1. Module 5

1.6. Page 4

Lesson 1

Module 5—Cell Division: The Processes of Mitosis and Meiosis

Reflect and Connect

 

Self-Check

 

Complete the following review questions on cell division.

 

SC 1. In what three general ways is cell division important to your body?

 

SC 2. In general terms, compare binary fission to mitosis.

 

SC 3. Give the main advantage of meiosis and why it is important to populations.

 

chromatid: one-half or one of two threadlike strands into which a chromosome divides during cell division

SC 4. Differentiate between chromosome, chromatid, and chromatin.

 

SC 5. What characteristics are common between homologous chromosomes?

 

SC 6. What can scientists learn from creating a karyotype of a developing fetus?

 

Check your work.
Self-Check Answers

 

SC 1. Cell division is essential for repair (healing, the replacement of worn-out cells), for maintaining the life functions of the cells, and for the growth of new cells.

 

SC 2. Binary fission is a form of asexual reproduction among unicellular organisms, such as bacteria, that leads to an increase in the number of organisms. Mitosis is the division of one cell to create two new daughter cells within an organism. It yields more cells, but does not increase the number of organisms.

 

SC 3. Meiosis creates variation in the population. This enables a population to better withstand a changing environment.

 

SC 4. Chromosomes are condensed strands of DNA that are visible during cellular division. Chromatids are copies of chromosomes existing as single strands of doubled chromosomes still attached at the centromere. Chromatin refers to all the invisible uncondensed strands of chromosomes in a nucleus.

 

SC 5. Homologous chromosomes contain the same type of genetic information or genes (but not the exact same form or alleles). They are the same size and shape and, when stained, have the same banding pattern and placement of the centromere.

 

SC 6. A karyotype clearly displays the number and type of chromosomes present. From this, scientists can diagnose many major syndromes like Down syndrome, which is caused by an extra chromosome 21. They can also determine gender:  XX for female, XY for male.

 

 

Reflect on the Big Picture

 

You have been introduced to the main types of cell reproduction: mitosis and meiosis. Each type is important and has a natural role to play in the cycle of life. Perhaps you have a better understanding of the areas scientists study as they try to discover how to extend life. Certainly at the heart of any new technology or procedure will be the need to ensure the proper number of chromosomes is maintained from one generation of cells to the next, and that they contain all the correct genetic information.

 

Module 5: Lesson 1 Assignment

 

Submit your completed Module 5: Lesson 1 Assignment to your teacher for assessment.