Cell Cycle Basics
What are the two main stages of the cell cycle?
Interphase and M phase (mitosis + cytokinesis).
During which phase do chromosomes line up in the middle of the cell?
Metaphase
What structure holds sister chromatids together?
Centromere
What is a mutation?
A change in the DNA sequence.
Uncontrolled cell growth
During which stage does the cell grow and replicate DNA?
Interphase (specifically S phase for DNA replication).
Identify the phase where sister chromatids separate.
Anaphase
Human body cells have 46 chromosomes. After mitosis, how many chromosomes will each daughter cell have?
46
True or False: All mutations lead to changes in the phenotype.
What happens when checkpoints in the cell cycle fail?
Damaged or mutated cells continue dividing.
Why is the cell cycle important for multicellular organisms?
It allows growth, repair, and replacement of cells.
In which phase does the nuclear envelope re-form around chromosomes?
Telophase
What is the term for duplicated chromosomes connected at the centromere?
Sister chromatids
How can mutations affect the cell cycle?
They can alter proteins (cyclins and CDKs) that control cell division.
What role do tumor suppressor genes play?
They stop cell division or trigger cell death when DNA is damaged.
What happens during cytokinesis?
The cytoplasm divides, forming two identical daughter cells.
What happens during prophase?
Chromosomes condense, spindle fibers form, nuclear membrane breaks down.
Explain how chromosome number is maintained through mitosis.
DNA replicates once and divides once, ensuring equal distribution.
Give an example of a harmful mutation.
Example response: A mutation that prevents a tumor suppressor gene from working.
Explain how the cell cycle is normally regulated.
Proteins like cyclins and enzymes ensure each step occurs correctly
Explain why daughter cells created by mitosis have the same chromosome number as the parent cell.
DNA is replicated before division, and sister chromatids separate evenly.
What is the difference between S and G2?
The S (synthesis) phase is when a cell replicates its DNA, creating an exact copy of its genome. The G2 (gap 2) phase occurs afterward and is a period of rapid growth and protein synthesis, where the cell prepares its contents, such as organelles and proteins, for mitosis
Why is accurate DNA replication crucial before mitosis?
Errors can lead to mutations that disrupt cell function or cause disease.
How do mutations lead to cancer?
Cancer is uncontrolled cell growth caused by mutations in genes that control the cell cycle
Describe the connection between mutation, the cell cycle, and cancer.
Mutations disrupt cell cycle regulation → damaged cells divide unchecked → tumors form.