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1.1 IB bio
Introduction to Cells
Term | Definition |
---|---|
Magnification Calculation (S1) | Image/Actual |
Cm (S1) | 1 * 10^-2 |
Mm (S1) | 1 * 10^-3 |
Un (S1) | 1 * 10^-6 |
Nm (S1) | 1 * 10^-9 |
Robert Hooke (U1) | First to coin cell (1655) (Cork tree) |
Anton Van Leevwehoek (U1) | First observation of living cells (1674) |
Cell theory (3 points) (U1) | 1) All living things are made of one or more cell 2) All cells come from pre-existing cells 3) The cell is the smallest unit of life |
Cell theory exception (U1) | First life on earth |
Functions of life (7) (U2) | Nutrition Metabolism Growth Response Excretion Homoeostasis Reproduction |
Paramecium + Chlorella (A2) | N/A |
Exceptions of cell theory (3) (A1) | Skeletal Muscle Fungal Hyphae Giant Algae |
Skeletal muscle (A1) | Have cells with a single membrane but multiple nuclei |
Fungal Hyphae (A1) | Have cells with a single membrane but multiple nuclei |
Giant Algae (A1) | Cells have a single nucleus but are gigantic and have 3 complex and distinct anatomical parts |
SA/volume ratio (U3) | --SA of a membrane must be large enough to absorb nutrients, oxygen,other needed substances and to excrete waste products. --Need for nutrients and waste produced is determined by cell volume. --Small cells have larger SA/volume ratio than larger cells |
Emergent Properties (U4) | --Arise from the interaction of component parts - completely unpredictable --Cells interact to produce a tissue/organ/organism that can do things none of the individual cells could do. -- Eg. Individual brain neurons- full brain |
Specialized tissues and differentiation (U5 + U6) | --Every somatic (body) cell has the same genes and could develop in any way --Depending on position of each cell and cell to cell signalling such as with hormones, particular genes are switched on adn others are switched off |
Specialized tissues and differentiation (U5 + U6) - Continued | -- This determines development of the cells -- A group of these differentiated cells becomes a tissue |
Stem cells (U7) | -- Stem cells are undifferentiated (no function) -- They retain capacity to divide and have ability to differentiate along different paths into all types of cells (pluripotent/totipotent) |
Where are stem cells derived from? (A3) | -- Human embryos -- Leftover from IVF -- From the placenta -- The umbilical cord -- Adult tissue |
Steps of stem cell work (A3) | -- Desired type of stem cell is identified, extracted and grown -- Then placed in biochemical solution that will cause cells to differentiate into desired type -- Then implanted into patient's own tissues so they function with the body's natural cells |
Stem cells - Stargardts (A3) | -- New technologies rely on replacing diseased/dysfunctional cells with healthy/functioning ones -- Embryotic stem cells are isolated and injected into retina -- Cells differentiate into retinal cells -- Treatment is in clinical trials |
Stem cells - Leukemia (A3) | -- Bone marrow cancer -- Lots of non-functioning white blood cells --Treatment: Remove marrow (marrow produces blood-cells) -- Lost cells must be replaced |
Stem cells - Leukemia (A3) Continued | -- Haematopoetic stem cells are harvested from a healthy person's bone marrow -- Cells then used to replace cancerous bone marrow after chemo destroys cancerous tissues. |
Ethics of stem cells - Pros (A4) | Some diseases (like stargardts) have no other means of treatment -- Outcome of other diseases ( like Leukemia) are largely improved |
Ethics of stem cells - Cons (A4) | --Specially created embryos: Religious and moral objection to detroying human embryos -- Umbilical cords:Playing god - it's unnatural -- Adult tissues: Research is very expensive and money may be spent in better ways -- All apply to above |