant dry until you can see a visual difference. The longer it dries the less water there will be. Weigh your plant again and record your findings. Note the difference in the weights Subtract the dry mass from the wet mass: that is how much water was in your plant.
13. Extensions Research properties of water that make it such an important substance for life(stores heat efficiently, bonds with other substances). Make oversized models of cells with approximate area taken up by water.
14. Standard Links 6.4.5 Investigate and explain that all living things are composed of cells whose details are usually visible only through a microscope. Language Arts 6.2.1 Features of Informational and Technical Materials: Identify the structural features of popular media (newspapers, magazines, online information) and use the features to obtain information.
