B. MORPHOLOGICAL AND PHYSIOLOGICAL CHARAC- 

 TERISTICS OF LIVING THINGS 



Living matter, or protoplasm, is not a single chemical compound, 

 but is a combination of many albumen-like compounds. It exists 

 only in the form of cells, individual masses of protoplasm contain- 

 ing a denser body, the nucleus. 



I. CELL STRUCTURES. 



In sections through the root-tip of an onion observe the shape and 

 size of the cells. Having found one or more complete cells with 

 round nucleus observe and draw the following parts: I. Cell Mem- 

 brane. 2. Xucleus. 3. Cytoplasm (protoplasm surrounding nucleus). 

 In the nucleus observe : 4. Nuclear Membrane. 5. Chromatin 

 (stained part of nucleus). 6. Achromatin (unstained part of 

 nucleus ) . 



II. CELL FUNCTIONS. 



Each cell performs all the fundamental functions of life it 

 nourishes and reproduces itself, is contractile and sensitive, though 

 some cells are devoted more exclusively to one of these functions 

 than to the others ( Specialization ) . In this place we study only 

 the functions of reproduction and movement. 



i. CELL REPRODUCTION. All cells reproduce by division; the 

 nucleus first divides, in one of two ways, after which the cell body 

 constricts into two. Nuclear division occurs by the indirect process 

 (Mitosis), or bv the direct process (Amitosis). 



(i). Indirect Nuclear Division (Mitosis). In prepared slides 

 of the root-tip of the onion observe nuclei in mitosis, and note (a) 

 the Spindle, (b) the Chromosomes (chromatic rods), (c) the 

 Equatorial Plate (stage in which the chromosomes surround the 

 equator of the spindle). The stages of division leading up to the 

 equatorial plate are ( d ) the Prophase ; the equatorial plate stage, 

 during which each chromosome splits longitudinally, is (e) the 

 Metaphase ; the stage after the equatorial plate during which the 

 halves of each chromosome separate, moving toward the poles of 

 the spindle, is ( f ) the Anaphase ; later stages in the division of 

 the cell body, and the formation of daughter nuclei are known as 

 (g) the Telophase. Draw cells in each of these phases of division. 



(2). Direct Nuclear Division (Amitosis). In prepared slides 

 of the follicle cells surrounding the egg of the cricket observe 



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