What happens in the cell cycle?
Have you ever considered how cells divide or why? What happens in the cell cycle? If you are like most students, probably not, but the cell cycle is an essential building block to understanding biology.
As cancers seem to touch us more and more, understanding the cell cycle becomes important as a healthcare consumer.
Most students are familiar with mitosis. It is something that is taught from early elementary through high school. Unfortunately, almost every student I have ever met will tell me that they have no idea what I am talking about when I discuss cell division. So let me save you some time and energy with this refresher.
Looking for lesson ideas? Check out my ideas to teach mitosis: Mitosis Content Workshop. Science Teacher Professional Development.
What is the cell cycle?
The Background
Mitosis is one part of a larger cell cycle. The “typical” cell cycle of a human cell is around 24 hours, that cell would only be in mitosis for 4-6 of those hours.
During mitosis, the cell (specifically the DNA located) is dividing. Mitosis is a way to divide a single cell into two identical cells. It allows for asexual reproduction, growth, and cellular replacement.
What happens during the cell cycle?
The cell cycle has 3 parts: Interphase, Mitosis, & Cytokinesis.
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Interphase
Interphase is the part of the cell cycle that is before mitosis. During this phase, the cell is performing its normal functions and preparing for the upcoming division (mitosis). One of the things that occur during interphase is that the DNA is duplicated (organelles and cellular machinery are also duplicated) during this time.
Interphase itself is divided into its own parts:
G1 Stage
AKA Gap 1 Stage is when the cell grows and makes the proteins needed for mitosis AND the normal functions of the cell.
S Phase
AKA Synthesis Phase is when the cell’s DNA is copied.
G2 Stage
AKA Gap 2 Stage is another period of growth and is when organelles such as the mitochondria divide to prepare for mitosis.
Mitosis
Mitosis divides the duplicated DNA into two distinct cells.
The 4 phases of Mitosis:
- Prophase: chromosomes appear
- Metaphase: chromosomes align in the center of the cell
- Anaphase: chromosomes split apart
- Telophase: chromosomes uncoil into the “normal” form of DNA
Cytokinesis occurs after mitosis
Cytokinesis occurs after mitosis (although some books will label it the end of mitosis). During cytokinesis, the remaining parts of the cell are divided between the two new cells (including the organelles).
The Cell Cycle Summary
The simple answer to “What happens in the cell cycle?” is that the cell functions normally, prepare for dividing into two identical cells, divides the nucleus and cytoplasm (including organelles), and completes the process by closing the cell membrane around two distinct (but identical) cells.
Looking for other topics in biology?
This is the fifth post in a weekly series about how to Prepare for College Biology. These posts include notes and access to online lecture materials. These posts (and lectures) are a review. The previous topics are homeostasis; general chemistry; organic chemistry; and cell membranes.
If you want access to the notes and lecture for this topic and the previous lectures, click below.
