Zoology Study Guide

Zoology Study Guide - 1 The three key aspects of...

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Growth - Cell division and Cell Expansion Differentation - Specialization and Commitment Morphogenesis - generation of form and shaping of cell Environmental cues trigger development through protein receptors Development never ceases till death 2 The experiment that shows that with differentiation there is generally no irreversibility in the genome is… Carrots - Differentiated cells of a carrot root are removed, and dedifferentiate when starved in the right conditions and formed a new carrot plant. Dolly - was the animal example… Cells were removed from one sheep and egg from a different kind. The egg is enucleated and starved to stop the cell cycle. The cells are fused together and begin dividing The embryo was transplanted into the egg donor sheep Dolly is born, identical to the sheep the cell was removed from Dolly reproduces delivering a healthy offspring. The environment to which the cells are associated induces the differentiation of stem cells Differential Gene Expression - 3 Polarity is… Difference between one end of an organism and the other. Cytoplasmic segregation causes polarity and is important because both the animal and vegetal pole halves are required to produce a normal larva. Induction is… A factor secreted from one cell which causes another to differentiate. Induction Example: The eye of a frog develops as different tissues take their turns inducing one another. The optic vesicle bulges out from the forebrain. The optic vesicle induces overlying tissue to form the lens placode. The optic cup forms and induces lens formation. The developing lens separates from surface tissue and induces it to form the cornea. 4 Apoptosis is… Programmed cell death and it gives us definition by freeing tissue like fingers and toes to move freely. Organ identity genes code for proteins that act in combination with one another. Morphogen gradients decide what forms in the organism based on differential gene expression in their target cells. The gradient causes polarity in the organism. 5 Differential Gene Expression- Environment controls what cell becomes Developmental potential of cells becomes restricted fairly early in normal development. o
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This note was uploaded on 04/18/2008 for the course BIO 120 taught by Professor Freeman during the Spring '08 term at St. John Fisher College.

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Zoology Study Guide - 1 The three key aspects of...

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