Biology Cell Cycle: Set 2

Explain why DNA must be replicated in a careful manner before a cell is reproduced.  

• So that each new daughter cell receives a complete and accurate copy of the genetic information

Describe the basic semi-conservative method of replication of DNA:

• the process of making two molecules of DNA from one DNA molecule, each containing one original DNA strand and one newly synthesised DNA strand

  1. The leading strand is synthesized continuously

• Enzymes help by unwinding the double helix

Compare prokaryotic and eukaryotic DNA structure.

• prokaryotic DNA is typically circular and found freely in the cytoplasm

• eukaryotic DNA is linear, organized into chromosomes within a nucleus 

Discuss why the cell cycle is important, how the timing of the cycle is different in various cells, what might lead to the cell cycle being initiated, and why it is important that this process is carefully regulated. 

• It’s important because it ensures the cell grows,replicates DNA, and divides properly. Without the cell cycle, organisms wouldn’t be able to produce new cells to replace damaged ones.

• Timing: some are rapidly dividing, some are non-dividing cells and enter G0 phase (after G-1), and cancer cells have uncontrolled timing, leading to rapid, unregulated growth.

Students will explain that checkpoints are used in the cell cycle and explain what happens if the cell does not carefully complete each stage of the cycle.

• Checkpoints in the cell cycle ensure each stage is completed correctly. If errors occur, damaged cells may form, leading to problems like uncontrolled growth or cancer.

Students will describe how spindle fibers and centrioles are involved in the process of mitosis. 

• Centrioles are on opposite sides of the cell

• Form spindle fibers, which connect to the centrioles of chromosomes

• Pull sister chromatids apart, ensuring that each new cell gets an equal number of chromosomes.

Students will explain cytokinesis.

• Division of the cytoplasm to form 2 separate daughter cells

• final stage in cell cycle / comes after mitosis

Students will describe how the cell cycle is used by some organisms for asexual reproduction.

• Some organisms use the cell cycle for asexual reproduction, creating offspring without a mate. Through mitosis, one parent cell divides into two identical cells.

Students will describe what is meant by cell differentiation. 

• Cell differentiation is when a simple cell changes into a specific type of cell with a special job. Once a cell changes, it usually can’t switch to another type.

Explain the idea of stem cells, differentiating between adult and   embryonic stem cells, and describe how gene regulation determines differentiation of cell types.

• Stem cells are special cells that can turn into different types of cells in the body.

  1. Embryonic stem cells can become any cell type.

  2. Adult stem cells can only become certain types of cells, like blood or bone cells.

• Gene regulation controls what a cell becomes by turning certain genes on or off. This tells the cell what job to do, like becoming a muscle or nerve cell.