Unit Test: Cells Study Guide Part 2

1. Unit Test: CellsStudy Guide Part 2

2. 1. What are the two main reasons why cells divide instead of continuing to grow? • As a cell grows, it used information in DNA; eventually the cell will use all of the information, so it must divide. • As a cell grows, it must take in more nutrients and expel more waste, but its surface area shrinks as it grows, so it must divide.

3. 2. Explain why/how a cell struggles to exchange materials as it grows. • As a cell grows, its surface area to volume ratio decreases. • This means that the demands of the increasing volume outweigh the ability of the surface area to send waste out and absorb nutrients.

4. 3. What is cell division? • Cell division is the process by which one cell divides into two new daughter cells

5. 4. Describe each form of cell division, and include a detailed diagram. • Sexual reproduction • Two parent cells produce one offspring who shares half of the genetic information from each parent. • Asexual reproduction • One parent cell divides into two new daughter cells whose genetic material is identical

6. 5. Draw a chromosome and label and explain each of the three parts. centromere Where chromatids are joined together – in the center chromatids duplicated chromosomes DNA and Histone Proteins Histone proteins wrap around DNA and form a “super coil”

7. The chromosome’s structure is unique. In a complete sentence, describe the structure of a chromosome in your own words. Include the following terms in your description: (1)DNA (2)histone proteins (3)super coil – use twice (4)wrapped around (5)chromatids (6) centromere • In chromosomes, DNA is wrapped around histone proteins which forms a supercoil. The supercoil forms chromatids which meet in the middle at the centromere.

8. 7. (1) What are genes? (2) Where are genes located? (3) What structure carries our genes? • Genes are the part of DNA that code our individual traits • Genes are located inside of our DNA • Chromosomes carry our genes

9. 8. Fill in the blanks processes • The ____________________ of cell division are different, but when the ­­­­­­­­­­­­­­­______________’s role is fulfilled, new cells always have ____________________ that are copied from the _____________ _____________. chromosome genes parent cell

10. 9. What is the chromosome’s role in cell division? • Chromosomes carry genetic information to new cells and to the next generation of offspring.

11. 10. Draw a complete illustration of the 4 phases of mitosis and cytokinesis. Include the following in your diagram: (1) chromosomes (2) nuclear envelope (3) spindle fibers (4) centromere (5) nucleusList the events that occur during each phase.

12. 1. PROPHASE Spindle Centrioles • Chromosomes coil more tightly and become visible • The spindle forms from centrioles outside of the nucleus • Nuclear envelope disappears.

13. 2. Metaphase • Centromeres line up across the center of the cell • Spindle fibers connect the centromere of each chromosome to the two poles of the spindle

14. 3. Anaphase • Chromatids separate and move apart to opposite sides of the cell Centrioles Chromatids

15. 4. Telophase Spindle and centriole • Chromosomes spread out • Nuclear envelope reforms • Spindle breaks apart • At the end of telophase , we have two nuclei with duplicate set of chromosomes Two nuclei

16. Cytokinesis Spindle and centriole • Cell membrane moves inwards and pinches the cytoplasm to separate the new daughter cells. Nuclei Chromosomes