2.1.1 Outline cell theory.

Three main principles of cell theory:

            -all organisms are composed of one or more cells

            -cells are the smallest units of life

            -all cells come from pre-existing cells

2.1.2 Discuss the evidence of the cell theory.

-Humans have not been able to find any living entity that is not made of at least one cell.

-After sterilizing chicken broth by boiling, Louis Pasteur showed that living organisms would not ‘spontaneously’ reappear. Only after exposure to pre-existing cells was life able to re-establish itself in the sterilized chicken broth.

-By looking through a microscope, Robert Hooke first described cells in 1665 while observing cork. Other scientists after him had made similar statements about cells. 

2.1.3 State that unicellular organisms carry out all the functions of life.

Unicellular organisms carry out all the functions of life. 

2.1.4 Compare the relative sizes of molecules, cell membrane thickness, viruses, bacteria, organelles and cells, using the appropriate SI unit.

-A molecule = 1 nm
-Thickness of cell membrane = 10 nm
-Viruses = 100 nm
-Bacteria = 1μm
-Organelles = up to 10 μm
-Eukaryotic cells = up to 100 μm

2.1.5 Calculate the linear magnification of drawings and the actual size of specimens in images known as magnification. (use an example or explain how to)

How To:

            1.Take a measurement of the drawing (width or length)

            2.Take same measurement of the specimen

            3.Convert units if needed

            4.Place your values into the equation

            5.Magnification=length of drawing/length of actual specimen

            *You can also calculate the length of the specimen if it is unknown: length of the                   drawing/magnification

2.1.6 Explain the importance of the surface area to volume ratio as a factor limiting cell size.

Substances need to be taken into the cell to fuel the many reactions that occur within the cell and waste products need to be taken out. When the cell increases in size, so does its chemical activity, so more substances need to be taken in and removed. The surface area affects the rate at which particles can enter and exit the cell. Volume affects the rate at which materials are made or used within the cell, hence the chemical activity per unit of time. As the volume of the cell increases, so does its surface area. However, when the cell gets bigger its surface area to volume ratio gets smaller. If the surface area to volume ratio gets too small, the substances won’t be able to enter the cell fast enough to fuel the reactions and waste products will build up. The cell will also not be able to lose heat fast enough, so it may overheat. 

2.1.7 State that multicellular organisms show emergent properties.

Multicellular organisms show emergent properties.