Meristems undifferentiated plant cells Plant cell differentiation is reversible Plant 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 organs The floral meristem produces four whorls of organs all are modified leaves 1 2 3 4 Sepals Petals Stamens makes pollen Carpels ovary makes embryo ABC 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 carpel http biology kenyon edu courses biol114 Chap13 abc model gif Abc hypothesis is just growing the reproductive organs specifically before that several phases have to happen 1 Plant goes from sexual immaturity to sexual maturity it starts growing a flower 2 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 mutants 1 Type Sepal petal stamen carpel nothing missing normal flower 2 Type Carpel stamen stamen carpel translocation of gene c deletion of gene a 3 Type Sepal sepal carpel carpel no b gene present 4 Type Sepal petal petal sepal translocation and reversal of gene a deletion of gene c Chapter 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 diverse o Cells that are spaced out with a connecting matrix o Cells suspended in extracellular fluid that is clear colorless viscous with glycosaminoglycans and proteoglycans o Many types are fibrous o Blood collagen scars bone o Loose connective tissue Fat collagen Holds organs and blood vessels in place Nervous tissue o Controls muscles glands mental activity homeostasis o Neurons o Neuroglia also called glial cells http upload wikimedia org wikipedia commons thumb 7 73 Blausen 0672 NeuralTissue png 6 40px Blausen 0672 NeuralTissue png Muscle o Smooth cardiac skeletal o 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 tract o Cardiac heart muscle striated and branching one nucleus per cell o Skeletal striated but no branching multiple nuclei per cell Epithelial o Regulates materials coming into the body o Protects outside of body o Transports nutrients and water across layers o Apical and basal side each cell has polarity so opposite ends have different shape and function o Basal side connects cell to other tissues o Lines trachea and gastro intestinal tract http pharmaworld pk cws3 my hosting panel com products gallery gal753 t43 jpg Surface area to volume Organisms 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 elephant