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otherwise specified.
BIO 1305 – Modern Concepts in Bioscience I – Campbell Textbook
Week 9 – Chapters 12 & 13
Hi guys! I can’t believe we are halfway through the semester! I hope you are enjoying your
biology class. Today we are going to talk about chapter 12, which covers the cell cycle, and we
are going to start talking about the genetics aspect of biology in chapter 13. Don’t forget that
Gabriel and I hold weekly group tutoring sessions on Thursdays from 5-6 pm. Sign up to join
us here: https://baylor.edu/tutoring. We would love to see you there!
Keywords for this week: Cell Cycle, Binary Fission, Mitosis, Meiosis
As usual, I’ve linked videos to aid you as you read through the resource. After you read each
section, watch the videos as review!
Chapter 12: The Cell Cycle
Cell division is vitally important and is the reason you are who you are! Before we talk about
cell division, let’s talk about some cellular features that will play a role in the cell’s life cycle.
Each one of your cells contains a copy of your genome, which is all of your genetic information.
Your genome is packaged into chromosomes which have to be copied before your cells can
divide. Our somatic cells (body cells) specifically have 46 chromosomes, while our gametes
(reproductive cells) have 23 chromosomes.
After chromosomes are copied before division, each chromosome
will have two sister chromatids that are attached to each other.
The picture on the right shows that the sister chromatids of a
single chromosome are attached at their centromeres.
Video: Cellular Organization and Bacterial Cell Division
Now we can start laying the foundation of cell division.
There are two main phases in a cell’s division:
Mitosis: division on genetic material
Cytokinesis: division of cytoplasm
Stages of the Cell Cycle
Mitosis is part of the cell cycle, but it is actually the
shortest part of the entire life cycle of a cell. When a cell is
not dividing, it is in interphase, a period of growth and
development. Interphase consists of several distinct phases:
G1 – growth
S – “synthesis”
G2 – more growth
