Picture: Trees in the Great Dismal Swamp  
The cells that make up the leaves, trunks and roots these cypress trees are very different from the cells  that make up animal cells such as the beaver  which lives nearby in its habitat (see below). 

 
 
What are some of the differences between these two cell types and what environmental conditions caused these different adaptations? 
 

1. Click here to check your answer.  click 
 
 
 
 
 
 
 
 
 
 

 Picture: Fern plants on a forest floor. 

Do these organisms carry out the process of photosynthesis? Do they  require special structures in their cells to carry out this process? The energy which drives photosynthesis comes from the sun. 

What adaptive structures would these cells have to display the photosynthetic organs in order to receive maximum sunlight? 
 
 

Picture: Snakes sunning on a log. 

Are these organisms able to move off of the log? What cell differences compared to plant cells would the cells of the snake have to allow this movement? 

2.  Click you check your answers.  click 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

The basic structural and functional units of life are cells.  The smallest organisms consist  of single cells. The largest are made up of billions of cells, each of which maintain the characteristics of life discussed in miniunit Alpha. Cells of all organisms are similar to one another, both in their physical organization and their chemical processes.  A common thread found in all cell types are that individual cells are self-contained and partially self-sufficient units bonded by an outer membrane called the cell membrane which controls the passage of materials in and out of the cell and all cells contain DNA (deoxyribonucleic acid) which provides a cell with a mechanism to duplicate. Review nucleic acids by reading the pages indicated by B-1 in the text. This concept will be investigated in miniunit Gamma. DNA also stores and provides a mechanism for the transfer of  all genetic information so that the cell can  physiologically function in its own unique manner.  This allows cells to be very diverse. This concept will be investigated in miniunit Delta. Within your own body there are more than one hundred distinct cells types. Plants and Fungi are composed of cells that are very different from those of your body. 
 

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The figures above show two major types of cells - eukaryote and prokaryote. Notice the eukaryote contains many structures in its cytoplasm - red and blue linear structures represents DNA; whereas the prokaryote cell contains relative few structures in its cytoplasm - 1 = circular DNA,   2 = cell membrane,  3 = cytoplasm with ribosomes. The prokaryote cell is not only simpler than the eukaryote cell but it is also more primitive. Two prokaryote cell types you may be familiar with are unicellular bacteria and cyanobacteria (blue green algae). 

By the mid 1800s several naturalists  had examined cells of plants and animal and reported similarities between all cells types. From the observations three principles of the cell theory evolved. 

These naturalists were Robert Hooke 1665,  Anton van Leeuwenhoek 1673, Theodor Schwann 1839, Mattias Schleiden 1850 and Rudolf Virchow 1850. 

 The principles of the cell theory are: 

A. Every living thing is composed of one or more cells. 

B. The smallest living organisms are single cells, and cells are the functional units of 
     multicellular organisms. 
 
C. All cells arise form preexisting cells. 
 
Write these in your notes. 
 

3. Place the following molecules and structures in the correct hierarchical order going from the most simplest to the most complex. Identify these terms using the glossary in your text. Read the pages indicated by B-2 in your text. 

      (biosphere, cells, biomes, ecological communities, macromolecules, 
        populations, tissues, organs, organism, species, systems) 

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4. Which of the following cell types appeared first on Earth? 

  a) Eukaryote cell types in the form of  unicellular amoeba. 
  b) Prokaryote cell types in the form of  plants. 
  c) Eukaryote cell types in the  form of multicellular animals. 
  d) Prokaryote cell types in the form of  bacteria. 

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You must answer the following question correctly to move to the next page. 

5. Which of the following lists of cell structures are present in all cell types? 

 a )  cell wall, cell membrane, DNA 
 b )  cell wall, cell membrane 
 c )  DNA cell wall, cell membrane 
 d )  cell membrane only 
 e )  cell membrane, DNA 
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