All living organisms are composed of cells, from just one to many trillions, whose details usually are visible only through a microscope. This week our objectives are as follows:
a. recognize that all organisms are composed of cells, and that many organisms are single-celled organisms.
b. Compare and contrast plant and animal cells, including major organelles (cell membrane, cell wall, nucleus, cytoplasm, chloroplasts, mitochondria, vacuoles.
c. Recognize that within cells, many of the basic functions of organisms (e.g., extracting energy from food and getting rid of waste) are carried out.
d. The way in which cells function is similar in all living organisms.
e. Describe the hierarchical organization of multi-cellular organisms from cells to tissues to organs to systems to organisms.
In this week’s lesson, we will learn about the structure of cells and compare the inner workings of a cell to the structure of a city to gain a better understanding of what goes on in the cell. We will then use this knowledge to construct a map of “cell city”.
Just as our bodies contain many organs, a cell contains many organelles, which carry out basic functions such as extracting energy from food and getting rid of waste. While there are different types of cells, today we will focus on the structure of an animal cell. However, before jumping into our study of the structure and function of a cell, we will begin by discussing something more familiar: the structure and function of a city.
In cities, it is very important for different activities to be organized into different areas. For example, we do not build schools in the middle of landfills nor do we construct dangerous power plants in the middle of a public playground. For a city to thrive and grow it must have certain systems, services and facilities. Below, I have listed several of these necessary systems, services and facilities.
i. Town hall, the heart of a city, the control center where blue prints and information about the entire city is stored and organized.
ii. Transportation systems and roadways to facilitate the movement of people and goods.
iii. Recycling plants or scrap yards where much of the trash generated by the city is reduced and reused.
iv. Energy plant where raw materials are converted into energy.
v. Parks and other open spaces where people meet and interact with each other during the course of their daily lives.
While it may seem a big leap from a working city to a living cell, the organization of different activities into different areas, the transportation of raw materials, the building of new structures, the production of energy, and the removal of waste are all just as important for a cell, as they are for a city.
While towns and cities vary greatly in size, no matter where they are in the world, they share many similar features. Likewise, despite the vast variety of life forms and cell types, different cells have many features in common. As I mentioned before, we are going to concentrate on the structure and function of animal cells. However, most of the same basic structures and organizing principles apply equally well to cells in plants as they do to cells in animals.
Just as there are organs in our body, there are several major organ-like parts in cells, which are called organelles. The organelles we will be focusing on include the cell membrane, cell wall, nucleus, cytoplasm, chloroplasts, mitochondria, and vacuoles. Don’t worry about writing all those names down. Instead, open your science notebooks to today’s page and you will find a list already written out. In a moment, I will assign each of you a organelle to research. Once the organelles have been assigned, we will take 10 to 15 minutes to do independent research online and in the materials I handed out. The object of our research will be to find a clear definition and description of the organelle I assigned you. Once you find a definition and/or description, write it down in the space provided for you on the worksheets in your science notebooks. When we have completed our research, we will meet back up to share our findings with each other.
Definitions/Descriptions of Major Organelles In An Animal Cell
Cell Wall: Provide the boundaries for activities that go on within the cell.
Nucleus: Control center for the cell.
Cytoplasm: The part of the cell outside of the nucleus; a jellylike substance in which the organelles sit.
Chromosomes: The set of blue prints for how the cell is built and how each part of it is made.
Mitochondria: The power center where energy is created and stored.
Golgi Apparatus: Adjusts, sorts, packages and transports substances out of the cell or to another organelle where they can be used by the cell.
Lisosome: Recycles waste that is produced by the mitochondria.
Now that we have created a working definition and/or description of each organelle we will begin our hands-on activity. For this activity everyone will be given the same assignment: to figure out what city system, structure or facility has the same purpose as each of the organelle. You will make maps to represent your cell city and label each structure/organelle on it. Before you begin constructing, come up with a city analogy for each organelle we’ve discussed thus far. Write your ideas in the corresponding spaces provided on your activity sheets. Remember to show me all of your analogies before you begin constructing your map/model of Cell city.
MAP OF CELL CITY