1. A: What were the two prevailing thoughts concerning how living things were created and organized
              prior to 1650?
    B: Why do discoveries concerning cells, since 1650, come in clusters? (For example Hooke and
              Leeuwenhoek only 10 years apart & Schleiden, Schwann and Virchow only 17  years apart)

2. A sponge is a colonial organism. This means that the sponge consists of "a group of unicellular
           organisms that live together in closely connected groups". In the case of thesponge each cell
           obtains its own food and oxygen, yet these cells will seek each other out so that they form a
           larger "body" of cells that we see as the sponge.
                A: How does a sponge behave like a unicellular organism?
                B: How does a sponge behave like a multicellular organism?
                C: Why do some scientists consider the sponge to be the evolutionary link between
                            unicellular and multicellular organisms?

3. According to the cell theory all living things are built of cells, and use cells to reproduce.   This
          implies that the cell is the most basic (and vital) unit of life on earth. What can the cell theory NOT
          tell scientists about cells themselves?

4. Answer the following questions concerning the diversity of sizes of cells.
         A: Plant cells are generally larger than animal cells. The larger a cell is however, the more
               support it needs. How might plant cells be better adapted for their larger sizes?
         B: Humans are composed of cells. Bacteria are also composed of cells. Where does a
                  cold bacteria go once it enters the human body (assuming the human develops a cold)?
         C: 1) Which type of cells (plant/animal/prokaryotes) is largest?
              2) On average, most animals cells are approximately how many micrometers long?

5. What is the advantage for each of the following cells to take the shape they do?
         A: red blood cells are round                    C: nerve cells are very long and very thin
         B: skin cells are cubic                                D: many plants cells are cubic (different reason than skin)

6. A: Why might the following cells have large numbers of the cell organelles listed?
         1) muscle cells -> mitochondria
         2) salivary gland cells -> Golgi apparatus
         3) plant cells (inside leaves) -> chloroplasts
         4) white blood cells -> lysosomes
         5) epithelial cells (lining windpipe) -> cilia
         6) sperm cells -> flagella
    B: Why might red blood cells lose almost all their organelles as they become mature?

7. A: List 3 cell organelles found only in plant cells.
    B: List 5 organelles found in both plants cells and animal cells.

8. All cells have a cell membrane surrounding and containing their cytoplasm. Most cells have a cell
          membrane that is not perfectly round, but instead has many folds.    Additionally most cell
          membranes so not block everything from entering the cell, but instead are selectively permeable.
     A: List two purposes for a cell membrane.
     B: What advantage is it to a cell to have many folds in its cell membrane (ie How do the folds help it
               do its job)?
     C: What does it mean to say a cell membrane is selectively permeable?
     D: Why might it be an advantage for a cell membrane to be selectively permeable?

9. Both the nucleolus and chromatin are located inside the nucleus of a cell, but they serve very
          different purposes.
     A: The nucleolus appears to control the production of which biochemical
                  (carbohydrate/protein/lipid/nucleic acid)? Explain your answer.
     B: Chromatin appears to play a role in what basic life process? Explain your answer.

10. Match the following plastids with their descriptions.
         A: leucoplasts       1) common in leaves // collect light for photosynthesis
         B: chromoplasts   2) common in fruit // stores food for the plant or its seeds
         C: chloroplasts     3) common in flowers & skin of fruit // gives plant parts different colors

11. Match the following structures to their descriptions.
         A: organs               1) brick walls
         B: tissues               2) a complete house
         C: cells                    3) a brick
         D: systems            4) a water heater & water softner
         E: organism           5) all electrical wires, outlets, fuse boxes, lights, door bell, etc.

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Critical Thinking Questions:
12. Explain how the following features help the cell and/or the organism.
         A: large vacuoles in plant cells.       C: colors in flowers and fruits
         B: thick cell walls in plant cells         D: cell membranes composed of both lipids & proteins

13. Each of the following specialized cells has developed an unusual trait. Explain how that trait serves
          each cell.
    A: White Blood Cells -> can change shape
    B: Nerve Cells -> do not reproduce / are as old as the body
    C: Fat Cells -> can swell and shrink considerably in size
    D: Sweat gland cells -> secrete water along with any other chemicals in excess in the body
    E: Cardiac muscle cells -> multiple nuclei and interbranched, connecting neighboring muscle fibers
    F: Skeletal muscle cells -> can change length and shape

14. Look at the data below comparing the Surface Area (SA) of a cell with its Volume (V).
                  Notice how these two factors change as a cell grows.
                                                                             S.A.                V.
                                Cells (original size)               10                  1
                                If cell size doubles                40                  8
                                If cell size triples                    90                27
                                If cell size quadruples         160                64
           a) Which factor (Surface Area or Volume) increases at a faster RATE as a cell grows?
           b) Why is there a limit to how large most cells will grow?