Pg 243
1) Cells divide because the larger the cell becomes, the more demands the cell places on its dNA. The more trouble the cell has moving nutrients and wastes across the cell membrane.
2)The cells DNA is like books in a library because it supplies all the information for the cell.
3)The solution to the problem caused by cell growth is the daughter cell gets 1 complete set of genetic information.
4)As a cell increases in size volume increases more rapidly.
5)The ratio of surface area to volume in a cubic cell with a length of 4cm is 1.5:1
Pg 249
1) The main events of the cell cycle is prep for mitosis, mitosis, cell growth and DNA replication.
2) Prophase- chromosomes become visible, centrioles take up positions on opposite sides of the nucleus.
Metaphase- Chromosomes line up across the center of the cell.
Anaphase- Chromosomes move until they form groups near the poles of the spindle.
Telophase- Nucleolus becomes visible in each daughter nucleus, nuclear envelope reforms around each cluster of chromosomes.
3) Interphase is the period of cell growth between divisions of the cell.
4) Chromosomes are made of chromatids.
5) Prokaryotic cells divide by the simple matter of seperating the contents of the cell into two parts.
6) Cytokinesis in plant cells is similar to cytokinesis in animal cells because the cell membrane is drawn inward until the cytoplasm is pinched into 2 nearly equal parts.
Pg 252
1) The chemicals that regulate the timing if the cel cycle are cyclins.
2) The thing that happens when cells do not respond to the signals that normally regulate thier growth is that they will stop dividing.
3) The way cells respond to contact with other cells is they stop growing.
4) Cancer can be considered a disease of the cell cycle because it affects the cells during cell division.
5) If cyclin were injected into a cell that was in mitosis then it would speed up or slow down the process because cyclin regulates timing.
Pg 257
1) A
2) C
3) B
4) C
5) C
6)A
7)B
8)B
9)A
10)A
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