10 -6 meters (m)

IB Biology
Topic 1: Cell Biology
1.1 Introduction to cells
Name: _________________________________
 According to the cell theory, living organisms are composed of cell(s).
 Organisms consisting of only 1 cell carry out all functions of life in that cell.
 Surface Area to Volume ratio is important in the limitation of cell size.
 Multicellular organisms have properties that emerge from the interaction of their cellular components.
 Specialized tissues can develop by cell differentiation in multicellular organisms.
 Differentiation involves the expression of some genes and not others in a cell’s genome.
 The capacity of stem cells to divide and differentiate along different pathways in embryonic development and
also makes stem cells suitable for therapeutic uses.
Applications & Skills:
1. State the name and briefly describe the functions of life:
 nutrition
 excretion
 metabolism
 homeostasis
 growth
 reproduction
 response to stimuli
2. State the 3 parts to the cell theory
3. Question (present arguments against) the cell theory using atypical examples:
 striated muscle cells
 aseptate fungal hyphae
 giant algae
4. Investigate the functions of life of Paramecium and one named photosynthetic unicellular organism.
(this will be done in the lab)
5. Outline the use of stem cells as a treatment for Stargardt’s disease and one other named condition.
6. Describe the ethics of the therapeutic use of stem cells from:
 specially created embryos
 an adult’s own tissue
 the umbilical cord blood of a new born baby
7. Use a light microscope to investigate the structure of cells and tissues along with drawings of cells.
(this will be done in the lab)
8. Calculate the magnification of drawings and the actual size of structures and ultra structures shown in drawings
or micrographs. (Scale bars will sometimes be used to indicate actual size)
Relative Sizes:
A molecule = 1 nm
Cell membrane thickness = 7.5 nm
Virus = 100 nm (range: 20 - 200 nm)
Bacteria = 1 - 5 um
Organelles = <10 um
Eukaryotic cells = <100 um
Conversions: Beware students tend to struggle with these. PRACTICE
1 meter (m) =
1 meter (m) =
1 meter (m) =
1 meter (m) =
1 centimeter (cm) =
1 millimeter (mm) =
1 micrometer (m) =
1 nanometer (nm) =
102 centimeters (cm)
103 millimeters (mm)
106 micrometers (m)
109 nanometers (nm)
10-2 meters (m)
10-3 meters (m)
10-6 meters (m)
10-9 meters (m)
Here is a sample problem:
The cell below was found in the basement at ARC. It’s unlike anything scientists have ever seen. Help them classify the
cell by calculating its size with the help of scale bars.
20 um