Copy of Meiosis Introduction w/Questions (5/28/2026) - Jason Poe | Knihovna

B.4.5 Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and (3) mutations caused by environmental factors.

Learning Goals:

I can explain most of the events of meiosis I and II.
I can explain the purpose behind meiosis.
I can explain how meiosis is related to reproduction.
I can explain the difference between haploid and diploid cells and in which types of cells we find them.

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The result of meiosis are cells (sperm and egg) called

The zygote, which is formed by the fusion of two haploid gametes, is , which refers to the number of chromosomes that it possesses.

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*Each structure in the diagrams are identified in the reading using the labels in the diagram.

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Meiosis consists of two rounds of called: meiosis I and meiosis II.

Meiosis I, the first round of meiosis, results in cells that are , which means that they have half of the typical number of chromosomes that a typical diploid cells does.

In prophase I (prophase of meiosis I), the cell begins with which are paired chromosomes.

In prophase I, once the homologous chromosomes come together, may occur, which is the swapping of DNA from on chromosome to another.

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During metaphase of meiosis I (metaphase I), each chromosome consists of . During this stage, these chromosomes will along the equator (middle; metaphase plate) of the cell and spindle fibers will attach to one side of each pair of homologous chromsomes.

During of meiosis I, the homologous chromosomes (in this article, sister chromatids 1 and 2) move to the left and right sides of the cell.

By the end of meiosis I (telophase I), the chromosomes have been distributed into daughter cells.

When the cell leaves meiosis I and enters meiosis II, each chromosome still consists of sister chromatids.

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daughter cells enter meiosis II.

The sister chromatids will be separated during of meiosis II.

During telophase of meiosis II, the cells are divided; this is called .

At the end of telophase of meiosis II, cells are formed after cytokinesis occurs.

In males, the gametes must undergo further in order to function as sperm cells.

In males, meiosis results in the formation of four gametes (sperm cells); however, in females, this same process results in only ovum (egg). During fertilization, these two haploid gametes will fuse to form one diploid cell.

2

Use the information in the above reading to help you sequence each of these statements according to their proper order in meiosis.

Přetahovatelná položka		Odpovídající položka
Seventh		Homologous pairs of chromosome line up in the center of the cell.
Sixth		Homologous pairs of chromosomes are separated, each moving to opposite sides of the cells.
Second		Cytokinesis occurs on two already existing cells.
Eighth		Two (2) nuclear membranes form that are haploid (n).
Third		Four (4) nuclear membranes form that are haploid (n).
First		Spindle fibers attach to one side of each homologous pairs of chromosomes
Fifth		Individual chromatids are separated and are moved to opposite sides of the cells.
Fourth		Crossing over may occur.

3

Use the above reading to help you to identify the stage of meiosis that each statement is in. Each stage may be used more than one time.

	Prophase I	Metaphase I	Anaphase I	Telophase I	Prophase II	Metaphase II	Anaphase II	Telophase II
Homologous chromosome line up in the center of the cell
The individual chromatids separate apart.
Homologous pairs pairs of chromosomes move to opposite sides of each cell
Four (4) haploid (n) daughter cells form
Individual (non-paired) chromosomes line up across the middle of the cell.
Chromosomes condense (wrap tightly around histones) and become visible.
Sister chromatids separate from each other.
Two (2) haploid (n) daughter cells form
Sister chromatids separate into individual chromosomes.
Two (2) nuclear envelopes reform.
Spindle fibers attach to one side of the homologous chromosome pairs
One nuclear envelope breaks down.
Unpaired chromosomes line up; spindle fibers are attached to both sides of each chromosome
Crossing over occurs.