Section Assessment Chapter 3.5 “CELL DIVISION” Teacher Notes for Students
(Read textbook pp.95-102)
Directions for Students:
Use your own ‘SECTION ASSESSMENT’ notes along with these teacher notes below to review the
questions and responses from chapter 3.5 ‘S.A.’ (Section Assessment) mainly about HOW WHEN A CELL
DIVIDES (reproduces) A COPY OF THE ORIGINAL DNA IS COPIED OVER AND OVER AGAIN INTO EACH
NEW CELL THAT HAS RESULTED FROM THE DIVISIONS!
Important Memo = You may review all questions and answers below; however, for the test,
you will be have been notified already for which answers below are ‘most targeted’ to be on
the test! 
1a. The 3 stages of the cell cycle are: Interphase, mitosis, and cytokinesis.
1b. While observing closely the images on pgs. 98 & 99, which is an overall great picture of the actual
‘cell cycle’/ Figure 21, it is awesome to see how, in PROPHASE, the chromatin condenses to form
chromosomes. In METAPHASE, the chromosomes line up across the center of the cell and attach to
the spindle fibers. In ANAPHASE, the chromatids separate, and each moves to an opposite end of the
cell. In TELOPHASE, the chromosomes begin to stretch out and lose their rod-like appearance. Wow!
So amazing to see this ‘REPRODUCTION’ of each cell = ‘CELL DIVISON’ in the ‘CELL CYCLE’!
1c. The role of the ‘spindle fibers’ during cell division is to have the chromosomes move along the
spindle fibers to the ends of the cell. (It’s like spindle fibers are totally attracting the chromosomes
chemically/ chemical bonds & physical bonds… without the spindle fibers in place, the chromosomes
probably wouldn’t go anywhere!?! Hooray to the spindles! )
2a. Adenine, Thymine, Cytosine, and Guanine are the 4 nitrogen bases.
2b. Below study how the nitroten bases actual pair-up:
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Adenine pairs with Thymine in a DNA Molecule! = A with T!!!!!! = A:T, and it could also be
T:A!!!! (A little heads-up/ foreshadowing…. This pairing will be slightly different when we learn
about RNA during our upcoming ‘Genetics Unit #4’ since there is no Thymine in RNA! See, the
DNA needs to interact with the RNA and vis-versa for reasons you’ll learn about soon! So…
Adenine will bond with a different chemical known as Uracil when the RNA molecule comes into
play. More on this RNA vs. DNA interaction in our next UNIT, though! )
Cytocine pairs with Guanine in a DNA Molecule! = C with G!!!!!! = C:G, and it could also be
G:C!!!! (Heads-up and easy, with the RNA molecule, again to be learned at a later lesson, the
RNA WILL ACTUALLY STILL HAVE CYTOCINE AND GUANINE bonding with each other! Hooray,
because this will be easy to transfer my thinking from DNA base pairs to RNA base pairs! Staytuned for ‘near-future’ lessons on the relationship of DNA to RNA! Fascinating! You will love it;
so cool!)