+ 1.1 Cell Biology False-colour scanning electron micrograph (SEM) of neurones (nerve cells) from the cerebral cortex - the outer, heavily folded, grey matter of the brain.
+ Cell theory Robert Hooke (1635 – 1703) was the first to observe cells under the microscope which he invented. What common features do you think exist amongst all cells? Membranes, genetic material, enzyme- catalyzed reactions, generate their own energy
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+ Use a light microscope to investigate the structure of human cheek cell & onion cell. Draw diagrams of each cell type. Drawing rules: 1.Use a sharp pencil 2.Draw lines carefully 3.Use a ruler for labeling lines
+ Magnification =Size of image / Actual size of specimen Practice questions page 6/7
+ Prepare for test on 2.1 – 2.3. Test Thursday 11 th September. You will have a review Tuesday. Homework
+ What is the magnification of the image when we view it down the compound microscope? Multiply these values: Eyepiece X Objective 10x40 = 400x magnification
+ Standard international (si) units of measurement: UnitAbbr.Metric equivalent Kilometrekm1000m10 3 m Metrem1m- Centimetrecm0.1m10 -2 m Millimetremm0.001m10 -3 m Micrometre mm m10 -6 m Nanometrenm m10 -9m
+ Microscopy calculations Use these calculations to find the magnifications or actual sizes of images. Rule 1: Convert all units to make them the same (where appropriate) Rule 2: Perform calculations Rule 3: Convert answers to appropriate SI units, using scientific notation where needed.
+ Calculations: 2 types: Actual Size of an image Magnification of an image
+ Magnification Magnification = Measured length ____________________ Scale bar label
+ Actual size Actual Size = Measured Length ____________________ Magnification
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+ What are the 7 ‘functions of life’? 1. Nutrition 2. Metabolism 3. Growth 4. Response 5. Excretion 6. Homeostasis 7. Reproduction
+ A comparison UnicellularMulticellular Organism consisting of only one cell carry out all functions of life. Some can move using cillia, some drift using currents/air etc. Size limited. Surface to Volume ratio Often live in colonies Have properties that emerge from the interactions of their cellular components. Specialized tissues result from cell differentiation Humans have 220 specialized cells. Differentiation involves in expressing some genes but not others from the whole genome. Paramecium, ChalmydomasCaenorhabditis elegans
+ Paramecium 1.Asexual reproduction 2.Food vacuoles 3.Waste excreted by diffusion through cell membrane 4.Contractile vesicles – regulate water content 5.Cilia in order to move
+ Chlamydomonas 1.Asexual reproduction 2.Cell wall freely permeable, inner membrane is not. 3.Contractile vesicles 4.Chloroplasts for photosynthesis 5.Flagella for movement
+ Volvox aureus 1.Algae colony 2.Ball made up of a protein gel or more cells in a colony
+ Caenorhabditis elegans 1.Worm 2.1mm (approx. adult length) cells 4.Decomposer 5.Hermaphrodite 6.1/3 of cells are neurons
+ Stem cells The capacity of stem cells to divide and differentiate along different pathways is necessary in embryonic development. It also makes stem cells suitable for therapeutic uses. Ethics of 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 tissue.