Problem Analysis and Solution
The provided image contains a worksheet about
mitosis as part of the cell cycle. The task involves answering questions based on the information presented in
Model 1 (a diagram of the mitotic phases) and the accompanying text. Below is a detailed explanation and solution for each question.
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Model 1: Mitosis as Part of the Cell Cycle
The diagram illustrates the four phases of mitosis:
1.
Prophase: Chromosomes condense, the nuclear membrane breaks down, and spindle fibers begin to form.
2.
Metaphase: Chromosomes align at the metaphase plate (equatorial plane) with spindle fibers attached to their centromeres.
3.
Anaphase: Sister chromatids separate and are pulled to opposite poles of the cell by the spindle fibers.
4.
Telophase: Chromosomes reach the poles, the nuclear membrane reforms, and the chromosomes decondense.
Additionally, the diagram shows
cytokinesis, which occurs after telophase, resulting in the division of the cytoplasm and the formation of two daughter cells.
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Questions and Solutions
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Question 1
> Refer to Model 1. List the four phases in the mitosis process.
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Solution:
The four phases of mitosis are:
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Prophase
-
Metaphase
-
Anaphase
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Telophase
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Question 2
> Where is mitosis in the cell cycle? Before _______ and after _______.
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Solution:
Mitosis is part of the
M phase of the cell cycle. It occurs:
-
Before:
Cytokinesis (the division of the cytoplasm).
-
After:
G₂ phase (the second gap phase, where the cell prepares for mitosis).
Therefore, the completed sentence is:
- Before:
cytokinesis
- After:
G₂
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Question 3
> What three phases of the cell cycle are considered interphase?
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Solution:
Interphase is the period between mitotic divisions and consists of three phases:
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G₁ phase (first gap phase): Growth and preparation for DNA synthesis.
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S phase (synthesis phase): DNA replication occurs.
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G₂ phase (second gap phase): Further growth and preparation for mitosis.
Therefore, the three phases of interphase are:
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G₁
-
S
-
G₂
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Question 4
> Refer to the cell cycle shown.
> a. How many cells are present at the beginning of mitosis?
> b. How many cells are present at the end of mitosis?
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Solution:
a. At the
beginning of mitosis, there is
one cell that is undergoing division.
b. At the
end of mitosis, the single cell has divided into
two daughter cells.
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Final Answers
1. Prophase, metaphase, anaphase, and telophase.
2. Before:
cytokinesis, After:
G₂
3. G₁, S, and G₂
4. a. One cell
b. Two cells
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Boxed Final Answer
\[
\boxed{
\begin{array}{l}
1. \text{Prophase, metaphase, anaphase, and telophase.} \\
2. \text{Before: cytokinesis, After: G₂} \\
3. \text{G₁, S, and G₂} \\
4. \text{a. One cell, b. Two cells}
\end{array}
}
\]
Parent Tip: Review the logic above to help your child master the concept of cellular division worksheet.
