The first phase of somatic cell division is (A) __________, when the cell’s chromosomes condense, and the nuclear envelope that holds the chromosomes starts to break up. During this time, structures called the (B) __________ form from centrioles, which will attach to the centromere of sister chromatids in a later phase and move the copies of each chromosome apart to opposite poles of the cell. The next phase is (C) __________, when duplicated chromosomes are lined up halfway between the poles.
Since this is not my area of expertise, I searched Google under the key words "somatic cell division" to get these possible sources:
https://www.google.com/search?client=safari&rls=en&q=somatic+cell+division&ie=UTF-8&oe=UTF-8
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.
To find the answers to your questions, we can look into the process of somatic cell division, also known as mitosis. Mitosis is a type of cell division that results in the formation of two genetically identical daughter cells. Let's break down the questions one by one:
A) The first phase of somatic cell division, where the cell's chromosomes condense and the nuclear envelope starts to break up, is called "prophase." During prophase, the chromatin in the nucleus becomes tightly coiled and condensed into visible chromosomes. The nuclear envelope breaks down, allowing the chromosomes to become more accessible for subsequent steps of mitosis.
B) The structures that form from centrioles and attach to the centromere of sister chromatids in a later phase are known as "spindle fibers" or "microtubules." Centrioles are small cylindrical structures found near the nucleus, and they play a key role in organizing the spindle fibers during mitosis. The spindle fibers extend from the centrioles and interact with the chromosomes to ensure their proper separation during cell division.
C) The phase when duplicated chromosomes are lined up halfway between the poles is called "metaphase." During metaphase, the spindle fibers attach to the centromeres of each duplicated chromosome, causing the chromosomes to align and form a plane called the metaphase plate. This alignment facilitates the accurate separation of sister chromatids during the next stage of mitosis.
By understanding the process of mitosis and the different phases involved, we can determine the answers to your questions.