- Concept:
- Cell Theory:
- Cells are the smallest units of life
- All cells come from pre-existing cells.}Note: Although most organisms can be applied to the cell theory, there are exceptions. (3.1)
- Every living organism on earth is either composed of one cell or more, and they all carry out the same functions:
- Growth; all organisms grow, some more than others but growth is always evident
- Reproduction: it is the process through which hereditary molecules are passed to offspring
- Response: depending on how the organism responses to the enviroment sorrounding it, it may or may not survive
- Homeostasis: process which is involved in maintaining the body's interal temperature
- Nutrition; consists of providing minerals, vitamin and other chemical bounds that provide energy and nutrients necessary for life
- Cell Size
- Cell Differentiation (Multicellular Organisms)
- Stem Cells
Because of this ability, stem cells have been used and tested by scientists and medical experts in order to repair lost tissue and cure diseases in humans. However, there are ethical problems to the application of stem cells in humans:
- People argue that the use of stem cells involves the death of an embryo thus taking away a human life.
- Stem cells are used for good causes, for instance, curing leukaemia patients by the use of blood stem cells. People argue that utilization of stem cell reduces human sufering and therefore is acceptable.
Applications and skills:
- Application: Questioning the cell theory using atypical examples, including striated muscle, giant algae and aseptate fungal hyphae.
- Application: Investigation of functions of life in Paramecium and one named photosynthetic unicellular organism.
- Application: Use of stem cells to treat Stargardt’s disease and one other named condition.
- Application: Ethics of the therapeutic use of stem cells from specially created embryos, from the umbilical cord blood of a new-born baby and from an adult’s own tissues.
- Skill: Use of a light microscope to investigate the structure of cells and tissues, with drawing of cells. Calculation of the magnification of drawings and the actual size of structures and ultrastructures shown in drawings or micrographs. Refer to: http://i-biology.net/ibdpbio/02-cells/cell-theory/ (slides 25-39)
Theory Of Knowledge:
- There is a difference between the living and the non-living environment. How are we able to know the difference?