The Cell Cycle
What are the three main parts of the cell cycle?
The Prophase, Metaphase, Anaphase, and Telophase can collectively be known as the "Mitosis stage".
Interphase, Mitosis (Prophase, Metaphase, Anaphase, Telophase), Cytokinesis
What is the first stage of mitosis?
(Interphase takes place before the Mitosis stages)
Prophase
What molecule carries a cell's genetic information?
DNA
What is the main purpose of mitosis in the human body?
Growth and repair of damaged tissues.
A body cell has 46 chromosomes. How many chromosomes should each daughter cell have after mitosis?
46 chromosomes.
What are the three stages of interphase, in order?
G1 (Gap 1), S (Synthesis), and G2 (Gap 2).
During which phase do chromosomes line up in the middle of the cell?
Metaphase.
What is chromatin?
Less-condensed DNA associated with proteins, as it exists during most of the cell cycle.
What is the difference between mitosis and cytokinesis?
Mitosis divides the nucleus; cytokinesis divides the cytoplasm.
A cell is copying its DNA. Which stage of interphase is it in?
S phase.
What happens during G1, S, and G2?
G1 — growth; S — DNA replication; G2 — preparation for mitosis.
During which phase do sister chromatids separate and move toward opposite poles?
Anaphase.
What is the centromere, and what does it connect?
The centromere is the region that joins two sister chromatids.
How do the two daughter cells compare genetically to the original cell?
They are genetically identical to the original cell under normal mitotic division.
Put these stages in the correct order: telophase, prophase, anaphase, metaphase.
Prophase → Metaphase → Anaphase → Telophase (PMAT).
Why is interphase important even though the cell is not yet dividing?
Interphase allows the cell to grow, replicate its DNA, and prepare for division.
Describe two things that happen during telophase.
Two new nuclei form, nuclear envelopes and nucleoli reappear, chromosomes become less condensed, and the spindle breaks down.
Explain the relationship between DNA, chromosomes, and sister chromatids.
DNA contains genetic information. DNA and proteins form chromosomes; after DNA replication, each copied chromosome consists of two sister chromatids joined at the centromere.
What is the difference between the nucleus and cytoplasm in cell division?
Mitosis divides the nucleus and organizes the genetic material; cytokinesis physically divides the cytoplasm to separate the two daughter cells.
A chemical prevents spindle fibers from forming. What problem will this cause during mitosis?
Chromosomes will not be able to move normally or line up properly at the cell's center because spindle fibers help organize and move them.
A cell grows, copies its DNA, and prepares to divide. Match each activity to G1, S, or G2.
Growth → G1; DNA copying → S; preparation for mitosis → G2.
A cell's chromosomes are visible, its nuclear envelope is breaking down, and its spindle is beginning to form. Identify the phase and explain your reasoning.
Prophase. Chromosomes condense and become visible, the nuclear envelope breaks down, and the spindle begins forming.
Why does DNA replication increase the amount of DNA without immediately doubling the chromosome number?
DNA replication creates two sister chromatids joined together as one replicated chromosome. The chromosome count does not double until the sister chromatids separate and become individual chromosomes.
Explain how mitosis and cytokinesis work together to produce two complete daughter cells.
Mitosis separates the duplicated genetic material into two new nuclei. Cytokinesis then divides the cytoplasm, producing two complete daughter cells with the same chromosome number as the parent cell.
A parent body cell has 46 chromosomes. After division, a student says each daughter cell has 23. Explain the error and state the correct number.
The student confused mitosis with a division that halves chromosome number. Mitosis preserves chromosome number, so each daughter cell should have 46 chromosomes, not 23.