Marking Period 2: Gen Biology

The Cell Cycle & Mitosis

Therefore, I reasoned that study of the cell cycle responsible for the reproduction of cells was important and might even be illuminating about the nature of life. Paul Nurse

We need to know about how cells make more cells.  This unit will help us understand the steps the cell must undergo to make more cells, and describe why cells are the size they are.  This is a technical series of steps, with a unique terminology that must be memorized.  You will have to understand why the sequence works the way it does, but ultimatly you will also have to memorize some vocabulary. 

Sex Cells & Meiosis

“Fertilization – the fusion of gametes to produce a new organism – is the culmination of a multitude of intricately regulated cellular processes.” Marcello Fet. al., ertilization, ADV. EXP. BIOL. 757:321 (2013)

Somatic cells (body cells) contain the full compliment of DNA - one copy form each parent.  Sex cells, on the other hand, must contain only a sub-set of the DNA so that, upon union, the full compliment is regained.  There must be a mechanism similar to Mitosis that  reduces the number of chromosomes whil simuntaneously introduces variability.  The full value of sexual reproduction is the production of variable offspring (offspring that is different from either parent).