Module 5 Cell Division

Lesson 3.5.1

3.5.1 page 4

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 this is important to populations.

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), as well as for growth of multi-cellular organisms.

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 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’s Syndrome, which is caused by an extra chromosome 21. They can also determine gender: XX for female, XY for male.