Meristems- undifferentiated plant cells- Plant cell differentiation is reversiblePlant differentiation signaling- Based on environmental cues (such as the weather getting warm in spring)A floral meristem is a modified shoot apical meristem that produces flowers containing reproductive organsThe floral meristem produces four whorls of organs (all are modified leaves)1. Sepals2. Petals3. Stamens- makes pollen4. Carpels- ovary- makes embryoABC HYPOTHESIS- Three genes (a, b, and c) control the production of sepals, petals, stamens, and carpels- Gene a makes sepal- Gene a and gene b together make petals- Gene b and gene c together make stamen- Gene c makes carpelhttp://biology.kenyon.edu/courses/biol114/Chap13/abc_model.gif- Abc hypothesis is just growing the reproductive organs specifically, before that several phases have to happen1. Plant goes from sexual immaturity to sexual maturity- it starts growing a flower2. Apical meristem must change from vegetative type to floral type (called inflorescence) 3. The actual sepal petal stamen carpel grow (where ABC hypothesis matters)In class pair and share: what is wrong with various mutants1. Type: Sepal petal stamen carpel- nothing missing, normal flower2. Type: Carpel stamen stamen carpel- translocation of gene c, deletion of gene a3. Type: Sepal sepal carpel carpel- no b gene present4. Type: Sepal petal petal sepal- translocation and reversal of gene a, deletion of gene cChapter 42- animal structure (anatomy and physiology)In biology structure is function. Body size influences how animals work because volume increase faster than surface area.Tissue types- connective nervous muscle epithelial- Connective- most diverseo Cells that are spaced out with a connecting matrixo Cells suspended in extracellular fluid that is clear, colorless, viscous, with glycosaminoglycans and proteoglycanso Many types are fibrouso Blood, collagen (scars), boneo Loose connective tissue Fat, collagen Holds organs and blood vessels in place- Nervous tissueo Controls muscles, glands, mental activity, homeostasiso Neuronso Neuroglia (also called glial cells)http://upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blausen_0672_NeuralTissue.png/640px-Blausen_0672_NeuralTissue.png- Muscleo Smooth, cardiac, skeletalo Only skeletal muscle is voluntary (can be consciously controlled)o Smooth- one nucleus per cell, spindle shaped (the ends are narrow and the middle is fat), no striations, line the outside of blood vessels, digestive tract, urinary tracto Cardiac- heart muscle, striated and branching, one nucleus per cello Skeletal- striated but no branching, multiple nuclei per cell- Epithelialo Regulates materials coming into the bodyo Protects outside of bodyo Transports nutrients and water across layerso Apical and basal side, each cell has polarity, so opposite ends have different shapeand functiono Basal side connects cell to other tissueso Lines trachea and gastro-intestinal tracthttp://pharmaworld.pk.cws3.my-hosting-panel.com/products/gallery/gal753_t43.jpgSurface area to volumeOrganisms with a lower surface area to volume ratio (big animals) need less food per amount of mass than organisms with a high surface area to volume ratio (small animals)The same mass of mice needs more food than the same mass of